Endocrinology Practice Questions

Q: Which of the following is NOT a typical presentation of hyperthyroidism?

Hypotension. In hyperthyroidism, the excess of circulating thyroid hormones ($T_3$ and $T_4$) leads to a hypermetabolic state and increased sympathetic nervous system sensitivity. **Why Hypotension is the Correct Answer:** Hyperthyroidism typically causes **systolic hypertension** and a **widened pulse pressure** [2]. Thyroid hormones decrease systemic vascular resistance (vasodilation) while simultaneously increasing cardiac output, heart rate, and stroke volume. This results in an elevated systolic BP and a low-to-normal diastolic BP. Hypotension is not a feature; in fact, if a patient with hyperthyroidism presents with low blood pressure, one must suspect **adrenal insufficiency** (Schmidt syndrome) or **thyroid storm** progressing to high-output heart failure. **Analysis of Incorrect Options:** * **Atrial Fibrillation:** This is the most common arrhythmia in hyperthyroidism, especially in elderly patients [1]. Thyroid hormones have a direct pro-arrhythmic effect on the atrial myocardium. * **Tremor:** A characteristic high-frequency, low-amplitude **fine tremor** is a classic sign of thyrotoxicosis, best observed by placing a sheet of paper on the patient's outstretched hands [2]. * **Panic Attacks:** Hyperthyroidism often mimics psychiatric disorders [2]. Patients frequently present with anxiety, irritability, emotional lability, and symptoms indistinguishable from panic disorder. **High-Yield Clinical Pearls for NEET-PG:** * **Apathetic Hyperthyroidism:** Seen in the elderly; presents with depression and lethargy rather than typical hyperactivity. * **Thyroid Storm:** Characterized by hyperpyrexia, tachycardia, and altered mental status. * **Treatment of choice for symptoms:** Propranolol (non-selective beta-blocker) is used to control tachycardia and tremors and also inhibits the peripheral conversion of $T_4$ to $T_3$ [3].

Q: Vitamin D-resistant rickets is associated with all of the following, except?

Osteoporosis. **Explanation:** **Vitamin D-Resistant Rickets (VDRR)**, most commonly inherited as X-linked Hypophosphatemic Rickets, is characterized by a defect in renal phosphate handling and impaired vitamin D metabolism. **Why Osteoporosis is the Correct Answer:** Osteoporosis is a **quantitative** defect where the bone density is low, but the mineralization of the remaining bone matrix is normal. In contrast, VDRR is a **qualitative** defect of mineralization [1]. In VDRR, the primary pathology is the failure to mineralize the osteoid (bone matrix) due to low phosphate levels, leading to "soft bones" rather than "porous bones." **Analysis of Other Options:** * **Hypophosphatemia:** This is the hallmark of VDRR [1]. Mutations (e.g., in the *PHEX* gene) lead to increased levels of FGF-23, which causes renal phosphate wasting and inhibits the 1-alpha-hydroxylase enzyme. * **Osteomalacia:** This is the adult manifestation of defective mineralization [1]. While children get rickets (affecting growth plates), adults with VDRR develop osteomalacia, characterized by bone pain and pseudofractures. * **Increased calcium absorption:** This is the **incorrect** statement regarding the pathophysiology of VDRR, but it is often listed as a distractor. In VDRR, there is actually **decreased** intestinal calcium and phosphate absorption due to low 1,25(OH)₂D levels. However, in the context of this "Except" question, Osteoporosis is the most definitive pathological mismatch. **Clinical Pearls for NEET-PG:** * **Biochemical Profile:** Low Serum Phosphate, Normal Serum Calcium, Normal/Low 1,25(OH)₂D, and **Elevated Alkaline Phosphatase (ALP)**. * **Key Difference:** Unlike nutritional rickets, VDRR does **not** respond to physiological doses of Vitamin D. Treatment requires oral phosphate supplements and Calcitriol. * **Radiology:** Look for "Looser’s zones" (pseudofractures) in osteomalacia and widening of the epiphyseal plates in rickets [1].

Q: Which of the following conditions is most likely to be associated with the clinical findings shown in the image?

Hypothyroidism. ***Hypothyroidism*** - The image demonstrates classic **myxedematous facies** with **periorbital puffiness**, **dry coarse skin**, and **loss of outer third of eyebrows**. - The **dull facial expression** and overall appearance are characteristic of **severe hypothyroidism** (myxedema). *Acromegaly* - Features **coarse facial features** with **enlarged nose**, **thick lips**, and **prognathism** (protruding jaw), which are not present here. - Associated with **macroglossia** and **enlarged hands and feet** due to excess **growth hormone**. *Cushing syndrome* - Characterized by **moon face** with **central facial plethora** and **hirsutism**, contrasting with the pale, puffy appearance seen. - Often presents with **purple striae**, **buffalo hump**, and **truncal obesity** due to excess **cortisol**. *Graves' disease* - Typically shows **exophthalmos** (bulging eyes) and **lid retraction** with a **staring appearance**. - Associated with **hyperthyroid features** like **weight loss**, **tremor**, and **goiter**, opposite to the findings shown.

Q: Galactorrhea may be associated with the use of all the following drugs except?

Pyridoxine. The regulation of prolactin is primarily under the **inhibitory control of Dopamine** (Prolactin Inhibiting Factor). Any drug that decreases dopamine levels or blocks dopamine receptors will lead to hyperprolactinemia and subsequent galactorrhea [1]. **Why Pyridoxine is the correct answer:** **Pyridoxine (Vitamin B6)** is a cofactor in the synthesis of dopamine (it aids the conversion of L-Dopa to Dopamine). By increasing central dopamine levels, pyridoxine actually **inhibits** prolactin secretion. In fact, high doses of Pyridoxine have historically been used to suppress lactation, making it the "except" in this list. **Analysis of incorrect options:** * **Methyldopa (Option A):** This centrally acting antihypertensive acts as a false neurotransmitter and depletes central dopamine stores, leading to increased prolactin. * **Tricyclic Antidepressants (Option B):** TCAs (like Amitriptyline) can cause galactorrhea by inhibiting dopamine reuptake or through mild serotonergic stimulation, which stimulates prolactin release. * **Phenothiazines (Option D):** These are typical antipsychotics (e.g., Chlorpromazine) that act as potent **D2 receptor antagonists** in the tuberoinfundibular pathway, frequently causing significant hyperprolactinemia [1]. **NEET-PG High-Yield Pearls:** 1. **Metoclopramide and Domperidone** (anti-emetics) are common causes of drug-induced galactorrhea due to D2 blockade [1]. 2. **Verapamil** is a unique calcium channel blocker known to cause galactorrhea by interfering with dopamine synthesis. 3. **Hypothyroidism** can cause galactorrhea because increased TRH (Thyrotropin-Releasing Hormone) acts as a prolactin-releasing factor [1]. 4. **Bromocriptine and Cabergoline** (Dopamine agonists) are the treatments of choice for pathological hyperprolactinemia.

Q: In hyperparathyroidism, which of the following is not typically seen?

Decreased phosphate in urine. In **Primary Hyperparathyroidism (PHPT)**, the fundamental pathology is the autonomous overproduction of Parathyroid Hormone (PTH), usually due to a parathyroid adenoma [1]. ### Why "Decreased phosphate in urine" is the correct answer: PTH has a potent **phosphaturic effect**. It acts on the proximal convoluted tubules of the kidney to inhibit the sodium-phosphate cotransporter (NaPi-2a), thereby decreasing phosphate reabsorption [2]. This leads to **increased phosphate excretion in the urine (Hyperphosphaturia)**. Therefore, "decreased phosphate in urine" is the incorrect statement regarding the typical presentation of hyperparathyroidism. ### Explanation of other options: * **A. Normal alkaline phosphatase:** In many mild or early cases of PHPT, Alkaline Phosphatase (ALP) remains within the normal range. It only rises significantly when there is extensive bone involvement (Osteitis fibrosa cystica). * **C. Increased calcium:** Hypercalcemia is the hallmark of PHPT [1]. PTH increases serum calcium by enhancing bone resorption, increasing renal distal tubule calcium reabsorption, and stimulating Vitamin D activation (which increases intestinal absorption) [2]. * **D. Hypophosphatemia:** Due to the phosphaturic effect mentioned above, the kidneys "waste" phosphate, leading to low serum phosphate levels [1], [2]. ### NEET-PG High-Yield Pearls: * **Classic Triad:** Hypercalcemia, Hypophosphatemia, and Hyperphosphaturia. * **Urinary cAMP:** PTH increases urinary cyclic AMP; this is a classic biochemical marker. * **Radiology:** Look for "subperiosteal resorption" (pathognomonic), especially on the radial aspect of the middle phalanges, and "salt and pepper" appearance of the skull. * **Mnemonic for symptoms:** "Stones (renal), bones (aches), abdominal groans (peptic ulcers/pancreatitis), and psychic overtones (depression)" [3].

Q: What fasting blood glucose level is indicative of diabetes mellitus?

126 mg/dl. **Explanation:** The diagnosis of Diabetes Mellitus (DM) is based on specific glycemic thresholds defined by the American Diabetes Association (ADA). **1. Why Option A is correct:** According to current diagnostic criteria, a **Fasting Plasma Glucose (FPG) level ≥ 126 mg/dl (7.0 mmol/L)** is indicative of Diabetes Mellitus [1]. "Fasting" is defined as no caloric intake for at least 8 hours. This threshold is chosen because it correlates with a significantly increased risk of developing microvascular complications, particularly diabetic retinopathy [1]. **2. Analysis of Incorrect Options:** * **Option B (140 mg/dl):** While this value is diagnostic of diabetes (as it is >126 mg/dl), it is not the *minimum* threshold. Additionally, 140 mg/dl is the cutoff for the 2-hour post-load glucose in **Impaired Glucose Tolerance (IGT)**. * **Option C (100 mg/dl):** This is the upper limit of normal. An FPG between **100–125 mg/dl** is categorized as **Impaired Fasting Glucose (IFG)**, a state of pre-diabetes [1]. * **Option D (200 mg/dl):** This is the diagnostic threshold for a **Random Plasma Glucose** (in a symptomatic patient) or a **2-hour Plasma Glucose** during an Oral Glucose Tolerance Test (OGTT). **High-Yield Clinical Pearls for NEET-PG:** * **HbA1c Criteria:** A level of **≥ 6.5%** is diagnostic for DM; **5.7–6.4%** indicates pre-diabetes. * **Confirmatory Testing:** Unless there is clear clinical hyperglycemia (polyuria, polydipsia, weight loss) with a random glucose ≥ 200 mg/dl, the diagnosis requires **two abnormal test results** from the same sample or two separate test samples. * **Gold Standard:** The OGTT is considered the most sensitive test for diagnosis, though FPG and HbA1c are more commonly used in clinical practice.

Q: All of the following occur in adrenal deficiency except?

Hypocalcemia. In adrenal insufficiency (Addison’s disease), the primary pathology is the deficiency of cortisol and aldosterone [1]. **Why Hypocalcemia is the Correct Answer:** Adrenal deficiency actually causes **Hypercalcemia**, not hypocalcemia. Cortisol normally antagonizes Vitamin D action and promotes renal calcium excretion. When cortisol is deficient, there is increased renal tubular reabsorption of calcium and increased sensitivity to Vitamin D, leading to elevated serum calcium levels in about 10-20% of patients. **Explanation of Incorrect Options:** * **Hypoglycemia:** Cortisol is a counter-regulatory (diabetogenic) hormone that stimulates gluconeogenesis. Its absence leads to decreased glucose production and increased insulin sensitivity, resulting in low blood sugar. * **Hypotension:** This occurs due to two mechanisms: (1) Aldosterone deficiency leads to sodium and water wasting (volume depletion) [1], and (2) Cortisol is required to maintain the pressor response of blood vessels to catecholamines. * **Hyponatremia:** This is the most common electrolyte abnormality. It results from the loss of sodium in urine (due to low aldosterone) and the "inappropriate" secretion of ADH (cortisol normally inhibits ADH release) [2]. **NEET-PG High-Yield Pearls:** * **Classic Electrolyte Triad:** Hyponatremia, Hyperkalemia, and Metabolic Acidosis (due to aldosterone deficiency). * **Hyperpigmentation:** Seen only in *Primary* adrenal insufficiency due to increased ACTH/POMC levels (MSH-like activity). * **Diagnosis:** The gold standard is the **ACTH Stimulation Test** (Cosyntropin test) [2]. * **Eosinophilia:** A common but often overlooked hematological finding in Addison’s disease.

Question 1

Which of the following is NOT a typical presentation of hyperthyroidism?

Accepted Answer

Hypotension

Answer

Atrial fibrillation

Answer

Tremor

Answer

Panic attacks

Question 2

A 75-year-old woman presents with mild congestive heart failure 6 weeks after a myocardial infarction. She has a past history of neck surgery for parathyroid adenoma 5 years ago. Her EKG shows slow atrial fibrillation. Serum calcium is 13.0 mg/dL and urinary calcium is 300 mg/24 hr. On examination, there is a small mass in the paratracheal position behind the right clavicle. What is the appropriate management at this time?

Accepted Answer

Ultrasound-guided alcohol injection of the mass

Answer

Repeat neck surgery

Answer

Treatment with Technetium-99

Answer

Observation and repeat serum calcium in two months

Question 3

Vitamin D-resistant rickets is associated with all of the following, except?

Accepted Answer

Osteoporosis

Answer

Hypophosphatemia

Answer

Increased calcium absorption

Answer

Osteomalacia

Question 4

Which of the following conditions is most likely to be associated with the clinical findings shown in the image?

Accepted Answer

Hypothyroidism

Answer

Acromegaly

Answer

Cushing syndrome

Answer

Graves' disease

Question 5

Galactorrhea may be associated with the use of all the following drugs except?

Accepted Answer

Pyridoxine

Answer

Methyldopa

Answer

Tricyclic antidepressants

Answer

Phenothiazine

Question 6

In hyperparathyroidism, which of the following is not typically seen?

Accepted Answer

Decreased phosphate in urine

Answer

Normal alkaline phosphatase

Answer

Increased calcium

Answer

Hypophosphatemia

Question 7

Hypophosphatemia is seen in which of the following conditions?

Accepted Answer

Rickets

Answer

Pseudohypoparathyroidism

Answer

Chronic renal failure (CRF)

Answer

Hyperparathyroidism

Question 8

What fasting blood glucose level is indicative of diabetes mellitus?

Accepted Answer

126 mg/dl

Answer

140 mg/dl

Answer

100 mg/dl

Answer

200 mg/dl

Question 9

What is the immediate treatment of hypercalcemia of malignancy?

Accepted Answer

IV fluids

Answer

Bisphosphonates

Answer

Calcitonin

Answer

Glucocorticoids

Question 10

All of the following occur in adrenal deficiency except?

Accepted Answer

Hypocalcemia

Answer

Hypoglycemia

Answer

Hypotension

Answer

Hyponatremia

Endocrinology — MCQs

Endocrinology — MCQs

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