Nephrology Practice Questions

Q: A 60-year-old man with chronic kidney disease presents with complaints of increasing fatigue, dyspnea on exertion, and signs of congestive heart failure. On evaluation, he is found to have anemia. What is the most appropriate next step in management?

Intravenous iron infusion. Intravenous iron infusion - Patients with chronic kidney disease (CKD) and anemia often have associated iron deficiency, which is necessary to correct before starting erythropoiesis-stimulating agents (ESAs). [1] - Intravenous iron is strongly preferred over oral iron in CKD, especially in dialysis patients, due to poor gastrointestinal absorption and high risk of non-compliance. Oral iron therapy - Oral iron is less effective and poorly tolerated in patients with CKD due to altered absorption and potential for gastrointestinal side effects. - It is not the initial treatment of choice when a rapid and efficient iron correction is needed to prepare for ESA therapy. Blood transfusion - This is reserved for patients with symptomatic severe anemia (e.g., severe dyspnea, hemodynamic instability) that is refractory to other treatments or requires immediate intervention. - Transfusion carries risks like volume overload (especially in heart failure) and sensitization, making it unsuitable as a routine initial step. Darbepoetin alfa - Darbepoetin alfa (an ESA) is used to correct the underlying erythropoietin deficiency in CKD-related anemia. [1] - ESAs are typically initiated only after iron stores have been adequately replenished (target ferritin >500 ng/mL or transferrin saturation >30%) to maximize response and minimize dosing.

Q: A 55-year-old man presents with altered sensorium and deep labored breathing. ABG is given below. What is the most likely acid-base disorder? pH: 7.20 pCO₂: 31 mmHg HCO₃⁻:16 mEq/L Na⁺: 130 mEq/L Cl⁻: 84 mEq/L PaO₂: 80 mmHg

Metabolic acidosis. ***Metabolic acidosis*** - The **low pH (7.20)** indicates **acidosis** [2]. The primary cause is low **bicarbonate (HCO₃⁻ 16 mEq/L)**, defining it as metabolic acidosis [1]. - This patient presents with **Kussmaul breathing** (deep, labored breathing) as a respiratory attempt to compensate (blowing off CO₂) for the underlying metabolic acidosis, suggested by the low **pCO₂ (31 mmHg)** [1]. *Metabolic alkalosis* - This would be characterized by a **high pH (>7.45)** and a **high HCO₃⁻** level, which is the opposite of the current findings [3]. - Commonly caused by conditions like **vomiting** or excessive intake of **alkali** substances [3]. *Respiratory acidosis* - This requires a **high pCO₂ (>45 mmHg)**, which is the cause of acidemia, typically due to **hypoventilation** or respiratory failure [2]. - The current pCO₂ (31 mmHg) is low, indicating **hyperventilation** (compensation). *Respiratory alkalosis* - This would show a **high pH (>7.45)** caused by a **low pCO₂ (<35 mmHg)** due to **hyperventilation** (e.g., anxiety, high altitude) [2]. - While pCO₂ is low, the pH is acidic (7.20), not alkaline, ruling out primary respiratory alkalosis [2].

Q: A 68-year-old male with a history of COPD presents to the emergency room with severe dyspnea and altered mental status. An arterial blood gas (ABG) is drawn with the following results: pH: 7.28 PaCO2: 60 mmHg HCO3-: 28 mEq/L Na+: 142 mEq/L Cl-: 100 mEq/L Based on these results, what is the calculated anion gap?

B. 14 mEq/L. ***14 mEq/L*** - The **anion gap (AG)** is calculated using the formula: $\text{AG} = [\text{Na}^+] - ([\text{Cl}^-] + [\text{HCO}_3^-])$. [1] - Plugging in the patient's values: $142 - (100 + 28) = 142 - 128 = **14 \text{ mEq/L}**$. *10 mEq/L* - This value is below the calculated 14 mEq/L and would be considered low if the normal range upper limit is 12, suggesting a calculation error. [1] - An anion gap of 10 mEq/L is typically a normal value, but it is not the mathematically correct result based on the patient's **serum electrolyte** values. *18 mEq/L* - Obtaining this value would imply that $[\text{Cl}^-] + [\text{HCO}_3^-]$ equaled 124 mEq/L ($142 - 18$), which is incorrect as the sum is **128 mEq/L**. - An anion gap of 18 mEq/L indicates a **High Anion Gap Metabolic Acidosis (HAGMA)**, which is metabolically possible but mathematically inconsistent with the provided electrolyte numbers. [1] *24 mEq/L* - This value is significantly higher than 14 mEq/L and would suggest a severe uncompensated **HAGMA** (e.g., severe ketoacidosis or lactic acidosis). [1] - The calculation based on the given **plasma concentrations** of sodium, chloride, and bicarbonate simply does not support this result.

Q: Patient came with severe headache and seizures. Sodium on admission was 98 meq/L. We have started correction with 3 % saline and now after 24 hours of infusion sodium is 110 meq/L. Patient develops mutism and altered sensorium. Which investigation will you perform now?

MRI Head. ***MRI Head*** - A rapid correction of **severe chronic hyponatremia** (from 98 to 110 mEq/L in 24 hours, exceeding the recommended limit of 8-10 mEq/L) puts the patient at very high risk for **Osmotic Demyelination Syndrome (ODS)** (previously Central Pontine Myelinolysis). [1] - The new onset of **mutism** and **altered sensorium** are classic, late symptoms of ODS, necessitating an **MRI head** to visualize characteristic **pontine** (and sometimes extrapontine) lesions. *LP for CSF biochemistry* - LP is primarily indicated for diagnosing infections or inflammatory conditions of the CNS, which is less likely given the clear history of electrolyte imbalance and complication following rapid correction. - While CSF analysis can reveal demyelination products, an **MRI** is the definitive, non-invasive imaging modality for diagnosing ODS. *Brainstem evoked potentials* - Brainstem auditory evoked potentials (BAEP) primarily assess the **integrity of the auditory pathways** through the brainstem. [2] - While ODS affects the brainstem, BAEP is not the standard or most sensitive first-line investigation for confirming demyelinating lesions in the pons. *EEG* - EEG measures the electrical activity of the cerebral cortex and is primarily useful for localizing seizure foci or assessing the severity of encephalopathy. [2] - The symptoms (mutism, altered sensorium) point strongly to a structural brainstem lesion (ODS), which is best confirmed by **MRI head**, not EEG.

Q: Which of the following is not a recognised cause of recurrent renal stone formation?

Hypercitraturia. ***Hypercitraturia*** - It is generally **protective** against calcium stone formation because **citrate** binds to calcium in the urine, making it more soluble and inhibiting crystal nucleation. [1] - **Hypocitraturia** (low urinary citrate), not hypercitraturia, is a well-recognized metabolic risk factor for the formation of **calcium oxalate stones**. *Hyperoxaluria* - **Oxalate** readily binds with calcium to form **calcium oxalate stones**, the most common type of kidney stone. - Both primary and secondary hyperoxaluria significantly increase the degree of urinary **supersaturation**, driving stone formation. *Hypercalciuria* - High levels of urinary calcium increases urine saturation, leading to the precipitation of calcium salts, primarily forming **calcium oxalate** or **calcium phosphate** stones. [1] - It is the most frequent metabolic abnormality observed in patients with **recurrent nephrolithiasis**. *Hyperuricosuria* - Excess urinary **uric acid** directly causes **uric acid stones**, especially in acidic urine. [1] - Importantly, uric acid crystals can also serve as a **nidus** for the heterogeneous nucleation of **calcium oxalate** stones, increasing overall stone risk. [1]

Q: Which is correct about the sign shown?

Hypocalcemia. ***Hypocalcemia*** - The image shows **Trousseau's sign** (carpal spasm/obstetrician's hand), which is the **classic sign of hypocalcemia** caused by increased neuromuscular excitability. - **Hypocalcemia** leads to **tetany** and sustained muscle contractions due to decreased threshold for nerve and muscle membrane depolarization. *Hypomagnesemia* - While **hypomagnesemia** can cause tetany, it typically does so by causing **functional hypoparathyroidism** and secondary hypocalcemia. - **Isolated hypomagnesemia** without hypocalcemia rarely causes the classic Trousseau's sign seen in this image. *Hyponatremia* - **Hyponatremia** primarily causes **neurological symptoms** like confusion, seizures, and cerebral edema due to osmotic water shifts. - It does **not cause tetany** or the sustained muscle contractions characteristic of Trousseau's sign. *Hypophosphatemia* - **Hypophosphatemia** typically causes **flaccid muscle weakness**, respiratory muscle weakness, and metabolic disturbances. - It does **not cause tetany** or the carpal spasm pattern seen in Trousseau's sign, which requires increased membrane excitability.

Q: A 45-year-old male patient with a history of smoking over 20 years develops hypertension renal angiography was performed. The most common cause for this condition is?

Atherosclerosis. ***Atherosclerosis*** - The patient's history of **smoking over 20 years** is a significant risk factor for atherosclerosis, which commonly affects the **renal arteries** and can lead to **renovascular hypertension**. - The renal angiogram (as indicated by the arrow on the corresponding image, showing a focal stenosis near the renal artery origin) is consistent with an **atherosclerotic plaque** causing renal artery stenosis. *Fibromuscular dysplasia* - This condition primarily affects **younger individuals**, especially women, and typically presents with a **"string of beads"** appearance on angiography, which is not seen here. - While it can cause renal artery stenosis and hypertension, the patient's age and smoking history make atherosclerosis a more likely etiology. *Takayasu arteritis* - This is a **large vessel vasculitis** predominantly affecting the **aorta and its main branches**, usually seen in **young women (10-40 years old)**, not a 45-year-old male smoker. - While it can involve renal arteries, the clinical context and typical angiographic findings (long, smooth stenoses or occlusions) do not fit as well as atherosclerosis. *Aortic dissection* - Aortic dissection involves a **tear in the aorta's inner lining**, leading to blood flowing between the layers and dissecting the wall. - Although it can present with hypertension and involve major arterial branches, the angiogram here shows a **focal stenosis** of the renal artery, not a dissection.

Q: A 30-year-old hypertension patient presents with flank pain. CT abdomen was performed. All are true about the condition shown except?

Bilateral kidney transplantation is the treatment of choice. ***Bilateral kidney transplantation is the treatment of choice*** - While kidney transplantation is the **definitive treatment** for end-stage renal disease in ADPKD, it's not always bilateral. A single kidney transplant is often sufficient. - The image shows **polycystic kidneys and liver**, characteristic of **Autosomal Dominant Polycystic Kidney Disease (ADPKD)**. This condition often leads to **end-stage renal disease**, but a bilateral kidney transplant is not the primary intervention for all patients or the immediate treatment for flank pain. *Autosomal dominant disorder* - **ADPKD** is indeed an **autosomal dominant genetic disorder**, meaning only one copy of the defective gene is needed to cause the disease. - This genetic inheritance pattern explains the widespread occurrence of **cysts in the kidneys and liver**, as seen in the CT scan. *Chromosome 16 and 4 are involved* - The most common forms of ADPKD are linked to mutations in the **PKD1 gene on chromosome 16** (about 85% of cases) and the **PKD2 gene on chromosome 4** (about 15% of cases). - These genetic mutations lead to the development of numerous **cysts in the kidneys and other organs**. *Most common cause of death is cardiovascular causes* - **Cardiovascular complications**, such as **hypertension, left ventricular hypertrophy, and cerebral aneurysms**, are the leading causes of morbidity and mortality in ADPKD patients. - The patient's history of **hypertension** is a common early manifestation and a significant risk factor for these cardiovascular outcomes.

Q: A patient presents with recurrent episodes of gross hematuria, anterior lenticonus (as shown in the image), and sensorineural deafness. Which diagnosis is most likely?

Alport syndrome. ***Alport syndrome*** - This syndrome is characterized by the classic triad of **recurrent gross hematuria**, ocular abnormalities like **anterior lenticonus**, and **sensorineural deafness**. - It results from genetic mutations in **type IV collagen**, which is crucial for the structure of the glomerular basement membrane, cochlea, and lens.

Question 1

A 60-year-old man with chronic kidney disease presents with complaints of increasing fatigue, dyspnea on exertion, and signs of congestive heart failure. On evaluation, he is found to have anemia. What is the most appropriate next step in management?

Accepted Answer

Intravenous iron infusion

Answer

Blood transfusion

Answer

Darbepoetin alfa

Answer

Oral iron therapy

Question 2

A 55-year-old man presents with altered sensorium and deep labored breathing. ABG is given below. What is the most likely acid-base disorder?
pH: 7.20
pCO₂: 31 mmHg
HCO₃⁻:16 mEq/L
Na⁺: 130 mEq/L
Cl⁻: 84 mEq/L
PaO₂: 80 mmHg

Accepted Answer

Metabolic acidosis

Answer

Respiratory acidosis

Answer

Respiratory alkalosis

Answer

Metabolic alkalosis

Question 3

A 68-year-old male with a history of COPD presents to the emergency room with severe dyspnea and altered mental status. An arterial blood gas (ABG) is drawn with the following results:
pH: 7.28
PaCO2: 60 mmHg
HCO3-: 28 mEq/L
Na+: 142 mEq/L
Cl-: 100 mEq/L
Based on these results, what is the calculated anion gap?

Accepted Answer

B. 14 mEq/L

Answer

A. 10 mEq/L

Answer

D. 24 mEq/L

Answer

C. 18 mEq/L

Question 4

Patient came with severe headache and seizures. Sodium on admission was 98 meq/L. We have started correction with 3 % saline and now after 24 hours of infusion sodium is 110 meq/L. Patient develops mutism and altered sensorium. Which investigation will you perform now?

Accepted Answer

MRI Head

Answer

LP for CSF biochemistry

Answer

EEG

Answer

Brainstem evoked potentials

Question 5

Which of the following is not a recognised cause of recurrent renal stone formation?

Accepted Answer

Hypercitraturia

Answer

Hypercalciuria

Answer

Hyperuricosuria

Answer

Hyperoxaluria

Question 6

Which is correct about the sign shown?

Accepted Answer

Hypocalcemia

Answer

Hypomagnesemia

Answer

Hyponatremia

Answer

Hypophosphatemia

Question 7

A 45-year-old male patient with a history of smoking over 20 years develops hypertension renal angiography was performed. The most common cause for this condition is?

Accepted Answer

Atherosclerosis

Answer

Fibromuscular dysplasia

Answer

Takayasu arteritis

Answer

Aortic dissection

Question 8

A 30-year-old hypertension patient presents with flank pain. CT abdomen was performed. All are true about the condition shown except?

Accepted Answer

Bilateral kidney transplantation is the treatment of choice

Answer

Autosomal dominant disorder

Answer

Chromosome 16 and 4 are involved

Answer

Most common cause of death is cardiovascular causes

Question 9

A patient presents with recurrent episodes of gross hematuria, anterior lenticonus (as shown in the image), and sensorineural deafness. Which diagnosis is most likely?

Accepted Answer

Alport syndrome

Answer

Answer

Answer

Question 10

All are true about the condition shown in the above figure except:

Accepted Answer

Seen with polyarteritis nodosa

Answer

Failure to achieve BP control with optimal medical therapy needs angioplasty

Answer

Decline in GFR while on ACE inhibitors needs angioplasty

Answer

Secondary cause of hypertension

Nephrology — MCQs

Nephrology — MCQs

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