Renal Replacement Therapy — MCQs
All of the following are indications for hemodialysis in acute kidney injury, EXCEPT:
IV fluid replacement (volume & rate) in a trauma patient is determined by:
The most common cause of acquired AV fistula is:
Which of the following is not an absolute indication for hemodialysis?
What is the cause of intracorpuscular defects in hemolysis?
Best immediate management of hyperkalemia includes all except?
At what glomerular filtration rate (GFR) is the term "end-stage renal disease (ESRD)" typically classified?
For shock patient, best guideline to check for adequacy of fluid replacement therapy:
Prerenal and renal azotemia are differentiated on the basis of.
Absolute contraindication of hormone replacement therapy is:
Renal Replacement Therapy Indian Medical PG Practice Questions and MCQs
Question 1: All of the following are indications for hemodialysis in acute kidney injury, EXCEPT:
- A. Severe metabolic acidosis
- B. Hyperkalemia
- C. Hypertension (Correct Answer)
- D. Pulmonary edema
Explanation: ***Hypertension*** - While hypertension can be a complication of **acute kidney injury (AKI)**, it is generally managed with **antihypertensive medications** and **fluid removal**, and does not by itself necessitate urgent hemodialysis unless it is severe and refractory, alongside other uremic symptoms. - Hemodialysis primarily addresses life-threatening electrolyte imbalances, fluid overload, and uremic symptoms. [2] *Severe metabolic acidosis* - **Severe metabolic acidosis (pH < 7.1)** is a critical indication for hemodialysis in AKI because the kidneys are unable to excrete acid or regenerate bicarbonate. - Hemodialysis can rapidly remove acids and correct the pH imbalance, preventing further organ dysfunction. *Hyperkalemia* - **Life-threatening hyperkalemia (potassium > 6.5 mEq/L)**, especially when refractory to medical management (e.g., insulin, glucose, calcium gluconate), is a major indication for hemodialysis. [1] - Hemodialysis is highly effective at rapidly lowering potassium levels, which is crucial to prevent cardiac arrhythmias. [1] *Pulmonary edema* - **Severe fluid overload** leading to **pulmonary edema** that is refractory to diuretic therapy is a strong indication for hemodialysis in AKI. [2] - Hemodialysis can efficiently remove excess fluid, thereby alleviating respiratory distress and improving oxygenation.
Question 2: IV fluid replacement (volume & rate) in a trauma patient is determined by:
- A. Chest condition
- B. BP
- C. CVP
- D. Urine output (Correct Answer)
Explanation: ***Urine output*** - **Urine output** is a sensitive indicator of **renal perfusion** and overall **hemodynamic stability**, reflecting adequate tissue perfusion and fluid resuscitation in trauma patients. - Maintaining a urine output of **0.5-1.0 mL/kg/hour** is a common target during fluid resuscitation, demonstrating effective restoration of circulating volume. *Chest condition* - The **"chest condition"** (interpreted as respiratory status or thoracic trauma) primarily guides management of ventilatory support and thoracic interventions, not directly IV fluid rates. - While significant chest trauma can impact hemodynamics, it does not alone determine the specific **volume and rate** of IV fluid resuscitation. *BP* - **Blood pressure (BP)** can be a delayed and insensitive indicator of **hypovolemia** in trauma, as compensatory mechanisms can maintain BP until significant blood loss has occurred. - Relying solely on BP may lead to inadequate resuscitation or fluid overload, especially in patients with pre-existing hypertension. *CVP* - **Central Venous Pressure (CVP)** reflects **right atrial pressure** and can be influenced by multiple factors, including cardiac function, intrathoracic pressure, and venous tone, making it an unreliable sole indicator of fluid status in trauma. - CVP measurements can be misleading in situations like **cardiac tamponade** or **tension pneumothorax**, which are common in severe trauma.
Question 3: The most common cause of acquired AV fistula is:
- A. Bacterial infection
- B. Fungal infection
- C. Blunt trauma
- D. Penetrating trauma (Correct Answer)
Explanation: ***Penetrating trauma*** - **Penetrating trauma** is the most common cause of **acquired AV fistulas** due to direct injury to adjacent artery and vein. - This type of injury can result from causes like **gunshot wounds, stab wounds, or iatrogenic procedures** (e.g., catheterizations). *Bacterial infection* - While infections can cause vascular damage, they are **not the most common cause** of acquired AV fistulas. - Infections like **endocarditis** or localized abscesses can lead to vascular erosion, but this is less frequent than trauma. *Fungal infection* - **Fungal infections** are a much rarer cause of vascular damage leading to AV fistulas compared to bacterial infections or trauma. - They typically occur in immunocompromised individuals or in specific settings, not as a common cause of acquired AV fistulas. *Blunt trauma* - **Blunt trauma** can cause vascular injury, but it is **less likely to directly create an AV fistula** compared to penetrating trauma. - Blunt force is more commonly associated with vessel rupture, dissection, or pseudoaneurysm formation, rather than a direct connection between an artery and a vein.
Question 4: Which of the following is not an absolute indication for hemodialysis?
- A. GI bleeding (Correct Answer)
- B. Convulsions
- C. Pericarditis
- D. Hyperkalemia of 6.5 mEq/L
Explanation: ***GI bleeding*** - While patients on dialysis may experience gastrointestinal bleeding, it is not a direct indication for initiating or continuing **hemodialysis**. - **GI bleeding** in end-stage renal disease (ESRD) patients can be due to various causes and requires specific management of the bleeding itself, not necessarily an alteration in dialysis prescription. *Convulsions* - **Convulsions** in patients with renal failure, especially due to uremia, are a severe manifestation of **uremic encephalopathy**. - This is an absolute indication for **hemodialysis** as it rapidly removes uremic toxins causing central nervous system dysfunction. *Pericarditis* - **Uremic pericarditis**, characterized by inflammation of the pericardium due to accumulation of uremic toxins, is a serious complication of renal failure. - It is an absolute indication for **hemodialysis** to prevent further cardiac complications like cardiac tamponade. *Hyperkalemia of 6.5 mEq/L* - Severe **hyperkalemia** (typically > 6.0-6.5 mEq/L) is a life-threatening electrolyte imbalance that can cause cardiac arrhythmias. - **Hemodialysis** is highly effective in rapidly removing potassium from the body and is an absolute indication, especially if unresponsive to other medical therapies.
Question 5: What is the cause of intracorpuscular defects in hemolysis?
- A. PNH (Correct Answer)
- B. Portal hypertension
- C. Paroxysmal cold hemoglobinuria (PCH)
- D. Uremic syndrome
Explanation: ***PNH*** - Paroxysmal nocturnal hemoglobinuria (PNH) is caused by a defect in the **GPI anchor**, leading to increased susceptibility of red blood cells to lysis by complement [1]. - The condition is characterized by **intracorpuscular defects**, resulting in hemolysis due to the inability to protect red blood cells from complement-mediated destruction [1]. *Portal hypertension* - This condition primarily affects the **portal venous system** and is not directly related to **intracorpuscular defects** in red blood cells. - It commonly leads to complications like **variceal bleeding** and ascites, rather than hemolysis. *PCH* - Paroxysmal cold hemoglobinuria (PCH) involves **cold agglutinins** and triggers hemolysis upon exposure to cold, unrelated to **intracorpuscular defects**. - PCH has a different mechanism involving **IgG antibodies**, resulting in hemolysis when exposed to low temperatures. *Uremic syndrome* - Uremic syndrome is a complication of **chronic kidney disease**, leading to hemolysis but due to **extracorpuscular factors** like toxic metabolites rather than intrinsic defects in red blood cells. - It does not specifically cause **intracorpuscular defects** in hemolysis as seen in PNH. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 650-651.
Question 6: Best immediate management of hyperkalemia includes all except?
- A. Salbutamol nebulization
- B. Insulin drip
- C. Calcium gluconate
- D. MgSO4 (Correct Answer)
Explanation: ***MgSO4*** - **Magnesium sulfate** is not used for the immediate management of **hyperkalemia**; its primary uses include treating hypomagnesemia, eclampsia, and certain arrhythmias. - While magnesium can have effects on electrolyte balance, it directly addresses calcium or potassium levels in an acute hyperkalemic crisis. *Calcium gluconate* - **Calcium gluconate** is crucial for **cardiac stabilization** in hyperkalemia by protecting the myocardium from potassium's effects [1]. - It does not lower potassium levels but prevents life-threatening arrhythmias by antagonizing the cardiac membrane effects of potassium [1]. *Insulin drip* - An **insulin drip** (often with dextrose) shifts potassium **intracellularly**, thereby lowering serum potassium levels [1]. - This effect is rapid, making it an effective measure for immediate management. *Salbutamol nebulization* - **Salbutamol (albuterol)** nebulization can also help shift potassium into cells, thus reducing serum potassium levels. - It works by stimulating beta-2 adrenergic receptors, which activate the **Na+/K+-ATPase pump**.
Question 7: At what glomerular filtration rate (GFR) is the term "end-stage renal disease (ESRD)" typically classified?
- A. less than 15% of normal (Correct Answer)
- B. 10%—25% of normal
- C. 15%—25% of normal
- D. 5%—10% of normal
Explanation: ***Less than 15% of normal*** - **End-stage renal disease (ESRD)** is defined by a **glomerular filtration rate (GFR)** that falls below **15 mL/min/1.73 m²**, which is approximately **less than 15% of normal function**. - At this stage, **renal replacement therapy** (dialysis or transplantation) is typically required to sustain life. *15%—25% of normal* - This GFR range (15-25 mL/min/1.73 m²) corresponds to **Stage 4 chronic kidney disease (CKD)**, which is severe but not yet formally "end-stage." - Patients in this stage require careful monitoring and management, but may not immediately need renal replacement therapy. *10%—25% of normal* - This range overlaps with both **severe CKD (Stage 4)** and the beginning of **ESRD (Stage 5)**, but it is not the precise definition for ESRD. - The critical threshold for ESRD is uniformly established as GFR below 15 mL/min/1.73 m². *5%—10% of normal* - While a GFR in this range certainly indicates **ESRD**, the official classification includes any GFR **below 15% of normal** (or below 15 mL/min/1.73 m²), making "less than 15%" the most accurate and inclusive answer. - This smaller range describes a more advanced state within ESRD, but not the general definition.
Question 8: For shock patient, best guideline to check for adequacy of fluid replacement therapy:
- A. Central Venous Pressure
- B. Urine output (Correct Answer)
- C. Hemoglobin
- D. Blood pressure and pulse
Explanation: Detailed assessment of a shock patient involves monitoring multiple parameters to guide fluid therapy. ***Urine output*** is a sensitive indicator of **renal perfusion** and overall tissue perfusion, reflecting the adequacy of fluid resuscitation [1]. A target urine output of **0.5-1 mL/kg/hour** is generally used in shock patients to ensure sufficient organ perfusion. *Central Venous Pressure* - **Central Venous Pressure (CVP)** can be a misleading indicator of fluid status, as it reflects right atrial pressure and not necessarily ventricular preload or cardiac output [1]. - While it provides some information, it has limitations as a sole measure for guiding fluid resuscitation due to its poor correlation with **volume responsiveness**, and certain conditions like pulmonary hypertension may raise CVP even in hypovolemia [1]. *Hemoglobin* - **Hemoglobin** levels primarily reflect the oxygen-carrying capacity of the blood and are crucial for diagnosing **anemia** or assessing **blood loss**. - It does not directly indicate the adequacy of fluid volume or tissue perfusion, especially in cases of distributive or cardiogenic shock without significant hemorrhage. *Blood pressure and pulse* - **Blood pressure** and **pulse rate** are important vital signs for assessing the initial response to fluid resuscitation and the presence of shock [1]. - However, they can be maintained within normal limits by compensatory mechanisms even in ongoing hypoperfusion (**compensated shock**), making them less reliable as a sole indicator of adequate fluid replacement [1].
Question 9: Prerenal and renal azotemia are differentiated on the basis of.
- A. Creatinine clearance
- B. Serum creatinine level
- C. Sodium fraction excretion (Correct Answer)
- D. Urine bicarbonate level
Explanation: ***Sodium fraction excretion*** - **Fractional excretion of sodium (FENa)** is a key indicator for differentiating prerenal azotemia from intrinsic renal azotemia [2]. - In **prerenal azotemia**, the kidneys avidly reabsorb sodium to conserve volume, leading to a **low FENa (<1%)**. In contrast, **renal azotemia** (e.g., acute tubular necrosis) typically presents with a **high FENa (>2%)** due to impaired sodium reabsorption [2]. *Creatinine clearance* - **Creatinine clearance** is a measure of **glomerular filtration rate (GFR)**, which is reduced in both prerenal and renal azotemia [1], [3]. - It does not specifically differentiate between the underlying cause of the reduced GFR (i.e., whether it's due to hypoperfusion or intrinsic kidney damage). *Serum creatinine level* - An **elevated serum creatinine level** is present in both prerenal and renal azotemia, indicating **renal dysfunction** [1]. - This measurement alone cannot distinguish whether the kidney injury is due to decreased perfusion or damage to the kidney itself. *Urine bicarbonate level* - **Urine bicarbonate levels** are primarily relevant in the assessment of **renal tubular acidosis** or other acid-base disorders. - They do not play a direct role in differentiating between prerenal and renal causes of azotemia.
Question 10: Absolute contraindication of hormone replacement therapy is:
- A. Fibroadenoma
- B. Thrombosis (Correct Answer)
- C. Fibrocystic disease
- D. Hemorrhage
Explanation: ***Thrombosis*** - A history of **thrombosis** (e.g., DVT, pulmonary embolism) is an **absolute contraindication** to hormone replacement therapy (HRT) due to the increased risk of further **thromboembolic events**, as estrogen can promote coagulation [1], [2]. - HRT can increase the risk of **blood clot formation**, making it unsafe for individuals with a prior or current thrombotic condition [1]. *Fibroadenoma* - **Fibroadenomas** are **benign breast lumps** and are generally not considered an absolute contraindication for HRT. - While HRT can potentially cause some **breast density** changes, fibroadenomas do not typically preclude its use, though monitoring may be advised. *Fibrocystic disease* - **Fibrocystic breast disease** is a common **benign breast condition** characterized by lumpy, tender breasts, and it is **not an absolute contraindication** for HRT. - HRT might occasionally exacerbate breast tenderness in some women with fibrocystic changes, but it does not pose a severe health risk. *Hemorrhage* - Acute or uncontrolled **vaginal hemorrhage**, especially of undetermined etiology, is a contraindication to initiating HRT until the cause is identified and managed. - However, once the hemorrhage is controlled and its cause is determined not to be uterine cancer, previous hemorrhage itself is **not an absolute contraindication** to long-term HRT.
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