Nephrology Practice Questions

Q: A child has serum osmolality of 270 mOsm/kg and urine osmolality of 1200 mOsm/kg. What is the most probable diagnosis?

SIADH. SIADH - In SIADH (Syndrome of Inappropriate Antidiuretic Hormone), there is excessive ADH secretion, leading to water retention, low serum osmolality (dilute blood), and concentrated urine. [1] - The serum osmolality of 270 mOsm/kg is low-normal/mildly low [3], while the urine osmolality of 1200 mOsm/kg is very high [1], indicating the kidneys are inappropriately conserving water and concentrating urine despite diluted plasma. Nephrogenic diabetes insipidus - This condition involves the kidneys being unable to respond to ADH [2], leading to the excretion of large volumes of dilute urine despite dehydration. - While serum osmolality might be high due to dehydration, urine osmolality would be low (dilute), contrary to the given values. Water deprivation - In water deprivation, the body compensates by releasing ADH, which leads to concentrated urine to conserve water and a high serum osmolality. - Here, the serum osmolality is low-normal, which does not align with the expected high serum osmolality seen in water deprivation. Central diabetes insipidus - Characterized by the lack of ADH production by the pituitary gland [2], resulting in the excretion of large volumes of dilute urine. - Patients with central DI would typically have high serum osmolality (due to water loss) and low urine osmolality (dilute urine), which is the opposite of the given values.

Q: Pseudohyponatremia occurs in which of the following conditions?

Hyperlipidemia. Hyperlipidemia - Pseudohyponatremia, or **factitious hyponatremia**, occurs when the measured sodium concentration is artificially low due to an increased proportion of the non-aqueous component of plasma. - In severe hyperlipidemia, the elevated **lipid concentration** displaces plasma water, leading to a falsely low sodium reading when measured by flame photometry, as the electrode measures sodium concentration per unit of plasma, rather than per unit of plasma water. *CHF* - **Congestive Heart Failure** (CHF) causes true hyponatremia, often due to increased antidiuretic hormone (ADH) secretion in response to reduced effective circulating volume [1]. - This leads to **water retention** and dilutional hyponatremia, where the total body sodium is relatively preserved but is diluted by excess water [1]. *SIADH* - **Syndrome of Inappropriate Antidiuretic Hormone** (SIADH) causes true **euvolemic hyponatremia** due to excessive ADH release, leading to impaired free water excretion despite normal renal and adrenal function [1]. - This results in a dilutional hyponatremia, characterized by concentrated urine (**high urine osmolality**) and elevated urine sodium output. *Severe dehydration* - **Severe dehydration** typically leads to **hypernatremia** or isotonic hyponatremia, but rarely pseudohyponatremia. - True hyponatremia in dehydration is unusual unless there is predominant free water loss relative to solute loss, or inappropriate fluid replacement with hypotonic fluids.

Q: A CKD patient had to undergo dialysis. His Hb was 5.5. So two blood transfusions were to be given. First bag was completed in 2 hours. Second was started and midway between he developed shortness of breath, hypertension. Vitals: BP 180/120 mm Hg and pulse rate 110/min. What is the cause?

Transfusion related circulatory overload (TACO). ***Transfusion related circulatory overload (TACO)*** - The patient's presentation with **shortness of breath**, **hypertension**, and **tachycardia** following blood transfusion, especially in a **CKD patient** with likely compromised cardiac and renal function, is highly suggestive of **TACO** [1]. - **Fluid overload** from the transfused blood, exacerbated by pre-existing renal impairment, leads to acute pulmonary edema and cardiovascular stress. *Allergic* - Allergic reactions typically manifest with **urticaria**, **pruritus**, **bronchospasm**, or **anaphylaxis**, often without severe hypertension or primary respiratory distress in this manner [1], [2]. - While mild allergic reactions can occur, the prominent hypertension and acute respiratory distress point away from a simple allergic response. *FNHTR* - **Febrile non-hemolytic transfusion reaction (FNHTR)** is characterized by a temperature increase of at least 1°C, chills, and rigors, usually without significant respiratory distress or marked hypertension [1]. - The patient's symptoms are dominated by respiratory and cardiovascular overload rather than fever. *TRALI* - **Transfusion-related acute lung injury (TRALI)** is characterized by acute respiratory distress with **hypoxemia** and **bilateral pulmonary infiltrates** due to non-cardiogenic pulmonary edema, typically associated with hypotension, not hypertension. - The prominent hypertension and the patient's underlying CKD make TACO a more likely diagnosis than TRALI.

Q: A 30 year old man presents to the emergency with complaints of muscle weakness, nausea, vomiting and fatigue. ECG showed tall peaked T waves, prolonged PR interval, wide QRS and absent P. which of the following drugs is not used in management?

Beta antagonist. Beta antagonist - The patient's symptoms (muscle weakness, nausea, vomiting, fatigue) and ECG findings (tall peaked T waves, prolonged PR interval, wide QRS, absent P waves) are classic signs of severe hyperkalemia. Beta-antagonists are not used in the management of hyperkalemia and can potentially worsen it by shifting potassium out of cells or interfering with renal potassium excretion. - While beta-antagonists may be used for other cardiac conditions, they are contraindicated or not indicated for the acute management of hyperkalemia. Insulin - Insulin (often given with glucose) is a cornerstone of hyperkalemia treatment as it drives potassium from the extracellular space back into the intracellular space by stimulating the Na-K ATPase pump [1]. - This rapid cellular shift helps to lower serum potassium levels and stabilize the cardiac membrane [1]. Calcium gluconate - Calcium gluconate does not lower serum potassium levels but is crucial for protecting the cardiac membrane from the effects of hyperkalemia [2]. - It works by antagonizing the membrane excitability caused by high potassium, indicated by the wide QRS and absent P waves [2]. Sodium bicarbonate - In patients with metabolic acidosis (which can exacerbate hyperkalemia by causing potassium to shift out of cells), sodium bicarbonate can be administered. - By correcting acidosis, it promotes the intracellular shift of potassium, thereby helping to lower serum potassium levels.

Q: A patient presented with edema, oliguria and frothy urine. He has no past history of similar complaints. On examination, his urine was positive for 3+ proteinuria, no RBCs/WBCs and no casts. His serum albumin was 2.5 gm/L and serum creatinine was 0.5 mg/dL. The most likely diagnosis is:

Minimal change disease. ***Minimal change disease*** - The classic presentation of **edema**, **oliguria**, and **frothy urine** (due to heavy proteinuria), along with **isolated proteinuria** (no RBCs/WBCs/casts) and **low serum albumin**, points to **nephrotic syndrome** [1]. **Minimal change disease** is the most common cause of nephrotic syndrome in children and a significant cause in adults, often presenting acutely without prior history [1]. - The **normal serum creatinine** (0.5 mg/dL) indicates preserved renal function, which is typical in early minimal change disease before significant complications arise [2]. *Interstitial nephritis* - This condition is characterized by **inflammation of the renal interstitium**, often leading to **acute kidney injury** with an elevation in serum creatinine. It's typically associated with a history of **drug exposure** or **systemic autoimmune diseases**. - Urinalysis usually reveals **white blood cells**, **eosinophils**, and sometimes **WBC casts**, which are absent in this patient. *Membranous nephropathy* - While it causes **nephrotic syndrome** with heavy proteinuria, it often presents more **insidiously** and is more common in older adults. - Urinalysis typically shows **microscopic hematuria** in a significant proportion of cases, secondary to glomerular injury, which is not noted here. *IgA nephropathy* - This is a common cause of **glomerulonephritis**, primarily characterized by **recurrent macroscopic or microscopic hematuria**, often following an upper respiratory or gastrointestinal infection. - While proteinuria can occur, it's typically **not in the nephrotic range** (3+ proteinuria suggests heavy proteinuria), and prominent edema is usually absent unless severe renal failure has developed.

Q: An elderly patient presents with hypertension and diabetes, proteinuria without renal failure. Antihypertensive of choice is

Enalapril. ***Enalapril*** - As an **ACE inhibitor**, enalapril is the **antihypertensive of choice** for patients with diabetes and proteinuria due to its **renoprotective effects** [2], [3]. - It reduces **glomerular hydrostatic pressure** and decreases proteinuria by dilating the efferent arteriole of the glomerulus [2], [3]. *Propranolol* - **Beta-blockers** like propranolol are generally not first-line for hypertension in diabetic patients because they can mask symptoms of **hypoglycemia** and may worsen **insulin resistance**. - While effective for hypertension, they don't offer the specific **renoprotective benefits** of ACE inhibitors in the presence of proteinuria. *Methyldopa* - **Methyldopa** is primarily used for hypertension in **pregnancy** due to its favorable safety profile in this population. - It is not a preferred agent for general hypertension management, particularly in patients with diabetes and proteinuria, as it lacks the **renoprotective effects** of ACE inhibitors. *Furosemide* - **Furosemide** is a loop diuretic primarily used to manage **fluid overload** and severe hypertension, especially in patients with **renal impairment** or heart failure [4]. - While it lowers blood pressure, it does not offer the same **renoprotective advantages** in reducing proteinuria as ACE inhibitors and may not be suitable as a monotherapy for chronic hypertension with diabetes [1].

Q: A 70 year old male, known case of chronic renal failure suffers from a pathological fracture of Rt femur, the diagnosis is -

Secondary Hyperparathyroidism. ***Secondary Hyperparathyroidism*** - **Chronic renal failure** causes **hyperphosphatemia** and **decreased production of calcitriol (active vitamin D)**. - This leads to hypocalcemia, which stimulates the parathyroid glands to produce excessive **parathyroid hormone (PTH)**, resulting in bone demineralization and **pathological fractures** [2]. *Scurvy* - Caused by **vitamin C deficiency**, leading to impaired collagen synthesis and fragility of blood vessels. - While it can cause bone pain and potential for fractures in severe cases, it is not directly associated with **chronic renal failure** as a primary cause of pathological fracture. *Vitamin D Resistant rickets* - This is a genetic disorder (e.g., X-linked hypophosphatemia) characterized by impaired renal phosphate reabsorption and normal or elevated PTH levels. - While it causes bone demineralization, it is typically a **childhood-onset condition** [1] and not directly linked to **acquired chronic renal failure** in a 70-year-old male. *Primary Hyperparathyroidism* - Characterized by autonomous **overproduction of PTH** due to parathyroid gland adenoma or hyperplasia, leading to **hypercalcemia** and hypophosphatemia. - Unlike secondary hyperparathyroidism, which is a compensatory response to hypocalcemia in the context of renal failure, primary hyperparathyroidism is a direct parathyroid gland pathology.

Q: Which of the following indicates radiograph contrast induced nephropathy?

Increased creatinine levels. ***Increased creatinine levels*** - **Contrast-induced nephropathy (CIN)** is defined as an abrupt increase in **serum creatinine** following the intravascular administration of contrast material [1]. - A typical increase is defined as an absolute increase in serum creatinine of at least 0.3 mg/dL (26.5 µmol/L) or a 50% relative increase from baseline within 48-72 hours. *Decreased urine output* - While a **decreased urine output** (oliguria) can be a symptom of acute kidney injury, it is not the primary diagnostic criterion for **contrast-induced nephropathy**. - The diagnosis of CIN relies more specifically on changes in **renal function markers** like creatinine, rather than just urine volume [1]. *Increased bilirubin* - **Increased bilirubin** levels typically indicate **liver dysfunction** or **hemolysis**, not necessarily kidney injury. - There is no direct causal link between contrast media administration and elevated bilirubin as a marker of acute kidney damage. *Decreased bilirubin* - **Decreased bilirubin** levels are not associated with any form of organ damage and generally hold no clinical significance. - This finding would not indicate **contrast-induced nephropathy** or any other common pathology.

Q: Five days after an uneventful cholecystectomy, an asymptomatic middle-aged woman is found to have a serum sodium level of 125 mEq/L. Which of the following is the most appropriate management strategy for this patient?

Restriction of free water. ***Restriction of free water*** - The patient has **mild asymptomatic hyponatremia** (125 mEq/L) developed post-operatively, likely due to increased ADH secretion causing **dilutional hyponatremia**. [1, 3] - **Restricting free water intake** gently corrects the sodium concentration by limiting further dilution, allowing the kidneys to excrete excess water. [1] *Administration of hypertonic saline solution* - This is typically reserved for **severe (Na < 120-125 mEq/L) or symptomatic hyponatremia** (e.g., seizures, altered mental status). - In this asymptomatic patient, rapid correction with hypertonic saline can lead to **osmotic demyelination syndrome**, a severe neurological complication. [1] *Hemodialysis* - Hemodialysis is an invasive procedure generally indicated for **severe, refractory hyponatremia** or when there are signs of **water intoxication with cerebral edema**, neither of which is present here. - It is an **overly aggressive treatment** for mild asymptomatic hyponatremia. *Plasma ultrafiltration* - This procedure removes plasma water and solutes and is primarily used in cases of **fluid overload with hyponatremia** (e.g., in heart failure or renal failure) when other diuretics are ineffective. - In an asymptomatic patient with mild hyponatremia, ultrafiltration is **unnecessary and carries risks** associated with invasive procedures.

Q: Pseudohyponatremia is found in all of the following EXCEPT:

Aldosterone excess. ***Aldosterone excess*** - **Aldosterone excess** typically leads to increased **sodium reabsorption** [2] and potassium excretion [1], which can result in **hypernatremia** or normal sodium levels, but not pseudohyponatremia. - It does not interfere with the measurement of plasma sodium concentration. *Extreme hyperproteinemia* - **Extreme hyperproteinemia** leads to an increase in the non-aqueous component of plasma, causing a falsely low sodium reading when measured by **flame photometry** (indirect ion-selective electrodes). - This is because the sodium concentration in the **aqueous phase** remains normal, but the total plasma volume is disproportionately high due to protein. *Severe hyperglycemia* - **Severe hyperglycemia** causes an **osmotic shift** of water from the intracellular to the extracellular compartment, diluting extracellular sodium. This can cause **translocational hyponatremia**, which is a form of pseudohyponatremia. - For every 100 mg/dL increase in glucose above normal, serum sodium typically decreases by 1.6-2.4 mEq/L. *Severe hyperlipemia* - **Severe hyperlipemia** (hypertriglyceridemia) falsely lowers the measured sodium concentration due to the large volume occupied by lipids in the plasma sample. - Similar to hyperproteinemia, this is an artifact of measurement methods that assume a constant proportion of plasma is water, causing a low reading even though sodium concentration in plasma water is normal.

Question 1

A child has serum osmolality of 270 mOsm/kg and urine osmolality of 1200 mOsm/kg. What is the most probable diagnosis?

Accepted Answer

SIADH

Answer

Nephrogenic diabetes insipidus

Answer

Water deprivation

Answer

Central diabetes insipidus

Question 2

Pseudohyponatremia occurs in which of the following conditions?

Accepted Answer

Hyperlipidemia

Answer

CHF

Answer

SIADH

Answer

Severe dehydration

Question 3

A CKD patient had to undergo dialysis. His Hb was 5.5. So two blood transfusions were to be given. First bag was completed in 2 hours. Second was started and midway between he developed shortness of breath, hypertension. Vitals: BP 180/120 mm Hg and pulse rate 110/min. What is the cause?

Accepted Answer

Transfusion related circulatory overload (TACO)

Answer

Allergic

Answer

FNHTR

Answer

TRALI

Question 4

A 30 year old man presents to the emergency with complaints of muscle weakness, nausea, vomiting and fatigue. ECG showed tall peaked T waves, prolonged PR interval, wide QRS and absent P. which of the following drugs is not used in management?

Accepted Answer

Beta antagonist

Answer

Insulin

Answer

Calcium gluconate

Answer

Sodium bicarbonate

Question 5

A patient presented with edema, oliguria and frothy urine. He has no past history of similar complaints. On examination, his urine was positive for 3+ proteinuria, no RBCs/WBCs and no casts. His serum albumin was 2.5 gm/L and serum creatinine was 0.5 mg/dL. The most likely diagnosis is:

Accepted Answer

Minimal change disease

Answer

Interstitial nephritis

Answer

Membranous nephropathy

Answer

IgA nephropathy

Question 6

An elderly patient presents with hypertension and diabetes, proteinuria without renal failure. Antihypertensive of choice is

Accepted Answer

Enalapril

Answer

Propranolol

Answer

Methyldopa

Answer

Furosemide

Question 7

A 70 year old male, known case of chronic renal failure suffers from a pathological fracture of Rt femur, the diagnosis is -

Accepted Answer

Secondary Hyperparathyroidism

Answer

Scurvy

Answer

Vitamin D Resistant rickets

Answer

Primary Hyperparathyroidism

Question 8

Which of the following indicates radiograph contrast induced nephropathy?

Accepted Answer

Increased creatinine levels

Answer

Decreased urine output

Answer

Increased bilirubin

Answer

Decreased bilirubin

Question 9

Five days after an uneventful cholecystectomy, an asymptomatic middle-aged woman is found to have a serum sodium level of 125 mEq/L. Which of the following is the most appropriate management strategy for this patient?

Accepted Answer

Restriction of free water

Answer

Administration of hypertonic saline solution

Answer

Hemodialysis

Answer

Plasma ultrafiltration

Question 10

Pseudohyponatremia is found in all of the following EXCEPT:

Accepted Answer

Aldosterone excess

Answer

Extreme hyperproteinemia

Answer

Severe hyperglycemia

Answer

Severe hyperlipemia

Nephrology — MCQs

Nephrology — MCQs

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