Endocrinology Practice Questions

Q: Which of the following is the most common cause of insulin resistance?

Obesity. **Explanation:** **1. Why Obesity is the Correct Answer:** Obesity is the most common cause of insulin resistance worldwide. The underlying mechanism involves the release of **Free Fatty Acids (FFAs)** and pro-inflammatory **adipokines** (such as TNF-alpha, IL-6, and Resistin) from excess adipose tissue [1]. These substances interfere with the insulin signaling pathway, specifically inhibiting the phosphorylation of Insulin Receptor Substrates (IRS). Furthermore, obesity leads to a decrease in **Adiponectin**, a hormone that normally enhances insulin sensitivity [2]. **2. Why the Other Options are Incorrect:** * **Post-receptor defects:** While post-receptor signaling abnormalities (like impaired GLUT-4 translocation) are the actual *molecular* mechanism of resistance, they are usually secondary to obesity or genetic syndromes [2]. They are not the "cause" in a clinical epidemiological sense. * **Liver dysfunction:** While the liver is a primary site of insulin action, liver disease (like NAFLD) is more often a *consequence* or a co-morbidity of insulin resistance rather than its primary inciting cause. * **Pancreatic dysfunction:** This typically refers to impaired insulin *secretion* (Beta-cell failure), which leads to Type 2 Diabetes progression, but it does not cause resistance to the insulin already present in the system [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Acanthosis Nigricans:** The most common clinical cutaneous marker of insulin resistance. * **Metabolic Syndrome:** Insulin resistance is the pathophysiological hallmark, characterized by abdominal obesity, hypertension, and dyslipidemia [1]. * **Gold Standard Investigation:** The **Hyperinsulinemic Euglycemic Clamp** is the gold standard for measuring insulin resistance, though HOMA-IR is more commonly used in research. * **PCOS:** A very common cause of insulin resistance in young females, often independent of BMI but exacerbated by obesity.

Q: Which of the following is NOT a common symptom of pheochromocytoma?

Hypotension. Pheochromocytoma is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla. The clinical presentation is primarily driven by the excessive release of epinephrine and norepinephrine [2]. **Why Hypotension is the Correct Answer:** The hallmark of pheochromocytoma is **Hypertension**, not hypotension. Excess catecholamines cause potent vasoconstriction (via $\alpha_1$ receptors) and increased cardiac output (via $\beta_1$ receptors), leading to persistent or paroxysmal high blood pressure [2]. While "orthostatic hypotension" can occasionally occur due to low plasma volume and impaired autonomic reflexes, absolute hypotension is not a common or characteristic symptom [1]. **Why the other options are incorrect:** * **Headache (A):** This is the most common symptom (seen in ~90% of symptomatic patients). It is typically paroxysmal, severe, and bilateral. * **Palpitations (B):** Excess catecholamines increase the heart rate and myocardial contractility, leading to forceful or rapid heartbeats [2]. * **Abdominal pain (C):** While less famous than the "classic triad," abdominal pain can occur due to catecholamine-induced mesenteric vasoconstriction or the mass effect of the tumor itself. **High-Yield Clinical Pearls for NEET-PG:** * **The Classic Triad:** Episodic **P**alpitations, **H**ache, and **D**iaphoresis (P-H-D). * **Rule of 10s:** 10% are bilateral, 10% are extra-adrenal (Paragangliomas), 10% are malignant, and 10% are familial. * **Diagnosis:** Best initial screening test is **24-hour urinary fractionated metanephrines** or plasma free metanephrines. * **Management:** Always start **Alpha-blockers first** (e.g., Phenoxybenzamine) before Beta-blockers to prevent a hypertensive crisis caused by unopposed alpha-mediated vasoconstriction [1].

Q: Goitrous hypothyroidism commonly occurs in all of the following conditions except?

Thyroprivic hypothyroidism. The core concept behind **Goitrous Hypothyroidism** is the compensatory hypertrophy of the thyroid gland. When thyroid hormone levels (T3/T4) fall, the pituitary gland increases the secretion of **TSH** [2]. If the thyroid tissue is present and capable of responding, TSH stimulates glandular growth, leading to a goiter. **Why Thyroprivic Hypothyroidism is the correct answer:** "Thyroprivic" refers to the **loss or absence of thyroid tissue**. This occurs in conditions like thyroid agenesis (congenital), surgical removal (thyroidectomy), or total destruction via radioactive iodine therapy [1]. Since there is little to no thyroid tissue left to respond to TSH stimulation, a goiter cannot form. This is a "non-goitrous" form of hypothyroidism. **Analysis of Incorrect Options:** * **Hashimoto’s Thyroiditis:** This is the most common cause of goitrous hypothyroidism in iodine-sufficient areas. Lymphocytic infiltration and TSH stimulation lead to a firm, rubbery goiter. * **Dyshormonogenesis:** These are genetic defects in the enzymatic pathways of thyroid hormone synthesis (e.g., Pendred syndrome) [1]. The biosynthetic block leads to low T4, high TSH, and subsequent thyroid enlargement. * **Iodine Deficiency:** The most common cause of goitrous hypothyroidism worldwide (Endemic Goiter). Lack of iodine prevents hormone synthesis, triggering a massive TSH response and glandular hypertrophy. **High-Yield Clinical Pearls for NEET-PG:** * **Wolff-Chaikoff Effect:** Goitrous hypothyroidism induced by excessive iodine intake (e.g., Amiodarone). * **Pendred Syndrome:** Characterized by dyshormonogenetic goiter and sensorineural deafness. * **Most common cause of Goiter:** Iodine deficiency (Worldwide); Hashimoto’s (Developed nations). * **Thyroprivic vs. Trophoprivic:** Thyroprivic is a primary thyroid tissue loss; Trophoprivic refers to secondary hypothyroidism due to loss of TSH (pituitary failure).

Q: Which of the following is the most common cause of hypergonadotropic hypogonadism in males?

Klinefelter's syndrome. **Explanation:** **Hypergonadotropic hypogonadism** (Primary Hypogonadism) is characterized by testicular failure leading to low testosterone levels, which results in a compensatory rise in gonadotropins (FSH and LH) due to the loss of negative feedback on the pituitary gland [1]. **Why Klinefelter’s Syndrome is correct:** Klinefelter’s syndrome (47, XXY) is the **most common congenital cause** and the most common cause overall of primary testicular failure [1]. The extra X chromosome leads to progressive hyalinization and fibrosis of the seminiferous tubules and dysfunction of Leydig cells [1]. This results in azoospermia, low testosterone, and characteristically elevated FSH and LH levels [1]. **Analysis of Incorrect Options:** * **Viral Orchitis (e.g., Mumps):** While it is a common *acquired* cause of testicular atrophy, it is less frequent than Klinefelter’s syndrome in the general population presenting with hypogonadism [1]. * **Kallmann’s Syndrome:** This is a form of **hypogonadotropic hypogonadism** (Secondary Hypogonadism). It is caused by a failure of GnRH-secreting neurons to migrate, leading to low FSH/LH and low testosterone, often associated with anosmia. * **Noonan Syndrome:** Often called the "Male Turner Syndrome," it can cause cryptorchidism and primary hypogonadism, but it is significantly rarer than Klinefelter’s syndrome [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Karyotype:** 47, XXY is the most common; Barr bodies are present on buccal smear. * **Clinical Features:** Tall stature, eunuchoid body proportions, gynecomastia, small firm testes (<2 cm), and female-pattern hair distribution [1]. * **Biochemical Profile:** ↓ Testosterone, ↑ FSH, ↑ LH, and ↑ Estradiol [1]. * **Risk:** Increased risk of breast cancer (20x) and extragonadal germ cell tumors (mediastinal) [1].

Q: Recurrent balanoposthitis is commonly seen in which of the following conditions?

Diabetes Mellitus. **Explanation:** **Recurrent balanoposthitis** (inflammation of the glans penis and prepuce) is a classic clinical marker for **Diabetes Mellitus (DM)**. In many cases, it is the initial presenting symptom that leads to a new diagnosis of Type 2 DM. **1. Why Diabetes Mellitus is the Correct Answer:** The underlying mechanism is primarily due to **hyperglycosuria** (glucose in the urine). The presence of sugar on the skin of the genital area provides an ideal culture medium for fungi, specifically *Candida albicans*. Furthermore, hyperglycemia impairs neutrophil function and cell-mediated immunity, making diabetic patients more susceptible to persistent and recurrent fungal infections. Chronic inflammation can eventually lead to acquired phimosis. **2. Analysis of Incorrect Options:** * **Herpes Simplex (HSV):** While HSV causes genital ulcers (vesicles on an erythematous base), it typically presents as episodic painful sores rather than generalized inflammation of the glans (balanitis). It is not the "most common" cause of generalized recurrent balanoposthitis in clinical practice compared to DM. * **Smoking & Alcohol consumption:** These are general risk factors for various systemic diseases but have no direct causal or strong statistical link to the development of balanoposthitis. **Clinical Pearls for NEET-PG:** * **High-Yield Association:** In any uncircumcised male presenting with recurrent balanoposthitis or fungal infections, the first investigation to perform is a **Fast Blood Sugar (FBS) or HbA1c**. * **SGLT-2 Inhibitors:** Modern diabetes medications like Dapagliflozin increase urinary glucose excretion and are notorious for causing an increased risk of genital mycotic infections (balanoposthitis in men, vulvovaginitis in women). * **Pathogen:** *Candida albicans* is the most common organism isolated in diabetic balanoposthitis.

Q: Which of the following are symptoms of hyperthyroidism?

All of the above. **Explanation:** Hyperthyroidism is a clinical syndrome resulting from excessive circulating thyroid hormones ($T_3$ and $T_4$), which leads to a generalized hypermetabolic state and increased sympathetic nervous system activity [1]. **Why "All of the above" is correct:** * **Muscle Weakness (Option A):** Excess thyroid hormone promotes a catabolic state, leading to protein breakdown. This results in **proximal myopathy**, where patients typically struggle with tasks like climbing stairs or rising from a chair [2]. * **Weight Loss (Option B):** Despite an increased appetite (polyphagia), patients experience weight loss due to a significantly elevated **Basal Metabolic Rate (BMR)** and increased thermogenesis [1]. * **Lid Lag (Option C):** This is a classic sign of sympathetic overactivity. Increased adrenergic tone causes contraction of the **Müller’s muscle** (superior tarsal muscle), leading to the characteristic "lid lag" (von Graefe’s sign) where the upper eyelid does not follow the downward movement of the eyeball smoothly. **Clinical Pearls for NEET-PG:** 1. **Cardiovascular:** Sinus tachycardia and **Atrial Fibrillation** (especially in elderly patients) are high-yield associations [3]. 2. **Neuromuscular:** Look for fine tremors, hyperreflexia, and anxiety [1]. 3. **Graves’ Disease Specifics:** While lid lag is seen in all forms of thyrotoxicosis, **Exophthalmos** (proptosis) and **Pretibial Myxedema** are specific to Graves’ disease due to TSH-receptor antibody activity [1], [2]. 4. **Apathetic Hyperthyroidism:** In elderly patients, typical symptoms may be absent; they may present only with weight loss or new-onset AFib.

Question 1

Polyglandular syndrome (Schmidt syndrome) is associated with adrenocortical deficiency and which of the following conditions?

Accepted Answer

Graves disease

Answer

Hypoparathyroidism

Answer

Hashimoto's thyroiditis

Answer

Islet cell adenoma

Question 2

Which of the following is the most common cause of insulin resistance?

Accepted Answer

Obesity

Answer

Post-receptor defects

Answer

Liver dysfunction

Answer

Pancreatic dysfunction

Question 3

Which of the following is NOT a common symptom of pheochromocytoma?

Accepted Answer

Hypotension

Answer

Headache

Answer

Palpitations

Answer

Abdominal pain

Question 4

A 65-year-old man presents with vision loss, headaches, cold intolerance, and unintentional weight gain of 5kg in 3 months. Examination reveals bitemporal hemianopia and a pulse of 50 bpm. A thyroid function test is ordered. Which of the following test results is most likely to be seen in this patient?

Accepted Answer

TSH: Low, Free T4: Low, Free T3: Low

Answer

TSH: High, Free T4: Low, Free T3: Low

Answer

TSH: High, Free T4: Normal, Free T3: Normal

Answer

TSH: Low, Free T4: High, Free T3: High

Question 5

Goitrous hypothyroidism commonly occurs in all of the following conditions except?

Accepted Answer

Thyroprivic hypothyroidism

Answer

Hashimoto's thyroiditis

Answer

Dyshoromonogenesis

Answer

Iodine deficiency

Question 6

Which of the following is the most common cause of hypergonadotropic hypogonadism in males?

Accepted Answer

Klinefelter's syndrome

Answer

Viral orchitis

Answer

Kallman's syndrome

Answer

Noonan syndrome

Question 7

Which of the following is NOT a common clinical manifestation of thyrotoxicosis?

Accepted Answer

Weight gain

Answer

Gynaecomastia

Answer

Loss of libido

Answer

Goiter

Question 8

Recurrent balanoposthitis is commonly seen in which of the following conditions?

Accepted Answer

Diabetes Mellitus

Answer

Herpes simplex

Answer

Smoking

Answer

Alcohol consumption

Question 9

Autonomic neuropathy is characterized by all of the following except:

Accepted Answer

Gustatory sweating

Answer

Tachycardia

Answer

Diarrhoea

Answer

Pupillary dilatation

Question 10

Which of the following are symptoms of hyperthyroidism?

Accepted Answer

All of the above

Answer

Muscle weakness

Answer

Weight loss

Answer

Lid lag

Endocrinology — MCQs

Endocrinology — MCQs

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