Nephrology Practice Questions

Q: All of the following are true about anemia of chronic kidney disease except

Anemia is proportional to the kidney disease. ***Anemia is proportional to the kidney disease*** - While anemia is a common complication of **CKD**, its severity doesn't always directly correlate with the degree of **kidney function decline** [1]. - Other factors like **inflammation**, **iron deficiency**, and **dialysis-related blood loss** can independently influence the severity of anemia, sometimes disproportionately [2]. *Normocytic normochromic anemia* - **Anemia of chronic kidney disease (CKD)** is typically a **normocytic normochromic anemia**, meaning the red blood cells are normal in size (normocytic) and hemoglobin content (normochromic). - This is primarily due to the **reduced production of erythropoietin** by the kidneys [3]. *Dialysis worsens anemia of renal failure* - **Dialysis** can indeed worsen anemia in patients with renal failure due to several factors including **blood loss during the dialysis procedure**, residual blood in the dialyzer, and increased **hepcidin levels** leading to **iron sequestration** [2], [3]. - Additionally, hemodialysis can induce **inflammation**, which further contributes to **hyporesponsiveness to erythropoietin**. *Erythropoietin improves the symptom* - **Erythropoietin-stimulating agents (ESAs)** are a cornerstone of treatment for anemia of CKD, as they replace the deficient **endogenous erythropoietin** and stimulate red blood cell production [3]. - While ESAs improve **hemoglobin levels** and consequently the symptoms associated with anemia, they do not cure the underlying kidney disease or address all aspects of anemia management, such as **iron deficiency** [3].

Q: A 40-year-old man has been diagnosed with autosomal dominant polycystic kidney disease. How should the cysts be present in USG to call it ADPKD?

≥2 cysts in each kidney bilaterally. >=2 cysts in each kidney bilaterally - For individuals aged 30-59 years, a diagnosis of **autosomal dominant polycystic kidney disease (ADPKD)** typically requires at least **2 cysts in each kidney** observed on ultrasound. - This diagnostic criterion helps to differentiate ADPKD from simple renal cysts, which are common in the general population [1]. >=4 cysts in each kidney bilaterally - While more cysts are often present in advanced ADPKD, **4 cysts in each kidney** is a criterion for individuals under 30 years or 60 years and above, not typically for the 30-59 age group. - Using this criterion for a 40-year-old might **underdiagnose earlier stages** of ADPKD. >=1 cyst in each kidney bilaterally - Having only **1 cyst in each kidney** is generally considered insufficient for a definitive diagnosis of ADPKD in a 40-year-old. - This presentation could be consistent with **simple renal cysts**, which are common and not indicative of ADPKD [1]. >=3 cysts in each kidney bilaterally - Although indicative of polycystic kidneys, **3 cysts in each kidney** is a higher threshold than necessary for a 40-year-old. - The established criteria for the 30-59 age group is **2 cysts in each kidney**, making this option overly stringent for a diagnosis.

Q: Dialysis patients are prone to develop

Aluminium toxicity. ***Aluminium toxicity*** - **Aluminium toxicity** is a significant concern in dialysis patients due to impaired renal excretion of aluminium, which can accumulate from dialysate, oral phosphate binders, or contaminated water. - This toxicity can lead to various complications, including **osteomalacia**, **encephalopathy**, and **anemia**. *Zinc toxicity* - **Zinc toxicity** is uncommon in dialysis patients and typically results from excessive supplementation, not a direct complication of dialysis itself. - Excess zinc can interfere with **copper absorption**, potentially leading to copper deficiency. *Iron toxicity* - While iron supplementation is often used in dialysis patients to treat anemia, **iron toxicity** due to overload is usually managed by monitoring iron levels and adjusting dosage. - It is not an inherent predisposition due to dialysis itself, but rather a potential consequence of therapy. *Lead toxicity* - **Lead toxicity** is primarily associated with environmental exposure and is not a specific complication directly linked to the dialysis process or renal failure [1]. - Lead accumulation is not typically worsened by impaired renal function in the same manner as aluminium [1].

Q: Microscopic Hematuria is defined as:

>5 RBCs/high power field. ***>5 RBCs/high power field*** - The presence of more than 5 **red blood cells (RBCs) per high power field (HPF)** in a properly collected and spun urine sample is the established definition of **microscopic hematuria** [1]. - This threshold indicates an abnormal amount of blood in the urine that is not visible to the naked eye, necessitating further investigation. *>10 RBCs/high power field* - While 10 RBCs/HPF would certainly constitute hematuria, it is a higher threshold than the generally accepted definition for **microscopic hematuria**. - Using this higher threshold might lead to missed diagnoses for individuals with clinically significant, but less pronounced, hematuria. *>20 RBCs/high power field* - A count of 20 RBCs/HPF indicates a significant amount of blood, usually prompting immediate investigation, but it exceeds the **standard definition** for simply identifying the presence of **microscopic hematuria**. - This level of hematuria is unambiguous, but the definition is based on a lower threshold to capture milder cases. *>15 RBCs/high power field* - Similarly to the other incorrect options, 15 RBCs/HPF is above the common and widely accepted definition of **microscopic hematuria**. - The standard definition is set to be sensitive enough to detect potential underlying pathology without being overly broad.

Q: Acute hyponatremia in an 8-month-old infant may produce all except:

Diarrhea. ***Diarrhea*** - While diarrhea can lead to **dehydration** and subsequent electrolyte imbalances, it is not a direct symptom caused by acute hyponatremia itself. - In fact, severe diarrhea can be a cause of hyponatremia due to excessive loss of sodium and water from the body or by administration of hypotonic fluids to replace losses. *Vascular collapse* - Severe acute hyponatremia can lead to **cerebral edema**, which increases intracranial pressure and can impair brainstem function, leading to **cardiovascular instability** and vascular collapse. - This is a critical and potentially fatal complication due to the rapid shift of fluid into brain cells. *Convulsions* - Rapidly developing hyponatremia can cause significant **brain swelling (cerebral edema)** as water shifts into brain cells osmotiically. - This increase in intracranial pressure and neuronal dysfunction can manifest as **seizures** or convulsions in infants. *Muscle cramps and weakness* - Hyponatremia directly affects muscle cell function due to altered **water and electrolyte balance**. - This can lead to symptoms such as **muscle cramps**, twitching, and generalized weakness.

Q: Following surgery, a patient develops oliguria. You believe the patient is hypovolemic, but you seek corroborative data before increasing intravenous fluids. The best data is?

Fractional excretion of sodium less than 1. ***Fractional excretion of sodium less than 1*** - A **fractional excretion of sodium (FENa) less than 1%** is a classic indicator of **prerenal azotemia** or hypovolemia, as the kidneys are avidly reabsorbing sodium and water to preserve circulating volume. - This indicates the kidneys are functioning appropriately in response to perceived hypoperfusion, attempting to conserve sodium and thus water. *Urine chloride of 15 meq/L* - While a **low urine chloride** can sometimes be seen in volume depletion, it is not as specific or reliable an indicator of hypovolemia as FENa. - Urine chloride is more helpful in differentiating causes of **metabolic alkalosis**, particularly saline-responsive versus saline-unresponsive. *Urine sodium of 28 meq/L* - A urine sodium concentration of **less than 20 mEq/L** is a more classic cutoff for prerenal azotemia/hypovolemia, indicating aggressive sodium reabsorption. - A value of 28 mEq/L, although relatively low, is less definitive than a low FENa in strongly supporting hypovolemia. *Urine/Serum creatinine ratio of 20* - A **urine/serum creatinine ratio greater than 20:1** is indicative of prerenal azotemia, suggesting the kidneys are concentrating urine in response to hypovolemia. - While supportive, FENa is often considered a more precise and widely accepted marker, especially in the absence of diuretic use or chronic kidney disease.

Q: A 17-year-old boy comes to the physician because of edema of both legs as well as pen- orbital edema There is no history of diarrhea and no urinary symptoms suggestive of infection. He had a throat infection 3 weeks ago. His blood pressure is 110/70 mmHg. He undergoes a kidney biopsy and light microscopy is normal. The patient is treated and makes a full recovery. Which of the following is the most likely diagnosis?

Minimal change glomerulonephritis. ***Minimal change glomerulonephritis*** - The presentation of **edema**, particularly **periorbital edema**, in a young patient without significant hypertension or hematuria, despite a recent infection, is highly suggestive of **nephrotic syndrome** [1]. - **Normal light microscopy** on kidney biopsy is characteristic of minimal change disease, as the pathology is primarily confined to **effacement of podocyte foot processes** visible only on electron microscopy [1]. *ANCA associated vasculitis* - ANCA-associated vasculitides typically present with **rapidly progressive glomerulonephritis** and systemic symptoms, often including **hematuria** and significant renal dysfunction, which are not described here. - While a kidney biopsy would show features of **pauci-immune crescentic glomerulonephritis**, light microscopy would not be normal [3]. *Post-streptococcal glomerulonephritis* - Often presents with **edema** and a history of a recent throat infection, but is primarily a **nephritic syndrome** characterized by **hematuria**, **hypertension**, and **red blood cell casts** in the urine [2]. - Light microscopy would show **diffuse proliferative glomerulonephritis** with immunoglobulin and complement deposits [2]. *Accelerated hypertension* - Accelerated hypertension is defined by a **sudden, severe increase in blood pressure** often associated with end-organ damage, such as papilledema, renal failure, or cardiac complications. - The patient's blood pressure of **110/70 mmHg is normal**, making accelerated hypertension an incorrect diagnosis.

Q: High anion gap acidosis is seen in all except:

Diarrhea. ***Diarrhea*** - Diarrhea causes **non-anion gap metabolic acidosis** due to the loss of bicarbonate from the gastrointestinal tract [3]. - The anion gap remains normal because chloride reabsorption in the kidneys increases to compensate for the lost bicarbonate. *Salicylate poisoning* - Salicylate poisoning causes **high anion gap metabolic acidosis** by uncoupling oxidative phosphorylation, leading to increased production of lactic acid and other organic acids [2]. - Early stages may also involve a superimposed respiratory alkalosis due to direct stimulation of the respiratory center [1]. *Acute renal failure* - Acute renal failure leads to a **high anion gap metabolic acidosis** because the kidneys are unable to excrete metabolic acids (e.g., phosphates, sulfates) and reabsorb bicarbonate effectively [3]. - This results in the accumulation of unmeasured anions and a decrease in serum bicarbonate. *Lactic acidosis* - Lactic acidosis is a common cause of **high anion gap metabolic acidosis**, resulting from increased production or decreased metabolism of lactic acid [1]. - It occurs when there is inadequate tissue oxygenation (Type A, e.g., shock) or other conditions like certain drugs or toxins (Type B) [1].

Question 1

What is the most common cause of normal anion gap metabolic acidosis?

Accepted Answer

Diarrhoea

Answer

Ingestion of ammonium chloride

Answer

Lactic acidosis

Answer

Ethylene glycol intoxication

Answer

Renal tubular acidosis

Answer

Salicylate intoxication

Answer

External pancreatic drainage

Answer

Chronic renal failure

Answer

Methanol/Formaldehyde intoxication

Answer

Uterosigmoidostomy

Answer

Ketoacidosis

Question 2

All of the following are true about anemia of chronic kidney disease except

Accepted Answer

Anemia is proportional to the kidney disease

Answer

Normocytic normochromic anemia

Answer

Dialysis worsens anemia of renal failure

Answer

Erythropoietin improves the symptom

Question 3

A 40-year-old man has been diagnosed with autosomal dominant polycystic kidney disease. How should the cysts be present in USG to call it ADPKD?

Accepted Answer

≥2 cysts in each kidney bilaterally

Answer

≥4 cysts in each kidney bilaterally

Answer

≥1 cyst in each kidney bilaterally

Answer

≥3 cysts in each kidney bilaterally

Question 4

Dialysis patients are prone to develop

Accepted Answer

Aluminium toxicity

Answer

Zinc toxicity

Answer

Iron toxicity

Answer

Lead toxicity

Question 5

Microscopic Hematuria is defined as:

Accepted Answer

>5 RBCs/high power field

Answer

>10 RBCs/high power field

Answer

>20 RBCs/high power field

Answer

>15 RBCs/high power field

Question 6

Acute hyponatremia in an 8-month-old infant may produce all except:

Accepted Answer

Diarrhea

Answer

Vascular collapse

Answer

Convulsions

Answer

Muscle cramps and weakness

Question 7

Following surgery, a patient develops oliguria. You believe the patient is hypovolemic, but you seek corroborative data before increasing intravenous fluids. The best data is?

Accepted Answer

Fractional excretion of sodium less than 1

Answer

Urine chloride of 15 meq/L

Answer

Urine sodium of 28 meq/L

Answer

Urine/Serum creatinine ratio of 20

Question 8

Regarding FeNa, which of the following is true?

Accepted Answer

FeNa is higher in intrinsic renal failure than pre renal failure

Answer

Measurement of FeNa is NOT affected by use of diuretic

Answer

FeNa is lower in neonates when compared to children

Answer

FeNa is similar in both pre term and term neonate

Question 9

A 17-year-old boy comes to the physician because of edema of both legs as well as pen- 
orbital edema There is no history of diarrhea and no urinary symptoms suggestive of 
infection. He had a throat infection 3 weeks ago. His blood pressure is 110/70 mmHg. He 
undergoes a kidney biopsy and light microscopy is normal. The patient is treated and makes 
a full recovery.

Which of the following is the most likely diagnosis?

Accepted Answer

Minimal change glomerulonephritis

Answer

ANCA associated vasculitis

Answer

Post-streptococcal glomerulonephritis

Answer

Accelerated hypertension

Question 10

High anion gap acidosis is seen in all except:

Accepted Answer

Diarrhea

Answer

Salicylate poisoning

Answer

Acute renal failure

Answer

Lactic acidosis

Nephrology — MCQs

Nephrology — MCQs

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