Endocrinology — MCQs

A patient with mild skin pigmentation presents with sudden abdominal pain, fever, and a rigid abdomen. Laboratory findings include blood sugar of 55 mg/dL, Na of 119 mEq/L, and K of 6.2 mEq/L. Her blood pressure is 88/58 mmHg. She undergoes an exploratory laparotomy. Which of the following statements is true?

Q395Medium

Wolfram syndrome is characterized by all of the following except?

Q396Medium

In which of the following patients, thyrotoxicosis should not be suspected?

Q397Medium

All of the following statements about Diabetic Ketoacidosis are true, EXCEPT:

Q398Medium

Treatment of thyroid storm includes all of the following EXCEPT:

Q399Easy

Diabetes is diagnosed in all of the following criteria except:

Q400Medium

A 43-year-old male presents with persistent dizziness upon standing quickly, chronic fatigue, muscle weakness, and an unusual craving for salty foods. He has a noticeable "bronze tan." Blood work reveals hypoglycemia, hyperkalemia, and hyponatremia. What is the underlying cause of these symptoms?

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 391: What are the characteristic radiographic findings associated with hyperparathyroidism?

A. Multiple bone cysts
B. Subperiosteal bone resorption
C. Brown's tumor
D. All of the above (Correct Answer)

Explanation: **Explanation:** Hyperparathyroidism (HPT), particularly the primary form, leads to excessive secretion of Parathyroid Hormone (PTH). PTH increases osteoclast activity, resulting in accelerated bone resorption and the replacement of bone marrow with fibrous tissue—a condition known as **Osteitis Fibrosa Cystica** [1]. **Breakdown of Findings:** * **Subperiosteal Bone Resorption:** This is the **most specific** radiographic sign of hyperparathyroidism. It is most commonly seen on the radial aspect of the middle phalanges of the 2nd and 3rd fingers. It can also occur in the skull (producing a "Salt and Pepper" appearance) and the distal clavicles. * **Brown’s Tumor (Osteoclastoma):** These are non-neoplastic lytic lesions caused by localized rapid bone resorption. The "brown" color is due to vascularity, hemorrhage, and hemosiderin deposition within the fibrous cysts. * **Multiple Bone Cysts:** Chronic PTH excess leads to the formation of cystic spaces within the bone as the marrow is replaced by fibrous tissue [1]. **Why "All of the Above" is Correct:** All three features are classic components of the skeletal involvement in advanced hyperparathyroidism. While modern screening often detects HPT in the asymptomatic stage, these radiographic hallmarks remain high-yield for exam purposes. **High-Yield Clinical Pearls for NEET-PG:** * **Rugger-Jersey Spine:** Characteristic of secondary hyperparathyroidism (seen in Chronic Kidney Disease), showing bands of increased bone density at the vertebral endplates. * **Salt and Pepper Skull:** Multiple tiny lucencies in the calvarium. * **Biochemical Triad:** Hypercalcemia, Hypophosphatemia, and elevated PTH (in Primary HPT) [1]. * **Most common cause:** Solitary parathyroid adenoma (85%).

Question 392: A 35-year-old woman presents with epigastric pain that did not improve on ranitidine. Upper endoscopy reveals a nonhealing pyloric channel ulcer. Her serum calcium level is 12 mg/dL. What is the most likely underlying diagnosis?

A. Watery diarrhea, hypokalemia, and achlorhydria (WDHA) syndrome
B. Somatostatinoma
C. Multiple endocrine neoplasia type-1 (MEN-1) (Correct Answer)
D. MEN-2A

Explanation: ### Explanation The patient presents with a classic clinical triad suggestive of **Multiple Endocrine Neoplasia Type 1 (MEN-1)**, also known as Wermer syndrome. **1. Why MEN-1 is correct:** The key to this diagnosis is the coexistence of **Zollinger-Ellison Syndrome (ZES)** and **Hypercalcemia**. * **ZES (Gastrinoma):** The nonhealing pyloric ulcer despite H2-blocker (ranitidine) therapy indicates a refractory peptic ulcer caused by excessive gastrin secretion. Gastrinomas are the most common functional enteropancreatic tumors in MEN-1 [1]. * **Hypercalcemia (12 mg/dL):** This suggests **Primary Hyperparathyroidism**, which is the most common and often the earliest manifestation of MEN-1 (occurring in >95% of patients). * **The Concept:** MEN-1 is characterized by the "3 Ps": **P**arathyroid hyperplasia, **P**ancreatic islet cell tumors (like Gastrinoma), and **P**ituitary adenomas. **2. Why other options are incorrect:** * **WDHA Syndrome (VIPoma):** Presents with "tea-colored" watery diarrhea, hypokalemia, and achlorhydria. It does not cause peptic ulcers; in fact, it inhibits gastric acid. * **Somatostatinoma:** Presents with a triad of diabetes mellitus, cholelithiasis, and steatordhea due to the inhibitory effects of somatostatin. * **MEN-2A (Sipple Syndrome):** Characterized by Medullary Thyroid Carcinoma, Pheochromocytoma, and Parathyroid hyperplasia. It is not associated with gastrinomas or refractory peptic ulcers. **Clinical Pearls for NEET-PG:** * **Inheritance:** MEN-1 is autosomal dominant; the gene is located on **Chromosome 11q13** (Menin protein). * **Screening:** In a patient with ZES, always check serum calcium to rule out MEN-1. * **Most common Pancreatic tumor in MEN-1:** Gastrinoma (though Insulinoma is also frequent). * **Treatment Priority:** In MEN-1, hyperparathyroidism should usually be treated surgically before addressing the gastrinoma, as hypercalcemia can worsen gastrin secretion.

Question 393: Rotten apple smell of breath is associated with which of the following conditions?

A. Liver insufficiency
B. Kidney insufficiency
C. Uncontrolled insulin-dependent diabetes mellitus (Correct Answer)
D. Respiratory problems

Explanation: The "rotten apple" or "fruity" odor of the breath is a classic clinical sign of **Diabetic Ketoacidosis (DKA)**, which occurs in uncontrolled insulin-dependent diabetes mellitus (Type 1 DM) [1]. **1. Why Option C is Correct:** In the absence of insulin, the body cannot utilize glucose for energy and instead shifts to rapid fat metabolism (lipolysis) [3]. This process produces excess **ketone bodies**: acetoacetate, beta-hydroxybutyrate, and **acetone** [3]. Acetone is highly volatile and is excreted through the lungs. The distinct, sweet, "rotten apple" or fruity smell is specifically due to the exhalation of these acetone vapors [2]. **2. Why Other Options are Incorrect:** * **Liver Insufficiency:** Associated with **Fetor Hepaticus**, described as a "musty," "mousy," or "sweet and fecal" breath odor caused by dimethyl sulfide. * **Kidney Insufficiency:** Associated with **Uremic Fetor**, described as an "ammonia-like" or "fishy" breath odor due to the breakdown of urea into ammonia in the saliva. * **Respiratory Problems:** Conditions like lung abscess or bronchiectasis typically present with a **foul-smelling (putrid)** breath due to anaerobic bacterial infections, not a fruity odor. **Clinical Pearls for NEET-PG:** * **DKA Triad:** Hyperglycemia, Ketosis, and Metabolic Acidosis (Anion Gap). * **Kussmaul Breathing:** Deep, rapid sighing respirations seen in DKA as a compensatory mechanism for metabolic acidosis [2]. * **Ketone detection:** Nitroprusside test (Rothera's test) detects acetoacetate and acetone but **not** beta-hydroxybutyrate.

Question 394: A patient with mild skin pigmentation presents with sudden abdominal pain, fever, and a rigid abdomen. Laboratory findings include blood sugar of 55 mg/dL, Na of 119 mEq/L, and K of 6.2 mEq/L. Her blood pressure is 88/58 mmHg. She undergoes an exploratory laparotomy. Which of the following statements is true?

A. Treatment with exogenous steroids is usually ineffective.
B. This condition is commonly seen as a consequence of metastasis of distant cancers, such as lung or breast, to the adrenal glands.
C. Death from untreated chronic adrenal insufficiency may occur within hours of surgery. (Correct Answer)
D. The most common underlying cause today is infection with multidrug-resistant tuberculosis.

Explanation: ### Explanation The patient presents with a classic **Addisonian Crisis** (Acute Adrenal Insufficiency). The clinical triad of hypotension (88/58 mmHg), hypoglycemia (55 mg/dL), and electrolyte imbalances (Hyponatremia 119 mEq/L and Hyperkalemia 6.2 mEq/L) in a patient with pre-existing skin pigmentation (suggesting chronic ACTH elevation) is diagnostic [1]. #### 1. Why the Correct Answer is Right **Option C:** Patients with chronic adrenal insufficiency have a limited "adrenal reserve." The physiological stress of surgery or a "rigid abdomen" (acute abdomen) requires a massive surge in cortisol [1]. In these patients, the inability to produce cortisol leads to cardiovascular collapse and refractory shock. If they undergo surgery without steroid cover, the added surgical stress can lead to **death within hours** due to acute circulatory failure. #### 2. Why the Other Options are Wrong * **Option A:** Exogenous steroids (IV Hydrocortisone) are the **gold standard** and life-saving treatment for this condition [1]. * **Option B:** While the adrenals are common sites for metastasis, clinical adrenal insufficiency occurs only when **>90% of the gland** is destroyed. Metastasis rarely causes overt Adrenal insufficiency compared to autoimmune or infectious causes [3]. * **Option D:** Globally, **Autoimmune Adrenalitis** (80% of cases) is the most common cause of Addison’s disease [2]. While TB remains a significant cause in developing nations, it is no longer the "most common" cause worldwide [2]. #### 3. High-Yield Clinical Pearls for NEET-PG * **Electrolyte Signature:** Low Na+, High K+, High H+ (Metabolic Acidosis), and Low Glucose [1]. * **Diagnosis:** The most specific test is the **ACTH Stimulation Test** (Cosyntropin test) [1]. * **Management:** Immediate IV fluid resuscitation (Normal Saline) and **IV Hydrocortisone** (100mg bolus). * **Note:** Hydrocortisone is preferred over Dexamethasone because it provides both glucocorticoid and mineralocorticoid activity [3].

Question 395: Wolfram syndrome is characterized by all of the following except?

A. Optic atrophy
B. Diabetes mellitus
C. Diabetes insipidus
D. Parathyroid hyperplasia (Correct Answer)

Explanation: Wolfram Syndrome is a rare, autosomal recessive neurodegenerative disorder caused by a mutation in the **WFS1 gene** (encoding the protein Wolframin). It is classically defined by the mnemonic **DIDMOAD**, which represents its four hallmark clinical features. **1. Why Parathyroid Hyperplasia is the correct answer:** Parathyroid hyperplasia is **not** a component of Wolfram Syndrome. It is typically associated with **Multiple Endocrine Neoplasia (MEN) syndromes** (Type 1 and 2A) [1]. In Wolfram Syndrome, the endocrine dysfunction is primarily focused on the pancreas and the posterior pituitary, not the parathyroid glands. **2. Analysis of Incorrect Options (Features of Wolfram Syndrome):** * **Diabetes Insipidus (Option C):** Specifically **Central Diabetes Insipidus**, occurring in approximately 70% of patients due to vasopressin deficiency [2]. * **Diabetes Mellitus (Option B):** This is usually the first manifestation (often diagnosed around age 6). It is non-autoimmune, insulin-dependent diabetes. * **Optic Atrophy (Option A):** A mandatory diagnostic criterion, leading to progressive loss of visual acuity and color vision, usually appearing by age 15. * **Deafness:** Sensorineural hearing loss (the "D" in DIDMOAD) is also a classic feature. **Clinical Pearls for NEET-PG:** * **Mnemonic:** **DIDMOAD** (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness). * **Genetics:** Autosomal Recessive; **WFS1 gene** on chromosome 4p16. * **Other features:** Urinary tract abnormalities (dilated renal pelvis/ureters) and neurological symptoms (ataxia, myoclonus). * **Prognosis:** It is a progressive disorder; the median age of death is approximately 30 years, often due to respiratory failure secondary to brainstem atrophy.

Question 396: In which of the following patients, thyrotoxicosis should not be suspected?

A. Unexplained weight loss
B. Unexplained diarrhea
C. Distal muscle weakness (Correct Answer)
D. Paroxysmal atrial tachycardia

Explanation: **Explanation:** In thyrotoxicosis, the correct clinical finding is **proximal muscle weakness**, not distal [1]. This is a classic high-yield distinction in medical exams. **1. Why "Distal muscle weakness" is the correct answer (Why it's NOT suspected):** Thyrotoxic Myopathy typically affects the **proximal muscles** (shoulders and hips) [1]. Patients often complain of difficulty climbing stairs or rising from a seated position. Distal muscles (hands and feet) are generally spared until very late stages of the disease. Therefore, if a patient presents primarily with distal weakness, a clinician should look for other neurological causes rather than thyrotoxicosis. **2. Why the other options are wrong (Why they ARE suspected):** * **Unexplained weight loss:** This is one of the most common presentations [4]. Excess thyroid hormone increases the basal metabolic rate (BMR), leading to weight loss despite a normal or increased appetite [4]. * **Unexplained diarrhea:** Hyperthyroidism increases gastrointestinal motility, leading to hyperdefecation or osmotic diarrhea. * **Paroxysmal atrial tachycardia:** Thyroid hormones increase the sensitivity of cardiac $\beta$-adrenergic receptors. This leads to palpitations [4], sinus tachycardia [2], and most characteristically, **Atrial Fibrillation** or paroxysmal supraventricular tachycardias [2]. **Clinical Pearls for NEET-PG:** * **Thyrotoxic Periodic Paralysis:** A rare but serious complication, more common in Asian males, characterized by sudden hypokalemia and muscle paralysis. * **Apathetic Hyperthyroidism:** Seen in the elderly; they may present only with weight loss or atrial fibrillation without the typical "hyper" symptoms [3]. * **Reflexes:** In thyrotoxicosis, there is a **brisk** (hyperreflexic) relaxation phase, whereas in hypothyroidism, there is a "hung-up" (delayed) relaxation phase.

Question 397: All of the following statements about Diabetic Ketoacidosis are true, EXCEPT:

A. DKA is commoner in type 1 diabetes.
B. Anion gap is increased.
C. Serum pH is less than 7.4.
D. Serum bicarbonate in DKA is greater than 15 mEq/L. (Correct Answer)

Explanation: ### Explanation **1. Why Option D is the Correct Answer (The Exception):** In Diabetic Ketoacidosis (DKA), the hallmark is a **metabolic acidosis** caused by the accumulation of ketoacids (β-hydroxybutyrate and acetoacetate). These acids dissociate, releasing hydrogen ions ($H^+$) which are buffered by bicarbonate ($HCO_3^-$). This process leads to a significant consumption of bicarbonate [1]. According to the ADA (American Diabetes Association) diagnostic criteria, serum bicarbonate in DKA is **characteristically low**: * **Mild DKA:** 15–18 mEq/L * **Moderate DKA:** 10 to <15 mEq/L * **Severe DKA:** <10 mEq/L Therefore, the statement that bicarbonate is "greater than 15 mEq/L" is generally incorrect for moderate-to-severe cases and serves as the exception. **2. Analysis of Incorrect Options:** * **Option A:** True. DKA is the classic acute complication of **Type 1 Diabetes** due to absolute insulin deficiency [1]. While it can occur in Type 2 DM (ketosis-prone), it is significantly more common in Type 1. * **Option B:** True. DKA is a classic cause of **High Anion Gap Metabolic Acidosis (HAGMA)**. The unmeasured anions (ketoacids) increase the gap ($Na^+ - [Cl^- + HCO_3^-]$) beyond the normal range of 10–12 mEq/L. * **Option C:** True. By definition, acidosis implies a **serum pH < 7.30**. Since normal physiological pH is 7.4, any DKA patient will have a pH less than 7.4 [1]. **3. NEET-PG High-Yield Clinical Pearls:** * **Diagnostic Triad:** Hyperglycemia (>250 mg/dL), Ketosis (ketonemia/ketonuria), and Metabolic Acidosis (pH <7.3 or $HCO_3$ <18) [1]. * **Management Priority:** The first step in management is always **aggressive fluid resuscitation** (Normal Saline), followed by Insulin and Potassium replacement [1]. * **Potassium Paradox:** Total body potassium is always **depleted**, even if serum levels appear normal or high due to the extracellular shift caused by acidosis [2]. * **Most common precipitant:** Infection (often UTI or Pneumonia) [1].

Question 398: Treatment of thyroid storm includes all of the following EXCEPT:

A. Propranolol
B. Radioactive iodine (Correct Answer)
C. Hydrocortisone
D. Lugol's iodine

Explanation: Thyroid storm is a life-threatening medical emergency characterized by severe hypermetabolism. The management strategy focuses on four pillars: inhibiting new hormone synthesis, blocking hormone release, preventing peripheral conversion of T4 to T3, and controlling systemic symptoms [1]. **Why Radioactive Iodine (RAI) is the Correct Answer:** Radioactive iodine is **contraindicated** in the acute management of thyroid storm. RAI works by causing radiation-induced thyroiditis and permanent destruction of the gland over weeks to months. In the acute phase, it can cause a transient release of stored thyroid hormone, potentially worsening the storm [1]. It is reserved for definitive therapy only after the patient has achieved a stable, euthyroid state. **Analysis of Incorrect Options (Standard Treatments):** * **Propranolol (A):** A non-selective beta-blocker used to control sympathetic overactivity (tachycardia, tremors, agitation) [1]. At high doses, it also inhibits the peripheral conversion of T4 to T3. * **Hydrocortisone (C):** Glucocorticoids are vital as they inhibit the peripheral conversion of T4 to T3, provide adrenal support (to prevent relative adrenal insufficiency), and may reduce the autoimmune process in Graves' disease. * **Lugol's Iodine (D):** High doses of stable iodine inhibit the release of preformed thyroid hormones from the colloid (the **Wolff-Chaikoff effect**). *Crucial Note:* Iodine must be administered at least 1 hour **after** starting thionamides (like PTU) to prevent the iodine from being used as a substrate for new hormone synthesis (Jod-Basedow effect). **NEET-PG High-Yield Pearls:** 1. **Drug of Choice:** **Propylthiouracil (PTU)** is preferred over Methimazole in thyroid storm because it additionally inhibits peripheral T4 to T3 conversion. 2. **Sequence Matters:** Always give Thionamides *before* Iodine. 3. **Burch-Wartofsky Point Scale:** Used clinically to diagnose thyroid storm (Score >45 is highly suggestive). 4. **Supportive Care:** Aggressive cooling (avoid aspirin as it displaces T4 from TBG) and IV fluids are essential [1].

Question 399: Diabetes is diagnosed in all of the following criteria except:

A. HbA1c > 6.5%
B. Fasting Blood Sugar (FBS) ≥ 126 mg/dL
C. Post Prandial Blood Sugar (PPBS) ≥ 200 mg/dL
D. Random Blood Sugar > 200 mg/dL (with symptoms) (Correct Answer)

Explanation: Diabetes is diagnosed in all of the following criteria except: The diagnosis of Diabetes Mellitus is based on specific glycemic thresholds established by the ADA (American Diabetes Association). This question tests the precision of these diagnostic cut-offs. ### **Explanation of the Correct Answer** The correct answer is **D** because the option states **"Random Blood Sugar > 200 mg/dL"**, whereas the actual diagnostic criterion is **≥ 200 mg/dL**. In competitive exams like NEET-PG, numerical values and "greater than" vs. "greater than or equal to" distinctions are critical. Furthermore, a random plasma glucose (RPG) only qualifies as a diagnosis in a single sitting if the patient is also experiencing classic symptoms of hyperglycemia (polyuria, polydipsia, weight loss) or a hyperglycemic crisis [1]. ### **Analysis of Other Options** * **A. HbA1c ≥ 6.5%:** This is a standard diagnostic criterion. It reflects average glycemia over the preceding 2–3 months. * **B. Fasting Blood Sugar (FBS) ≥ 126 mg/dL:** Fasting is defined as no caloric intake for at least 8 hours. This is a primary diagnostic threshold [1]. * **C. 2-hour Post-Prandial (or OGTT) ≥ 200 mg/dL:** During an Oral Glucose Tolerance Test (using 75g anhydrous glucose), a value of 200 mg/dL or higher confirms diabetes [1]. ### **NEET-PG High-Yield Pearls** * **Prediabetes Criteria:** HbA1c (5.7–6.4%), FBS (100–125 mg/dL), or 2-hr PPBS (140–199 mg/dL) [1]. * **Repeat Testing:** Unless there is clear clinical diagnosis (symptoms + RPG ≥ 200), a diagnosis requires **two abnormal test results** from either the same sample or two separate test samples. * **HbA1c Limitations:** It can be falsely low in conditions with high red cell turnover (e.g., hemolytic anemia, pregnancy, recent hemorrhage) and falsely high in iron deficiency anemia.

Question 400: A 43-year-old male presents with persistent dizziness upon standing quickly, chronic fatigue, muscle weakness, and an unusual craving for salty foods. He has a noticeable "bronze tan." Blood work reveals hypoglycemia, hyperkalemia, and hyponatremia. What is the underlying cause of these symptoms?

A. Adrenal insufficiency (Correct Answer)
B. Pituitary insufficiency
C. Lack of insulin
D. Lack of glucagon

Explanation: The clinical presentation describes a classic case of **Primary Adrenal Insufficiency (Addison’s Disease)**. [1] The underlying cause is the destruction of the adrenal cortex, leading to a deficiency in both mineralocorticoids (aldosterone) and glucocorticoids (cortisol). 1. **Why Adrenal Insufficiency is correct:** * **Hyponatremia & Hyperkalemia:** Lack of aldosterone leads to renal wasting of sodium and retention of potassium. [1] * **Salt Craving & Hypotension:** Sodium loss causes volume depletion, leading to orthostatic dizziness and salt cravings. * **Hypoglycemia:** Cortisol is a counter-regulatory hormone; its absence impairs gluconeogenesis. [1] * **Hyperpigmentation ("Bronze tan"):** Low cortisol triggers a compensatory increase in ACTH. [1] ACTH is derived from POMC, which also produces Melanocyte-Stimulating Hormone (MSH), leading to increased skin pigmentation. [2] 2. **Why other options are incorrect:** * **Pituitary Insufficiency:** While it causes low cortisol, it does **not** cause hyperpigmentation (ACTH is low) or significant electrolyte imbalances (the Renin-Angiotensin system still regulates aldosterone). * **Lack of Insulin:** This would cause hyperglycemia, not hypoglycemia. * **Lack of Glucagon:** While it can cause hypoglycemia, it does not explain the electrolyte shifts or hyperpigmentation. **High-Yield NEET-PG Pearls:** * **Most common cause:** Autoimmune adrenalitis (Developed countries); Tuberculosis (Developing countries like India). [2] * **Diagnosis:** Best initial test is the **ACTH Stimulation Test** (Cosyntropin test). [1] * **Management:** Glucocorticoid (Hydrocortisone) and Mineralocorticoid (Fludrocortisone) replacement. [2] * **Adrenal Crisis:** Presents as refractory shock; treat immediately with IV fluids and high-dose Dexamethasone/Hydrocortisone. [1]

Practice by Chapter

Diabetes Mellitus

Practice Questions

Thyroid Disorders

Practice Questions

Adrenal Gland Disorders

Practice Questions

Pituitary Disorders

Practice Questions

Calcium and Bone Metabolism

Practice Questions

Reproductive Endocrinology

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Lipid Disorders

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Endocrine Hypertension

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Multiple Endocrine Neoplasia

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Obesity and Metabolic Syndrome

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Neuroendocrine Tumors

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Endocrine Emergencies

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