Endocrinology Practice Questions

Q: What is the most likely underlying diagnosis in this 82-year-old patient with diabetes mellitus who had undergone a total hip replacement 10 years previously?

Colon cancer. ***Colon cancer*** - In an **82-year-old diabetic patient**, colon cancer is highly likely given the age demographics and potential **apple-core lesion** or **colonic mass** on imaging studies. - **Metastatic colon cancer** can present with bone lesions near prosthetic joints, and diabetes increases cancer risk through chronic inflammation and immune dysfunction. *Hypogammaglobulinemia* - This **immunodeficiency disorder** typically presents with recurrent infections rather than structural abnormalities on imaging. - Would not cause the characteristic **mass lesions** or **apple-core appearance** seen in gastrointestinal malignancies. *Hypophosphatasia* - A rare **genetic metabolic disorder** affecting bone mineralization, typically diagnosed in childhood or early adulthood. - Would show **osteomalacia** and **rickets-like changes**, not focal mass lesions characteristic of malignancy in elderly patients. *Osteosarcoma* - Primarily affects **children and adolescents** with peak incidence in the second decade of life. - In elderly patients, osteosarcoma is extremely rare and would typically arise from **Paget's disease** or post-radiation, not associated with diabetes or hip prostheses.

Q: What substance is deposited in Bronze diabetes?

Iron. **Explanation:** **Bronze Diabetes** is the clinical triad of skin hyperpigmentation, diabetes mellitus, and cirrhosis [1]. It is the classic presentation of **Hereditary Hemochromatosis**, an autosomal recessive disorder (most commonly involving the *HFE* gene mutation) [1], [4]. **Why Iron is the correct answer:** In Hemochromatosis, there is an inappropriate increase in intestinal iron absorption. This excess **Iron** is deposited in various organs as **hemosiderin** [1]. * **Skin:** Iron deposition stimulates melanin production, leading to a "bronze" or metallic-gray skin discoloration [1]. * **Pancreas:** Iron deposits cause selective destruction of beta cells in the Islets of Langerhans, resulting in insulin deficiency and secondary diabetes mellitus [1], [3]. * **Liver:** Deposition leads to micronodular cirrhosis and increases the risk of Hepatocellular Carcinoma (HCC) [1], [2]. **Why other options are incorrect:** * **Bronze:** This is a metal alloy (copper and tin) and not a physiological substance found in the body. The name "Bronze diabetes" refers only to the skin color, not the deposit. * **Copper:** Excess copper deposition is the hallmark of **Wilson’s Disease**, which typically presents with Kayser-Fleischer (KF) rings and basal ganglia involvement, not diabetes. * **Carbon:** Carbon deposition (Anthracosis) is commonly seen in the lungs of smokers or coal miners and does not cause diabetes. **High-Yield Clinical Pearls for NEET-PG:** * **Screening Test:** Serum Transferrin Saturation (Best initial test; >45% is suggestive). * **Confirmatory Test:** Genetic testing for *HFE* gene (C282Y mutation) [2], [4]. * **Gold Standard:** Liver biopsy (Perls' Prussian Blue stain shows iron) [2]. * **Treatment of Choice:** Therapeutic Phlebotomy [2]. * **Other manifestations:** Restrictive cardiomyopathy, "Square-off" bone spurs in the 2nd/3rd MCP joints, and hypogonadotropic hypogonadism [1].

Q: What is the most common cause of hyperparathyroidism?

Adenoma. ### Explanation Primary Hyperparathyroidism (PHPT) is characterized by the autonomous overproduction of parathyroid hormone (PTH), leading to hypercalcemia [1]. **1. Why Adenoma is Correct:** A **solitary parathyroid adenoma** is the most common cause of primary hyperparathyroidism, accounting for approximately **85–90%** of cases [4]. It typically involves a single gland, while the remaining three glands remain suppressed due to high serum calcium levels. **2. Analysis of Incorrect Options:** * **Hyperplasia (Option B):** Diffuse enlargement of all four parathyroid glands accounts for about **10–15%** of cases. It is frequently associated with hereditary syndromes like MEN 1 and MEN 2A [3]. * **Carcinoma (Option A):** Parathyroid carcinoma is a very rare cause, occurring in ** 14 mg/dL) and a palpable neck mass is present. * **Familial Isolated Hyperparathyroidism (Option D):** This is a rare genetic condition and does not represent the majority of cases in the general population [3]. **3. Clinical Pearls for NEET-PG:** * **Most common presentation:** Today, most patients are **asymptomatic**, discovered via routine biochemical screening (incidental hypercalcemia) [4]. * **Classic Symptom Triad:** "Stones (renal calculi), bones (osteitis fibrosa cystica), abdominal groans (peptic ulcers/pancreatitis), and psychic overtones (depression)" [2][3]. * **Radiological Hallmark:** Subperiosteal bone resorption, most classically seen on the radial side of the middle phalanges. * **Biochemical Profile:** High Serum Calcium, Low Serum Phosphate, and inappropriately High/Normal PTH [4]. * **Localization:** Sestamibi scan (Technetium-99m) is the investigation of choice to localize an adenoma before surgery [2].

Q: A 45-year-old patient has a Fasting Blood Sugar (FBS) of 111 mg/dL, Postprandial Blood Sugar (PPBS) of 181 mg/dL, and HbA1c of 6.1%. What is the diagnosis?

Pre-diabetes. ### Explanation The diagnosis of **Pre-diabetes** (also known as Intermediate Hyperglycemia) is based on blood glucose levels that are higher than normal but do not yet meet the threshold for a diagnosis of Diabetes Mellitus [1]. According to the American Diabetes Association (ADA) criteria, a patient is diagnosed with pre-diabetes if they meet **any** of the following: 1. **Impaired Fasting Glucose (IFG):** FBS between 100–125 mg/dL. (Patient: 111 mg/dL) [1] 2. **Impaired Glucose Tolerance (IGT):** 2-hour post-load glucose (OGTT) or PPBS between 140–199 mg/dL. (Patient: 181 mg/dL) [1] 3. **HbA1c:** Between 5.7% and 6.4%. (Patient: 6.1%) Since all three parameters in this patient fall within these specific ranges, the diagnosis is Pre-diabetes. [1] **Why other options are incorrect:** * **Type 2 & Type 1 Diabetes Mellitus:** Diagnosis requires FBS ≥126 mg/dL, PPBS/Random ≥200 mg/dL, or HbA1c ≥6.5% [1]. This patient’s values are below these cut-offs. * **Stress Hyperglycemia:** This refers to transiently elevated glucose levels (usually >140 mg/dL) during acute illness or physiological stress in patients without prior diabetes. While the sugars are elevated here, the HbA1c of 6.1% indicates a chronic state of dysglycemia rather than an acute spike. **High-Yield Clinical Pearls for NEET-PG:** * **Normal Values:** FBS <100 mg/dL, 2hr-PPBS <140 mg/dL, HbA1c <5.7%. * **Screening:** In asymptomatic adults, screening for pre-diabetes/diabetes should begin at age 35 (recently lowered from 45). * **Management:** Lifestyle modification (weight loss and exercise) is the first-line treatment. Metformin is considered for high-risk pre-diabetics (BMI ≥35, age <60, or women with prior GDM).

Q: What is the characteristic feature of primary aldosteronism?

Low serum potassium. **Explanation:** Primary aldosteronism (Conn’s syndrome) is characterized by the autonomous overproduction of aldosterone from the adrenal cortex, independent of the renin-angiotensin system. **Why Low Serum Potassium is Correct:** Aldosterone acts on the principal cells of the distal convoluted tubule and collecting duct [1]. It promotes the reabsorption of sodium and the **secretion of potassium and hydrogen ions** into the urine [1]. This excessive potassium wasting leads to **hypokalemia**, which clinically manifests as muscle weakness, fatigue, or cardiac arrhythmias [1]. **Analysis of Incorrect Options:** * **A. Low serum sodium:** Aldosterone increases sodium reabsorption. While patients are hypervolemic, they rarely show significant hypernatremia due to "aldosterone escape" (atrial natriuretic peptide release causing pressure natriuresis) [2], but they definitely do **not** have hyponatremia. * **B. High plasma renin:** This is the hallmark of *secondary* aldosteronism. In primary aldosteronism, high aldosterone levels suppress renin production via negative feedback, leading to a **low plasma renin activity (PRA)**. * **C. High serum creatinine:** Primary aldosteronism does not typically cause renal failure unless there is long-standing, untreated hypertensive nephrosclerosis. **NEET-PG High-Yield Pearls:** * **Screening Test:** Plasma Aldosterone Concentration (PAC) to Plasma Renin Activity (PRA) ratio. A **PAC:PRA ratio >20-30** is highly suggestive. * **Confirmatory Test:** Oral or IV Saline Suppression Test (failure to suppress aldosterone). * **Classic Triad:** Hypertension, Hypokalemia, and Metabolic Alkalosis. * **Most Common Cause:** Adrenal Adenoma (Conn’s Syndrome), followed by Bilateral Adrenal Hyperplasia.

Q: Which of the following is NOT a steroid?

Relaxin. **Explanation:** The classification of hormones based on their chemical structure is a high-yield topic for NEET-PG. Hormones are generally divided into three categories: **Steroids**, **Peptides/Proteins**, and **Amino acid derivatives**. **Why Relaxin is the correct answer:** Relaxin is a **peptide hormone** (specifically a protein belonging to the insulin superfamily). It is produced primarily by the corpus luteum in females and the prostate in males. Its primary physiological role is to relax the pelvic ligaments and soften the cervix during childbirth. Because it is a protein, it acts via cell-surface receptors (G-protein coupled receptors) [1], unlike steroids which typically act on intracellular receptors [1]. **Why the other options are incorrect:** * **Estrogen, Progesterone, and Testosterone** are all **steroid hormones** [2], [3]. * Steroid hormones are derived from **cholesterol** and are lipid-soluble [2]. * They are secreted by the adrenal cortex (cortisol, aldosterone), ovaries (estrogen, progesterone), and testes (testosterone) [2]. **Clinical Pearls for NEET-PG:** 1. **Steroid Hormones mnemonic:** Remember "The **Adrenal Cortex** and the **Gonads**." (Cortisol, Aldosterone, Estrogen, Progesterone, Testosterone) [2]. Vitamin D is also a steroid hormone [1]. 2. **Mechanism of Action:** Steroids are lipophilic; they cross the cell membrane and bind to **intracellular/nuclear receptors** to alter gene transcription [1]. 3. **Relaxin’s Clinical Role:** In pregnancy, it increases glomerular filtration rate (GFR) and renal blood flow, contributing to the physiological changes of gestation. 4. **Quick Check:** If a hormone name ends in **"-one"** or **"-ol"** (e.g., Aldosterone, Cortisol, Estradiol), it is almost always a steroid [2]. Relaxin is a notable exception to the "sound-alike" rule.

Q: Which of the following is not involved in MEN II syndrome?

Pituitary tumor. Multiple Endocrine Neoplasia (MEN) syndromes are autosomal dominant conditions characterized by tumors involving two or more endocrine glands. The distinction between MEN I and MEN II is a high-yield topic for NEET-PG. **1. Why Pituitary Tumor is the correct answer:** Pituitary tumors are a hallmark of **MEN I (Wermer Syndrome)**, not MEN II. MEN I is classically defined by the "3 Ps": **P**ituitary adenoma (most commonly prolactinoma), **P**arathyroid hyperplasia/adenoma, and **P**ancreatic islet cell tumors (e.g., Gastrinoma, Insulinoma). **2. Why the other options are incorrect (Components of MEN II):** MEN II (Sipple Syndrome) is caused by a mutation in the **RET proto-oncogene** and is characterized by: * **Medullary Thyroid Carcinoma (MTC):** Occurs in 100% of cases; it is the most common and earliest manifestation. * **Pheochromocytoma:** Occurs in approximately 50% of patients, often bilateral. * **Parathyroid Adenoma/Hyperplasia:** Seen specifically in **MEN IIA** (not IIB). **High-Yield Clinical Pearls for NEET-PG:** * **MEN IIA (Sipple Syndrome):** MTC + Pheochromocytoma + Parathyroid hyperplasia. * **MEN IIB (Gorlin Syndrome):** MTC + Pheochromocytoma + Mucosal neuromas + Marfanoid habitus (Note: Parathyroid involvement is **absent** in MEN IIB). * **Screening:** For MEN II, the first step in a suspected patient is to screen for Pheochromocytoma (via urinary/plasma metanephrines) before performing thyroid surgery to prevent a hypertensive crisis during anesthesia. * **Prophylactic Thyroidectomy:** Often recommended in RET mutation carriers due to the high penetrance of MTC.

Q: Pituitary adenomas are regarded as macroadenomas when their size is:

> 1 cm. Pituitary adenomas are benign tumors of the anterior pituitary gland and are classified primarily based on their size, which dictates both clinical presentation and surgical approach. **1. Why the correct answer is right:** The standard radiological classification (based on MRI findings) divides pituitary adenomas into two categories [3]: * **Microadenomas:** 1 cm (10 mm)** in diameter [3]. These are significant because they are large enough to compress adjacent structures, such as the optic chiasm (causing bitemporal hemianopia) or the normal pituitary tissue (causing hypopituitarism) [2], [4]. **2. Why the incorrect options are wrong:** * **Options B, C, and D (> 1.5 cm, > 2 cm, > 2.5 cm):** While these sizes technically qualify as macroadenomas, they do not represent the established diagnostic threshold. A tumor is labeled a macroadenoma the moment it exceeds the 1 cm mark [3]. Tumors exceeding 4 cm are specifically termed **Giant Pituitary Adenomas**. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common type:** Prolactinoma is the most common secretory pituitary adenoma. * **Mass Effect:** Macroadenomas typically present with the "classic triad": Headache, bitemporal hemianopia (due to optic chiasm compression), and hypopituitarism [2]. * **Imaging Gold Standard:** Contrast-enhanced MRI of the Sella Turcica [3]. * **Treatment:** For most macroadenomas, **Transsphenoidal surgery** is the first-line treatment [1], *except* for Prolactinomas, where medical management (Dopamine agonists like Cabergoline) is preferred regardless of size [2], [4].

Question 1

What is the most likely underlying diagnosis in this 82-year-old patient with diabetes mellitus who had undergone a total hip replacement 10 years previously?

Accepted Answer

Colon cancer

Answer

Hypogammaglobulinemia

Answer

Hypophosphatasia

Answer

Osteosarcoma

Question 2

Manifestations of endemic cretinism include:

Accepted Answer

Strabismus and spastic diplegias

Answer

Deafness and facial nerve involvement

Answer

Blindness and hypothyroidism

Answer

Multinodular goitre and mental retardation

Question 3

What substance is deposited in Bronze diabetes?

Accepted Answer

Iron

Answer

Bronze

Answer

Copper

Answer

Carbon

Question 4

Albright's syndrome includes all except?

Accepted Answer

Patchy pigmentation

Answer

Polyostotic fibrous dysplasia

Answer

Precocious puberty in girls

Answer

Pseudohypoparathyroidism

Question 5

What is the most common cause of hyperparathyroidism?

Accepted Answer

Adenoma

Answer

Carcinoma

Answer

Hyperplasia

Answer

Familial isolated hyperparathyroidism

Question 6

A 45-year-old patient has a Fasting Blood Sugar (FBS) of 111 mg/dL, Postprandial Blood Sugar (PPBS) of 181 mg/dL, and HbA1c of 6.1%. What is the diagnosis?

Accepted Answer

Pre-diabetes

Answer

Type 2 Diabetes Mellitus

Answer

Type 1 Diabetes Mellitus

Answer

Stress hyperglycemia

Question 7

What is the characteristic feature of primary aldosteronism?

Accepted Answer

Low serum potassium

Answer

Low serum sodium

Answer

High plasma renin

Answer

High serum creatinine

Question 8

Which of the following is NOT a steroid?

Accepted Answer

Relaxin

Answer

Estrogen

Answer

Progesterone

Answer

Testosterone

Question 9

Which of the following is not involved in MEN II syndrome?

Accepted Answer

Pituitary tumor

Answer

Medullary carcinoma of thyroid

Answer

Pheochromocytoma

Answer

Parathyroid adenoma

Question 10

Pituitary adenomas are regarded as macroadenomas when their size is:

Accepted Answer

> 1 cm

Answer

> 1.5 cm

Answer

> 2 cm

Answer

> 2.5 cm

Endocrinology — MCQs

Endocrinology — MCQs

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