Endocrinology Practice Questions

Q: What is the most common presentation of sick euthyoid state?

Low T3 with normal T4. **Explanation:** **Sick Euthyroid Syndrome (SES)**, also known as Non-Thyroidal Illness Syndrome (NTIS), refers to alterations in thyroid function tests seen in patients with severe systemic illness (e.g., sepsis, trauma, or starvation) in the absence of pre-existing thyroid disease. **Why Option A is Correct:** The most common and earliest finding in SES is a **Low T3 level with a normal T4 and normal TSH**. This occurs due to the inhibition of the enzyme **5’-deiodinase**, which normally converts T4 (pro-hormone) to T3 (active hormone) in peripheral tissues [1]. Instead, T4 is diverted to form **Reverse T3 (rT3)**, which is metabolically inactive. **Analysis of Incorrect Options:** * **Option B (Low T3, Low T4):** This is seen in **severe or prolonged illness**. As the severity of the systemic disease increases, T4 levels also drop (Low T4 syndrome), which is a poor prognostic indicator. However, it is not the *most common* initial presentation. * **Option C & D:** These patterns are not characteristic of SES. High T4 is rarely seen unless there is an inhibition of T4 uptake by hepatocytes (transiently in acute illness), and high T3 is never a feature of sick euthyroid state. **NEET-PG High-Yield Pearls:** 1. **Hallmark:** Low T3, High Reverse T3 (rT3), and Normal TSH. 2. **TSH Paradox:** Although T3 is low, TSH remains normal (or mildly low) because the pituitary-thyroid axis is "reset" during stress. 3. **Management:** Do **NOT** treat with thyroxine. The condition resolves spontaneously once the underlying systemic illness is treated. 4. **Prognosis:** A very low T4 level in a critically ill patient is associated with a high mortality rate.

Q: A 45-year-old obese woman presents to the emergency department in a semi-comatose state. Laboratory investigations reveal K+ (5.8 mmol/L), Na+ (136 mmol/L), blood pH (7.1), HCO3 (12 mmol/L), and ketone bodies (350 mg/dL). What is the expected blood glucose level for this patient?

Greater than 180 mg/dL. ### Explanation The patient presents with the classic triad of **Diabetic Ketoacidosis (DKA)**: hyperglycemia, metabolic acidosis (pH 7.1, low $HCO_3^-$), and ketonemia (350 mg/dL). **1. Why Option C is Correct:** The underlying pathophysiology is a relative or absolute **insulin deficiency** combined with an excess of counter-regulatory hormones (glucagon, cortisol, epinephrine). Insulin deficiency leads to: * **Decreased peripheral glucose uptake** (via GLUT-4). * **Increased Gluconeogenesis and Glycogenolysis**, resulting in significant hyperglycemia (typically >250 mg/dL, but clinically defined as >180–200 mg/dL in DKA). * **Uninhibited Lipolysis:** The absence of insulin allows hormone-sensitive lipase to break down adipose tissue into free fatty acids, which undergo $\beta$-oxidation in the liver to form ketone bodies (Acetoacetate and $\beta$-hydroxybutyrate), causing the observed acidosis. **2. Why Other Options are Incorrect:** * **Options A, B, and D:** These represent hypoglycemic or normoglycemic states. While "Euglycemic DKA" can occur (especially with SGLT-2 inhibitors), the standard presentation of DKA involves high blood sugar. Low glucose levels (<75 mg/dL) would suggest an insulinoma or insulin overdose, which would suppress ketone body formation rather than promote it. **3. Clinical Pearls for NEET-PG:** * **Hyperkalemia in DKA:** Note the $K^+$ of 5.8 mmol/L. Acidosis causes a shift of $K^+$ out of cells in exchange for $H^+$. Despite high serum levels, the **total body potassium is actually depleted** due to osmotic diuresis. * **Anion Gap:** DKA is a classic cause of High Anion Gap Metabolic Acidosis (HAGMA). * **Key Enzyme:** **HMG-CoA Synthase** is the rate-limiting enzyme for ketogenesis in the mitochondria.

Q: Hirsutism can be caused by all of the following, EXCEPT:

Spironolactone. **Explanation:** **Hirsutism** is defined as the presence of terminal hair in females in a male-pattern distribution (androgen-dependent areas). The correct answer is **Spironolactone** because it is a treatment for hirsutism, not a cause. 1. **Why Spironolactone is correct:** Spironolactone is a potassium-sparing diuretic that acts as a potent **androgen receptor antagonist** and a weak inhibitor of androgen synthesis (inhibiting 17α-hydroxylase). Because it blocks the action of dihydrotestosterone (DHT) on hair follicles, it is a first-line pharmacological treatment for hirsutism. 2. **Why other options are incorrect:** * **Steroidogenic enzyme defects:** Conditions like **Congenital Adrenal Hyperplasia (CAH)**, specifically 21-hydroxylase deficiency, lead to an accumulation of androgen precursors, causing virilization and hirsutism. * **Minoxidil:** This is a potent vasodilator. While it is used to treat alopecia, its systemic absorption or topical use can cause **hypertrichosis** (generalized excessive hair growth), which is often clinically grouped with hirsutism in exams, though technically distinct. * **Acromegaly:** Excess Growth Hormone (GH) and IGF-1 stimulate hair follicles both directly and by increasing local androgen sensitivity, leading to hirsutism. **High-Yield Clinical Pearls for NEET-PG:** * **Ferriman-Gallwey Score:** Used to quantify hirsutism; a score of **≥8** is generally considered diagnostic. * **Hirsutism vs. Hypertrichosis:** Hirsutism is androgen-dependent (face, chest, back); Hypertrichosis is androgen-independent (generalized, often drug-induced by Phenytoin, Cyclosporine, or Minoxidil). * **Most common cause:** Polycystic Ovary Syndrome (PCOS) is the most common cause of hirsutism. * **Rapid onset:** Sudden, severe hirsutism with virilization suggests an **androgen-secreting tumor** (adrenal or ovarian).

Q: A 35-year-old woman, 6 months postpartum after a difficult delivery complicated by severe cervical lacerations and hemorrhagic shock, presents with continued amenorrhea, weight loss, and decreased muscle strength. Which of the following findings would be expected on further investigation?

Decreased serum cortisol. **Explanation:** The clinical presentation described is a classic case of **Sheehan’s Syndrome** (Postpartum Pituitary Necrosis). This condition occurs due to severe obstetric hemorrhage and hypovolemic shock, leading to ischemic necrosis of the anterior pituitary gland, which is physiologically enlarged and highly vascular during pregnancy. **Why Option A is Correct:** Sheehan’s Syndrome results in **panhypopituitarism**. The loss of ACTH (Adrenocorticotropic Hormone) leads to secondary adrenal insufficiency, resulting in **decreased serum cortisol**. This explains the patient's weight loss and decreased muscle strength (weakness). Other common signs include failure to lactate (loss of prolactin) and persistent amenorrhea (loss of FSH/LH). **Why Other Options are Incorrect:** * **B. Hyperestrogenism:** In Sheehan’s Syndrome, there is a deficiency of gonadotropins (FSH/LH), leading to **hypoestrogenism**, which causes amenorrhea and vaginal atrophy. * **C. Hyperglycemia:** Cortisol and Growth Hormone (GH) are counter-regulatory hormones. Their deficiency leads to **hypoglycemia**, not hyperglycemia. * **D. Increased serum free thyroxine:** Loss of TSH leads to secondary hypothyroidism, resulting in **decreased** levels of free thyroxine (T4). **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Sign:** Failure of lactation (agalactia) is often the first clinical clue. * **Most Common Initial Hormone Loss:** Growth Hormone (GH) and Prolactin are usually the first to be affected. * **Diagnosis:** Gold standard is **MRI of the pituitary**, which shows an "Empty Sella" in the chronic phase. * **Management:** Lifelong hormone replacement therapy (Cortisol must be replaced *before* Thyroxine to avoid precipitating an adrenal crisis).

Q: What is the confirmatory test for Cushing's disease?

Bilateral inferior petrosal sinus sampling. ### Explanation The diagnostic approach to Cushing’s syndrome follows a strict hierarchy: first, confirm hypercortisolism; second, determine if it is ACTH-dependent; and third, localize the source [1]. **Why Bilateral Inferior Petrosal Sinus Sampling (BIPSS) is correct:** BIPSS is the **gold standard** for differentiating between a pituitary source (Cushing’s Disease) and an ectopic source of ACTH. It involves measuring ACTH levels in the venous drainage of the pituitary gland compared to peripheral blood. A central-to-peripheral ACTH ratio of **≥2:1 (basal)** or **≥3:1 (after CRH stimulation)** confirms Cushing’s disease with high sensitivity and specificity. It is typically performed when biochemical tests suggest a pituitary source but MRI is inconclusive or negative. **Analysis of Incorrect Options:** * **B & C (24-hour Urine Free Cortisol & Overnight DST):** These are **screening tests** used to establish the presence of hypercortisolism (Cushing’s Syndrome) [1]. They do not differentiate the underlying cause (pituitary vs. adrenal vs. ectopic). * **A (High-dose Dexamethasone Suppression Test - HDDST):** Historically used to distinguish Cushing’s disease from ectopic ACTH, HDDST is no longer considered the "confirmatory" test due to its lower accuracy compared to BIPSS and modern imaging [1]. **NEET-PG High-Yield Pearls:** * **Screening:** Best initial test is either Late-night salivary cortisol, 24-hr urinary free cortisol, or Low-dose DST [1]. * **Localization:** If ACTH is high (>20 pg/mL), it is ACTH-dependent [2]. Perform MRI Brain. * **The "Rule of 6mm":** If MRI shows a pituitary adenoma **>6 mm**, Cushing’s disease is confirmed. If <6 mm or MRI is normal, **BIPSS** is the next step to confirm the source. * **Most common cause** of endogenous Cushing’s syndrome: Cushing’s Disease (Pituitary adenoma).

Q: A 33-year-old man complains of a tingling sensation in his hands for several months, which occasionally awakens him during sleep. The patient has noticed he has gained weight and no longer wears his wedding ring as it has become too tight. Upon examination, the patient is noted to be sweating while speaking and has a prominent jaw, furrowed tongue, and large hands. His blood pressure is 142/91 mmHg. What is the most appropriate investigation?

Glucose tolerance test. ### Explanation The clinical presentation of weight gain, tightening of rings (soft tissue swelling), prominent jaw (prognathism), furrowed tongue (macroglossia), and excessive sweating is classic for **Acromegaly**, caused by excessive Growth Hormone (GH) secretion. The tingling in the hands suggests **Carpal Tunnel Syndrome**, a common complication of acromegaly due to soft tissue overgrowth compressing the median nerve. #### Why Option B is Correct The **Oral Glucose Tolerance Test (OGTT) with GH measurement** is the **gold standard confirmatory test** for acromegaly [1]. In a healthy individual, a high glucose load (75g) suppresses GH levels to <1 ng/mL. In acromegaly, there is a failure to suppress GH, or even a paradoxical rise, confirming autonomous secretion [1]. While Serum IGF-1 is the best *screening* test, OGTT is the definitive biochemical investigation [1]. #### Why Other Options are Incorrect * **A. MRI scan of the pituitary:** This is the investigation of choice for *localization* of the tumor (usually a macroadenoma) [1]. However, biochemical confirmation (OGTT) must always precede imaging to avoid incidentaloma findings [2]. * **C. Growth hormone levels:** A single random GH measurement is unreliable because GH is secreted in pulsatile bursts and has a short half-life. * **D. Serum prolactin levels:** While 25-30% of GH-secreting tumors also secrete prolactin (mammosomatotrophs), it is not the diagnostic test for acromegaly [1]. #### NEET-PG High-Yield Pearls * **Best Screening Test:** Serum IGF-1 (reflects GH activity over 24 hours) [1]. * **Best Confirmatory Test:** OGTT (GH suppression test) [1]. * **Most Common Cause of Death:** Cardiovascular disease (Cardiomyopathy/Hypertension). * **Associated Cancer Risk:** Increased risk of **Colonic Polyps and Adenocarcinoma**; screening colonoscopy is recommended [1]. * **Visual Defect:** Bitemporal hemianopia (due to optic chiasm compression) [2].

Q: A 35-year-old mother of two children, aged 5 and 6 years, has had amenorrhea and galactorrhea for the past 12 months. Her serum prolactin level is 450 ng/ml. What is the most likely diagnosis?

Pituitary adenoma. **Explanation:** The clinical presentation of **amenorrhea** and **galactorrhea** (the classic "Amenorrhea-Galactorrhea Syndrome") in a reproductive-age woman is highly suggestive of **Hyperprolactinemia**. Prolactin inhibits the pulsatile release of GnRH from the hypothalamus, leading to low FSH/LH levels and subsequent amenorrhea. **Why Pituitary Adenoma is correct:** The serum prolactin level is the diagnostic key here. While physiological causes (pregnancy, stress) or drugs usually cause mild elevations ( 200 ng/ml** is highly specific for a **Prolactinoma** (a pituitary adenoma). A level of 450 ng/ml strongly indicates a macroprolactinoma (>10 mm), necessitating an MRI of the Sella Turcica. **Why other options are incorrect:** * **Menopause:** While it causes amenorrhea, it is characterized by high FSH levels and does not cause galactorrhea or massive prolactin elevation. * **Intraductal papilloma:** This presents with unilateral, bloody nipple discharge from a single duct, without systemic endocrine symptoms like amenorrhea or elevated prolactin. * **Sheehan's syndrome:** This is postpartum pituitary necrosis resulting in *hypopituitarism*. It leads to a failure to lactate (due to prolactin deficiency) and secondary amenorrhea, rather than hyperprolactinemia. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of choice:** Dopamine agonists like **Cabergoline** (preferred due to better efficacy and fewer side effects) or Bromocriptine. * **Hook Effect:** In cases of extremely high prolactin, lab assays may show falsely low levels; serial dilution is required. * **Visual Field Defect:** Large adenomas can compress the optic chiasm, leading to **bitemporal hemianopia**. * **Rule of thumb:** Prolactin >200 ng/ml = Prolactinoma until proven otherwise.

Question 1

A 40-year-old non-diabetic woman presents to the emergency department with hypoglycemia. The paramedics suspect an insulin overdose, while you suspect an insulinoma. Which laboratory result would confirm your suspicion of insulinoma?

Accepted Answer

Insulin level is inappropriately high for the degree of hypoglycemia and is accompanied by a detectable C-peptide level

Answer

Insulin level is significantly elevated compared to C-peptide level

Answer

Insulin level is significantly lower than C-peptide level

Answer

Insulin antibody level is equal to the insulin level

Question 2

A patient with Addison's disease presented with adrenal crisis. What is the drug of choice?

Accepted Answer

Hydrocortisone

Answer

Betamethasone

Answer

Dexamethasone

Answer

Prednisolone

Question 3

What is the most common presentation of sick euthyoid state?

Accepted Answer

Low T3 with normal T4

Answer

Low T3 with low T4

Answer

Low T3 with high T4

Answer

High T3 with high T4

Question 4

A 45-year-old obese woman presents to the emergency department in a semi-comatose state. Laboratory investigations reveal K+ (5.8 mmol/L), Na+ (136 mmol/L), blood pH (7.1), HCO3 (12 mmol/L), and ketone bodies (350 mg/dL). What is the expected blood glucose level for this patient?

Accepted Answer

Greater than 180 mg/dL

Answer

Less than 45 mg/dL

Answer

Less than 120 mg/dL

Answer

Less than 75 mg/dL

Question 5

Hirsutism can be caused by all of the following, EXCEPT:

Accepted Answer

Spironolactone

Answer

Steroidogenic enzyme defects

Answer

Minoxidil

Answer

Acromegaly

Question 6

A 35-year-old woman, 6 months postpartum after a difficult delivery complicated by severe cervical lacerations and hemorrhagic shock, presents with continued amenorrhea, weight loss, and decreased muscle strength. Which of the following findings would be expected on further investigation?

Accepted Answer

Decreased serum cortisol

Answer

Hyperestrogenism

Answer

Hyperglycemia

Answer

Increased serum free thyroxine

Question 7

What is the confirmatory test for Cushing's disease?

Accepted Answer

Bilateral inferior petrosal sinus sampling

Answer

High-dose dexamethasone suppression test

Answer

24-hour urine free cortisol

Answer

Overnight dexamethasone suppression test

Question 8

A 33-year-old man complains of a tingling sensation in his hands for several months, which occasionally awakens him during sleep. The patient has noticed he has gained weight and no longer wears his wedding ring as it has become too tight. Upon examination, the patient is noted to be sweating while speaking and has a prominent jaw, furrowed tongue, and large hands. His blood pressure is 142/91 mmHg. What is the most appropriate investigation?

Accepted Answer

Glucose tolerance test

Answer

MRI scan of the pituitary

Answer

Growth hormone levels

Answer

Serum prolactin levels

Question 9

A 50-year-old man with a history of diabetes presents with a poor urinary stream, hesitancy, difficulty in micturition, and incomplete bladder emptying. What is the most likely diagnosis?

Accepted Answer

Autonomic neuropathy

Answer

Benign prostatic hyperplasia (BPH)

Answer

Urinary tract infection (UTI)

Answer

Atonic bladder

Question 10

A 35-year-old mother of two children, aged 5 and 6 years, has had amenorrhea and galactorrhea for the past 12 months. Her serum prolactin level is 450 ng/ml. What is the most likely diagnosis?

Accepted Answer

Pituitary adenoma

Answer

Menopause

Answer

Intraductal papilloma of the breasts

Answer

Sheehan's syndrome

Endocrinology — MCQs

Endocrinology — MCQs

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