Endocrinology Practice Questions

Q: Which of the following is NOT typically seen in myxedema coma?

Tachycardia. **Explanation:** Myxedema coma is a life-threatening complication of severe, untreated hypothyroidism. It is characterized by a global slowing of metabolic processes. **1. Why Tachycardia is the correct answer:** In severe hypothyroidism, there is a marked decrease in metabolic rate and sympathetic activity. This leads to **bradycardia** (slow heart rate), not tachycardia [1]. The heart muscle also suffers from decreased contractility and reduced stroke volume. Therefore, tachycardia is inconsistent with the clinical presentation of myxedema coma. **2. Why the other options are wrong:** * **Hypothermia (A):** This is a hallmark feature. Due to the lack of thyroid hormone, thermogenesis is impaired. Patients often present with temperatures below 35°C (95°F). * **Hypotension (C):** Reduced cardiac output and decreased vascular tone lead to low blood pressure. This can progress to shock if not treated promptly. * **Hyponatremia (D):** This is frequently seen due to an increase in Antidiuretic Hormone (ADH) secretion (SIADH-like picture) and reduced free water clearance by the kidneys. **Clinical Pearls for NEET-PG:** * **Precipitating Factors:** Sepsis, cold exposure, myocardial infarction, or sedative use. * **Classic Triad:** Altered mental status (coma/lethargy), hypothermia, and a precipitating event. * **Treatment:** Immediate IV Levothyroxine (T4) and/or Liothyronine (T3). **Crucial:** Always administer **IV Hydrocortisone** before thyroid hormone replacement to avoid precipitating an adrenal crisis (as the patient may have concomitant adrenal insufficiency). * **Lab findings:** High TSH, low Free T4, and often hypoglycemia.

Q: Chvostek sign is seen in:

Hypothyroidism. **Explanation:** The **Chvostek sign** is a clinical indicator of hyperexcitability of the facial nerve, typically associated with **hypocalcemia**. In the context of this question, **Hypothyroidism** is the correct answer because it is frequently associated with **Hypoparathyroidism** (either due to autoimmune destruction or as a post-surgical complication of thyroidectomy). A deficiency in Parathyroid Hormone (PTH) leads to low serum calcium levels, which decreases the threshold for nerve depolarization [1]. * **Mechanism:** Tapping the facial nerve at the angle of the jaw (anterior to the tragus) causes ipsilateral twitching of the facial muscles (nose or lips). **Analysis of Options:** * **Hypothyroidism (Correct):** Often co-exists with hypocalcemia via associated hypoparathyroidism or as part of polyglandular autoimmune syndromes. * **Hypercalcemia (Incorrect):** High calcium levels actually stabilize neuronal membranes, leading to decreased excitability and diminished reflexes. * **Insulinoma & Diabetes Mellitus (Incorrect):** These are disorders of glucose metabolism and do not typically affect serum ionized calcium levels or neuromuscular irritability. **NEET-PG High-Yield Pearls:** 1. **Trousseau Sign:** Carpopedal spasm induced by inflating a BP cuff above systolic pressure for 3 minutes. It is **more sensitive and specific** than Chvostek sign for latent tetany. 2. **Other causes of Chvostek Sign:** Hypomagnesemia, metabolic alkalosis (which decreases ionized calcium), and hyperventilation. 3. **False Positives:** Approximately 10% of healthy individuals with normal calcium levels may exhibit a positive Chvostek sign. 4. **ECG in Hypocalcemia:** Look for **prolonged QT interval**, a classic exam favorite [1].

Q: Vitamin D resistant rickets occurs due to all EXCEPT:

Alpha-1-hydroxylase deficiency. **Explanation:** The term **Vitamin D Resistant Rickets (VDRR)** refers to conditions where rickets occurs despite normal or high intake of Vitamin D, typically due to defects in phosphate metabolism or end-organ resistance [1]. **Why Option A is the Correct Answer:** **Alpha-1-hydroxylase deficiency** is the underlying cause of **Vitamin D Dependent Rickets (VDDR) Type 1**, not Vitamin D *Resistant* Rickets. In this condition, the body cannot convert 25(OH)D into its active form, 1,25(OH)₂D. It is classified as "dependent" because it can be successfully treated with physiological doses of active Vitamin D (Calcitriol). **Analysis of Incorrect Options:** * **Renal Tubular Acidosis (RTA):** Distal (Type 1) and Proximal (Type 2) RTA cause chronic metabolic acidosis, which leads to hypercalciuria and phosphate wasting. This results in rickets that does not respond to standard Vitamin D therapy, classifying it as a "resistant" form. * **Fanconi Syndrome:** This is a generalized dysfunction of the proximal tubule leading to phosphaturia. The resulting hypophosphatemia causes rickets that is resistant to Vitamin D alone and requires phosphate supplementation. * **Drugs:** Long-term use of certain drugs, most notably **Anticonvulsants** (like Phenytoin or Phenobarbital), induces hepatic cytochrome P450 enzymes. This accelerates the catabolism of Vitamin D into inactive metabolites, leading to a resistant state. **High-Yield Clinical Pearls for NEET-PG:** * **X-linked Hypophosphatemic Rickets:** The most common cause of Vitamin D Resistant Rickets (due to PHEX gene mutation and increased FGF-23) [1]. * **VDDR Type 2:** Caused by a mutation in the **Vitamin D Receptor (VDR)**; often presents with **alopecia**. * **Biochemical Hallmark of VDRR:** Low serum phosphate with normal serum calcium and normal/high 1,25(OH)₂D (except in FGF-23 mediated types).

Q: Which vaccine can be given to an individual with chronic diabetes mellitus?

Meningococcal and pneumococcal vaccines at recommended intervals, and influenza vaccine annually.. Explanation: Patients with Diabetes Mellitus (DM) are considered immunocompromised due to impaired neutrophil function and humoral immunity, making them highly susceptible to vaccine-preventable infections [1]. **Why Option A is Correct:** Current clinical guidelines (ADA and ACIP) strongly recommend the following for diabetic patients: 1. **Influenza Vaccine:** Administered **annually** to all diabetic patients (≥6 months of age) to prevent severe respiratory complications. 2. **Pneumococcal Vaccine:** Diabetic adults (19–64 years) should receive PPSV23 [2]. At age ≥65, additional doses (PCV15/20) are indicated. 3. **Meningococcal Vaccine:** While not specific only to diabetes, it is part of the "recommended intervals" for adults in high-risk settings or as per age-appropriate schedules. **Analysis of Incorrect Options:** * **Option B & D:** Hepatitis B vaccine is indeed recommended for diabetic adults (age 19–59), but it is **not given annually**. It is a 2 or 3-dose series providing long-term immunity. * **Option C:** While Tetanus (Tdap/Td) is part of routine adult maintenance (every 10 years), the inclusion of the **annual Influenza vaccine** alongside **Pneumococcal** and **Meningococcal** coverage makes Option A the most comprehensive choice regarding the specific increased risks associated with DM. **High-Yield Clinical Pearls for NEET-PG:** * **Hepatitis B:** Should be administered as soon as possible after a DM diagnosis (ideally before age 60) due to the risk of transmission via blood glucose monitoring equipment. * **Pneumococcal:** DM is a "chronic medical condition" requiring PPSV23 before age 65 [2]. * **COVID-19:** Diabetic patients are a priority group for primary series and boosters. * **Zoster:** Recombinant Zoster vaccine is recommended for diabetic patients ≥50 years.

Q: Hypothyroidism is seen in which of the following conditions?

Hashimoto's thyroiditis. **Explanation:** **Hashimoto’s Thyroiditis (Correct Answer):** Hashimoto’s thyroiditis (Chronic Autoimmune Thyroiditis) is the most common cause of hypothyroidism in iodine-sufficient regions. It is characterized by the autoimmune destruction of the thyroid gland mediated by T-cell-induced apoptosis and the presence of anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) antibodies. Histologically, it shows diffuse lymphocytic infiltration and the presence of **Hürthle cells** (Askanazy cells). **Why the other options are incorrect:** * **Graves’ Disease:** This is an autoimmune condition caused by Thyroid Stimulating Immunoglobulins (TSI) that bind to and activate the TSH receptor, leading to **hyperthyroidism**, not hypothyroidism [1]. * **Toxic Multinodular Goiter (Plummer Disease):** This involves autonomous hyperfunctioning nodules that secrete excess thyroid hormones (T3/T4) independent of TSH, resulting in **hyperthyroidism**. * **Struma Ovarii:** This is a rare specialized ovarian teratoma composed predominantly of thyroid tissue. If this ectopic tissue becomes overactive, it leads to **hyperthyroidism** (ectopic thyrotoxicosis) with low iodine uptake in the neck. **NEET-PG High-Yield Pearls:** * **Most common cause of goitrous hypothyroidism:** Hashimoto’s thyroiditis. * **Most common cause of hypothyroidism worldwide:** Iodine deficiency. * **Marker of choice:** Anti-TPO antibodies are present in >90% of Hashimoto’s patients. * **Associated Risk:** Patients with Hashimoto’s have an increased risk of developing **B-cell Non-Hodgkin Lymphoma** of the thyroid. * **Wolff-Chaikoff Effect:** A transient reduction in thyroid hormone levels following ingestion of a large amount of iodine, often seen in Hashimoto's patients.

Q: A 40-year-old patient presents with episodic hypertension, severe headache, diaphoresis, and palpitations. The CT scan of the abdomen is shown in the image. What is the most likely diagnosis?

Pheochromocytoma. ***Pheochromocytoma*** - The classic triad of **episodic hypertension**, **severe headache**, **diaphoresis**, and **palpitations** strongly suggests **catecholamine excess** from a pheochromocytoma. - CT imaging typically shows an **adrenal mass** with **heterogeneous enhancement** and possible **central necrosis**, confirmed by elevated **24-hour urine metanephrines** or **plasma metanephrines**. *Coarctation of the aorta* - Presents with **continuous hypertension** and **blood pressure differential** between upper and lower extremities, not episodic symptoms. - Associated with **rib notching** on chest X-ray and **weak femoral pulses**, which are absent in this case. *Primary hyperaldosteronism* - Causes **sustained hypertension** with **hypokalemia** and **metabolic alkalosis**, not episodic catecholamine symptoms. - Presents with **muscle weakness** and **polyuria** due to **aldosterone excess**, lacking the classic triad described. *Renal artery stenosis* - Results in **renovascular hypertension** with **renal bruit** and possible **flash pulmonary edema**, not episodic symptoms. - Associated with **atherosclerotic disease** or **fibromuscular dysplasia**, typically showing **kidney size asymmetry** on imaging.

Question 1

Which of the following is NOT typically seen in myxedema coma?

Accepted Answer

Tachycardia

Answer

Hypothermia

Answer

Hypotension

Answer

Hyponatremia

Question 2

A 60-year-old male presented with skin hyperpigmentation, central obesity, violet striae, and proximal myopathy. His blood pressure is 160/90 mmHg. Lab studies show hypokalemic metabolic alkalosis. Which of the following statements is true regarding this condition?

Accepted Answer

Serum potassium level <3.3 mmol/L is suggestive of ectopic ACTH production.

Answer

Basal ACTH level is likely to be low.

Answer

Circulating corticotropin-releasing hormone is likely to be elevated.

Answer

Pituitary magnetic resonance imaging (MRI) will visualize all ACTH-secreting tumors.

Question 3

Chvostek sign is seen in:

Accepted Answer

Hypothyroidism

Answer

Hypercalcemia

Answer

Insulinoma

Answer

Diabetes mellitus

Question 4

Vitamin D resistant rickets occurs due to all EXCEPT:

Accepted Answer

Alpha-1-hydroxylase deficiency

Answer

Renal tubular acidosis

Answer

Fanconi syndrome

Answer

Drugs

Question 5

A smoker presented with altered sensorium. His blood osmolality was found to be 240 mOsm/kg, urine osmolality 340 mOsm/kg, and serum Na+ is 122 mEq/L. What is the most likely diagnosis?

Accepted Answer

Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH)

Answer

Diabetes insipidus

Answer

Renal tubular acidosis

Answer

Cerebellar degeneration

Question 6

Which vaccine can be given to an individual with chronic diabetes mellitus?

Accepted Answer

Meningococcal and pneumococcal vaccines at recommended intervals, and influenza vaccine annually.

Answer

Meningococcal and tetanus vaccines at recommended intervals, and hepatitis B vaccine annually.

Answer

Tetanus and pneumococcal vaccines at recommended intervals, and influenza vaccine annually.

Answer

Meningococcal and pneumococcal vaccines at recommended intervals, and hepatitis vaccine annually.

Question 7

Hypothyroidism is seen in which of the following conditions?

Accepted Answer

Hashimoto's thyroiditis

Answer

Graves disease

Answer

Toxic multinodular goiter

Answer

Struma ovarii

Question 8

A 33-year-old woman presents with gradually increasing coarse hair on her upper lip, chin, and lower abdomen for the past 3 years. She has mild facial acne but denies frontal balding or deepening of voice. Her menses are irregular, occurring every 28 to 60 days. Her BMI is 29.0 and her waist circumference is 36 inches. There is mild acanthosis nigricans of the axillae. Pelvic examination is normal without ovarian mass or clitoromegaly. What evaluation is indicated for her hirsutism?

Accepted Answer

Serum testosterone and dehydroepiandrosterone-sulfate (DHEA-S) level

Answer

Glucose tolerance test

Answer

Overnight dexamethasone suppression test with 8 am cortisol level

Answer

CT scan of adrenals

Question 9

A 40-year-old patient presents with episodic hypertension, severe headache, diaphoresis, and palpitations. The CT scan of the abdomen is shown in the image. What is the most likely diagnosis?

Accepted Answer

Pheochromocytoma

Answer

Coarctation of the aorta

Answer

Primary hyperaldosteronism

Answer

Renal artery stenosis

Question 10

A 18-year-old male presents with severe weakness, dizziness, sleepiness, unquenchable thirst, and increased urination over the past 4 weeks. He has also experienced drowsiness and generalized tiredness in a previous episode 3 weeks earlier and has lost 4kg of weight. Laboratory findings on admission show a glucose of 560 mg/dl, urine that is 4+ for glucose and has "large" acetone, and an HbA1c of 14%. Which of the following is true regarding this patient?

Accepted Answer

Increased lipolysis

Answer

Increased glucose uptake

Answer

Decreased hepatic glucose output

Answer

Decreased protein catabolism

Endocrinology — MCQs

Endocrinology — MCQs

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