Assignment Level: Intermediate

Board-level postgraduate nephrology self-assessment.

Complete all 10 single-best-answer questions to receive detailed clinical explanations on the results page.

Sodium, Water Balance, and Dysnatremias

Ten board-style single-best-answer questions covering diagnosis, interpretation, and management of hyponatraemia and hypernatraemia, including iatrogenic causes and complications.

1 / 10

A 58-year-old man with type 2 diabetes presents with weakness. Plasma sodium is 122 mmol/L and plasma glucose is 30 mmol/L. Which is the best estimate of his corrected plasma sodium (accounting for hyperglycaemia)?

116 mmol/L

122 mmol/L

129 mmol/L

135 mmol/L

142 mmol/L

Correct measured sodium upward in significant hyperglycaemia (approximately +1.6 mmol/L per 5.6 mmol/L glucose above 5.6 mmol/L) to assess true sodium status.

Hyperglycaemia causes a translocational hyponatraemia by osmotic movement of water from intracellular to extracellular space. The commonly used Adrogue-Madias correction adds approximately 1.6 mmol/L to measured sodium for every 5.6 mmol/L rise in glucose above 5.6 mmol/L. Here glucose excess = 30 − 5.6 = 24.4 mmol/L; 24.4/5.6 ≈ 4.36 × 1.6 ≈ 7 mmol/L. Corrected Na ≈ 122 + 7 = 129 mmol/L.

Why the others are less appropriate:
- 116 mmol/L would imply further lowering of sodium by glucose, which is incorrect mechanistically.
- 122 mmol/L ignores the effect of hyperglycaemia.
- 135 and 142 mmol/L are too high and inconsistent with the correction calculation.

Note: Multiple correction formulas exist (some use 2.4 mmol/L per 5.6 mmol/L for severe hyperglycaemia), but the Adrogue-Madias 1.6/mmol per 5.6 mmol/L is widely used for bedside estimation.

2 / 10

A 72-year-old woman is found collapsed. On arrival she has seizures and plasma sodium is 112 mmol/L with low serum osmolality. Which immediate management is most appropriate?

Rapid infusion of 3% hypertonic saline bolus to raise sodium promptly

Start aggressive fluid restriction and oral urea

Administer a loop diuretic and normal saline

Begin long-term tolvaptan therapy

Give isotonic 0.9% saline rapidly

In severe acute symptomatic hyponatraemia (e.g. seizures, coma), give hypertonic saline bolus to produce a prompt modest rise in sodium and relieve cerebral oedema, with close monitoring to avoid overcorrection.

This patient has severe, acute, symptomatic hyponatraemia with neurological compromise (seizures). Immediate therapy is to raise serum sodium promptly and stabilise the brain; a bolus of hypertonic saline (concentrated sodium chloride) is the recommended initial treatment to produce a controlled acute rise in sodium and reduce cerebral oedema and seizures. The goal is a small, urgent increase (typically aiming for an initial 4–6 mmol/L rise or enough to stop seizures), not overly rapid correction overall.

Why the others are less appropriate:
- Fluid restriction and oral urea are measures for chronic or less severe hyponatraemia and are too slow in this emergency.
- Loop diuretic plus normal saline is not first-line for a patient with severe cerebral symptoms and may be inappropriate depending on volume status.
- Tolvaptan is not for acute emergency correction and is not appropriate to start during seizures.
- Isotonic 0.9% saline may be ineffective or even harmful in some causes of hyponatraemia (e.g. SIADH) and will not raise sodium quickly enough for severe symptomatic cases.

Careful monitoring of plasma sodium and neurological state is essential after hypertonic saline to avoid overcorrection.

3 / 10

Which strategy best minimises the risk of osmotic demyelination when treating chronic hyponatraemia?

Aim for a sodium increase of ≤8 mmol/L over the first 24 hours and monitor closely

Correct sodium rapidly to normal within 12 hours to avoid brain swelling

Use continuous saline infusion until sodium normalises regardless of rate

Always treat with tolvaptan to achieve controlled aquaresis

Restrict potassium intake until sodium normalises

Limit correction of chronic hyponatraemia (generally ≤8 mmol/L in 24 hours) and monitor frequently to reduce risk of osmotic demyelination.

Chronic hyponatraemia (developed over >48 hours or of unknown duration) carries a risk of osmotic demyelination if plasma sodium is corrected too quickly. Best practice is to limit correction (commonly recommended ≤8 mmol/L in the first 24 hours) and to monitor frequently. If overcorrection occurs, re-lowering sodium (e.g. with dextrose 5% infusion and desmopressin) can be considered.

Why the others are less appropriate:
- Rapid correction to normal within 12 hours is dangerous in chronic hyponatraemia and increases the risk of osmotic demyelination.
- Continuous saline infusion without attention to rate may lead to overcorrection and is unsafe.
- Tolvaptan is not universally appropriate and may cause overly rapid aquaresis; it is not a universal safety strategy.
- potassium management is important but restricting potassium is not a recognised measure to reduce osmotic demyelination risk.

Frequent monitoring (serum sodium every 2–4 hours initially) and adjustment of therapy are critical.

4 / 10

A 65-year-old man is found to have serum sodium 124 mmol/L and serum osmolality 260 mOsm/kg. On exam he appears euvolaemic. Urine sodium is 68 mmol/L and urine osmolality 520 mOsm/kg. What is the most likely diagnosis?

Primary polydipsia

Hypovolaemic hyponatraemia from diuretics

Syndrome of inappropriate ADH secretion (SIADH)

Pseudohyponatraemia from hyperlipidaemia

Beer potomania

In hypotonic hyponatraemia, euvolaemia with concentrated urine and high urine sodium suggests SIADH.

This patient has hypotonic hyponatraemia (low serum osmolality). Examination shows euvolaemia. High urine osmolality (>100 mOsm/kg) and elevated urine sodium (>30 mmol/L) in the setting of euvolaemia are typical of SIADH, where ADH-mediated water retention produces concentrated urine and renal sodium loss.

Why the others are less appropriate:
- Primary polydipsia causes very dilute urine (urine osmolality typically <100), not concentrated urine of 520 mOsm/kg. - Hypovolaemic hyponatraemia from diuretics would produce clinical volume depletion rather than euvolaemia, though diuretics can mimic SIADH biochemically. - Pseudohyponatraemia from hyperlipidaemia/artifact occurs with normal serum osmolality (isotonic) and is typically excluded by measuring osmolality. - Beer potomania typically presents with low urine sodium and low solute intake leading to impaired free water excretion; urine sodium would usually be low. Context and volume assessment are essential when evaluating hyponatraemia.

5 / 10

A patient has polyuria and polydipsia. Plasma sodium is 152 mmol/L and urine osmolality 120 mOsm/kg. After administration of desmopressin (DDAVP) his urine osmolality rises to 520 mOsm/kg. What is the most likely diagnosis?

Primary polydipsia

Nephrogenic diabetes insipidus

Central (neurogenic) diabetes insipidus

Syndrome of inappropriate ADH secretion

Psychogenic hypernatraemia

A significant increase in urine osmolality after desmopressin indicates central diabetes insipidus (ADH deficiency); absence of response suggests nephrogenic DI.

A low urine osmolality with hypernatraemia indicates inability to concentrate urine. A marked rise in urine osmolality after administration of desmopressin indicates that the collecting duct is responsive to ADH, implying a deficiency of ADH secretion — central diabetes insipidus.

Why the others are less appropriate:
- Primary (or psychogenic) polydipsia usually causes hyponatraemia or near-normal sodium due to excessive intake and causes low urine osmolality that may not respond significantly to desmopressin.
- Nephrogenic DI would not show a marked rise in urine osmolality after desmopressin because the kidney is unresponsive.
- SIADH would present with hyponatraemia and concentrated urine, not hypernatraemia with low urine osmolality.
- Psychogenic hypernatraemia is not a diagnosis here; the desmopressin response classically distinguishes central DI.

6 / 10

An 80-year-old nursing-home resident is brought in hypotensive with plasma sodium 160 mmol/L. He looks volume-depleted. What is the most appropriate immediate intravenous fluid to begin?

Rapid infusion of 3% hypertonic saline

Rapid infusion of isotonic 0.9% saline

Slow infusion of 5% dextrose in water

Intravenous tolvaptan

Oral free water via nasogastric tube only

In hypovolaemic hypernatraemia, restore intravascular volume first with isotonic 0.9% saline; address free water deficit only after haemodynamic stabilisation.

This patient has hypernatraemia with clinical hypovolaemia (hypotension and volume depletion). The immediate priority is haemodynamic resuscitation and restoration of intravascular volume; isotonic 0.9% saline is appropriate initial fluid to restore circulating volume. Once intravascular volume is restored and the patient is haemodynamically stable, then hypotonic fluids (for example, 5% dextrose) can be used to gradually lower plasma sodium, taking care to avoid overly rapid correction.

Why the others are less appropriate:
- Hypertonic saline is used to raise sodium and would worsen hypernatraemia; inappropriate here.
- Slow infusion of 5% dextrose as first-line in a hypotensive, volume-depleted patient risks further intravascular depletion.
- Tolvaptan is not indicated for acute hypovolaemic hypernatraemia and is contraindicated in hypovolaemia.
- Oral free water may be useful if the patient is safe to swallow and absorption appropriate, but in a hypotensive, collapsed elderly patient IV volume resuscitation is the priority.

After stabilisation, calculate free water deficit and plan safe gradual lowering of sodium (e.g. target ≤10 mmol/L per 24 hours).

7 / 10

A patient has a serum sodium of 118 mmol/L but measured serum osmolality is normal. Serum total protein and triglycerides are markedly elevated. Which is the best interpretation?

True hypotonic hyponatraemia requiring fluid restriction

Translocational hyponatraemia due to hyperglycaemia

Pseudohyponatraemia due to laboratory artefact from high lipids/proteins

Syndrome of inappropriate ADH secretion

Hypovolaemic hyponatraemia from diuretics

If a low sodium is accompanied by normal serum osmolality and high lipids/proteins, suspect pseudohyponatraemia due to laboratory artefact.

Pseudohyponatraemia occurs when sodium measurement by indirect ion-selective electrodes is falsely low because a significant proportion of plasma volume is occupied by lipids or proteins, leading to normal plasma water sodium concentration with an artifactual low reported sodium. In such cases measured serum osmolality is normal (isotonic), supporting pseudohyponatraemia.

Why the others are less appropriate:
- True hypotonic hyponatraemia would be associated with low serum osmolality.
- Translocational hyponatraemia from hyperglycaemia is associated with elevated measured osmolality and high glucose; here osmolality is normal and lipids/proteins are high.
- SIADH and hypovolaemic hyponatraemia are both hypotonic disorders with low measured serum osmolality, which is not the case here.

If pseudohyponatraemia is suspected, check osmolality or repeat sodium using a direct electrode method to confirm.

8 / 10

Which of the following best describes the pharmacological action of vasopressin V2 receptor antagonists (eg, 'vaptans') in hyponatraemia?

They promote natriuresis by inhibiting distal tubule sodium reabsorption

They increase free-water excretion (aquaresis) by blocking renal V2 receptors

They act as ADH agonists to concentrate urine

They are first-line in all acute symptomatic hyponatraemias

They correct hyponatraemia by replacing plasma albumin

Vaptans work by blocking renal V2 receptors to produce aquaresis (free-water excretion) and thereby increase serum sodium.

Vasopressin V2 receptor antagonists (vaptans) block vasopressin action at the renal V2 receptor in the collecting duct, reducing aquaporin insertion and thereby increasing free-water excretion (aquaresis) without major natriuresis. This raises serum sodium.

Why the others are less appropriate:
- They do not primarily promote natriuresis via distal tubule sodium inhibition.
- They are antagonists, not agonists — they cause aquaresis, not urine concentration.
- They are not first-line for all acute symptomatic hyponatraemias (they are not appropriate in emergency neurologic compromise and have specific indications/contraindications).
- They do not affect plasma albumin.

Use of vaptans requires careful patient selection and monitoring because of risk of overly rapid sodium rise and other adverse effects.

9 / 10

A 70-year-old woman on a thiazide diuretic presents with confusion and serum sodium 120 mmol/L. Which mechanism best explains thiazide-induced hyponatraemia?

Thiazides directly stimulate ADH secretion from the posterior pituitary

Thiazides cause large osmotic diuresis and net water loss

Thiazides impair renal dilution by promoting sodium loss and volume depletion, leading to ADH-mediated water retention

Thiazides cause pseudohyponatraemia by increasing plasma lipids

Thiazides reduce urea production causing water retention

Thiazide-induced hyponatraemia results from impaired renal dilution and secondary ADH-mediated water retention after natriuresis and mild volume depletion.

Thiazides impair the kidney's ability to dilute urine by inhibiting sodium reabsorption in the distal tubule, which reduces free-water clearance. They also cause mild volume depletion and natriuresis; the volume depletion stimulates ADH release and enhances water reabsorption, leading to hyponatraemia. Elderly patients are particularly susceptible.

Why the others are less appropriate:
- Thiazides do not directly stimulate pituitary ADH secretion as their primary action; the ADH increase is secondary to volume changes.
- Thiazides do not cause an osmotic diuresis; rather they reduce diluting capacity.
- Pseudohyponatraemia is due to lab artefact from lipids/proteins, unrelated to thiazides.
- Thiazides do not reduce urea production to a clinically relevant extent causing hyponatraemia.

Stopping the thiazide and carefully managing volume and sodium usually corrects the problem; monitor sodium during correction.

10 / 10

A patient develops hyponatraemia after subarachnoid haemorrhage. She is clinically hypovolaemic with urine sodium 120 mmol/L. Which is the most appropriate initial management?

Fluid restriction and demeclocycline

IV isotonic saline to restore intravascular volume

Immediate bolus of hypertonic saline to normalise sodium

Start tolvaptan to induce aquaresis

High-dose loop diuretic while restricting fluids

In hypovolaemic hyponatraemia after neurological injury (cerebral salt wasting), restore intravascular volume with isotonic saline rather than fluid restriction.

Post-neurological injury hyponatraemia can be due to cerebral salt wasting (CSW) where there is renal sodium loss leading to hypovolaemia. This patient's clinical hypovolaemia and high urine sodium support CSW. Management for CSW is volume repletion with isotonic saline (and often replacement of ongoing sodium losses), not fluid restriction.

Why the others are less appropriate:
- Fluid restriction and demeclocycline are treatments for SIADH (euvolaemic hyponatraemia) and would worsen hypovolaemia in CSW.
- Immediate hypertonic saline bolus is reserved for severe symptomatic hyponatraemia (e.g. seizures); routine normalisation with hypertonic saline is not first-line for CSW.
- Tolvaptan induces free-water loss and is inappropriate in hypovolaemic hyponatraemia.
- Loop diuretics would worsen volume depletion and are contraindicated in hypovolaemic states.

Accurate clinical assessment of volume status is essential because treatment differs markedly between SIADH and cerebral salt wasting.

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Postgraduate clinical case-vignette self-assessment. Complete all 10 questions to receive detailed explanations on the results page.

Hypocalcemia and Hypomagnesemia Clinical Case Vignettes — Intermediate

Intermediate postgraduate clinical case-vignette assessment focused on Hypocalcemia and Hypomagnesemia. Detailed explanations appear only after completion.

1 / 10

A patient on a loop diuretic remains hypokalemic despite replacement. Which concurrent abnormality commonly makes correction difficult?

Isolated hyperchloremia

Hypernatremia alone

Hypomagnesemia

High HDL cholesterol

Magnesium deficiency increases renal potassium secretion and impairs correction of hypokalemia. Repletion of potassium without addressing magnesium may produce a poor response, particularly in patients receiving ongoing diuretic therapy.

2 / 10

A patient develops perioral tingling, carpopedal spasm, and a prolonged QT interval after thyroid surgery. Which abnormality is most likely?

Hypermagnesemia

Hypercalcemia from immobilization

Hypocalcemia from hypoparathyroidism

Pseudohypernatremia

Postoperative hypocalcemia with neuromuscular irritability and QT prolongation is classic for acute hypoparathyroidism after neck surgery. Ionized calcium is especially useful because symptoms correlate with biologically active calcium, and urgent treatment may be required if symptoms are severe.

3 / 10

A patient has low total calcium, normal ionized calcium, and marked hypoalbuminemia. Which interpretation is best?

Low total calcium may reflect reduced albumin binding rather than low biologically active calcium

True symptomatic hypocalcemia is proven

The patient has primary hyperparathyroidism

Ionized calcium is irrelevant

Albumin binds a substantial fraction of total calcium, so hypoalbuminemia lowers total calcium without necessarily lowering ionized calcium. When the clinical question is whether calcium is biologically deficient, ionized calcium is more reliable than a correction formula alone.

4 / 10

A patient with severe hypomagnesemia has refractory hypokalemia and hypocalcemia. Which mechanism best explains the pattern?

The findings exclude gastrointestinal losses

Magnesium deficiency always causes hyperkalemia

Low magnesium increases calcitonin secretion only

Magnesium deficiency promotes renal potassium wasting and impairs PTH release or action

Severe magnesium deficiency can increase distal potassium secretion and produce refractory hypokalemia. It can also impair parathyroid hormone secretion and action, contributing to hypocalcemia. Both abnormalities may persist until magnesium is corrected.

5 / 10

A patient with chronic kidney disease has hypocalcemia, hyperphosphatemia, and elevated PTH. Which mechanism is most likely?

Primary hypoparathyroidism with low PTH

Secondary hyperparathyroidism from phosphate retention and reduced calcitriol production

Excess intestinal calcitriol absorption

Pseudohypocalcemia from isolated leukocytosis

CKD reduces phosphate excretion and impairs renal calcitriol production. The resulting lower calcium stimulus and phosphate retention promote secondary hyperparathyroidism. PTH is therefore elevated rather than suppressed in this typical CKD-mineral bone disorder pattern.

6 / 10

A patient with symptomatic hypocalcemia has tetany and a prolonged QT interval. Which treatment is most appropriate initially?

Loop diuretic monotherapy

Oral phosphate loading

Intravenous calcium in a monitored setting

Fluid restriction alone

Severe symptomatic hypocalcemia requires prompt intravenous calcium with ECG monitoring, while the underlying cause is investigated. Oral therapy is useful for less acute cases but is not adequate as the sole initial intervention in tetany or significant electrical instability.

7 / 10

A patient with hypomagnesemia has chronic diarrhea and ventricular ectopy. Which assessment is most useful for identifying the source of magnesium loss?

Measure serum albumin only

Measure only serum sodium

Assume all magnesium loss is renal

Review gastrointestinal losses and urinary magnesium excretion

Both gastrointestinal and renal losses can cause hypomagnesemia. Clinical history plus urinary magnesium assessment helps distinguish inappropriate renal wasting from appropriate renal conservation during gastrointestinal depletion, guiding treatment and medication review.

8 / 10

A patient has hypocalcemia, low PTH, and a history of neck irradiation. Which diagnosis is most likely?

Hypoparathyroidism

Pseudohypoparathyroidism

Tertiary hyperparathyroidism

Familial hypocalciuric hypercalcemia

Low calcium with an inappropriately low PTH after neck irradiation supports hypoparathyroidism from parathyroid injury. Pseudohypoparathyroidism generally features elevated PTH with resistance to its action.

9 / 10

A patient receiving a bisphosphonate develops symptomatic hypocalcemia. Which factor increases the risk?

High dietary calcium intake

Vitamin D deficiency or impaired calcium reserve

Mild isolated hypernatremia

Normal kidney function with replete vitamin D

Antiresorptive therapy can reduce calcium release from bone. Patients with vitamin D deficiency, renal impairment, hypoparathyroidism, or limited calcium reserve are more vulnerable to clinically significant hypocalcemia after treatment.

10 / 10

A patient with hypocalcemia has a normal total calcium but an alkalemic blood gas after hyperventilation. Which explanation is most likely for symptoms?

PTH excess causing hypercalcemia

Acute increase in ionized calcium

Reduced ionized calcium due to increased albumin binding during alkalemia

Laboratory contamination with phosphate

Alkalemia increases calcium binding to albumin and lowers ionized calcium even when total calcium is unchanged. This can cause paresthesias or carpopedal symptoms, especially in patients with limited calcium reserve.

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Postgraduate clinical case-vignette self-assessment. Complete all 10 questions to receive detailed explanations on the results page.

Hypernatremia Clinical Case Vignettes — Intermediate

Intermediate postgraduate clinical case-vignette assessment focused on Hypernatremia. Complete all 10 questions to view detailed explanations on the results page.

1 / 10

A 72-year-old patient with impaired thirst has a serum sodium of 164 mmol/L and a urine osmolality of 90 mOsm/kg. Which mechanism best explains the finding?

Excessive ADH secretion

Failure to generate concentrated urine despite hyperosmolarity

Pseudohyponatremia

Primary mineralocorticoid excess

A very dilute urine in the presence of marked hypernatremia indicates failure of renal water conservation, most consistent with diabetes insipidus. Inappropriately low ADH secretion suggests central disease, whereas nephrogenic disease reflects renal resistance. SIADH would produce concentrated urine and hyponatremia, not this pattern.

2 / 10

A patient with severe hypernatremia developed over several days after prolonged diarrhea. Which correction principle is safest?

Lower sodium immediately to normal

Give isotonic saline until sodium normalizes

Correct free-water deficit gradually while monitoring sodium frequently

Restrict all fluid until urine output falls

Hypernatremia that has been present for more than about 48 hours should generally be corrected gradually because rapid reduction can promote cerebral edema as brain osmolytes readjust. The fluid choice depends on hemodynamic status, but correction requires free water with close serial sodium monitoring.

3 / 10

A 30-year-old patient has polyuria, hypernatremia, and a marked rise in urine osmolality after desmopressin. Which diagnosis is most likely?

Nephrogenic diabetes insipidus

Osmotic diuresis from glucosuria

Primary polydipsia

Central diabetes insipidus

A substantial increase in urine osmolality after desmopressin indicates that the kidneys can respond to ADH and that endogenous ADH availability is deficient. This supports central diabetes insipidus. Nephrogenic diabetes insipidus shows little response because the renal concentrating pathway is resistant.

4 / 10

A patient with hypernatremia is hypotensive and tachycardic after profuse gastrointestinal losses. What is the initial fluid priority?

Rapid restoration of intravascular volume with an isotonic crystalloid

Free water by mouth only

Hypertonic saline

Loop diuretic therapy

In shock or significant hypovolemia, circulatory support takes priority. An isotonic crystalloid restores effective arterial volume; once perfusion is stabilized, the remaining free-water deficit can be corrected with an appropriate hypotonic fluid. Hypertonic saline would worsen hypernatremia.

5 / 10

A patient receiving lithium has polyuria, hypernatremia, and minimal response to desmopressin. Which renal defect is most likely?

Excessive proximal sodium reabsorption

Increased aldosterone synthesis

Collecting-duct resistance to ADH-mediated water reabsorption

Defective glomerular filtration only

Lithium can enter collecting-duct principal cells and impair ADH signaling, producing nephrogenic diabetes insipidus. The resulting inability to insert aquaporin-2 channels prevents urinary concentration and causes free-water loss. Desmopressin response is therefore limited.

6 / 10

A 68-year-old patient with hypernatremia has a urine osmolality of 700 mOsm/kg and ongoing osmotic diuresis from severe hyperglycemia. What is the main contributor to the hypernatremia?

Complete absence of ADH

Water loss exceeding electrolyte loss

Pseudohypernatremia from hyperlipidemia

Excessive free-water intake

A concentrated urine demonstrates preserved ADH-mediated water conservation. In severe hyperglycemia, glucosuria creates osmotic diuresis and can cause proportionally greater water loss than sodium loss, resulting in hypernatremia when intake cannot keep pace.

7 / 10

Which bedside finding most strongly suggests chronic rather than acute hypernatremia?

Seizure beginning minutes after sodium elevation

Marked hypoglycemia

Abrupt pulmonary edema

Neurologic adaptation with relatively mild symptoms despite a high sodium

The brain gradually accumulates intracellular osmolytes during chronic hypernatremia, partially restoring cell volume and reducing symptoms despite a high sodium concentration. This adaptation is also why overly rapid correction can cause cerebral edema.

8 / 10

A patient with central diabetes insipidus cannot take oral fluids after surgery. Which treatment most directly replaces the missing hormone effect?

Desmopressin

Spironolactone

Acetazolamide

Fludrocortisone

Desmopressin is a selective vasopressin analogue that restores V2-receptor stimulation and collecting-duct water reabsorption in central diabetes insipidus. It does not correct nephrogenic resistance, and the fluid deficit must still be replaced carefully.

9 / 10

A patient with hypernatremia has a low urine volume because of severe dehydration. Which calculation is most useful for initial planning?

Fractional excretion of sodium alone

Free-water deficit

Anion gap

Corrected calcium

The free-water deficit estimates the amount of electrolyte-free water needed to return total-body water toward a target sodium concentration. It is a starting estimate, not a substitute for serial sodium measurements, ongoing-loss assessment, and adjustment for comorbidities.

10 / 10

During treatment of hypernatremia, the serum sodium falls faster than intended. What is the most appropriate immediate response?

Continue unchanged because faster correction is always beneficial

Give hypertonic saline automatically

Reassess all fluid inputs and reduce or pause hypotonic replacement while monitoring closely

Start a loop diuretic without reassessing volume status

An unexpectedly rapid fall suggests that free-water delivery or ongoing losses have been misestimated. Hypotonic replacement should be reassessed and adjusted, with frequent sodium checks. Management must account for neurologic risk, hemodynamics, urine output, and the cause of the water loss.

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Difficulty: Intermediate postgraduate self-assessment focused on Renal Biopsy Pattern Recognition. Complete all 10 questions to view detailed clinical explanations on the results page.

Renal Biopsy Pattern Recognition — Intermediate

Advanced postgraduate nephrology self-assessment focused on Renal Biopsy Pattern Recognition. Complete all 10 questions to view detailed clinical explanations on the results page.

1 / 10

Light microscopy shows diffuse capillary-wall thickening, and immunofluorescence shows granular IgG along capillary loops. Which pattern is most consistent?

Membranous nephropathy

Minimal change disease

Anti-GBM disease

Pure acute tubular injury

Diffuse capillary-wall thickening with granular capillary-loop IgG suggests subepithelial immune deposits, the characteristic pattern of membranous nephropathy. Electron microscopy and antigen studies help refine the diagnosis and evaluate secondary causes.

2 / 10

Which immunofluorescence pattern is characteristic of anti-GBM disease?

Granular mesangial IgA only

Smooth linear IgG along the glomerular basement membrane

Full-house staining in every case

No staining with crescents

Anti-GBM antibodies bind continuously along the GBM, producing a smooth linear IgG pattern. This differs from granular immune-complex deposition and is an urgent clinicopathologic diagnosis when accompanied by rapidly progressive kidney injury or pulmonary hemorrhage.

3 / 10

Electron microscopy in minimal change disease typically shows which finding?

Intramembranous dense deposits

Subepithelial humps

Diffuse podocyte foot-process effacement without immune deposits

Linear electron-dense material along the GBM

Minimal change disease is characterized by diffuse podocyte foot-process effacement on electron microscopy with little or no immune deposition. Light microscopy may be near normal, so the diagnosis depends on clinicopathologic correlation.

4 / 10

A biopsy shows mesangial hypercellularity with dominant IgA staining. Which diagnosis is most likely?

Alport syndrome

Anti-GBM disease

Membranous nephropathy

IgA nephropathy

Mesangial-dominant IgA staining with compatible morphology supports IgA nephropathy. The clinical picture, Oxford features, proteinuria, eGFR, and secondary causes must still be assessed before risk stratification and treatment decisions.

5 / 10

What does a crescent represent histologically?

Proliferation of parietal epithelial cells and inflammatory cells in Bowman space after capillary-wall injury

A benign collecting-duct lesion

A subepithelial immune deposit alone

A normal glomerular aging change

Crescents form after severe capillary-wall injury allows fibrin and inflammatory mediators into Bowman space, stimulating parietal epithelial proliferation and macrophage influx. Their proportion, cellularity, and chronicity carry prognostic information.

6 / 10

Which biopsy feature indicates chronic irreversible damage more than active inflammation?

Endocapillary leukocytes alone

Interstitial fibrosis and tubular atrophy

Cellular crescents only

Fresh fibrin thrombi only

Interstitial fibrosis and tubular atrophy reflect established nephron loss and are less reversible than active inflammatory lesions. Biopsy reports should separate activity from chronicity because escalating immunosuppression cannot reverse extensive scarring.

7 / 10

“Full-house” immunofluorescence refers to staining for which combination?

Only IgG4

Only IgA and C3

IgG, IgA, IgM, C3, and C1q

Only fibrin

Full-house staining means deposition of multiple immunoglobulin classes together with complement components, classically associated with lupus nephritis. It is a pattern, not a substitute for clinical, serologic, and morphologic correlation.

8 / 10

Which finding is most suggestive of thrombotic microangiopathy on kidney biopsy?

Linear IgG staining alone

Diffuse podocyte effacement alone

Subepithelial humps only

Endothelial swelling, mesangiolysis, and fibrin thrombi in glomerular or arteriolar lumina

Renal TMA may show endothelial swelling, mesangiolysis, double contours, fibrin or platelet thrombi, and arteriolar injury. The biopsy must be integrated with platelet count, hemolysis, blood pressure, pregnancy, drugs, complement, and systemic disease.

9 / 10

A “starry sky” granular staining pattern in postinfectious GN usually reflects which process?

Immune-complex deposition with complement and immunoglobulin in capillary loops and mesangium

Direct antibody binding in a continuous line

Absence of deposits

Isolated amyloid fibrils

Postinfectious GN commonly shows granular immune-complex staining and, on electron microscopy, subepithelial humps. Recent infection, low complement, hematuria, and nephritic features support the diagnosis, but mimics must be considered.

10 / 10

Why is electron microscopy still important when light microscopy and immunofluorescence appear diagnostic?

It only measures kidney size

It localizes deposits, defines ultrastructural injury, and can reveal a different or additional lesion

It replaces clinical history

It is never useful in proteinuric disease

Electron microscopy identifies the location and character of deposits and podocyte injury, which can distinguish subendothelial, subepithelial, intramembranous, and organized deposits. It is especially valuable in mixed or apparently discordant patterns.

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Difficulty: Intermediate postgraduate self-assessment focused on Drug Dosing in CKD and Dialysis. Complete all 10 questions to view detailed clinical explanations on the results page.

Drug Dosing in CKD and Dialysis — Intermediate

Advanced postgraduate nephrology self-assessment focused on Drug Dosing in CKD and Dialysis. Complete all 10 questions to view detailed clinical explanations on the results page.

1 / 10

A patient with CKD has a renally cleared antibiotic. Which principle is most appropriate when estimating maintenance dosing?

Adjust dose or interval according to kidney function and therapeutic response

Increase the dose because uremia increases metabolism

Use the same dose regardless of eGFR

Stop all antibiotics once creatinine rises

Renally cleared drugs can accumulate when filtration falls. Maintenance dose, interval, or both should be adjusted using an appropriate kidney-function estimate, while indication, severity, drug levels, and clinical response are considered. A creatinine rise is not by itself a reason to stop needed treatment.

2 / 10

Which drug characteristic most strongly predicts removal during intermittent hemodialysis?

High protein binding and a large volume of distribution

Low protein binding, small volume of distribution, and low molecular size

Extensive intracellular sequestration

Irreversible tissue binding

Dialysis removes drugs most efficiently when they remain in the intravascular space, are poorly protein bound, and have a relatively small volume of distribution. Highly protein-bound or extensively distributed drugs are generally less dialyzable.

3 / 10

A stable outpatient with CKD starts an ACE inhibitor. Which laboratory change is usually acceptable if it stabilizes?

A progressive potassium rise without reassessment

Any creatinine increase above baseline

A modest creatinine increase after excluding volume depletion and renal artery disease

A fall in bicarbonate as the only expected effect

A modest early creatinine rise can reflect reduced intraglomerular pressure after efferent arteriolar dilation. The patient still needs review for volume depletion, NSAIDs, renal artery disease, and hyperkalemia; progressive deterioration is not automatically acceptable.

4 / 10

Which medication history is most important to review when kidney function acutely worsens?

Only vitamins

Only medications taken more than one year ago

Only topical medications

NSAIDs, renin-angiotensin blockers, diuretics, contrast, and recently added drugs

Medication reconciliation is central to AKI evaluation. NSAIDs, renin-angiotensin system blockers, diuretics, contrast exposure, antimicrobials, and new over-the-counter products may contribute through hemodynamic, tubular, interstitial, or obstructive mechanisms.

5 / 10

Why can serum creatinine-based eGFR be misleading for drug dosing in a patient with very low muscle mass?

Creatinine generation may be low and kidney function may be overestimated

Creatinine is always falsely high

Low muscle mass increases filtration

eGFR is independent of creatinine production

Creatinine production depends partly on muscle mass. In cachexia, amputation, or severe frailty, a low creatinine can overestimate filtration, so drug dosing should incorporate clinical context and, when needed, measured clearance or another validated estimate.

6 / 10

A dialyzable medication is prescribed to a patient receiving thrice-weekly hemodialysis. When is a supplemental dose commonly considered?

Immediately before every dialysis session regardless of drug

After dialysis when a clinically meaningful amount was removed

Only on non-dialysis days

Never, because dialysis cannot remove drugs

If dialysis removes a clinically important fraction of a drug, administration after the session or a post-dialysis supplement may be needed. The decision depends on the drug, dose, dialysis prescription, residual kidney function, and therapeutic target.

7 / 10

Which approach is safest when prescribing a narrow-therapeutic-index drug in advanced CKD?

Use routine dosing without monitoring

Double the dose to overcome uremia

Use individualized dosing with therapeutic drug monitoring when available

Avoid checking interacting medications

Narrow-therapeutic-index drugs require individualized dosing and close monitoring because small concentration changes can cause toxicity or treatment failure. Kidney function trends, interacting drugs, timing of levels, and clinical status all matter.

8 / 10

A patient with CKD develops severe hypoglycemia after a sulfonylurea dose increase. What is the key pharmacologic concern?

Only insulin can cause prolonged hypoglycemia

CKD always accelerates drug elimination

Hypoglycemia excludes a medication cause

Reduced clearance of the drug or active metabolites can prolong effect

Some sulfonylureas or active metabolites accumulate as kidney function declines, producing prolonged hypoglycemia. Therapy should be reassessed, alternative agents considered, and recurrent hypoglycemia monitored rather than treated as a transient isolated event.

9 / 10

Which statement about contrast-associated kidney risk is most accurate?

Risk assessment should consider baseline kidney function, volume status, and exposure context

All iodinated contrast is absolutely contraindicated in CKD

Oral hydration is never relevant

A single creatinine value predicts all risk

Contrast decisions should be individualized. Baseline kidney function, AKI, hemodynamic status, diabetes, volume depletion, nephrotoxins, contrast volume, and urgency of imaging should be considered; unnecessary exposure should be avoided but needed studies should not be withheld reflexively.

10 / 10

A patient on peritoneal dialysis receives a drug with substantial peritoneal clearance. What is the best dosing principle?

Assume peritoneal dialysis removes no drug

Use drug-specific pharmacokinetic guidance and account for modality and residual kidney function

Use the standard dose for normal kidney function

Change the dose only after a toxicity event

Peritoneal dialysis clearance varies with modality, dwell time, membrane transport, drug characteristics, and residual kidney function. Drug-specific guidance and clinical monitoring are preferable to applying a hemodialysis schedule or normal-kidney dose.

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Intermediate nephrology self-assessment icon

Renal Tubular Acidosis — Intermediate

Difficulty: Intermediate

Postgraduate nephrology self-assessment with 10 single-best-answer MCQs. Explanations are shown after quiz completion.

Renal Tubular Acidosis — Intermediate

Postgraduate nephrology self-assessment on Renal Tubular Acidosis. Difficulty: Intermediate. Explanations are shown after quiz completion.

1 / 10

A normal-anion-gap metabolic acidosis with inappropriately high urine pH suggests:

Distal renal tubular acidosis

Vomiting

Metabolic alkalosis

Respiratory acidosis

Review the key principles in this topic.

Correct: Distal renal tubular acidosis.

Distal RTA causes impaired hydrogen secretion and an inappropriately high urine pH despite systemic acidosis.

2 / 10

Which electrolyte abnormality is typical of distal RTA?

Severe hypernatremia in every case

Hypokalemia

Hypercalcemia in every case

Hypophosphatemia only

Review the key principles in this topic.

Correct: Hypokalemia.

Distal RTA commonly produces hypokalemia and may be associated with nephrolithiasis or nephrocalcinosis.

3 / 10

Proximal RTA is caused primarily by impaired:

Hydrogen secretion in the collecting duct only

Glomerular filtration only

Bicarbonate reabsorption in the proximal tubule

Renin production

Review the key principles in this topic.

Correct: Bicarbonate reabsorption in the proximal tubule.

Proximal RTA reflects reduced proximal bicarbonate reabsorption and can occur with Fanconi syndrome.

4 / 10

In type 4 RTA, the dominant mechanism is usually:

Excess aldosterone

Primary respiratory alkalosis

Increased ammonium excretion

Hypoaldosteronism or aldosterone resistance

Review the key principles in this topic.

Correct: Hypoaldosteronism or aldosterone resistance.

Type 4 RTA causes hyperkalemic normal-anion-gap acidosis through reduced aldosterone activity and ammonium excretion.

5 / 10

Which urine finding supports impaired ammonium excretion in metabolic acidosis?

Low urine ammonium excretion

Maximal ammonium excretion

Urine glucose only

Nephrotic-range proteinuria

Review the key principles in this topic.

Correct: Low urine ammonium excretion.

Reduced ammonium excretion limits net acid excretion and contributes to normal-anion-gap metabolic acidosis.

6 / 10

A patient with distal RTA and recurrent calcium stones may benefit from:

Chronic acid loading

Alkali therapy and correction of underlying disease

High-dose NSAIDs

Fluid restriction

Review the key principles in this topic.

Correct: Alkali therapy and correction of underlying disease.

Alkali therapy corrects acidosis and can reduce stone risk, while the underlying cause should be addressed.

7 / 10

Fanconi syndrome can include proximal tubular losses of:

Only sodium chloride

Only albumin

Bicarbonate, phosphate, glucose, and amino acids

Only calcium

Review the key principles in this topic.

Correct: Bicarbonate, phosphate, glucose, and amino acids.

Fanconi syndrome causes generalized proximal tubular dysfunction with multiple solute losses.

8 / 10

Which medication is a recognized cause of proximal tubular dysfunction in some patients?

Topical petrolatum

Inhaled saline

Acetaminophen at one normal dose

Ifosfamide

Review the key principles in this topic.

Correct: Ifosfamide.

Ifosfamide and several other drugs can cause proximal tubular injury and Fanconi syndrome.

9 / 10

In a patient with metabolic acidosis, a positive urine anion gap may suggest:

Low urinary ammonium excretion

High gastrointestinal bicarbonate loss

Respiratory alkalosis

Normal acid excretion in every case

Review the key principles in this topic.

Correct: Low urinary ammonium excretion.

A positive urine anion gap can act as an indirect marker of low ammonium excretion, though interpretation requires clinical context.

10 / 10

The first step in evaluating suspected RTA is to confirm:

A respiratory alkalosis only

A metabolic acidosis and characterize the anion gap

Nephrotic-range proteinuria

A high serum bicarbonate

Review the key principles in this topic.

Correct: A metabolic acidosis and characterize the anion gap.

RTA should be considered after confirming metabolic acidosis and assessing the anion gap and clinical context.

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Kidney Transplantation — Intermediate

Difficulty: Intermediate

Postgraduate nephrology self-assessment with 10 single-best-answer MCQs. Explanations are shown after quiz completion.

Kidney Transplantation — Intermediate

Postgraduate nephrology self-assessment on Kidney Transplantation. Difficulty: Intermediate. Explanations are shown after quiz completion.

1 / 10

The most common mechanism of acute cellular rejection is:

Mechanical ureteral obstruction only

Hypercalcemia

T-cell-mediated immune injury

Low dietary protein

Review the key principles in this topic.

Correct: T-cell-mediated immune injury.

Acute T-cell-mediated rejection involves recipient T-cell recognition and inflammatory injury to the graft.

2 / 10

A sudden rise in serum creatinine after transplantation should first prompt assessment of:

Leukopenia

Serum amylase alone

Dietary sodium alone

Volume status, obstruction, drug levels, infection, and rejection

Review the key principles in this topic.

Correct: Volume status, obstruction, drug levels, infection, and rejection.

Graft dysfunction has a broad differential and requires systematic assessment rather than assuming rejection.

3 / 10

Tacrolimus is primarily used as a:

Calcineurin inhibitor

Loop diuretic

Phosphate binder

Erythropoiesis-stimulating agent

Review the key principles in this topic.

Correct: Calcineurin inhibitor.

Tacrolimus suppresses T-cell activation through calcineurin inhibition and requires therapeutic monitoring.

4 / 10

Which adverse effect is associated with calcineurin inhibitors?

Permanent protection from hypertension

Nephrotoxicity

Severe hypoglycemia in every patient

Complete absence of infection risk

Review the key principles in this topic.

Correct: Nephrotoxicity.

Calcineurin inhibitors can cause vasoconstrictive nephrotoxicity, hypertension, tremor, and metabolic effects.

5 / 10

BK polyomavirus after transplantation is primarily associated with:

Improved graft function

Hyperthyroidism

Allograft dysfunction under immunosuppression

Kidney stone prevention

Review the key principles in this topic.

Correct: Allograft dysfunction under immunosuppression.

BK viremia can cause polyomavirus nephropathy and requires monitoring and immunosuppression adjustment.

6 / 10

A transplant recipient with fever should be evaluated promptly because immunosuppression increases risk of:

Complete infection protection

Only seasonal allergies

No complications

Serious infection

Review the key principles in this topic.

Correct: Serious infection.

Immunosuppression can blunt symptoms and increase the severity of bacterial, viral, fungal, and opportunistic infections.

7 / 10

Which drug interaction can increase tacrolimus exposure?

Strong CYP3A4 inhibitors such as clarithromycin

Topical saline

Calcium-free water

Simple emollients

Review the key principles in this topic.

Correct: Strong CYP3A4 inhibitors such as clarithromycin.

CYP3A4 inhibitors can raise tacrolimus levels and toxicity risk, so medication reconciliation is essential.

8 / 10

A transplant recipient with persistent proteinuria should be evaluated for:

Normal graft function by definition

Recurrent disease, rejection, infection, and glomerular graft disease

Only dehydration

Only hyperthyroidism

Review the key principles in this topic.

Correct: Recurrent disease, rejection, infection, and glomerular graft disease.

Proteinuria after transplant has a broad differential and may signal recurrent disease, rejection, infection, or de novo glomerular disease.

9 / 10

Vaccination planning after transplantation should generally emphasize:

Routine live vaccines immediately after transplant

No vaccines ever

Inactivated vaccines and avoidance of live vaccines when contraindicated

Only vaccines against kidney stones

Review the key principles in this topic.

Correct: Inactivated vaccines and avoidance of live vaccines when contraindicated.

Inactivated vaccines are commonly used, while live vaccines may be unsafe during significant immunosuppression.

10 / 10

The goal of maintenance immunosuppression is to:

Eliminate all immune function

Guarantee no malignancy risk

Replace blood-pressure treatment

Prevent rejection while minimizing infection and drug toxicity

Review the key principles in this topic.

Correct: Prevent rejection while minimizing infection and drug toxicity.

Transplant care balances rejection prevention against infection, malignancy, metabolic effects, and medication toxicity.

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Peritoneal Dialysis — Intermediate

Difficulty: Intermediate

Postgraduate nephrology self-assessment with 10 single-best-answer MCQs. Explanations are shown after quiz completion.

Peritoneal Dialysis — Intermediate

Postgraduate nephrology self-assessment on Peritoneal Dialysis. Difficulty: Intermediate. Explanations are shown after quiz completion.

1 / 10

The peritoneal membrane in peritoneal dialysis functions primarily as:

A red-cell reservoir

A semipermeable exchange membrane

A hormone-producing gland

A bile duct

Review the key principles in this topic.

Correct: A semipermeable exchange membrane.

The peritoneum permits diffusion and ultrafiltration between dialysate and the patient’s plasma.

2 / 10

The most common cause of cloudy peritoneal dialysis effluent is:

Improved clearance

Normal ultrafiltration

Peritonitis

Hypoglycemia

Review the key principles in this topic.

Correct: Peritonitis.

Cloudy effluent should be treated as peritonitis until evaluated, with cell count, differential, Gram stain, and culture.

3 / 10

Which symptom combination is concerning for peritoneal dialysis peritonitis?

Clear effluent and no symptoms

Improved appetite only

Isolated ear pain

Abdominal pain and cloudy effluent

Review the key principles in this topic.

Correct: Abdominal pain and cloudy effluent.

Abdominal pain, fever, or cloudy effluent are classic warning features of peritonitis.

4 / 10

The osmotic agent most commonly used to produce ultrafiltration in standard PD solutions is:

Glucose

Albumin

Urea

Bilirubin

Review the key principles in this topic.

Correct: Glucose.

Glucose-containing solutions create an osmotic gradient that draws water across the peritoneal membrane.

5 / 10

A sudden reduction in PD drainage may be caused by:

Improved membrane function only

Constipation or catheter displacement

High serum albumin

Hyperthyroidism

Review the key principles in this topic.

Correct: Constipation or catheter displacement.

Constipation, kinking, malposition, and fibrin can impair inflow or outflow.

6 / 10

Which metabolic effect is associated with chronic exposure to glucose-containing PD solutions?

Permanent hypoglycemia

Complete absence of appetite

Glucose absorption and weight gain

Low serum sodium in every case

Review the key principles in this topic.

Correct: Glucose absorption and weight gain.

Glucose absorption can contribute to hyperglycemia, weight gain, and adverse metabolic effects.

7 / 10

In a patient using automated PD, a machine alarm with poor drainage should first prompt assessment of:

Serum amylase only

Serum phosphate

Serum bicarbonate

Tubing, clamps, position, and constipation

Review the key principles in this topic.

Correct: Tubing, clamps, position, and constipation.

Mechanical causes are common and should be checked promptly before more invasive interventions.

8 / 10

Which measure reduces the risk of PD-related peritonitis?

Strict aseptic connection technique

Routine opening of the system

Reusing contaminated caps

Ignoring exit-site drainage

Review the key principles in this topic.

Correct: Strict aseptic connection technique.

Aseptic technique and exit-site care are central to preventing peritoneal infection.

9 / 10

A patient with PD has a painful erythematous catheter exit site. This should be evaluated for:

Improved dialysis adequacy

Exit-site or tunnel infection

Hypercalcemia only

Catheter malposition

Review the key principles in this topic.

Correct: Exit-site or tunnel infection.

Exit-site inflammation can progress to tunnel infection and peritonitis and requires prompt assessment.

10 / 10

PD adequacy is assessed using clinical status and measures such as:

Hair growth

Serum bilirubin only

Small-solute clearance and fluid balance

Chest circumference

Review the key principles in this topic.

Correct: Small-solute clearance and fluid balance.

Adequacy assessment includes clearance, ultrafiltration, volume status, nutrition, and symptom control.

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GN Serology and Complement — Intermediate

Difficulty: Intermediate

Postgraduate nephrology self-assessment with 10 single-best-answer MCQs. Explanations are shown after quiz completion.

GN Serology and Complement — Intermediate

Postgraduate nephrology self-assessment on GN Serology and Complement. Difficulty: Intermediate. Explanations are shown after quiz completion.

1 / 10

Low C3 with relatively preserved C4 most strongly suggests activation through:

Only the classical pathway

No complement activation

The coagulation pathway

The alternative complement pathway

Review the key principles in this topic.

Correct: The alternative complement pathway.

Alternative pathway activation often lowers C3 disproportionately, whereas classical pathway disease more often lowers both C3 and C4.

2 / 10

Which antibody is most specific for anti-GBM disease?

Anti-GBM antibody

Anti-mitochondrial antibody

Anti-thyroid peroxidase antibody

Anti-centromere antibody

Review the key principles in this topic.

Correct: Anti-GBM antibody.

Circulating anti-GBM antibodies support the diagnosis of anti-GBM disease in the correct clinical setting.

3 / 10

A patient with pulmonary hemorrhage and rapidly progressive GN should be urgently tested for:

Serum creatinine

ANCA and anti-GBM antibodies

Only urine glucose

Only serum amylase

Review the key principles in this topic.

Correct: ANCA and anti-GBM antibodies.

Pulmonary–renal syndrome requires urgent evaluation for ANCA-associated vasculitis and anti-GBM disease, among other causes.

4 / 10

Low C3 and low C4 with purpura and arthralgia should raise concern for:

Isolated thin basement membrane disease

Minimal-change disease only

Cryoglobulinemic GN

Diabetic nephropathy only

Review the key principles in this topic.

Correct: Cryoglobulinemic GN.

Cryoglobulinemia commonly causes immune-complex disease, low complement, purpura, arthralgia, and kidney involvement.

5 / 10

Which serology is classically associated with lupus nephritis?

Anti-CCP only

Anti-smooth muscle antibody only

Anti-Jo-1 only

Anti-dsDNA antibodies

Review the key principles in this topic.

Correct: Anti-dsDNA antibodies.

Anti-dsDNA antibodies and complement levels can help assess systemic lupus activity and kidney involvement.

6 / 10

A positive ANCA result should be interpreted with:

Clinical findings and kidney biopsy when indicated

No clinical context

A diagnosis of vasculitis in every case

The assumption that complement is always low

Review the key principles in this topic.

Correct: Clinical findings and kidney biopsy when indicated.

ANCA results require clinical correlation because assays are not perfectly specific and disease phenotype varies.

7 / 10

Which biopsy pattern is typical of immune-complex GN?

No immune deposits in every case

Granular immunoglobulin deposition

Only linear IgG staining

Purely tubular crystals

Review the key principles in this topic.

Correct: Granular immunoglobulin deposition.

Immune-complex disease typically produces granular immunoglobulin and complement staining on immunofluorescence.

8 / 10

Linear IgG staining along the GBM most strongly suggests:

IgA nephropathy

Membranous nephropathy in every case

Anti-GBM disease

Diabetic nephropathy

Review the key principles in this topic.

Correct: Anti-GBM disease.

Linear IgG along the GBM is characteristic of antibody binding to the GBM, as in anti-GBM disease.

9 / 10

Which complement result can support infection-related GN?

Persistently high C3 only

Absent serum albumin

High anti-GBM antibody by definition

Low C3 during active disease

Review the key principles in this topic.

Correct: Low C3 during active disease.

C3 is often reduced in infection-related GN, although complement patterns and recovery must be interpreted clinically.

10 / 10

The best general principle for interpreting GN serology is to:

Integrate serology, urine findings, kidney function, and biopsy

Treat every positive antibody without evaluation

Ignore the urine sediment

Use complement alone to determine therapy

Review the key principles in this topic.

Correct: Integrate serology, urine findings, kidney function, and biopsy.

Serology is most useful when integrated with the clinical syndrome, urine sediment, kidney function, and histopathology.

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Intermediate MCQs for Nephrologists

Assess your clinical reasoning in nephritic syndrome, serologic evaluation, complement patterns, biopsy interpretation, postinfectious and pauci-immune glomerulonephritis, supportive care, and urgent kidney replacement indications.

Glomerulonephritis — Intermediate

Difficulty: Intermediate

Test your clinical reasoning in nephritic syndrome, serologic evaluation, complement patterns, biopsy interpretation, postinfectious and pauci-immune glomerulonephritis, supportive care, and urgent kidney replacement indications. This quiz contains 10 single-best-answer questions. Explanations are shown after quiz completion.

1 / 10

Which clinical combination is most characteristic of a nephritic syndrome?

Hematuria, hypertension, reduced kidney function, and variable proteinuria

Massive proteinuria, hypoalbuminemia, and hyperlipidemia only

Glycosuria with normal blood glucose

Isolated pyuria without proteinuria

Nephritic syndrome reflects glomerular inflammation and commonly includes hematuria, hypertension, reduced GFR, and variable proteinuria.

2 / 10

A patient develops cola-colored urine, edema, hypertension, and a rising creatinine two weeks after streptococcal pharyngitis. Which diagnosis is most likely?

Postinfectious glomerulonephritis

IgA nephropathy

Minimal-change disease

Diabetic nephropathy

Postinfectious GN classically follows a latent interval after infection and presents with nephritic features, often with low C3.

3 / 10

Which urine microscopy finding most strongly supports glomerular bleeding?

Dysmorphic red cells and red-cell casts

Oval fat bodies only

Muddy brown granular casts only

Hexagonal crystals

Dysmorphic erythrocytes and red-cell casts indicate bleeding and inflammation originating within the glomerulus.

4 / 10

A patient with suspected rapidly progressive glomerulonephritis has pulmonary hemorrhage and rapidly rising creatinine. Which serologic test is particularly important for anti-GBM disease?

Anti-GBM antibodies

Anti-mitochondrial antibodies

Anti-CCP antibodies

Anti-thyroid peroxidase antibodies

Anti-GBM antibodies support the diagnosis of anti-GBM disease, which may cause pulmonary–renal syndrome and requires urgent treatment.

5 / 10

Which complement pattern is commonly associated with lupus nephritis?

Low C3 and low C4

Persistently high C3 and C4

Low C4 only with normal C3 in every case

Normal complement excludes lupus nephritis

Active immune-complex lupus nephritis commonly consumes complement, producing low C3 and C4, although complement results must be interpreted with the full clinical picture.

6 / 10

A patient has hematuria, proteinuria, and positive MPO-ANCA with pauci-immune necrotizing crescentic GN on biopsy. Which disease is most likely?

Microscopic polyangiitis

Membranous nephropathy

Postinfectious GN

Alport syndrome

MPO-ANCA is commonly associated with microscopic polyangiitis, and pauci-immune necrotizing crescentic GN is the characteristic renal lesion.

7 / 10

What is the primary purpose of kidney biopsy in a patient with suspected glomerulonephritis?

To establish the histopathologic pattern and guide disease-specific treatment

To measure serum potassium directly

To replace all serologic testing

To diagnose every case of uncomplicated urinary tract infection

Biopsy defines the pattern of injury and immune deposits, helps establish prognosis, and guides treatment when the result will change management.

8 / 10

A patient with glomerulonephritis has severe edema and hypertension. Which supportive measure is generally appropriate while the cause is being evaluated?

Sodium restriction with treatment of volume overload and blood pressure

Routine high-sodium fluid loading

Stopping all antihypertensive therapy

Empiric long-term antibiotics for every patient

Sodium restriction, diuretics when appropriate, and blood-pressure control help manage edema and hypertension while diagnostic evaluation proceeds.

9 / 10

Which biopsy immunofluorescence pattern is typical of pauci-immune glomerulonephritis?

Little or no immunoglobulin or complement staining

Diffuse linear IgG along the glomerular basement membrane

Strong granular IgG and C3 in capillary loops

Predominant mesangial IgA in every case

Pauci-immune GN has minimal or absent immune deposits on immunofluorescence and is often associated with ANCA vasculitis.

10 / 10

A patient with GN develops refractory hyperkalemia, pulmonary edema, and severe metabolic acidosis despite medical therapy. What is the most appropriate next step?

Urgent kidney replacement therapy assessment, usually dialysis

Observation until the next outpatient appointment

High-dose oral calcium alone

Restriction of protein only

Refractory hyperkalemia, pulmonary edema, and severe acidosis are urgent indications for kidney replacement therapy when not corrected medically.

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Assignment Level: Intermediate

Renal Tubular Acidosis — Intermediate

Kidney Transplantation — Intermediate

Peritoneal Dialysis — Intermediate

GN Serology and Complement — Intermediate

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