Endocrinology Practice Questions

Q: All of the following conditions are associated with hyperthyroidism, except?

Hashimoto's thyroiditis. The correct answer is **A. Hashimoto’s thyroiditis**. **1. Why Hashimoto’s thyroiditis is the correct answer:** Hashimoto’s thyroiditis is the most common cause of **hypothyroidism** in iodine-sufficient regions. It is an autoimmune destruction of the thyroid gland mediated by T-cells and anti-thyroid peroxidase (anti-TPO) antibodies. While a transient "Hashitoxicosis" can occur early in the disease due to the leakage of preformed hormones from damaged follicles, the definitive clinical state is chronic hypothyroidism. **2. Analysis of incorrect options:** * **Graves’ Disease:** The most common cause of hyperthyroidism. It involves Type II hypersensitivity where thyroid-stimulating immunoglobulins (TSI) bind to and activate the TSH receptor, causing excessive hormone synthesis [1]. * **Toxic Multinodular Goiter (Plummer Disease):** Characterized by focal patches of thyroid autonomy. These nodules function independently of TSH stimulation, leading to hyperthyroidism (usually in older adults). * **Struma Ovarii:** A rare form of monodermal teratoma where ovarian tissue contains >50% thyroid tissue. If this ectopic tissue becomes overactive, it causes hyperthyroidism without thyroid gland enlargement (low iodine uptake in the neck, high uptake in the pelvis). **Clinical Pearls for NEET-PG:** * **Jod-Basedow Phenomenon:** Iodine-induced hyperthyroidism (often after IV contrast or Amiodarone). * **Wolff-Chaikoff Effect:** A transient reduction in thyroid hormone levels caused by the ingestion of a large amount of iodine (the basis for using Lugol’s iodine before surgery). * **Amiodarone:** Can cause both Type 1 (excess iodine) and Type 2 (destructive thyroiditis) thyrotoxicosis, as well as hypothyroidism. * **Diagnosis:** Low TSH with high Free T4/T3 confirms hyperthyroidism. Radioactive Iodine Uptake (RAIU) is **high** in Graves’/TMNG but **low** in thyroiditis and Struma ovarii.

Q: Which of the following is NOT a recommended site for insulin administration?

Dorsum of hands. Explanation: Insulin must be administered into the **subcutaneous fat** layer to ensure predictable absorption and minimize pain [1]. **Why Option A is correct:** The **dorsum of the hands** is an inappropriate site because it lacks sufficient subcutaneous adipose tissue. Injecting here increases the risk of **intramuscular (IM) injection**, which leads to rapid, unpredictable absorption and severe hypoglycemia [1]. Furthermore, the presence of superficial tendons, nerves, and vessels makes it clinically unsafe. Examination of a patient with diabetes should always include checking insulin injection sites [2]. **Why the other options are incorrect:** * **Abdomen (Option D):** This is the preferred site for insulin administration. It offers the most rapid and consistent absorption rate. Patients are advised to inject at least 2 inches away from the umbilicus. * **Arms (Option B):** The posterior surface (triceps area) of the upper arm is a standard site with moderate absorption speed. * **Lateral Thigh (Option C):** The upper-outer aspect of the thigh is used for slower absorption, which can be beneficial for basal insulin. **High-Yield NEET-PG Pearls:** 1. **Absorption Speed:** Abdomen > Arms > Thighs > Buttocks. 2. **Lipohypertrophy:** Repeated injections in the exact same spot cause fatty lumps that delay insulin absorption. **Site rotation** is the most important preventive measure. 3. **Exercise Effect:** Injecting into a limb that is about to be exercised (e.g., thigh before running) increases blood flow and accelerates insulin absorption, risking hypoglycemia. 4. **Angle of Injection:** Usually 90 degrees with short needles (4-6mm); a 45-degree angle or skin fold may be used in very thin individuals to avoid IM injection [1].

Q: A 52-year-old woman presents with palpitations, sweating, and heat intolerance. Physical examination reveals a palpable mass over the anterior aspect of the neck. Which of the following features is most associated with this condition?

Ophthalmoplegia. ### **Explanation** The clinical presentation of palpitations, sweating, heat intolerance, and a neck mass (goiter) is classic for **Hyperthyroidism**. In a middle-aged woman, the most common cause of hyperthyroidism is **Graves' Disease**, an autoimmune disorder caused by TSH-receptor antibodies (TRAb) [1, 3]. **Why Option C is Correct:** **Ophthalmoplegia** (weakness or paralysis of extraocular muscles) is a hallmark of **Graves' Ophthalmopathy**. This occurs due to the activation of orbital fibroblasts by TSH-receptor antibodies, leading to the accumulation of glycosaminoglycans (GAGs), edema, and fibrosis of the extraocular muscles [2]. This results in proptosis, diplopia, and restricted eye movements. It is specific to Graves' disease and not seen in other causes of thyrotoxicosis [1]. **Why the Other Options are Incorrect:** * **A & D (Constipation and Slow relaxing reflexes):** These are classic features of **Hypothyroidism** [3]. In hyperthyroidism, patients typically experience increased frequency of bowel movements (diarrhea) and **brisk (hyperreflexic)** deep tendon reflexes. * **B (Elevated TSH):** In primary hyperthyroidism (like Graves'), high levels of circulating T3 and T4 exert negative feedback on the pituitary, leading to **suppressed (low) TSH levels** [2]. Elevated TSH with high T4 is rare and suggests a TSH-secreting pituitary adenoma. ### **NEET-PG High-Yield Pearls** * **Graves' Triad:** Hyperthyroidism (Goiter), Ophthalmopathy (Exophthalmos), and Dermopathy (Pretibial Myxedema) [1]. * **Most common muscle involved in Graves' Ophthalmopathy:** Inferior rectus (leading to restricted upward gaze). * **Diagnosis:** Low TSH, High Free T4, and positive **TSH-receptor antibodies (TRAb)** [1, 3]. * **Radioactive Iodine Uptake (RAIU):** Shows **diffuse, increased uptake** in Graves' disease, distinguishing it from thyroiditis (low uptake) [3].

Q: Which of the following can cause osteonecrosis?

Systemic Lupus Erythematosus (SLE). **Explanation:** **Osteonecrosis (Avascular Necrosis)** is the death of bone components due to an interruption of blood supply, most commonly affecting the femoral head. **Why SLE is the Correct Answer:** Systemic Lupus Erythematosus (SLE) is a major risk factor for osteonecrosis. The pathogenesis is multifactorial, involving **vasculitis**, secondary **antiphospholipid syndrome (APLS)** leading to thrombosis, and, most significantly, the chronic use of **high-dose corticosteroids** to manage the disease. In many clinical scenarios, SLE is considered an independent risk factor even when steroid doses are controlled. **Analysis of Other Options:** * **A. Sickle Cell Anemia:** While Sickle Cell Anemia is a classic cause of osteonecrosis (due to vaso-occlusive crises), in the context of this specific question format, SLE is often highlighted as the systemic autoimmune prototype. However, it is important to note that both A and B are technically well-known causes. * **B. Corticosteroid Use:** This is the **most common** non-traumatic cause of osteonecrosis. It induces fat hypertrophy in the marrow, increasing intraosseous pressure and reducing blood flow. * **C. Diabetes Mellitus:** While DM causes various bone pathologies (like Charcot joint), it is **not** a direct or primary cause of osteonecrosis. **NEET-PG High-Yield Pearls:** * **Most common site:** Femoral head (due to retrograde blood supply via the medial circumflex femoral artery). * **Imaging of choice:** **MRI** is the most sensitive investigation for early detection (shows "double line sign"). * **X-ray finding:** "Crescent sign" (subchondral collapse) is a late finding. * **Mnemonic for Causes (PLASTIC RAGS):** **P**ancreatitis, **L**upus (SLE), **A**lcohol, **S**ickle cell, **T**rauma, **I**diopathic, **C**aisson disease, **R**adiation, **A**myloidosis, **G**aucher disease, **S**teroids.

Q: A patient presents with thyrotoxicosis and exophthalmos. What would thyroid function tests reveal?

Increased T3, increased T4, decreased TSH. **Explanation:** The clinical presentation of **thyrotoxicosis** (excess circulating thyroid hormones) combined with **exophthalmos** (proptosis) is pathognomonic for **Graves' Disease**, the most common cause of hyperthyroidism [3], [4]. **1. Why Option C is Correct:** In Graves' Disease, the body produces Thyroid Stimulating Immunoglobulins (TSI) that bind to and activate the TSH receptors on the thyroid gland [3]. This leads to the autonomous and excessive synthesis and secretion of **T3 and T4**. Through the **negative feedback mechanism**, these high levels of circulating thyroid hormones inhibit the anterior pituitary from secreting Thyroid Stimulating Hormone (TSH) [2]. Therefore, the classic biochemical profile is **elevated T3/T4 with a suppressed (decreased) TSH** [4]. **2. Why Other Options are Incorrect:** * **Option A:** Normal TSH in the presence of high T3/T4 is physiologically inconsistent due to negative feedback, unless there is a rare TSH-secreting pituitary adenoma (Secondary Hyperthyroidism), which does not present with exophthalmos [1]. * **Option B:** This profile (Low T3/T4, High TSH) represents **Primary Hypothyroidism** (e.g., Hashimoto’s Thyroiditis) [1], [2]. * **Option C:** This profile (Low T3, Normal T4, Low TSH) is often seen in **Sick Euthyroid Syndrome**, not thyrotoxicosis. **3. NEET-PG High-Yield Pearls:** * **Exophthalmos:** Specific to Graves' Disease; caused by TSH-receptor antibodies reacting with orbital fibroblasts (not seen in other causes of thyrotoxicosis like toxic multinodular goiter) [3], [4]. * **Best Initial Test:** Serum TSH (most sensitive) [2]. * **T3 Toxicosis:** In early Graves', T3 may rise before T4. * **Wolff-Chaikoff Effect:** Reduction in thyroid hormone levels caused by ingestion of a large amount of iodine.

Question 1

A 60-year-old woman presents with menorrhagia. Her history is significant for lethargy, constipation, cold intolerance, and muscle stiffness. What is the most likely diagnosis?

Accepted Answer

Hypothyroidism

Answer

Uterine carcinoma

Answer

Systemic lupus erythematosus

Answer

Severe iron deficiency anemia

Question 2

All of the following conditions are associated with hyperthyroidism, except?

Accepted Answer

Hashimoto's thyroiditis

Answer

Graves' disease

Answer

Toxic multinodular goiter

Answer

Struma ovarii

Question 3

A patient presents with hyperphosphatemia, "sho" metacarpals, and cataracts. What is the most likely diagnosis?

Accepted Answer

Pseudohypoparathyroidism

Answer

Hypophosphatasia

Answer

Hyperparathyroidism

Answer

Osteomalacia

Question 4

Which of the following is NOT a recommended site for insulin administration?

Accepted Answer

Dorsum of hands

Answer

Arms

Answer

Lateral aspect of thigh

Answer

Abdomen around the umbilicus

Question 5

A 52-year-old woman presents with palpitations, sweating, and heat intolerance. Physical examination reveals a palpable mass over the anterior aspect of the neck. Which of the following features is most associated with this condition?

Accepted Answer

Ophthalmoplegia

Answer

Constipation

Answer

Elevated thyroid-stimulating hormone (TSH)

Answer

Slow relaxing reflexes

Question 6

Pheochromocytoma is a tumor of which of the following?

Accepted Answer

None of the above

Answer

Adrenal cortex

Answer

Parathyroids

Answer

Pituitary

Question 7

Which of the following can cause osteonecrosis?

Accepted Answer

Systemic Lupus Erythematosus (SLE)

Answer

Sickle cell anemia

Answer

Corticosteroid use

Answer

Diabetes Mellitus

Question 8

A 70-year-old male presented with severe confusion, shortness of breath, and obtundation. Lab findings revealed moderately raised serum calcium, mildly raised serum creatinine, mildly raised BUN, normal PTH, elevated PTHrP, and an abnormal chest x-ray. Which of the following drugs can be given for the treatment of hypercalcemia?

Accepted Answer

Prednisolone

Answer

Calcitonin

Answer

Furosemide

Answer

Normal Saline

Question 9

A patient presents with thyrotoxicosis and exophthalmos. What would thyroid function tests reveal?

Accepted Answer

Increased T3, increased T4, decreased TSH

Answer

Increased T3, increased T4, normal TSH

Answer

Decreased T3, decreased T4, increased TSH

Answer

Decreased T3, normal T4, decreased TSH

Question 10

Which of the following is NOT true regarding Cushing syndrome?

Accepted Answer

Hypoglycemia

Answer

Purplish striae

Answer

Plethora

Answer

Obesity

Endocrinology — MCQs

Endocrinology — MCQs

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