Endocrinology Practice Questions

Q: A woman presents with amenorrhea, headache, blurred vision, and galactorrhea. What is the most appropriate investigation?

Prolactin levels. ### Explanation The clinical presentation of **amenorrhea** and **galactorrhea** (the "Amenorrhea-Galactorrhea Syndrome") is the classic hallmark of **Hyperprolactinemia**. **Why Prolactin levels is the correct answer:** Prolactin inhibits the pulsatile release of GnRH from the hypothalamus, leading to low LH/FSH and subsequent amenorrhea. Simultaneously, it stimulates milk production (galactorrhea). The presence of **headache and blurred vision** (specifically bitemporal hemianopia) suggests a **Pituitary Adenoma** (Prolactinoma). As the tumor grows, it causes "mass effect" by compressing the optic chiasm and increasing intracranial pressure. Measuring serum prolactin is the essential first step to confirm the diagnosis before proceeding to imaging like an MRI. **Why the other options are incorrect:** * **LH and FSH:** While these levels are often low in hyperprolactinemia (hypogonadotropic hypogonadism), they are non-specific and do not identify the underlying cause of the galactorrhea or visual symptoms. * **HCG:** While pregnancy is the most common cause of secondary amenorrhea and must always be ruled out, it does not typically present with galactorrhea, headaches, and visual field defects. **High-Yield Clinical Pearls for NEET-PG:** * **Hook Effect:** In cases of giant prolactinomas with extremely high prolactin, lab tests may show falsely low levels. Serial dilution is required for an accurate reading. * **Drug-induced:** Always rule out dopamine antagonists (e.g., Metoclopramide, Risperidone) as they are common causes of hyperprolactinemia. * **Treatment:** Medical management with **Dopamine agonists (Cabergoline > Bromocriptine)** is the first-line treatment, even for large macroprolactinomas. Surgery is reserved for refractory cases.

Q: A lady presents with central obesity and abdominal skin showing purple striae. What is the most likely diagnosis?

Cushing's syndrome. ### Explanation The clinical presentation of **central obesity** and **purple striae** is a classic hallmark of **Cushing’s syndrome**, which results from chronic exposure to excess glucocorticoids (hypercortisolism). [1] **Why Cushing’s Syndrome is Correct:** Excess cortisol leads to a redistribution of fat to the trunk and face (moon facies, buffalo hump), while causing protein catabolism. The **purple striae** (typically >1 cm wide) occur because cortisol inhibits fibroblasts and causes loss of collagen, making the skin thin and translucent, allowing the underlying vascularity to show through. [1] **Analysis of Incorrect Options:** * **Conn’s Syndrome (Primary Hyperaldosteronism):** Characterized by the triad of hypertension, hypokalemia, and metabolic alkalosis. It does not cause obesity or skin changes. * **Addison’s Disease (Primary Adrenal Insufficiency):** This is the opposite of Cushing’s. It presents with weight loss, hypotension, and hyperpigmentation (due to high ACTH). * **Hypothyroidism:** While it causes weight gain, it is usually generalized (not central) and associated with dry skin, bradycardia, and non-pitting edema (myxedema), rather than purple striae. **High-Yield Clinical Pearls for NEET-PG:** 1. **Screening Tests:** The best initial tests are the 24-hour urinary free cortisol, late-night salivary cortisol, or the Low-Dose Dexamethasone Suppression Test (LDDST). [2] 2. **Proximal Myopathy:** Patients often have difficulty rising from a chair due to muscle wasting. [1] 3. **Striae Distinction:** Striae in Cushing’s are typically **wide (>1 cm) and violaceous**, distinguishing them from the pale/pink striae seen in normal pregnancy or rapid weight gain. 4. **Most Common Cause:** Overall, the most common cause is iatrogenic (exogenous steroids). The most common endogenous cause is Cushing’s Disease (ACTH-secreting pituitary adenoma). [1]

Q: Whipple's triad is seen in which of the following conditions?

Islet cell tumor. **Explanation:** Whipple’s triad is the classic clinical diagnostic criteria for **Insulinoma**, which is a functional **Islet cell tumor** of the pancreas [1]. It consists of three components: 1. Symptoms of hypoglycemia (e.g., sweating, palpitations, confusion) triggered by fasting or exertion. 2. Documentation of low blood glucose (<50 mg/dL) at the time of symptoms [3]. 3. Immediate relief of symptoms following the administration of glucose. **Why the other options are incorrect:** * **Carcinoma head of pancreas:** Typically presents with painless obstructive jaundice, weight loss, and a palpable gallbladder (Courvoisier’s law), not hypoglycemia. * **Argentaffinoma (Carcinoid Tumor):** These neuroendocrine tumors secrete serotonin, leading to Carcinoid syndrome (flushing, diarrhea, and wheezing) [2]. They do not typically cause hypoglycemia. * **Cholangiocarcinoma:** This is a malignancy of the bile ducts presenting with biliary obstruction and jaundice; it has no association with insulin secretion or Whipple’s triad. **NEET-PG High-Yield Pearls:** * **Insulinoma** is the most common endogenous cause of hyperinsulinemic hypoglycemia in adults. * **Rule of 10s:** 10% are malignant, 10% are multiple, and 10% are associated with **MEN-1 syndrome**. * **Diagnosis:** The gold standard is the **72-hour supervised fast**. * **Lab findings:** High Insulin, High C-peptide, and High Pro-insulin levels (unlike exogenous insulin intake where C-peptide is suppressed) [1]. * **Localization:** Endoscopic Ultrasound (EUS) is highly sensitive for detecting these small tumors.

Q: A 17-year-old girl presents with weight gain, hair loss, constipation, and weakness. Her free T4 level is low and TSH is increased. Which of the following is the most likely diagnosis?

Hashimoto's thyroiditis. ### Explanation **1. Why Hashimoto’s Thyroiditis is Correct:** The clinical presentation of weight gain, hair loss, constipation, and weakness is classic for **hypothyroidism** [1]. The laboratory findings of a **low free T4** and an **increased TSH** confirm **primary hypothyroidism**. In a 17-year-old female, the most common cause of primary hypothyroidism is Hashimoto’s thyroiditis (Chronic Lymphocytic Thyroiditis). It is an autoimmune destruction of the thyroid gland, often characterized by the presence of anti-TPO and anti-thyroglobulin antibodies. **2. Why the Other Options are Incorrect:** * **Graves' Disease:** This is the most common cause of *hyperthyroidism*. Patients typically present with weight loss, tachycardia, heat intolerance, and low TSH levels [1]. * **McCune-Albright Syndrome:** This is a triad of polyostotic fibrous dysplasia, café-au-lait spots, and autonomous endocrine hyperfunction (most commonly **precocious puberty**, not hypothyroidism). * **TSH-secreting Pituitary Adenoma:** This is a rare cause of *secondary hyperthyroidism*. It would present with **elevated** free T4 levels and an inappropriately normal or elevated TSH. **3. High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Histopathology showing **Hurthle cells** (Askanazy cells) and lymphocytic infiltration with germinal centers. * **Antibody Profile:** Anti-TPO (Antimicrosomal) antibodies are the most sensitive marker (found in >90% of cases). * **Associated Risk:** Hashimoto’s thyroiditis increases the risk of **Primary Thyroid B-cell Lymphoma**. * **Wolff-Chaikoff Effect:** Hashimoto’s patients are uniquely sensitive to iodine loads, which can precipitate or worsen hypothyroidism.

Q: What is the recommended target HbA1c to minimize the risk of vascular complications in a diabetic individual?

7% or less. The primary goal of diabetes management is to prevent chronic complications. Large-scale clinical trials (such as **UKPDS** for Type 2 DM and **DCCT** for Type 1 DM) have conclusively demonstrated that maintaining an **HbA1c of ≤ 7%** significantly reduces the risk of **microvascular complications** (retinopathy, nephropathy, and neuropathy) [1]. While the impact on macrovascular outcomes (stroke, MI) is more evident over long-term follow-up (the "legacy effect"), the 7% threshold remains the standard recommendation for most non-pregnant adults [2]. **Analysis of Options:** * **Option C (Correct):** An HbA1c < 7% balances the benefits of complication prevention with the risks of hypoglycemia. * **Options A, B, and D (Incorrect):** HbA1c levels of 8%, 9%, or 10% are associated with a progressive and exponential increase in the risk of tissue damage due to advanced glycation end-products (AGEs) and oxidative stress. **Clinical Pearls for NEET-PG:** 1. **Individualization:** While < 7% is the general target, a more stringent goal (**< 6.5%**) may be suggested for young patients with short disease duration and no CVD [1]. Conversely, a less stringent goal (**< 8%**) is preferred for elderly patients, those with limited life expectancy, or those with a history of severe hypoglycemia. 2. **Diagnosis:** An HbA1c **≥ 6.5%** is diagnostic of Diabetes Mellitus. 3. **The 3-Month Rule:** HbA1c reflects average glycemia over the preceding 8–12 weeks (the lifespan of an RBC). 4. **False Lows:** HbA1c may be falsely low in conditions with high RBC turnover (e.g., hemolytic anemia, pregnancy, or recent blood transfusion).

Q: A 3cm adrenal mass is found incidentally on CT scan. Which of the following investigations is NOT indicated?

Adrenalectomy. ### Explanation The management of an **Adrenal Incidentaloma** (an adrenal mass ≥1 cm found incidentally on imaging) follows a strict protocol: first, determine if the mass is **hormonally active**, and second, assess its **malignant potential** [1]. **Why Adrenalectomy is the correct answer:** Surgery is a **treatment**, not an investigation. An adrenalectomy is only indicated if the mass is functional (hormone-secreting), shows suspicious radiological features (e.g., size >4 cm, high Hounsfield units), or shows significant growth on follow-up [1]. A 3 cm non-functional mass with benign imaging characteristics is typically managed with observation, not immediate surgery. **Why the other options are incorrect (Investigations that ARE indicated):** * **Dexamethasone Suppression Test (1 mg overnight):** This is the primary screening tool to rule out **Autonomous Cortisol Secretion (Subclinical Cushing’s)** [3]. * **Urinary or Plasma Catecholamines/Metanephrines:** Essential to rule out **Pheochromocytoma**, even in asymptomatic patients, as a biopsy or surgery on an undiagnosed pheochromocytoma can trigger a lethal hypertensive crisis [1], [4]. * **Midnight Plasma/Salivary Cortisol:** Along with 24-hour urinary free cortisol, these are alternative or confirmatory tests for hypercortisolism [3]. **High-Yield Clinical Pearls for NEET-PG:** 1. **Size Cut-off:** Masses **>4 cm** are generally considered for resection due to increased risk of adrenocortical carcinoma [1]. 2. **Hounsfield Units (HU):** On non-contrast CT, **<10 HU** suggests a lipid-rich benign adenoma [1]. 3. **Hypertension Screening:** If the patient is hypertensive, you must also check the **Aldosterone-to-Renin Ratio (ARR)** to rule out Primary Aldosteronism [2]. 4. **Biopsy Rule:** Never biopsy an adrenal mass until a Pheochromocytoma has been biochemically ruled out [1].

Question 1

A 30-year-old woman presents with headache, visual disturbances, deepening of the voice, generalized weakness, amenorrhea for one year, and a recent requirement for a larger shoe size. Laboratory studies show impaired glucose tolerance. What additional diagnostic procedure would be most useful?

Accepted Answer

Magnetic resonance imaging of the sella turcica

Answer

Complete blood count with differential count

Answer

Computed tomography scan of the abdomen

Answer

Test for serum 21-hydroxylase activity

Question 2

A woman presents with amenorrhea, headache, blurred vision, and galactorrhea. What is the most appropriate investigation?

Accepted Answer

Prolactin levels

Answer

Luteinizing hormone (LH)

Answer

Follicle-stimulating hormone (FSH)

Answer

Human chorionic gonadotropin (HCG)

Question 3

A lady presents with central obesity and abdominal skin showing purple striae. What is the most likely diagnosis?

Accepted Answer

Cushing's syndrome

Answer

Conn's syndrome

Answer

Addison's disease

Answer

Hypothyroidism

Question 4

Hyperprolactinoma causes which of the following menstrual abnormalities?

Accepted Answer

Oligomenorrhea

Answer

Intermenstrual bleeding

Answer

Prolonged menstruation

Answer

Polymenorrhea

Question 5

Whipple's triad is seen in which of the following conditions?

Accepted Answer

Islet cell tumor

Answer

Carcinoma head of pancreas

Answer

Argentaffinoma

Answer

Cholangiocarcinoma

Question 6

A 17-year-old girl presents with weight gain, hair loss, constipation, and weakness. Her free T4 level is low and TSH is increased. Which of the following is the most likely diagnosis?

Accepted Answer

Hashimoto's thyroiditis

Answer

Graves' disease

Answer

McCune-Albright syndrome

Answer

TSH-secreting pituitary adenoma

Question 7

What is the recommended target HbA1c to minimize the risk of vascular complications in a diabetic individual?

Accepted Answer

7% or less

Answer

10% or more

Answer

8%

Answer

9%

Question 8

A 50-year-old man with fasting blood glucose >140 mg/dL on two occasions is put on a restricted caloric diet and started on a glucagon-like peptide-1 (GLP-1) receptor agonist. Which of the following laboratory studies is most likely to afford the best method of monitoring disease control in this man?

Accepted Answer

Glycosylated hemoglobin

Answer

Cholesterol, total

Answer

Fasting plasma glucose

Answer

Microalbuminuria

Question 9

A 3cm adrenal mass is found incidentally on CT scan. Which of the following investigations is NOT indicated?

Accepted Answer

Adrenalectomy

Answer

Dexamethasone suppression test

Answer

Measurement of urinary or plasma catecholamines

Answer

Midnight plasma cortisol measurement

Question 10

A diabetic patient in hypoglycemia does not regain consciousness despite blood glucose restoration to normal. Which one of the following is a not likely condition or explanation?

Accepted Answer

Alcohol intoxication

Answer

Cerebral edema

Answer

Post-ictal state

Answer

Cerebral haemorrhage

Endocrinology — MCQs

Endocrinology — MCQs

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