Endocrinology Practice Questions

Q: Which of the following drugs is NOT used in the management of SIADH?

Desmopressin. The Syndrome of Inappropriate Antidiuretic Hormone (SIADH) is characterized by excessive release of ADH (Vasopressin), leading to water retention, dilutional hyponatremia, and concentrated urine. **Why Desmopressin is the Correct Answer:** Desmopressin (dDAVP) is a **synthetic analogue of ADH** [1]. Since SIADH is a state of ADH excess, administering Desmopressin would worsen water retention and exacerbate life-threatening hyponatremia. Desmopressin is actually the treatment of choice for *Diabetes Insipidus*, which is the physiological opposite of SIADH [1]. **Analysis of Incorrect Options:** * **Hypertonic Saline (3% NaCl):** Used in the emergency management of severe or symptomatic hyponatremia in SIADH to acutely raise serum sodium levels. * **Demeclocycline:** An antibiotic that acts as an ADH antagonist at the renal collecting duct (induces nephrogenic diabetes insipidus) [2]. It is used in chronic SIADH management when fluid restriction fails [2]. * **Fludrocortisone:** A mineralocorticoid that increases sodium reabsorption in the distal tubule. It is sometimes used off-label in SIADH to help limit urinary sodium loss and maintain sodium balance. **NEET-PG High-Yield Pearls:** 1. **First-line treatment** for SIADH is always **Fluid Restriction** (<800ml/day) [2]. 2. **Vaptans (Tolvaptan, Conivaptan):** These are "Aquaretics" (V2 receptor antagonists) and are now preferred over Demeclocycline for chronic SIADH. 3. **Correction Rate:** In symptomatic hyponatremia, do not exceed a sodium rise of **8–10 mEq/L in 24 hours** to avoid **Osmotic Demyelination Syndrome (Central Pontine Myelinolysis)** [2].

Q: Which of the following is not seen in subacute thyroiditis?

High Radioiodine uptake. **Explanation:** Subacute thyroiditis (also known as De Quervain’s or Granulomatous thyroiditis) is a self-limiting inflammatory condition of the thyroid, often following a viral upper respiratory tract infection. **Why "High Radioiodine Uptake" is the correct answer:** In subacute thyroiditis, the primary pathology is the **destruction of thyroid follicles** due to inflammation. This leads to the leakage of pre-formed thyroid hormones into the bloodstream [1]. Because the follicular cells are damaged and inflamed, they are unable to actively trap iodine. Consequently, the **Radioactive Iodine Uptake (RAIU) is characteristically low (<5%)**, despite the patient being in a thyrotoxic state [1], [2]. This "thyrotoxicosis with low uptake" is a classic diagnostic hallmark. **Analysis of Incorrect Options:** * **Raised T4 levels:** During the initial "thyrotoxic phase," the release of stored hormones leads to elevated serum T4 and T3 levels and suppressed TSH [1]. * **Raised ESR:** Subacute thyroiditis is an inflammatory process. A markedly elevated Erythrocyte Sedimentation Rate (ESR), often >50–100 mm/hr, is a key diagnostic feature [1]. * **Pain:** This is the most common clinical presentation. Patients typically present with a **painful, tender thyroid gland**, often radiating to the jaw or ears [1]. **NEET-PG High-Yield Pearls:** * **Triad:** Painful goiter + Suppressed TSH + Low RAIU. * **Pathology:** Characterized by **multinucleated giant cells** and granulomatous inflammation. * **Treatment:** NSAIDs for mild cases; Glucocorticoids (Prednisone) for severe pain [1]. * **Biphasic Course:** Thyrotoxic phase → Hypothyroid phase → Recovery (Euthyroid).

Q: What is the most likely diagnosis in a full-term neonate with electrolyte abnormalities and specific exam findings?

Congenital adrenal hyperplasia. ***Congenital adrenal hyperplasia*** - Classic **21-hydroxylase deficiency** presents with **salt-wasting** electrolyte abnormalities (**hyponatremia**, **hyperkalemia**) and **ambiguous genitalia** in virilized females. - **Elevated 17-hydroxyprogesterone** levels and **decreased cortisol** and **aldosterone** production confirm the diagnosis in full-term neonates. *Hypospadias with cryptorchidism* - These are **isolated genital anomalies** in males that do not cause **electrolyte disturbances** or systemic metabolic abnormalities. - **Normal adrenal function** is maintained, so **salt-wasting** and **hyperkalemia** would not be present. *Preterm ovarian hyperstimulation syndrome* - This condition occurs in **reproductive-age women** undergoing **fertility treatments**, not in **neonates**. - Presents with **ovarian enlargement** and **fluid retention**, completely unrelated to neonatal electrolyte abnormalities. *Turner syndrome* - Typically presents with **normal female external genitalia** and **streak gonads**, not **virilized ambiguous genitalia**. - Associated with **cardiac defects** and **lymphedema**, but does not cause **salt-wasting** electrolyte abnormalities in neonates.

Q: A 72-year-old man is prescribed hydrochlorothiazide for hypertension. Which of the following is the most likely symptomatic side effect?

Sexual impotence. Thiazide diuretics, such as hydrochlorothiazide (HCTZ), are a cornerstone of hypertension management but are associated with several metabolic and symptomatic side effects [3]. Among the options provided, **sexual impotence (erectile dysfunction)** is a well-documented symptomatic side effect of thiazides [1]. While the exact mechanism is multifactorial, it is attributed to decreased peripheral vascular resistance and the depletion of zinc, which is essential for testosterone production [2]. **Analysis of Options:** * **A. Increased serum potassium:** Incorrect. Thiazides cause **hypokalemia** (decreased potassium) [4] by increasing sodium delivery to the distal tubule, which enhances potassium excretion. * **B. Metabolic acidosis:** Incorrect. Thiazides typically cause **metabolic alkalosis** (contraction alkalosis) [4] due to the loss of hydrogen ions and chloride alongside potassium. * **D. Respiratory alkalosis:** Incorrect. This is a primary respiratory pathology (hyperventilation) and is not a direct metabolic consequence of diuretic therapy. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Thiazide Side Effects (Hyper-GLUC):** Hyper**G**lycemia (impaired insulin release), Hyper**L**ipidemia, Hyper**U**ricemia (can precipitate Gout), and Hyper**C**alcemia (useful in patients with osteoporosis/nephrolithiasis). * **Electrolyte Profile:** Hypokalemia, Hyponatremia, and Hypomagnesemia. * **Clinical Note:** If a patient develops erectile dysfunction on a thiazide, switching to an ACE inhibitor or ARB may be beneficial, as these classes are generally "neutral" or even positive regarding sexual function.

Q: A 75-year-old woman presents with mild congestive heart failure 6 weeks after a myocardial infarction. She has a history of neck surgery for parathyroid adenoma 5 years ago and her ECG shows slow atrial fibrillation. Her serum calcium is 13.0 mg/dL and urinary calcium is 300 mg/24 h. Examination reveals a small mass in the paratracheal region behind the right clavicle. What is the most appropriate management at this time?

Ultrasound-guided alcohol injection of the mass. The patient presents with **persistent/recurrent primary hyperparathyroidism (PHPT)** (Calcium 13.0 mg/dL) and a localized parathyroid mass. The key to this question is the patient’s **recent myocardial infarction (6 weeks ago)** and current **congestive heart failure (CHF)**. [1] 1. **Why Option D is Correct:** In patients with symptomatic hypercalcemia who are **high-risk surgical candidates** (due to recent MI and CHF), invasive surgery is contraindicated. **Ultrasound-guided percutaneous ethanol injection (PEI)** is a minimally invasive alternative to ablate the overactive parathyroid tissue. It effectively reduces PTH and calcium levels without the risks of general anesthesia or complex neck re-exploration. 2. **Why Other Options are Incorrect:** * **Option A:** Repeat neck surgery is the definitive treatment for recurrent PHPT but is contraindicated here. Surgery within 6 months of an MI carries a high risk of perioperative mortality and cardiac complications. * **Option B:** Technetium-99m (Sestamibi) is a **diagnostic imaging modality** used for localization, not a treatment. [1] Radioactive iodine is used for thyroid, not parathyroid, ablation. * **Option C:** Observation is inappropriate. A calcium level of 13.0 mg/dL is significantly elevated (hypercalcemic crisis threshold is >14) and is likely exacerbating her cardiac issues (atrial fibrillation and CHF). **Clinical Pearls for NEET-PG:** * **Surgical Criteria for PHPT:** Serum Ca >1 mg/dL above normal, age <50, T-score <-2.5, or creatinine clearance <60 mL/min. [1] * **Localization:** Sestamibi scan is the gold standard for localizing adenomas before re-operation. [1] * **Post-MI Surgery:** Elective non-cardiac surgery should ideally be delayed **6 months** post-MI to minimize risk. * **ECG in Hypercalcemia:** Characterized by a **shortened QT interval**.

Question 1

All of the following conditions are known to cause diabetes insipidus except?

Accepted Answer

Multiple sclerosis

Answer

Head injury

Answer

Histiocytosis

Answer

Viral encephalitis

Question 2

Which of the following causes of gynecomastia is not associated with androgen deficiency?

Accepted Answer

Alcoholic Liver cirrhosis

Answer

Klinefelter's syndrome

Answer

Kallmann syndrome

Answer

Cryptorchidism

Question 3

Which statement is true regarding the treatment of hypertensive crisis with encephalopathy in a patient with a pheochromocytoma?

Accepted Answer

Treatment with phentolamine should be started with low-dose phenoxybenzamine to be titrated upward. Surgery should be done in 2 to 3 weeks once blood pressure is below 160/100 mmHg.

Answer

Immediate surgical removal of the mass is indicated.

Answer

High-dose phenoxybenzamine should be used to control blood pressure with surgery in 24 to 48 hours.

Answer

Beta blockade is contraindicated.

Question 4

Which of the following drugs is NOT used in the management of SIADH?

Accepted Answer

Desmopressin

Answer

Fludrocortisone

Answer

Demeclocycline

Answer

Hypertonic saline

Question 5

Obesity is associated with which of the following conditions?

Accepted Answer

Hypothalamic lesion

Answer

Cushing's syndrome

Answer

Pheochromocytoma

Answer

Insulinoma

Question 6

Which of the following is not seen in subacute thyroiditis?

Accepted Answer

High Radioiodine uptake

Answer

Raised T4 levels

Answer

Raised ESR

Answer

Pain

Question 7

What is the most likely diagnosis in a full-term neonate with electrolyte abnormalities and specific exam findings?

Accepted Answer

Congenital adrenal hyperplasia

Answer

Hypospadias with cryptorchidism

Answer

Preterm ovarian hyperstimulation syndrome

Answer

Turner syndrome

Question 8

A 72-year-old man is prescribed hydrochlorothiazide for hypertension. Which of the following is the most likely symptomatic side effect?

Accepted Answer

Sexual impotence

Answer

Increased serum potassium

Answer

Metabolic acidosis

Answer

Respiratory alkalosis

Question 9

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

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Answer

Neurogenic diabetes insipidus

Answer

Nephrogenic diabetes insipidus

Answer

Diabetes mellitus

Question 10

A 75-year-old woman presents with mild congestive heart failure 6 weeks after a myocardial infarction. She has a history of neck surgery for parathyroid adenoma 5 years ago and her ECG shows slow atrial fibrillation. Her serum calcium is 13.0 mg/dL and urinary calcium is 300 mg/24 h. Examination reveals a small mass in the paratracheal region behind the right clavicle. What is the most appropriate management at this time?

Accepted Answer

Ultrasound-guided alcohol injection of the mass

Answer

Repeat neck surgery

Answer

Treatment with Technetium-99

Answer

Observation and repeat serum calcium in two months

Endocrinology — MCQs

Endocrinology — MCQs

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