Endocrinology Practice Questions

Q: Which of the following conditions is a common cause of hypercalcemia?

Hyperthyroidism. **Explanation:** Hypercalcemia is a common clinical finding in endocrinology, primarily driven by increased bone resorption or decreased renal excretion [1]. **Why Hyperthyroidism is Correct:** Thyroid hormones (T3 and T4) have a direct stimulatory effect on osteoclasts, leading to increased bone turnover and resorption. In approximately 15-20% of patients with thyrotoxicosis, this accelerated bone breakdown exceeds the rate of bone formation, resulting in mild hypercalcemia [1]. Additionally, the increased calcium load suppresses Parathyroid Hormone (PTH), leading to hypercalciuria. **Analysis of Incorrect Options:** * **A. Adrenocortical insufficiency:** While Addison’s disease can cause hypercalcemia (due to decreased renal calcium clearance and increased bone resorption), it is considered an **uncommon** cause compared to the metabolic impact of hyperthyroidism [1]. * **B. Amyloidosis:** This is a restrictive/infiltrative disease. While it can lead to renal failure (which causes *hypocalcemia* due to phosphate retention and low Vitamin D) [2], it is not a recognized cause of hypercalcemia. * **D. Vitamin C intoxication:** Vitamin C (Ascorbic acid) is not involved in calcium metabolism. It is **Vitamin D** intoxication (increased intestinal absorption) [1] or **Vitamin A** intoxication (increased bone resorption) that causes hypercalcemia. **High-Yield NEET-PG Pearls:** * **Most common cause overall:** Primary Hyperparathyroidism (outpatient) and Malignancy (inpatient) [1]. * **Mnemonic for Hypercalcemia (CHIMPANZEES):** **C**alcium supplements, **H**yperparathyroidism, **I**atrogenic/Immobilization, **M**ilk-alkali syndrome, **P**aget’s disease, **A**ddison’s/Acromegaly, **N**eoplasia, **Z**ollinger-Ellison (MEN1), **E**xcess Vitamin D, **E**xcess Vitamin A, **S**arcoidosis [1]. * **ECG Finding:** Shortened QT interval is the classic sign of hypercalcemia.

Q: Which of the following is seen in Addison's disease?

Hypercalcemia. Addison’s disease (Primary Adrenocortical Insufficiency) results from the destruction of the adrenal cortex, leading to a deficiency of cortisol, aldosterone, and adrenal androgens [1]. **Why Hypercalcemia is correct:** Hypercalcemia is seen in approximately 10–20% of patients with Addison’s disease. The underlying mechanisms include: 1. **Decreased Renal Excretion:** Cortisol normally inhibits renal tubular reabsorption of calcium; its absence leads to increased calcium retention. 2. **Increased Bone Resorption:** Glucocorticoids normally antagonize the effects of Vitamin D; their deficiency leads to increased calcium mobilization from bones. 3. **Hemoconcentration:** Dehydration (due to mineralocorticoid deficiency) leads to a relative increase in serum calcium levels [3]. **Analysis of Incorrect Options:** * **A. Hypernatremia:** Incorrect. Aldosterone deficiency leads to "salt wasting" (loss of sodium in urine), resulting in **Hyponatremia** [1]. * **B. Hypokalemia:** Incorrect. Aldosterone normally promotes potassium excretion. Its absence leads to potassium retention, resulting in **Hyperkalemia** [1]. * **C. Hyperglycemia:** Incorrect. Cortisol is a counter-regulatory hormone that promotes gluconeogenesis. Its deficiency leads to **Hypoglycemia**. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Electrolyte Triad:** Hyponatremia, Hyperkalemia, and Metabolic Acidosis (Non-gap). * **Hyperpigmentation:** Seen only in *Primary* Adrenal Insufficiency due to increased ACTH (which shares a precursor with Melanocyte Stimulating Hormone - POMC) [2]. * **Diagnosis:** The screening test of choice is the **ACTH Stimulation Test** (Cosyntropin test) [2]. * **Hematology:** Patients often show eosinophilia and lymphocytosis.

Q: A 48-year-old Caucasian man, diagnosed with diabetes 5 years ago, presents with palpitations. Physical examination reveals diffuse skin darkening and testicular atrophy. Laboratory studies show elevated liver function and elevated blood sugars. A liver biopsy shows significantly elevated iron levels, leading to a diagnosis of hereditary hemochromatosis. Which one of the following laboratory findings is seen in hereditary hemochromatosis?

Decreased total iron-binding capacity. The clinical presentation of "Bronze Diabetes" (skin darkening and diabetes), testicular atrophy, and hepatomegaly in a middle-aged male is classic for **Hereditary Hemochromatosis (HH)** [2]. This is an autosomal recessive disorder (most commonly the HFE gene mutation) characterized by excessive intestinal iron absorption leading to systemic iron overload [1], [2]. **Why Option D is Correct:** In HH, the body is saturated with iron. **Total Iron-Binding Capacity (TIBC)** is an indirect measure of transferrin levels [4]. When iron stores are excessively high, the liver decreases the production of transferrin to prevent further transport of iron. Furthermore, since the existing transferrin molecules are highly saturated with iron (Transferrin Saturation >45-50%), the "capacity" to bind more iron is significantly **decreased**. **Why the Other Options are Incorrect:** * **Option A:** Decreased serum ceruloplasmin is the screening hallmark for **Wilson’s Disease** (copper overload), not hemochromatosis [3]. * **Option B:** Serum ferritin is an acute-phase reactant and a marker of total body iron stores. In HH, serum ferritin is **significantly elevated** (often >200-300 ng/mL) [1]. * **Option C:** Serum iron is **elevated** in HH due to increased absorption and release from damaged hepatocytes. **NEET-PG High-Yield Pearls:** * **Screening Test of Choice:** Transferrin Saturation (most sensitive early marker). * **Confirmatory Test:** Genetic testing for HFE mutation (C282Y) [1]. * **Gold Standard for Iron Quantification:** MRI (T2*) or Liver Biopsy (Perls' Prussian Blue stain) [1]. * **Classic Triad:** Cirrhosis, Diabetes Mellitus, and Skin Pigmentation [2]. * **Treatment:** Therapeutic phlebotomy is the mainstay; Deferoxamine is used if phlebotomy is contraindicated [1].

Q: In patients with significant atherosclerosis, which of the following conditions is increased approximately 100-fold in those with comorbid diabetes compared to non-diabetic patients?

Lower limb ischemia. The correct answer is **Lower limb ischemia (Peripheral Arterial Disease)**. While diabetes mellitus (DM) is a major risk factor for all forms of macrovascular disease, the relative risk increase is most dramatic for lower extremity involvement [1]. In patients with atherosclerosis, the presence of diabetes increases the risk of gangrene and non-traumatic lower limb amputation by approximately **100-fold** compared to non-diabetics. This is due to a combination of accelerated atherosclerosis in the infra-popliteal (distal) vessels, peripheral neuropathy (leading to unnoticed trauma), and impaired wound healing. **Analysis of Incorrect Options:** * **A & B (Myocardial Infarction and Ischemic Stroke):** Diabetes is indeed a "coronary artery disease equivalent," increasing the risk of MI and stroke by 2 to 4 times. However, this increase is significantly lower than the 100-fold risk associated with limb-threatening ischemia. * **D (Vertebrobasilar insufficiency):** While DM contributes to cerebrovascular disease, it does not show the specific, massive statistical predilection for the vertebrobasilar system that it does for the distal lower limb arteries. **High-Yield Clinical Pearls for NEET-PG:** * **Pattern of Involvement:** Atherosclerosis in diabetics tends to be more **distal** (below the knee, involving tibial and peroneal arteries) and **multisegmental** compared to non-diabetics [1]. * **The "Rule of 100":** Remember that DM increases the risk of lower limb gangrene by ~100x. * **Monckeberg Medial Sclerosis:** Diabetics often have calcification of the arterial media, which can lead to falsely elevated Ankle-Brachial Index (ABI) readings. * **Leading Cause:** Diabetes is the leading cause of non-traumatic lower extremity amputations worldwide.

Q: Which test can confirm autoimmune thyroiditis in a patient?

Thyroid peroxidase antibody (TPO). **Hashimoto’s thyroiditis (Chronic Autoimmune Thyroiditis)** is the most common cause of hypothyroidism in iodine-sufficient regions. The diagnosis is primarily clinical and biochemical, supported by the presence of specific autoantibodies. 1. **Why Option A is correct:** **Thyroid Peroxidase (TPO) antibodies** are the hallmark of autoimmune thyroiditis. They are present in more than **90-95%** of patients with Hashimoto’s. TPO is the enzyme responsible for iodine oxidation and organification; antibodies against it lead to thyroid follicle destruction [1]. While **Antithyroglobulin (anti-Tg)** antibodies can also be present, TPO antibodies are more sensitive and have a stronger correlation with the progression to overt hypothyroidism [1]. 2. **Why other options are incorrect:** * **B. Antinuclear antibody (ANA):** This is a screening test for systemic autoimmune diseases like SLE. While patients with Hashimoto’s may have co-existing autoimmune conditions, ANA is not specific to the thyroid. * **C. Thyroid uptake resin:** This (T3 resin uptake) is an older test used to estimate Thyroid Binding Globulin (TBG) levels. It does not identify the underlying autoimmune etiology. * **D. Thyroid aspiration (FNAC):** While FNAC can show characteristic Hurthle cells and lymphocytic infiltration, it is **not** the first-line confirmatory test. It is reserved for cases where a dominant nodule is present to rule out malignancy (e.g., Lymphoma or Papillary Carcinoma). **NEET-PG High-Yield Pearls:** * **Most sensitive marker:** Anti-TPO antibodies. * **Histology:** Lymphocytic infiltration with germinal centers and **Hurthle cells** (Askanazy cells/oxyphilic cells). * **Risk:** Increased risk of **B-cell Thyroid Lymphoma**. * **USG Finding:** Diffuse heterogenous echogenicity (often described as a "pseudonodular" appearance).

Q: Testicular descent is controlled by which factor?

Insulin-like factor 3 (INSL3). Testicular descent is a complex, two-stage process. The correct answer is **Insulin-like factor 3 (INSL3)** because it is the primary hormone responsible for the first phase of descent. ### **Mechanism of Testicular Descent** 1. **Transabdominal Phase (Weeks 8–15):** This stage is controlled by **INSL3**, a peptide hormone secreted by the fetal Leydig cells. INSL3 acts on its receptor (RXFP2) to cause the thickening and contraction of the **gubernaculum**, which anchors the testes near the internal inguinal ring. 2. **Inguinoscrotal Phase (Weeks 25–35):** This stage is primarily **androgen-dependent** (Testosterone/DHT). Androgens cause the regression of the cranial suspensory ligament and guide the testes through the inguinal canal into the scrotum. ### **Analysis of Incorrect Options** * **RANKL (B):** This is a cytokine involved in bone metabolism (osteoclast activation). It has no role in gonadal development or descent. * **FSH (C):** Follicle-Stimulating Hormone is essential for spermatogenesis and Sertoli cell function but does not trigger the mechanical descent of the testes. * **LH (D):** While LH stimulates Leydig cells to produce testosterone (important for the second phase), **INSL3** is the specific factor required for the initial gubernacular development. ### **High-Yield Clinical Pearls for NEET-PG** * **Cryptorchidism:** Failure of descent is most commonly seen in preterm infants. The most common site of an undescended testis is the **inguinal canal**. * **Malignancy Risk:** Cryptorchidism increases the risk of testicular germ cell tumors (most commonly **Seminoma**), even if surgically corrected (Orchidopexy). * **Orchidopexy Timing:** Ideally performed between **6 to 12 months** of age to preserve fertility and allow for easier screening.

Q: All of the following are typically seen in Diabetic Ketoacidosis (DKA) except?

Bradycardia. **Explanation:** Diabetic Ketoacidosis (DKA) is a life-threatening complication of Diabetes Mellitus characterized by the triad of hyperglycemia, ketosis, and metabolic acidosis [1]. **Why Bradycardia is the Correct Answer:** **Bradycardia** is not a typical feature of DKA. In fact, DKA patients almost always present with **Tachycardia** [1]. This occurs as a compensatory response to significant volume depletion (dehydration) and as a physiological reaction to metabolic stress and acidosis [1], [2]. If bradycardia is seen in a DKA patient, it is an ominous sign suggesting imminent cardiac arrest, severe hyperkalemia, or profound exhaustion. **Analysis of Incorrect Options:** * **Tachycardia:** As mentioned, this is a hallmark sign [1]. It is the body’s attempt to maintain cardiac output in the face of decreased intravascular volume (due to osmotic diuresis) [2]. * **Dehydration:** Hyperglycemia causes osmotic diuresis, leading to massive fluid loss [2]. Patients often have a fluid deficit of 5–10 liters, presenting with dry mucous membranes and decreased skin turgor [1]. * **Abdominal pain/tenderness:** This is a classic "pseudo-peritonitis" presentation in DKA, especially in children [1]. It is thought to be caused by delayed gastric emptying, ileus, or the metabolic acidosis itself. **NEET-PG High-Yield Pearls:** * **Kussmaul Respiration:** Deep, rapid breathing is a compensatory mechanism to blow off $CO_2$ and mitigate metabolic acidosis [1]. * **Potassium Paradox:** Total body potassium is always **depleted** in DKA (due to diuresis), but serum potassium may appear **normal or high** initially due to the extracellular shift of $K^+$ in exchange for $H^+$ ions [2]. * **Management Priority:** The first step in management is aggressive fluid resuscitation with Normal Saline (0.9% NaCl) [1]. * **Anion Gap:** DKA is a classic cause of High Anion Gap Metabolic Acidosis (HAGMA).

Question 1

Which of the following conditions is a common cause of hypercalcemia?

Accepted Answer

Hyperthyroidism

Answer

Adrenocortical insufficiency

Answer

Amyloidosis

Answer

Vitamin C intoxication

Question 2

Which of the following is seen in Addison's disease?

Accepted Answer

Hypercalcemia

Answer

Hypernatremia

Answer

Hypokalemia

Answer

Hyperglycemia

Question 3

All of the following are true about Diabetes mellitus EXCEPT:

Accepted Answer

Diabetic ketoacidosis is commoner in type I diabetes mellitus.

Answer

Hyperosmolar hyperglycemic state is primarily seen in individuals with type II diabetes mellitus.

Answer

Serum sodium in diabetic ketoacidosis is typically in the range of 125-135 mEq/L.

Answer

Serum bicarbonate in diabetic ketoacidosis is less than 15 mEq/L.

Question 4

A 48-year-old Caucasian man, diagnosed with diabetes 5 years ago, presents with palpitations. Physical examination reveals diffuse skin darkening and testicular atrophy. Laboratory studies show elevated liver function and elevated blood sugars. A liver biopsy shows significantly elevated iron levels, leading to a diagnosis of hereditary hemochromatosis. Which one of the following laboratory findings is seen in hereditary hemochromatosis?

Accepted Answer

Decreased total iron-binding capacity

Answer

Decreased serum ceruloplasmin

Answer

Decreased serum ferritin

Answer

Decreased serum iron

Question 5

In patients with significant atherosclerosis, which of the following conditions is increased approximately 100-fold in those with comorbid diabetes compared to non-diabetic patients?

Accepted Answer

Lower limb ischemia

Answer

Myocardial infarction

Answer

Ischemic stroke

Answer

Vertebrobasilar insufficiency

Question 6

Which of the following is true about primary aldosteronism?

Accepted Answer

Decreased K+

Answer

Pedal edema

Answer

Increased renin

Answer

Increased Na+

Question 7

Which test can confirm autoimmune thyroiditis in a patient?

Accepted Answer

Thyroid peroxidase antibody (TPO)

Answer

Antinuclear antibody

Answer

Thyroid uptake resin

Answer

Thyroid aspiration

Question 8

Testicular descent is controlled by which factor?

Accepted Answer

Insulin-like factor 3 (INSL3)

Answer

RANKL

Answer

FSH

Answer

LH

Question 9

All of the following are typically seen in Diabetic Ketoacidosis (DKA) except?

Accepted Answer

Bradycardia

Answer

Tachycardia

Answer

Dehydration

Answer

Abdominal pain/tenderness

Question 10

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?

Accepted Answer

Multiple endocrine neoplasia type-1 (MEN-1)

Answer

Watery diarrhea, hypokalemia, and achlorhydria (WDHA) syndrome

Answer

Somatostatinoma

Answer

MEN-2A

Endocrinology — MCQs

Endocrinology — MCQs

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