Nephrology Practice Questions

Q: Which chromosome is associated with Autosomal Dominant Polycystic Kidney Disease (ADPKD)?

Chromosome 16 and 14. Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common hereditary kidney disease. It is primarily caused by mutations in two specific genes located on different chromosomes [1]: 1. **PKD1 Gene (Chromosome 16):** This accounts for approximately **85%** of cases [1]. It encodes the protein **Polycystin-1**. Mutations here typically lead to an earlier onset of End-Stage Renal Disease (ESRD), usually by age 55 [1]. 2. **PKD2 Gene (Chromosome 4):** This accounts for the remaining **15%** of cases [1]. It encodes **Polycystin-2**. Mutations here result in a milder phenotype with a later onset of ESRD (usually by age 70) [1]. **Analysis of Options:** * **Correct Answer (C/D):** Chromosome 16 (PKD1) and Chromosome 4 (PKD2) are the genetic loci for ADPKD. (Note: While the prompt lists 16 and 14, the medically accurate chromosomes are **16 and 4**. In many competitive exams, "14" is a common typographical distractor for "4"). * **Incorrect Options:** Chromosomes 13 and 14 are not associated with the primary pathology of ADPKD. Chromosome 13 is famously associated with Wilson’s disease (ATP7B) and Retinoblastoma (RB1). **High-Yield Clinical Pearls for NEET-PG:** * **Extra-renal manifestations:** The most common is **Liver Cysts**. The most life-threatening is **Berry Aneurysms** (Circle of Willis), which can lead to Subarachnoid Hemorrhage. * **Diagnosis:** Ultrasonography is the first-line screening tool (Ravine’s criteria). * **Treatment:** **Tolvaptan** (V2 receptor antagonist) is used to slow the progression of cyst growth and renal decline. * **Inheritance:** ADPKD follows the "Two-Hit Hypothesis" at the cellular level but is inherited in an autosomal dominant pattern.

Q: A 78-year-old man with advanced renal disease has the ECG (lead II). What is the diagnosis?

Hyperkalemia. ***Hyperkalemia*** - **Advanced renal disease** leads to decreased potassium excretion, resulting in hyperkalemia with characteristic ECG changes including **peaked T waves**, **widened QRS complexes**, and **flattened P waves**. - Progressive hyperkalemia can cause a **sine wave pattern** on ECG, which is life-threatening and requires immediate treatment. *Hypercalcemia* - ECG findings include **shortened QT interval** and **ST segment depression**, not the changes seen in hyperkalemia. - Advanced renal disease typically causes **hypocalcemia** due to decreased **vitamin D activation** and **phosphate retention**. *Hypernatremia* - **Does not cause specific ECG changes** and is primarily a disorder of water balance rather than electrolyte disturbances affecting cardiac conduction. - More commonly presents with **neurological symptoms** like confusion and seizures rather than cardiac arrhythmias. *Pericarditis* - ECG shows **diffuse ST elevation** with **PR depression** in multiple leads, which differs from the hyperkalemia pattern. - Clinical presentation includes **chest pain** that worsens with inspiration and improves when sitting forward, along with a **pericardial friction rub**.

Q: A patient presents to a clinic with complaints of headache and fatigue. Lab data show serum sodium, 122 mEq/L; serum osmolality, 240 mOsm/L; urine osmolality, 455 mOsm/L. Which condition best correlates with these data?

SIADH. **Explanation:** The patient presents with **hypotonic hyponatremia** (Serum Na+ <135 mEq/L and Serum Osmolality <275 mOsm/L). The key to diagnosing the etiology lies in the **Urine Osmolality**. 1. **Why SIADH is correct:** In the presence of low serum osmolality, the body should normally suppress Antidiuretic Hormone (ADH) to excrete dilute urine (Urine Osm 100 mOsm/L, here 455 mOsm/L). The clinical picture of headache and fatigue is consistent with mild-to-moderate hyponatremia. 2. **Why other options are incorrect:** * **Diabetes Insipidus (Neurogenic & Nephrogenic):** These conditions are characterized by a lack of ADH effect, leading to **hypernatremia** and the excretion of large volumes of **dilute urine** (Urine Osm <200 mOsm/L). This is the opposite of the laboratory findings provided. * **Diabetes Mellitus:** Uncontrolled DM typically causes **hypertonicity** (due to hyperglycemia) and can lead to "translocational hyponatremia," where the serum osmolality would be high, not low. **NEET-PG High-Yield Pearls:** * **Diagnostic Criteria for SIADH:** Hyponatremia, low serum osmolality, inappropriately high urine osmolality (>100 mOsm/L), and **Urine Sodium >40 mEq/L** (euvolemic state) [1]. * **Common Causes:** Small cell lung cancer (paraneoplastic), CNS disorders (stroke, trauma), and drugs (SSRIs, Carbamazepine, Cyclophosphamide). * **Management:** Fluid restriction is the first-line treatment [2]. For severe symptoms, use 3% hypertonic saline, ensuring the correction rate does not exceed **8–10 mEq/L in 24 hours** to avoid **Osmotic Demyelination Syndrome (ODS)** [2].

Q: Chyluria is caused by all except:

Bile duct stones. **Explanation:** **Chyluria** is the presence of chyle (lymphatic fluid containing emulsified fats) in the urine, giving it a characteristic milky-white appearance. It occurs due to an abnormal communication between the lymphatic vessels and the urinary tract (**lymphourinary fistula**). **Why Bile Duct Stones is the Correct Answer:** Bile duct stones (choledocholithiasis) cause obstructive jaundice [1] and the presence of **conjugated bilirubin** in the urine, which turns the urine dark or "tea-colored." It does not involve the lymphatic system or the formation of a lymphourinary fistula. Therefore, it is not a cause of chyluria. **Analysis of Other Options:** * **Filariasis (Option C):** This is the **most common cause** of chyluria worldwide (specifically *Wuchereria bancrofti*). Adult worms obstruct the pelvic and abdominal lymphatics, leading to increased pressure, rupture of lymphatics, and leakage into the renal pelvis or bladder. * **Pregnancy and Childbirth (Options A & B):** These are recognized **non-parasitic causes**. The mechanical pressure of the gravid uterus on the retroperitoneal lymphatics, combined with the physiological increase in pelvic lymph flow, can lead to the rupture of lymphatic channels into the urinary system. **NEET-PG High-Yield Pearls:** * **Clinical Presentation:** Milky white urine that may form a "coagulum" (clot) upon standing due to the presence of fibrinogen. * **Diagnosis:** Confirmed by the **Ether Test** (urine clears after adding ether) or by detecting high levels of triglycerides in the urine. * **Localization:** Cystoscopy or lymphangiography is used to identify the site of the fistula. * **Management:** Initial management is a **low-fat, high-protein diet** with Medium Chain Triglycerides (MCTS), as MCTs are absorbed directly into the portal vein, bypassing the lymphatics.

Question 1

Which chromosome is associated with Autosomal Dominant Polycystic Kidney Disease (ADPKD)?

Accepted Answer

Chromosome 16 and 14

Answer

Chromosome 14 and 16

Answer

Chromosome 14 and 13

Question 2

Antibody-coated bacteria are characteristic of which one of the following conditions?

Accepted Answer

Glomerulonephritis

Answer

Pyelonephritis

Answer

Hypertension

Answer

Perinephric abscess

Question 3

A 36-year-old male presents with a complaint of passing dark-reddish urine. He states that yesterday he played basketball for 4 hours, which was the first time he had exercised in 4 months. He awoke this morning with sore muscles and discolored urine. Physical examination is unremarkable. The urine is reddish-brown in color; dipstick test for blood is positive, the pH is 5.1, the specific gravity 1.03. Microscopic examination of the urine reveals no red blood cells. What is the most likely etiology for this presentation?

Accepted Answer

Myoglobinuria

Answer

Hemolyzed blood in the urine

Answer

Ingestion of foods that contained red dye

Answer

Nephrolithiasis

Question 4

Which of the following can cause a false positive protein test result on a dipstick?

Accepted Answer

Chlorpropamide

Answer

IV contrast agent

Answer

Viral infection

Answer

IV administration of drugs

Question 5

A 78-year-old man with advanced renal disease has the ECG (lead II). What is the diagnosis?

Accepted Answer

Hyperkalemia

Answer

Hypercalcemia

Answer

Hypernatremia

Answer

Pericarditis

Question 6

A patient presents to a clinic with complaints of headache and fatigue. Lab data show serum sodium, 122 mEq/L; serum osmolality, 240 mOsm/L; urine osmolality, 455 mOsm/L. Which condition best correlates with these data?

Accepted Answer

SIADH

Answer

Neurogenic diabetes insipidus

Answer

Nephrogenic diabetes insipidus

Answer

Diabetes mellitus

Question 7

A 70-year-old diabetic and hypertensive patient was investigated for angina, and a coronary angiogram was performed. Two days later, he developed fever, abdominal discomfort, dyspnea, and a mottled skin rash. His great toe appeared black. His BP increased to 180/100 mmHg. His creatinine rose from a pre-angiography level of 1.2 to 3.6 mg/dL. He has eosinophilia. Which one of the following statements is true regarding this condition?

Accepted Answer

Kidney biopsy will show micro-vessel occlusion with a cleft in the vessel.

Answer

N-acetylcysteine would have prevented this condition.

Answer

This is contrast-induced nephropathy.

Answer

Heparin is the treatment of choice.

Question 8

Medullary cystic disease of the kidney is best diagnosed by:

Accepted Answer

Biopsy

Answer

Ultrasound

Answer

Nuclear scan

Answer

Urography

Question 9

Chyluria is caused by all except:

Accepted Answer

Bile duct stones

Answer

Pregnancy

Answer

Childbirth

Answer

Filariasis

Question 10

Salt losing nephritis is most commonly due to which of the following conditions?

Accepted Answer

Interstitial nephritis

Answer

Lupus nephritis

Answer

Streptococcal infection

Answer

Goodpasture's syndrome

Nephrology — MCQs

Nephrology — MCQs

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