Endocrinology Practice Questions

Q: Medical adrenalectomy is seen with:

Mitotane. **Explanation:** **Correct Answer: C. Mitotane** **Medical Adrenalectomy** refers to the pharmacological destruction or functional suppression of the adrenal cortex, mimicking a surgical removal. **Mitotane** is the drug of choice for this process. It is a derivative of the insecticide DDT and acts as a **cytotoxic antineoplastic agent** specifically targeting the adrenal cortex. It works via two primary mechanisms: 1. **Direct Adrenolytic Action:** It causes mitochondrial damage and necrosis of the cells in the *zona fasciculata* and *zona reticularis*, leading to atrophy of the gland. 2. **Biochemical Inhibition:** It inhibits enzymes involved in steroidogenesis (such as 11-beta-hydroxylase) and alters the peripheral metabolism of steroids. It is primarily used in the treatment of **inoperable Adrenocortical Carcinoma** and occasionally in refractory Cushing’s Syndrome. **Why other options are incorrect:** * **Vincristine & Vinblastine (Options A & B):** These are Vinca alkaloids that inhibit microtubule formation (M-phase specific). Their primary toxicities are neurological (Vincristine) and bone marrow suppression (Vinblastine), with no specific destructive effect on the adrenal glands. * **Methotrexate (Option D):** An antimetabolite that inhibits dihydrofolate reductase (DHFR). It is used for malignancies, ectopic pregnancy, and autoimmune conditions (RA/Psoriasis), but does not cause adrenal necrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Other drugs causing "Medical Adrenalectomy" (Functional):** Ketoconazole, Metyrapone, and Aminoglutethimide (these inhibit steroid synthesis rather than destroying the tissue). * **Mitotane Side Effect:** It is highly lipophilic and can cause significant GI distress and neurological symptoms (ataxia, lethargy). * **Nelson’s Syndrome:** Be aware that rapid reduction of cortisol (via surgery or drugs) can lead to an ACTH-secreting pituitary adenoma and hyperpigmentation.

Q: Maximum amount of alkaline phosphatase is seen in which of the following?

Semen. Alkaline Phosphatase (ALP) is a group of isoenzymes that catalyze the hydrolysis of phosphate esters at an alkaline pH. While ALP is commonly associated with the liver and bone in clinical practice, its highest concentration in the human body is found in **semen**. **1. Why Semen is Correct:** Semen contains exceptionally high levels of ALP, primarily secreted by the **prostate gland**. The concentration in seminal fluid is approximately **500 to 1000 times higher** than that found in normal serum. In forensic medicine, the detection of high ALP levels is used as a presumptive test to identify seminal stains [1]. **2. Analysis of Incorrect Options:** * **Placenta:** The placenta produces a specific heat-stable isoenzyme (Regan isoenzyme). While levels rise significantly during the third trimester of pregnancy, the total concentration does not reach the levels found in seminal fluid. * **CSF:** Normal Cerebrospinal Fluid contains negligible amounts of ALP. An increase in CSF-ALP is usually a pathological marker for certain germ cell tumors (like germinomas) or leptomeningeal metastasis. * **Plasma:** In healthy adults, plasma ALP originates mainly from the liver and bone. Normal reference ranges (approx. 40–140 U/L) are significantly lower than the concentrations found in the male reproductive tract [2]. **Clinical Pearls for NEET-PG:** * **Isoenzymes of ALP:** Remember the mnemonic **"BLP"** (Bone, Liver, Placenta) for the major sources. * **Heat Stability:** Placental ALP is the most heat-stable, while Bone ALP is the most heat-labile (**"Bone burns"**). * **Clinical Marker:** Elevated ALP with normal GGT suggests a **bone origin** (e.g., Paget’s disease, where ALP is markedly high). If both ALP and GGT are elevated, it suggests a **hepatobiliary origin**. * **Forensic Significance:** Along with Acid Phosphatase (ACP) and Prostate-Specific Antigen (PSA), ALP is a key marker for identifying semen in medico-legal cases [2].

Q: Which of the following is NOT true about dyshormonogenesis?

It follows autosomal dominant inheritance.. **Explanation:** **Dyshormonogenesis** refers to a group of genetic defects in the enzymatic pathways required for thyroid hormone synthesis [1]. 1. **Why Option A is the Correct Answer (The False Statement):** Dyshormonogenesis follows an **autosomal recessive** inheritance pattern, not autosomal dominant [1]. Most cases result from loss-of-function mutations in both alleles of genes encoding enzymes like TPO, thyroglobulin, or the sodium-iodide symporter. 2. **Analysis of Other Options:** * **Option B:** The most common biochemical defect in dyshormonogenesis is a deficiency or dysfunction of the **Thyroid Peroxidase (TPO)** enzyme, which impairs the organification of iodide [1]. * **Option C:** In mild enzymatic defects, increased TSH levels can compensate for the biosynthetic block, leading to a **euthyroid goiter**. However, severe defects typically present as congenital hypothyroidism (cretinism) [1]. * **Option D:** **Pendred Syndrome** is a classic example caused by mutations in the *SLC26A4* gene (encoding pendrin). It is characterized by a triad of sensorineural hearing loss, goiter, and a positive perchlorate discharge test (indicating an organification defect/TPO dysfunction). **High-Yield Clinical Pearls for NEET-PG:** * **Perchlorate Discharge Test:** Used to diagnose iodide organification defects (positive if >10-15% of the tracer is discharged). * **Goiter:** Unlike thyroid agenesis, dyshormonogenesis typically presents with a goiter due to chronic TSH overstimulation. * **Most common cause of Congenital Hypothyroidism:** Thyroid Dysgenesis (80-85%); Dyshormonogenesis accounts for the remaining 10-15% [1].

Q: An obese patient presented with random blood sugar 400 mg%, urine sugar +++, and ketones. Which drug is most useful in management?

Insulin. **Explanation:** The patient presents with significant hyperglycemia (RBS 400 mg/dL), glycosuria, and **ketonuria**. This clinical triad is highly suggestive of **Diabetic Ketoacidosis (DKA)** [3] or severe insulin deficiency. **Why Insulin is the Correct Choice:** Insulin is the definitive treatment for any patient presenting with ketosis. In the presence of ketones, there is an absolute or relative deficiency of insulin leading to lipolysis and ketone body formation. Insulin is required to: 1. Inhibit further ketogenesis by suppressing lipolysis. 2. Facilitate glucose uptake into cells. 3. Correct the metabolic acidosis [5]. Oral hypoglycemic agents (OHAs) are ineffective and contraindicated in the management of acute ketosis or DKA. **Why Other Options are Incorrect:** * **Glibenclamide (Sulfonylurea):** It works by stimulating insulin release from pancreatic beta cells [4]. In an acute state of ketosis, the pancreas cannot produce enough insulin to overcome the crisis, and the onset of action is too slow. * **Troglitazone (Thiazolidinedione):** These are insulin sensitizers that take weeks to reach maximum effect. Furthermore, Troglitazone was withdrawn globally due to severe hepatotoxicity. * **Metformin (Biguanide):** It is the first-line drug for stable Type 2 Diabetes but is **contraindicated** in states of severe dehydration or metabolic acidosis (like DKA) due to the risk of worsening lactic acidosis. **High-Yield Clinical Pearls for NEET-PG:** * **DKA Diagnosis:** Look for the "D-K-A" triad: Diabetes (Glucose >250 mg/dL), Ketones (positive in urine/serum), and Acidosis (pH <7.3 or Bicarbonate <18 mEq/L) [1]. * **Management Priority:** The first step in DKA management is aggressive fluid resuscitation (Normal Saline), followed by intravenous regular insulin [2]. * **Insulin Choice:** Regular (Short-acting) insulin is the preparation of choice for managing acute hyperglycemic emergencies [2].

Q: All are causes of hypercalcemia, except?

Phenytoin toxicity. **Explanation:** The correct answer is **Phenytoin toxicity**. Phenytoin is a well-known cause of **hypocalcemia**, not hypercalcemia [2]. It induces the Cytochrome P450 system in the liver, leading to accelerated metabolism of Vitamin D into inactive metabolites. This results in Vitamin D deficiency, reduced intestinal calcium absorption, and secondary hyperparathyroidism (osteomalacia/rickets) [2], [3]. **Analysis of Options:** * **Thyrotoxicosis:** Thyroid hormones (T3/T4) have a direct stimulating effect on osteoclasts, leading to increased bone resorption and hypercalcemia in approximately 15-20% of thyrotoxic patients [1]. * **Sarcoidosis:** This is a granulomatous disease where macrophages within the granulomas express the enzyme **1-alpha-hydroxylase**. This enzyme converts 25-hydroxyvitamin D to its active form (1,25-dihydroxyvitamin D), leading to increased intestinal calcium absorption and hypercalcemia [1]. * **Vitamin A toxicity:** Excessive Vitamin A stimulates osteoclast activity and inhibits osteoblasts, leading to increased bone turnover and elevated serum calcium levels. **High-Yield Clinical Pearls for NEET-PG:** 1. **Mnemonic for Hypercalcemia (PAM P. SCHMIDT):** Parathyroid (Primary HPT), Addison’s, Malignancy, Paget’s, Sarcoidosis, Cancer, Hyperthyroidism, Milk-alkali syndrome, Immobilization, Vitamin D/A toxicity, Thiazides [1]. 2. **Drugs causing Hypocalcemia:** Phenytoin, Phenobarbital, Bisphosphonates, Loop diuretics (Furosemide), and Calcitonin. 3. **Malignancy:** The most common cause of hypercalcemia in hospitalized patients (via PTHrP or bone metastasis), whereas **Primary Hyperparathyroidism** is the most common cause in outpatients [1]. 4. **EKG finding:** Hypercalcemia typically causes a **shortened QT interval**.

Q: A short metacarpal is a characteristic finding in which of the following conditions?

All of the above. **Explanation:** The characteristic finding of a short metacarpal (specifically the **4th and 5th metacarpals**) is known as **Archibald’s sign**. This occurs due to premature epiphyseal closure and is a classic high-yield physical finding shared by several genetic and endocrine disorders. 1. **Pseudohypoparathyroidism (PHP) Type 1a:** This condition is characterized by end-organ resistance to Parathyroid Hormone (PTH). Patients present with **Albright’s Hereditary Osteodystrophy (AHO)**, a phenotype comprising short stature, round face, obesity, subcutaneous calcifications, and short 4th/5th metacarpals [2]. 2. **Pseudopseudohypoparathyroidism (PPHP):** These patients possess the same genetic mutation (GNAS1) and the same **AHO phenotype** (including short metacarpals) as PHP, but they have **normal** calcium and PTH levels because the defect is inherited paternally [2]. 3. **Turner’s Syndrome (45, XO):** While primarily a chromosomal disorder, short 4th metacarpals are a recognized skeletal feature in approximately 35% of cases, alongside short stature, webbed neck, and streak ovaries [1]. **Clinical Pearls for NEET-PG:** * **Archibald’s Sign:** To elicit this, ask the patient to make a fist; the knuckle of the 4th/5th metacarpal will be replaced by a dimple. * **Differential Diagnosis:** Other causes of short metacarpals include **Homocystinuria** and **Hereditary Multiple Exostoses**. * **Biochemical Distinction:** Remember that PHP has low calcium/high phosphate (PTH resistance), whereas PPHP has normal biochemistry despite the physical findings [2].

Q: Glycemic control in diabetes is best assessed by:

HbA1c. **Explanation:** **Why HbA1c is the Correct Answer:** HbA1c (Glycated Hemoglobin) is considered the "gold standard" for assessing long-term glycemic control. It measures the percentage of hemoglobin that has glucose non-enzymatically attached to it [1]. Since the average lifespan of a Red Blood Cell (RBC) is approximately **120 days**, HbA1c provides a weighted average of blood glucose levels over the preceding **2–3 months** [1]. Unlike plasma glucose, it is not affected by short-term factors like recent meals, exercise, or acute stress, making it the most reliable indicator of overall glycemic stability and a strong predictor of chronic diabetic complications [2]. **Why Other Options are Incorrect:** * **Urinary Glucose (B):** This is a poor marker because glucose only appears in urine when blood levels exceed the renal threshold (approx. 180 mg/dL). It cannot detect hypoglycemia or mild hyperglycemia and is influenced by the individual's renal threshold. * **Fasting (C) and Post-prandial Glucose (D):** These provide only a "snapshot" of blood glucose at a specific moment [3]. While essential for daily dose adjustments and diagnosing diabetes, they do not reflect long-term control or fluctuations occurring at other times of the day [4]. **High-Yield Clinical Pearls for NEET-PG:** * **The 6-7-8-9 Rule:** HbA1c of 6% ≈ 126 mg/dL; 7% ≈ 154 mg/dL; 8% ≈ 183 mg/dL; 9% ≈ 212 mg/dL (Every 1% rise ≈ 28-30 mg/dL increase in average glucose) [2]. * **False Low HbA1c:** Seen in conditions with high RBC turnover (e.g., Hemolytic anemia, pregnancy, recent blood transfusion, EPO therapy). * **False High HbA1c:** Seen in conditions that prolong RBC lifespan (e.g., Splenectomy, Iron deficiency anemia, Vitamin B12 deficiency). * **Fructosamine Test:** Used to assess glycemic control over the past **2–3 weeks** (useful in pregnancy or hemolytic states).

Question 1

Medical adrenalectomy is seen with:

Accepted Answer

Mitotane

Answer

Vincristine

Answer

Vinblastine

Answer

Methotrexate

Question 2

Which of the following causative factors is not involved in the pathogenesis of diabetic gangrene?

Accepted Answer

Myelopathy

Answer

Infection

Answer

Atherosclerosis

Answer

Osteoarthropathy

Question 3

Maximum amount of alkaline phosphatase is seen in which of the following?

Accepted Answer

Semen

Answer

Placenta

Answer

CSF

Answer

Plasma

Question 4

Which of the following is NOT true about dyshormonogenesis?

Accepted Answer

It follows autosomal dominant inheritance.

Answer

The most common abnormality is with thyroid peroxidase activity.

Answer

Young patients may present with euthyroid goiter.

Answer

Pendred syndrome is a classic example of dyshormonogenesis due to TPO deficiency.

Question 5

Which of the following conditions is associated with pheochromocytoma?

Accepted Answer

Von Hippel-Lindau syndrome

Answer

Multiple endocrine neoplasia type I (MEN-I)

Answer

Neurofibromatosis

Answer

Insulinomas

Question 6

An obese patient presented with random blood sugar 400 mg%, urine sugar +++, and ketones. Which drug is most useful in management?

Accepted Answer

Insulin

Answer

Glibenclamide

Answer

Troglitazone

Answer

Metformin

Question 7

A patient, after bilateral adrenalectomy, develops gradual loss of vision, hyperpigmentation of the skin, and headache. What is the likely cause of these symptoms?

Accepted Answer

Nelson's syndrome

Answer

Addison's disease

Answer

Cushing's disease

Answer

Harrison's syndrome

Question 8

All are causes of hypercalcemia, except?

Accepted Answer

Phenytoin toxicity

Answer

Thyrotoxicosis

Answer

Sarcoidosis

Answer

Vitamin A toxicity

Question 9

A short metacarpal is a characteristic finding in which of the following conditions?

Accepted Answer

All of the above

Answer

Turner's syndrome

Answer

Pseudohypoparathyroidism

Answer

Pseudopseudohypoparathyroidism

Question 10

Glycemic control in diabetes is best assessed by:

Accepted Answer

HbA1c

Answer

Urinary glucose

Answer

Fasting glucose

Answer

Post-prandial glucose

Endocrinology — MCQs

Endocrinology — MCQs

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