Endocrinology Practice Questions

Q: Which condition can cause profound hyperlipidemia?

Hypothyroidism. **Explanation:** **Hypothyroidism** is a classic cause of secondary hyperlipidemia. Thyroid hormones play a critical role in lipid metabolism by upregulating the expression of **LDL receptors** on hepatocytes [1]. In a hypothyroid state, the decrease in thyroid hormones leads to a reduced number of LDL receptors, resulting in decreased clearance of LDL-cholesterol from the plasma. Additionally, hypothyroidism decreases the activity of **lipoprotein lipase (LPL)** and slows the oxidative metabolism of cholesterol into bile acids, leading to profound elevations in total cholesterol and LDL levels. **Analysis of Incorrect Options:** * **Hyperinsulinemia (Option A):** While insulin resistance is associated with metabolic syndrome and dyslipidemia (high triglycerides, low HDL), acute hyperinsulinemia typically promotes lipid storage and inhibits lipolysis [2]. * **Hyperparathyroidism (Option B):** This condition primarily affects calcium and phosphate homeostasis. It does not have a direct, significant impact on lipid profiles. * **Hyperthyroidism (Option D):** Excess thyroid hormone increases the expression of LDL receptors and accelerates cholesterol metabolism [1]. Consequently, hyperthyroidism typically causes **hypocholesterolemia**. **NEET-PG High-Yield Pearls:** * **Type IIb Hyperlipidemia:** Hypothyroidism most commonly presents as an elevation in LDL (Type IIa), but can also cause a mixed picture (Type IIb) with elevated VLDL. * **Statin Warning:** Always check TSH levels before starting a patient on statins. Hypothyroidism predisposes patients to **statin-induced myopathy** and rhabdomyolysis [2]. * **Other Secondary Causes:** Nephrotic syndrome (causes profound hypercholesterolemia), Obstructive jaundice, and Diabetes Mellitus.

Q: What is the appropriate treatment for a 42-year-old obese male presenting with a blood glucose of 450 mg/dL, urine albumin of 2+, urine sugar of 4+, and urine ketones of 1+?

Insulin. **Explanation:** The clinical presentation of severe hyperglycemia (450 mg/dL) associated with **ketonuria** (1+) and significant glycosuria (4+) indicates a state of severe insulin deficiency or acute metabolic decompensation. **Why Insulin is the Correct Choice:** In any patient presenting with marked hyperglycemia (>300 mg/dL) and ketosis, **Insulin** is the mandatory first-line treatment. The presence of urine ketones, even at 1+, suggests that the body has shifted to fat metabolism due to inadequate insulin action [1]. Insulin is required to rapidly suppress ketogenesis, lower blood glucose, and prevent progression to Diabetic Ketoacidosis (DKA) [3]. Furthermore, the presence of albuminuria (2+) suggests underlying diabetic nephropathy, where oral hypoglycemic agents (OHAs) must be used with extreme caution or avoided [4]. **Why Other Options are Incorrect:** * **Glibenclamide & Glipizide (Sulfonylureas):** These are secretagogues that require functional beta cells. In a glucose-toxic state (glucose >300 mg/dL), beta cells are "stunned" (glucose toxicity), making these drugs ineffective [2]. Moreover, they cannot treat ketosis. * **Metformin (Biguanide):** While a first-line drug for obese Type 2 diabetics, it is contraindicated in acute metabolic distress or severe renal impairment (suggested here by albuminuria) due to the risk of lactic acidosis. It is also insufficient to manage acute ketosis. **NEET-PG High-Yield Pearls:** * **Indications for Insulin in T2DM:** Severe hyperglycemia (>300 mg/dL or HbA1c >10%), ketonuria/DKA, pregnancy, surgery, or severe systemic illness [1]. * **Glucose Toxicity:** High glucose levels paradoxically inhibit insulin secretion; temporary insulin therapy "unmasks" beta-cell function. * **Albuminuria:** 2+ albuminuria indicates significant proteinuria; always check serum creatinine before prescribing Metformin [4].

Q: Which of the following is a criterion for the diagnosis of diabetes mellitus?

Hemoglobin A1c (HbA1c) >= 6.5%. The diagnosis of Diabetes Mellitus (DM) is based on specific glycemic thresholds established by the American Diabetes Association (ADA) and WHO. These criteria identify levels of hyperglycemia associated with an increased risk of microvascular complications, particularly retinopathy [1]. **Explanation of the Correct Option:** * **Option D (HbA1c ≥ 6.5%):** This is a standardized diagnostic criterion. HbA1c reflects the average blood glucose over the preceding 8–12 weeks. It is preferred for its convenience (no fasting required) and lower day-to-day variability compared to plasma glucose [1]. **Analysis of Incorrect Options:** * **Option A (Fasting Plasma Glucose > 100 mg/dL):** The diagnostic threshold for DM is **≥ 126 mg/dL** (7.0 mmol/L) [1]. A value between 100–125 mg/dL is classified as Impaired Fasting Glucose (Pre-diabetes). * **Options B & C (2-hour OGTT):** For the Oral Glucose Tolerance Test (75g anhydrous glucose), the diagnostic threshold for DM is **≥ 200 mg/dL**. A value of 140–199 mg/dL is classified as Impaired Glucose Tolerance (Pre-diabetes). **High-Yield Clinical Pearls for NEET-PG:** 1. **Random Plasma Glucose:** A value **≥ 200 mg/dL** in a patient with classic symptoms of hyperglycemia (polyuria, polydipsia, weight loss) or hyperglycemic crisis is also diagnostic [1]. 2. **Confirmation:** In the absence of unequivocal hyperglycemia (symptoms), the diagnosis requires two abnormal test results from the same sample or in two separate test samples. 3. **HbA1c Limitations:** It may be unreliable in conditions with high red cell turnover (e.g., hemolytic anemia, pregnancy, recent hemorrhage, or chronic kidney disease). 4. **Prediabetes Summary:** HbA1c 5.7–6.4%; FPG 100–125 mg/dL; 2-hr OGTT 140–199 mg/dL.

Q: Which one of the following features is NOT associated with primary hyperparathyroidism?

Hypercementosis.. Primary hyperparathyroidism (PHPT) is characterized by excessive secretion of Parathyroid Hormone (PTH), leading to increased bone resorption and hypercalcemia [1]. **Why Hypercementosis is the Correct Answer:** Hypercementosis (excessive deposition of cementum at the roots of teeth) is **not** associated with PHPT. Instead, it is a characteristic finding in **Paget’s disease of bone**, acromegaly, or local trauma. In PHPT, the primary skeletal effect is bone demineralization and resorption, which is the physiological opposite of the apposition seen in hypercementosis. **Analysis of Incorrect Options:** * **Giant cell tumor (Brown Tumor):** Excessive PTH stimulates osteoclastic activity, leading to localized bone destruction [1]. These "tumors" are actually non-neoplastic reactive lesions filled with fibrous tissue and giant cells, appearing as radiolucent areas. * **Sharply defined radiolucencies:** These represent "Brown tumors" or osteitis fibrosa cystica, which commonly occur in the maxilla and mandible. * **Partial loss of lamina dura:** The lamina dura is the cortical bone lining the tooth socket. Its resorption (loss of the white line around the root) is one of the earliest and most classic radiographic signs of hyperparathyroidism. **NEET-PG High-Yield Pearls:** * **Classic Triad:** "Stones (renal calculi), Bones (osteitis fibrosa cystica), Groans (abdominal pain/peptic ulcers), and Psychic Moans (depression/confusion)" [3]. * **Radiology:** Look for **subperiosteal bone resorption**, most specifically on the radial aspect of the middle phalanges (pathognomonic). * **Skull finding:** "Salt and pepper" appearance due to multiple tiny lucencies. * **Biochemical profile:** ↑ Serum Calcium, ↓ Serum Phosphate, ↑ PTH, and ↑ Alkaline Phosphatase [2].

Q: Pancreatitis, pituitary tumor, and pheochromocytoma may be associated with which of the following?

Medullary carcinoma of the thyroid. ### Explanation The correct answer is **Medullary Carcinoma of the Thyroid (MTC)**. This question tests the recognition of **Multiple Endocrine Neoplasia (MEN) syndromes**, specifically the overlap between MEN 1 and MEN 2. **Why Medullary Carcinoma is Correct:** Medullary carcinoma of the thyroid is a hallmark feature of **MEN 2A and 2B**. * **Pheochromocytoma** is a key component of both MEN 2A and 2B. * **Pituitary tumors** are a classic component of **MEN 1** (Wermer Syndrome). * **Pancreatitis** in this context is usually a secondary complication of **Hypercalcemia**, which results from **Primary Hyperparathyroidism** (found in both MEN 1 and MEN 2A). The presence of MTC alongside pheochromocytoma and hypercalcemia-induced pancreatitis strongly points toward the MEN spectrum. **Why the Other Options are Incorrect:** * **B, C, and D (Papillary, Anaplastic, and Follicular Carcinomas):** These are "Differentiated" or "Undifferentiated" thyroid cancers derived from follicular cells. Unlike MTC (which arises from parafollicular C-cells), these cancers are **not** associated with MEN syndromes or catecholamine-secreting tumors like pheochromocytoma. **High-Yield Clinical Pearls for NEET-PG:** * **MEN 1 (3 Ps):** **P**ituitary, **P**arathyroid, **P**ancreas (Enteropancreatic tumors like Gastrinoma/Zollinger-Ellison Syndrome). * **MEN 2A (1 M, 2 Ps):** **M**edullary Thyroid CA, **P**heochromocytoma, **P**arathyroid Hyperplasia. * **MEN 2B (2 Ms, 1 P):** **M**edullary Thyroid CA, **M**arfanoid habitus/Mucosal neuromas, **P**heochromocytoma. * **Genetic Marker:** MEN 2 is associated with the **RET proto-oncogene** mutation. Prophylactic thyroidectomy is often indicated in carriers. * **Biomarker:** Calcitonin is the tumor marker for Medullary Carcinoma of the Thyroid.

Q: Which of the following is NOT a recognized feature of pan-hypopituitarism?

Pigmentation of the mucous membranes. ### Explanation **1. Why "Pigmentation of the mucous membranes" is the correct answer:** Hyperpigmentation is a hallmark of **Primary Adrenal Insufficiency (Addison’s Disease)**, not pan-hypopituitarism [3]. In primary failure, the lack of cortisol feedback leads to an excess of Adrenocorticotropic Hormone (ACTH). ACTH is derived from a precursor molecule called Pro-opiomelanocortin (POMC), which also yields Melanocyte-Stimulating Hormone (MSH). High levels of ACTH/MSH stimulate melanocytes, causing pigmentation. In **pan-hypopituitarism**, there is a deficiency of ACTH; therefore, the skin and mucous membranes appear **pale** (alabaster skin) rather than pigmented [3]. **2. Analysis of incorrect options:** * **Option A (Increased insulin sensitivity):** Growth Hormone (GH) and Cortisol are "counter-regulatory" hormones that oppose insulin. Their deficiency in pan-hypopituitarism leads to increased insulin sensitivity and a tendency toward fasting hypoglycemia [2]. * **Option C (Low serum thyroxine and TSH):** This describes **Secondary Hypothyroidism**. Unlike primary hypothyroidism (where TSH is high), pituitary failure results in low T4 with a low or inappropriately "normal" TSH [1]. * **Option D (Loss of secondary sex characters):** Deficiency of Gonadotropins (LH and FSH) leads to secondary hypogonadism, resulting in loss of libido, erectile dysfunction, amenorrhea, and loss of axillary/pubic hair [1]. **Clinical Pearls for NEET-PG:** * **Sequence of hormone loss:** "Go Look For Adenoma" (GH → LH/FSH → TSH → ACTH). GH is usually the first to go [1]. * **Sheehan Syndrome:** Postpartum pituitary necrosis due to hemorrhage; the earliest sign is the failure of lactation (prolactin deficiency) [1]. * **Water Metabolism:** Polyuria is often *absent* in pan-hypopituitarism because cortisol is required for free water excretion; its absence masks underlying Diabetes Insipidus [2].

Q: A patient's lab investigations show decreased T3, decreased T4, and decreased TSH. Which of the following conditions is NOT a possible diagnosis?

Primary hypothyroidism. ### Explanation The key to solving this question lies in understanding the **Hypothalamic-Pituitary-Thyroid (HPT) axis** and the concept of negative feedback [1]. **1. Why Primary Hypothyroidism is the Correct Answer:** In **Primary Hypothyroidism**, the pathology lies within the thyroid gland itself (e.g., Hashimoto's thyroiditis). Because the gland cannot produce enough hormones, **T3 and T4 levels are low**. This lack of hormone removes the negative feedback on the pituitary gland, causing it to compensate by secreting **high levels of TSH** [1], [2]. Therefore, a lab profile of low T3/T4 with *decreased* TSH is physiologically inconsistent with primary hypothyroidism [3]. **2. Analysis of Other Options:** * **Panhypopituitarism (Secondary Hypothyroidism):** This is a classic cause of the "all-low" profile. If the anterior pituitary is diseased, it fails to secrete TSH [2]. Without TSH stimulation, the thyroid gland does not produce T3 and T4 [3]. * **Liver Disease (Euthyroid Sick Syndrome):** In systemic illnesses like liver cirrhosis, there is decreased peripheral conversion of T4 to T3 and alterations in thyroid-binding globulins. In severe or chronic cases, a "low T3, low T4, low/normal TSH" pattern can be seen, often referred to as Non-Thyroidal Illness Syndrome (NTIS). **Clinical Pearls for NEET-PG:** * **Most sensitive initial test** for thyroid dysfunction: **Serum TSH**. * **Primary Hypothyroidism:** ↑ TSH, ↓ T4 [3]. * **Secondary (Central) Hypothyroidism:** ↓/Normal TSH, ↓ T4 [3]. * **Subclinical Hypothyroidism:** ↑ TSH, Normal T4 (Patient is usually asymptomatic) [3]. * **Euthyroid Sick Syndrome:** Characterized initially by isolated **low T3** (due to inhibited 5'-deiodinase activity) with normal TSH. In severe cases, all parameters may drop.

Q: Which of the following findings would help to differentiate between SIADH and psychogenic polydipsia?

Urine osmolality 500 mOsm/L. In both **SIADH** and **Psychogenic Polydipsia**, patients present with **hypotonic hyponatremia** (low serum sodium and low serum osmolality). [2] The key to differentiating them lies in the body's physiological response to water excess, specifically the suppression of Antidiuretic Hormone (ADH). ### Why Option D is Correct * **Psychogenic Polydipsia:** Excessive water intake suppresses ADH. In the absence of ADH, the kidneys maximally dilute the urine to excrete the excess water. [1] Therefore, urine osmolality is typically **very low ( 100 mOsm/L, often >300-500 mOsm/L)**. * A urine osmolality of **500 mOsm/L** is concentrated, which is consistent with SIADH and rules out psychogenic polydipsia. ### Why Other Options are Incorrect * **A & B (BUN and Serum Osmolality):** Both conditions are characterized by **euvolemic hyponatremia**. [2] Dilutional effects lead to low serum osmolality and often low-to-normal BUN in both cases. They do not help in differentiation. * **C (Serum Potassium):** Potassium levels are typically normal in both SIADH and psychogenic polydipsia. Abnormal potassium would point toward other causes like diuretics or adrenal insufficiency. ### NEET-PG High-Yield Pearls * **Diagnostic Criteria for SIADH:** Hyponatremia, low serum osmolality ( 100), and high urine sodium (>40 mEq/L) in a euvolemic patient. * **Uric Acid:** Low serum uric acid (<4 mg/dL) is a classic finding in SIADH due to increased urate excretion. * **Treatment:** Fluid restriction is the first-line treatment for both; however, Vaptans (ADH antagonists) are specific for SIADH.

Question 1

All of the following can commonly occur in a patient who suffered a decelerating injury with damaged pituitary stalk, except one?

Accepted Answer

Diabetes mellitus

Answer

Thyroid insufficiency

Answer

Adrenocortical insufficiency

Answer

Diabetes insipidus

Question 2

An 18-year-old girl presents with hypertension, a masculine body, and clitoromegaly. Which of the following conditions causes hyperandrogenism and hypertension?

Accepted Answer

11-hydroxylase deficiency

Answer

17 beta hydroxylase deficiency

Answer

Turner syndrome

Answer

Rett syndrome

Question 3

Which condition can cause profound hyperlipidemia?

Accepted Answer

Hypothyroidism

Answer

Hyperinsulinemia

Answer

Hyperparathyroidism

Answer

Hyperthyroidism

Question 4

What is the appropriate treatment for a 42-year-old obese male presenting with a blood glucose of 450 mg/dL, urine albumin of 2+, urine sugar of 4+, and urine ketones of 1+?

Accepted Answer

Insulin

Answer

Glibenclamide

Answer

Glipizide

Answer

Metformin

Question 5

Which of the following is a criterion for the diagnosis of diabetes mellitus?

Accepted Answer

Hemoglobin A1c (HbA1c) >= 6.5%

Answer

Fasting plasma glucose > 100 mg/dL

Answer

2-hour plasma glucose after a glucose challenge 
>= 140 mg/dL

Answer

2-hour plasma glucose after a glucose challenge 
>= 180 mg/dL

Question 6

Which one of the following features is NOT associated with primary hyperparathyroidism?

Accepted Answer

Hypercementosis.

Answer

Giant cell tumor.

Answer

Sharply defined radiolucencies of maxilla and mandible.

Answer

Partial loss of lamina dura.

Question 7

Pancreatitis, pituitary tumor, and pheochromocytoma may be associated with which of the following?

Accepted Answer

Medullary carcinoma of the thyroid

Answer

Papillary carcinoma of the thyroid

Answer

Anaplastic carcinoma of the thyroid

Answer

Follicular carcinoma of the thyroid

Question 8

Which of the following is NOT a recognized feature of pan-hypopituitarism?

Accepted Answer

Pigmentation of the mucous membranes

Answer

Increased insulin sensitivity

Answer

Low serum thyroxine and TSH levels

Answer

Loss of secondary sex characters

Question 9

A patient's lab investigations show decreased T3, decreased T4, and decreased TSH. Which of the following conditions is NOT a possible diagnosis?

Accepted Answer

Primary hypothyroidism

Answer

Panhypopituitarism

Answer

Liver disease

Answer

None of the above

Question 10

Which of the following findings would help to differentiate between SIADH and psychogenic polydipsia?

Accepted Answer

Urine osmolality 500 mOsm/L

Answer

Blood urea nitrogen (BUN) 16 mg/dL

Answer

Serum osmolality 265 mOsm/L

Answer

Serum potassium 4 meq/L

Endocrinology — MCQs

Endocrinology — MCQs

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