Endocrinology Practice Questions

Q: Thyroid function tests performed on serum from a 33-year-old woman reveal increased TSH, decreased total T4, decreased free T4, and decreased T3 uptake. Which of the following clinical features would be most likely to be seen in this patient?

Weight gain. ### Explanation **Analysis of Thyroid Function Tests (TFTs):** The patient’s lab results—**increased TSH** and **decreased free T4**—are diagnostic of **Primary Hypothyroidism** [1]. The decreased T3 uptake further confirms a low thyroid hormone state (as there are more vacant binding sites on Thyroid Binding Globulin). In hypothyroidism, the basal metabolic rate (BMR) decreases significantly, leading to the clinical manifestations described. **Why Weight Gain is Correct:** In primary hypothyroidism, the deficiency of thyroid hormones leads to a generalized slowing of metabolic processes. **Weight gain** occurs due to a combination of a decreased metabolic rate and the accumulation of glycosaminoglycans (myxedema), which causes fluid retention. This is a classic "hypometabolic" symptom. **Why Other Options are Incorrect:** * **A. Diarrhea:** Hypothyroidism causes decreased gastrointestinal motility, leading to **constipation**. Diarrhea is a feature of hyperthyroidism. * **B. Heat intolerance:** Patients with hypothyroidism feel cold due to low thermogenesis (**cold intolerance**). Heat intolerance is seen in hyperthyroidism [2]. * **C. Hyperactivity:** Hypothyroidism is characterized by psychomotor retardation, fatigue, and lethargy. Hyperactivity and tremors are hallmarks of thyrotoxicosis [2]. **NEET-PG High-Yield Pearls:** * **Most common cause:** Worldwide, iodine deficiency is the leading cause; however, in iodine-sufficient areas (and frequently in exams), **Hashimoto’s Thyroiditis** (autoimmune) is the most common cause. * **Early Sign:** An elevated TSH is the most sensitive initial marker for primary hypothyroidism [1]. * **Wolff-Chaikoff Effect:** Transient hypothyroidism caused by the ingestion of a large amount of iodine (e.g., amiodarone or contrast dye). * **Clinical Sign:** Delayed relaxation of deep tendon reflexes (Hungry-bomb sign) is a highly specific physical finding.

Q: Increased intracellular insulin is characterized by all of the following EXCEPT:

Increased glucagon secretion. **Explanation:** The physiological effects of insulin are primarily anabolic and occur in response to high blood glucose levels [1], [2]. To understand this question, one must recognize the **reciprocal relationship** between insulin and glucagon [4]. **Why "Increased glucagon secretion" is the correct answer:** Insulin and glucagon act as counter-regulatory hormones [3]. When insulin levels are high (hyperinsulinemia), insulin acts directly on the alpha cells of the pancreas to **inhibit** the secretion of glucagon [1], [4]. Therefore, increased insulin is characterized by *decreased* glucagon secretion, making Option B the false statement. **Analysis of Incorrect Options:** * **A. Increased insulin secretion:** This is a direct cause of increased intracellular insulin signaling. In states like insulinoma or post-prandial surges, high circulating insulin leads to increased cellular uptake [2]. * **C. Hypoglycemia:** Insulin promotes glucose uptake into skeletal muscle and adipose tissue via GLUT-4 translocation and inhibits hepatic gluconeogenesis [1], [5]. An excess of insulin inevitably leads to a drop in blood glucose [2], [4]. * **D. Hypokalemia:** Insulin stimulates the **Na+/K+ ATPase pump**, driving potassium from the extracellular fluid into the intracellular compartment [5]. This is the physiological basis for using insulin-glucose infusions to treat hyperkalemia [5]. **NEET-PG High-Yield Pearls:** * **The "Shift" Rule:** Insulin shifts three things into cells: Glucose, Potassium ($K^+$), and Magnesium ($Mg^{2+}$). * **Paracrine Inhibition:** Within the Islets of Langerhans, insulin (from Beta cells) inhibits glucagon (from Alpha cells), and somatostatin (from Delta cells) inhibits both [4]. * **Clinical Correlation:** In Diabetic Ketoacidosis (DKA) management, always check potassium levels before starting insulin, as insulin will further worsen hypokalemia [5].

Q: Addison disease with hypoparathyroidism and mucocutaneous candidiasis is seen with which condition?

Autoimmune polyglandular syndrome 1. **Explanation:** The clinical triad of **Chronic Mucocutaneous Candidiasis (CMC)**, **Hypoparathyroidism**, and **Addison’s Disease** is the hallmark of **Autoimmune Polyglandular Syndrome Type 1 (APS-1)**, also known as **APECED** (Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy) [1]. 1. **Why APS-1 is correct:** It is an autosomal recessive disorder caused by a mutation in the **AIRE (Autoimmune Regulator) gene** on chromosome 21 [1]. This gene is crucial for promoting self-tolerance in the thymus. The components typically appear in a specific chronological order: Candidiasis (infancy), followed by Hypoparathyroidism (childhood), and finally Addison’s disease (adolescence). Diagnosis requires at least two of these three primary features [1]. 2. **Why other options are incorrect:** * **Isolated autoimmune adrenalitis:** This refers to Addison’s disease occurring alone without other endocrinopathies or candidiasis. * **Triple A Syndrome (Allgrove Syndrome):** Characterized by **A**chalasia cardia, **A**lacrimia, and **A**drenal insufficiency (ACTH resistance). It does not involve hypoparathyroidism or candidiasis. * **APS-2 (Schmidt Syndrome):** This is more common than APS-1 and is characterized by Addison’s disease plus autoimmune thyroid disease and/or Type 1 Diabetes Mellitus. It notably **lacks** hypoparathyroidism and candidiasis [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** APS-1 is Autosomal Recessive; APS-2 is Polygenic (linked to HLA-DR3/DR4) [1]. * **Order of Appearance:** In APS-1, Mucocutaneous Candidiasis is usually the first manifestation. * **Ectodermal Dystrophy:** Look for enamel hypoplasia, vitiligo, and nail dystrophy in APS-1 cases. * **Mnemonic:** APS-1 = **C**andidiasis, **A**ddison’s, **H**ypoparathyroidism (**CAH**).

Q: A 36-year-old female presents with symptoms of hyperparathyroidism, a tumor in the pancreas, adrenal cortical hyperplasia, pituitary adenomas, an islet cell tumor, and cutaneous angiofibromas. What is the diagnosis?

Multiple Endocrine Neoplasia type 1 (MEN 1). The patient presents with the classic triad of **MEN 1 (Wermer Syndrome)**, often remembered by the **"3 Ps"**: **P**arathyroid hyperplasia (leading to hyperparathyroidism), **P**ancreatic islet cell tumors (e.g., gastrinomas, insulinomas), and **P**ituitary adenomas (most commonly prolactinomas) [1]. The presence of **cutaneous angiofibromas**, collagenomas, and lipomas are recognized dermatological manifestations specific to MEN 1. While adrenal cortical hyperplasia can occur in MEN 1, it is less common than the primary triad but helps differentiate it from other syndromes. The condition is caused by a mutation in the **MEN1 gene** on chromosome **11q13**, which encodes the protein **menin**. **Why other options are incorrect:** * **MEN 2A (Sipple Syndrome):** Characterized by Medullary Thyroid Carcinoma (MTC), Pheochromocytoma, and Parathyroid hyperplasia. It lacks pituitary and pancreatic involvement. * **MEN 2B:** Characterized by MTC, Pheochromocytoma, and distinct physical features like **Mucosal neuromas** and a **Marfanoid habitus**. It does not involve the parathyroid or pancreas. * **MEN 2C:** This is an obsolete term sometimes previously used to describe familial medullary thyroid carcinoma without other endocrine features; it is not a standard diagnosis in modern classification. **NEET-PG High-Yield Pearls:** * **Most common initial presentation of MEN 1:** Primary Hyperparathyroidism (seen in >90% of patients by age 40). * **Most common pancreatic tumor in MEN 1:** Gastrinoma (Zollinger-Ellison Syndrome). * **Inheritance:** All MEN syndromes are **Autosomal Dominant** [1]. * **MEN 2 Association:** Both 2A and 2B are associated with mutations in the **RET proto-oncogene**.

Q: Which drug is used for the management of both Type I and Type II Diabetes Mellitus?

Insulin. **Explanation:** **Insulin** is the correct answer because it is the only pharmacological agent essential for Type 1 Diabetes Mellitus (T1DM) and frequently required for Type 2 Diabetes Mellitus (T2DM). [1] * **Type 1 DM:** Characterized by absolute insulin deficiency due to autoimmune destruction of pancreatic beta cells. Exogenous insulin is life-saving and mandatory for survival. [1] * **Type 2 DM:** Characterized by insulin resistance and progressive beta-cell exhaustion. While initial management involves lifestyle changes and oral hypoglycemics, many patients eventually require insulin for glycemic control (secondary failure) or during acute stress, surgery, or pregnancy. [1] **Analysis of Incorrect Options:** * **Glipizide & Tolbutamide (Sulfonylureas):** These drugs act by stimulating insulin secretion from functional pancreatic beta cells (via the SUR1 receptor). Since T1DM patients have no functional beta cells, these drugs are ineffective and contraindicated. * **Metformin (Biguanide):** Its primary mechanism is the inhibition of hepatic gluconeogenesis and improvement of peripheral insulin sensitivity [1]. It requires endogenous insulin to be effective; therefore, it is not a standard treatment for T1DM (where insulin is absent), though it is sometimes used as an adjunct in obese T1DM patients. [1] **High-Yield Clinical Pearls for NEET-PG:** * **Pramlintide:** An amylin analogue that can also be used in both T1DM and T2DM (as an adjunct to insulin). * **Insulin Requirement:** In T1DM, the typical daily dose is **0.5–1.0 U/kg/day**. * **Honeymoon Phase:** A transient period in early T1DM where exogenous insulin requirements decrease significantly due to temporary recovery of remaining beta cells. * **Drug of Choice:** Insulin is the drug of choice for DM during **pregnancy** and for patients with **end-stage renal or hepatic failure**. [1]

Q: Which of the following laboratory findings is characteristic of primary hypothyroidism?

Decreased T3, decreased T4, increased TSH. ### Explanation **Correct Answer: A. Decreased T3, decreased T4, increased TSH** **Understanding the Concept:** Primary hypothyroidism occurs due to a failure of the thyroid gland itself (most commonly Hashimoto’s thyroiditis). When the thyroid gland cannot produce sufficient thyroid hormones (**T4 and T3**), the negative feedback loop to the pituitary gland is lost [1]. In response, the anterior pituitary increases the secretion of **Thyroid Stimulating Hormone (TSH)** to "force" the thyroid to work [2]. Therefore, the hallmark of primary hypothyroidism is a **high TSH** accompanied by **low free T4** [1]. **Analysis of Incorrect Options:** * **Option B (Decreased T3, increased T4, decreased TSH):** This pattern is physiologically inconsistent. High T4 would typically suppress TSH, not occur alongside a low TSH unless there is an exogenous source, but T3 would not be low. * **Option C (Normal T3, normal T4, increased TSH):** This is the characteristic profile of **Subclinical Hypothyroidism**. The pituitary is sensing a mild deficiency and compensating by raising TSH to keep T4/T3 within the normal range. * **Option D (Decreased T3, decreased T4, normal/low TSH):** This indicates **Secondary (Central) Hypothyroidism**, where the pathology lies in the pituitary or hypothalamus. The thyroid is capable of working, but the "stimulus" (TSH) is missing. **NEET-PG High-Yield Pearls:** 1. **TSH is the most sensitive screening test** for thyroid dysfunction. 2. **T4 vs. T3:** T4 is the primary secretory product of the thyroid; T3 is often the last to fall in hypothyroidism because peripheral conversion of T4 to T3 is maintained. 3. **Hashimoto’s Thyroiditis:** The most common cause of primary hypothyroidism in iodine-sufficient areas; associated with **Anti-TPO antibodies**. 4. **Wolff-Chaikoff Effect:** Hypothyroidism induced by a large load of iodine (e.g., amiodarone).

Question 1

Thyroid function tests performed on serum from a 33-year-old woman reveal increased TSH, decreased total T4, decreased free T4, and decreased T3 uptake. Which of the following clinical features would be most likely to be seen in this patient?

Accepted Answer

Weight gain

Answer

Diarrhea

Answer

Heat intolerance

Answer

Hyperactivity

Question 2

Increased intracellular insulin is characterized by all of the following EXCEPT:

Accepted Answer

Increased glucagon secretion

Answer

Increased insulin secretion

Answer

Hypoglycemia

Answer

Hypokalemia

Question 3

A 40-year-old woman presents with symptoms of light-headedness, sweating, palpitations, and hunger, most pronounced when she misses a meal. Her physical examination, vital signs, and past medical history are unremarkable. During an episode, her blood glucose level was 30 mg/dL, and symptoms resolved with juice. What is the most likely diagnosis?

Accepted Answer

Tumor of the pancreatic beta-cells

Answer

Excess growth hormone

Answer

Cushing disease

Answer

Thyrotoxicosis

Question 4

Addison disease with hypoparathyroidism and mucocutaneous candidiasis is seen with which condition?

Accepted Answer

Autoimmune polyglandular syndrome 1

Answer

Isolated autoimmune adrenalitis

Answer

Triple A syndrome

Answer

Autoimmune polyglandular syndrome 2

Question 5

A 35-year-old female with a history of amenorrhea and galactorrhea, and children aged 5 and 6 years, has elevated prolactin levels on blood examination. What is the most likely finding on CT scan of the head?

Accepted Answer

Pituitary adenoma

Answer

Craniopharyngioma

Answer

Sheehan's syndrome

Answer

Pinealoma

Question 6

A 36-year-old female presents with symptoms of hyperparathyroidism, a tumor in the pancreas, adrenal cortical hyperplasia, pituitary adenomas, an islet cell tumor, and cutaneous angiofibromas. What is the diagnosis?

Accepted Answer

Multiple Endocrine Neoplasia type 1 (MEN 1)

Answer

Multiple Endocrine Neoplasia type 2A (MEN 2A)

Answer

Multiple Endocrine Neoplasia type 2B (MEN 2B)

Answer

Multiple Endocrine Neoplasia type 2C (MEN 2C)

Question 7

Which drug is used for the management of both Type I and Type II Diabetes Mellitus?

Accepted Answer

Insulin

Answer

Glipizide

Answer

Tolbutamide

Answer

Metformin

Question 8

Which of the following laboratory findings is characteristic of primary hypothyroidism?

Accepted Answer

Decreased T3, decreased T4, increased TSH

Answer

Decreased T3, increased T4, decreased TSH

Answer

Normal T3, normal T4, increased TSH

Answer

Decreased T3, decreased T4, normal TSH

Question 9

A 35-year-old male presents with symptoms of palpitations, tremors, nervousness, and headache. His father has a history of type 2 DM and his mother has a history of psychiatric illness. He has no chronic medical conditions and takes no medications. He appears anxious, sweaty, and shaky. His fingerstick glucose is 45 mg/dl. The patient is administered a bolus of 50% glucose which rapidly improves his symptoms. CECT abdomen shows a mass. Which of the following is likely to be seen after overnight fasting?

Accepted Answer

Serum insulin, Serum pro-insulin, C-peptide levels: Increased, Increased, Increased

Answer

Serum insulin, Serum pro-insulin, C-peptide levels: Normal, Normal, Normal

Answer

Serum insulin, Serum pro-insulin, C-peptide levels: Increased, Normal, Decreased

Answer

Serum insulin, Serum pro-insulin, C-peptide levels: Decreased, Increased, Increased

Question 10

A patient sustains a transaction of the pituitary stalk following an accident. Which of the following clinical manifestations will NOT occur?

Accepted Answer

Diabetes mellitus

Answer

Diabetes insipidus

Answer

Hyperprolactinemia

Answer

Hypothyroidism

Endocrinology — MCQs

Endocrinology — MCQs

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