Endocrinology Practice Questions

Q: A 30-year-old female complains of palpitations, fatigue, and insomnia. On physical exam, her extremities are warm and she is tachycardic. There is diffuse thyroid gland enlargement and proptosis. There is a thickening of the skin in the pretibial area. Which of the following lab values would you expect in this patient?

Decreased TSH, increased total thyroxine. **Explanation:** The clinical presentation of palpitations, tachycardia, warm extremities, and diffuse goiter indicates **Hyperthyroidism** [2]. The specific findings of **proptosis (exophthalmos)** and **pretibial myxedema** (thickening of the skin) are pathognomonic for **Graves' Disease** [1], [2]. In Graves' Disease, thyroid-stimulating immunoglobulins (TSI) bind to and activate the TSH receptor, leading to excessive synthesis and release of thyroid hormones (T4 and T3) [1]. Due to the **negative feedback loop**, high levels of circulating thyroid hormones suppress the anterior pituitary, resulting in **decreased (often undetectable) TSH levels** [2]. Therefore, the expected lab profile is a low TSH and elevated free/total T4. **Analysis of Incorrect Options:** * **Option A:** Increased TSH with increased T4 is seen in rare TSH-secreting pituitary adenomas or Thyroid Hormone Resistance syndrome, not Graves' disease. * **Option C:** In hyperthyroidism, T3 levels are increased, not decreased. T3 uptake increases because thyroid-binding globulin (TBG) sites are saturated by high endogenous T4. * **Option D:** While "T3 toxicosis" can present with low TSH and normal T4, the classic presentation of Graves' usually involves elevation of both hormones. Option B is the more standard biochemical finding for a primary hyperthyroid state. **NEET-PG High-Yield Pearls:** * **Graves' Disease Triad:** Hyperthyroidism + Exophthalmos + Pretibial Myxedema [1]. * **Antibody:** Anti-TSH receptor antibodies (TRAb/TSI) are the most specific [1]. * **Radioiodine Uptake (RAIU):** Shows **diffuse, increased uptake** (distinguishes it from thyroiditis where uptake is low). * **Treatment of choice (Pregnancy):** Propylthiouracil (PTU) in the 1st trimester; Methimazole in the 2nd and 3rd trimesters.

Q: Which of the following is not typically seen in Cushing syndrome?

Hypotension. **Explanation:** The correct answer is **Hypotension**. Cushing syndrome is characterized by a state of glucocorticoid excess, which typically leads to **Hypertension**, not hypotension. **Why Hypotension is the correct answer (Why it's NOT seen):** Glucocorticoids contribute to elevated blood pressure through several mechanisms: 1. **Mineralocorticoid effect:** At high levels, cortisol binds to mineralocorticoid receptors, leading to sodium and water retention. 2. **Vascular Sensitivity:** Cortisol increases the sensitivity of vascular smooth muscle to catecholamines (permissive action), leading to increased peripheral vascular resistance [2]. 3. **RAAS activation:** It stimulates the production of angiotensinogen. Therefore, hypertension is a hallmark feature, seen in approximately 75-80% of patients. **Why the other options are seen in Cushing Syndrome:** * **Peptic Ulcer:** Glucocorticoids increase gastric acid secretion and decrease the protective gastric mucosal barrier (prostaglandin inhibition), increasing the risk of peptic ulceration. * **Proximal Myopathy:** Excess cortisol causes protein catabolism and muscle wasting, specifically affecting proximal muscle groups (e.g., difficulty climbing stairs or rising from a chair) [1]. * **Glucose Intolerance:** Cortisol is a counter-regulatory hormone that promotes gluconeogenesis in the liver and decreases peripheral glucose uptake (insulin resistance), often leading to "Steroid Diabetes." **High-Yield NEET-PG Pearls:** * **Most common cause overall:** Iatrogenic (exogenous steroids) [4]. * **Most common endogenous cause:** Cushing Disease (ACTH-secreting pituitary adenoma) [1]. * **Screening tests:** 24-hour urinary free cortisol, Overnight Dexamethasone Suppression Test (ODST), or Late-night salivary cortisol [3]. * **Electrolyte hallmark:** Hypokalemic metabolic alkalosis (especially in ectopic ACTH syndrome) [4].

Q: In patients with thyrotoxicosis, which condition is associated with the least radioiodine uptake?

Subacute thyroiditis. **Explanation:** The core concept in answering this question is distinguishing between **hyperthyroidism** (increased synthesis of hormone) and **thyrotoxicosis due to thyroiditis** (release of pre-formed hormone). **Why Subacute Thyroiditis is correct:** In Subacute (De Quervain’s) Thyroiditis, there is an inflammatory destruction of thyroid follicles. This causes the leakage of stored thyroid hormones into the bloodstream, leading to thyrotoxicosis. However, because the follicular cells are damaged and TSH is suppressed by the high levels of circulating T4/T3, the gland's ability to actively trap iodine is severely impaired. Consequently, the Radioactive Iodine Uptake (RAIU) is **characteristically low or near zero (<5%).** **Why the other options are incorrect:** * **Graves’ Disease:** This is an autoimmune condition where TSH-receptor antibodies stimulate the entire gland, leading to **diffuse, high RAIU.** * **Toxic Adenoma:** This involves a single "hot" nodule that autonomously produces thyroid hormone, showing **increased focal uptake** with suppression of the rest of the gland. * **Multinodular Goiter (Toxic):** This presents with **patchy, heterogeneous increased uptake** in multiple autonomous nodules. **NEET-PG High-Yield Pearls:** * **Low RAIU Thyrotoxicosis:** Remember the mnemonic **"S-I-F-T"**: **S**ubacute thyroiditis, **I**atrogenic/Factitious (exogenous T4), **F**ollicular CA (metastatic), and **T**eratomata (Struma ovarii). * **Subacute Thyroiditis:** Look for a clinical history of a **painful/tender thyroid** following a viral upper respiratory tract infection and an **elevated ESR.** * **Amiodarone:** Can cause both high uptake (Type I) and low uptake (Type II) thyrotoxicosis.

Q: Which condition is characterized by the following clinical feature?

Graves disease. ***Graves disease*** - **Exophthalmos** (bulging eyes) is the pathognomonic sign of Graves disease, caused by **thyroid-stimulating immunoglobulins** that cross-react with **orbital tissues**. - The **autoimmune hyperthyroidism** leads to increased **orbital fat** and **extraocular muscle** inflammation, resulting in characteristic **proptosis**. *Hyperparathyroidism* - Primarily causes **bone disease** (**osteitis fibrosa cystica**) and **nephrolithiasis**, not ocular manifestations. - Clinical features include **muscle weakness**, **depression**, and **"stones, bones, groans, and psychiatric moans"**. *Cushing disease* - Characterized by **central obesity**, **moon facies**, and **purple striae**, but no eye involvement. - Patients develop **buffalo hump**, **easy bruising**, and **hyperglycemia** due to excess **cortisol**. *Addison disease* - Features **hyperpigmentation** of skin and mucous membranes due to increased **ACTH** and **MSH**. - Presents with **fatigue**, **weight loss**, and **hypotension**, but no ocular abnormalities.

Q: Which of the following is NOT seen in hyperparathyroidism?

Increase in serum calcitonin. Primary hyperparathyroidism (PHPT) is characterized by the autonomous overproduction of Parathyroid Hormone (PTH), usually due to a parathyroid adenoma [2]. **Why Option B is the correct answer:** Calcitonin is produced by the **parafollicular C-cells of the thyroid gland**. Its primary physiological role is to lower serum calcium by inhibiting osteoclast activity. In hyperparathyroidism, while serum calcium is high, there is no compensatory or pathological increase in calcitonin levels. In fact, calcitonin is clinically insignificant in the calcium homeostasis of adults with PHPT. Elevated calcitonin is instead a specific marker for **Medullary Thyroid Carcinoma (MTC)**. **Analysis of incorrect options:** * **Option A:** PTH directly increases serum calcium by increasing bone resorption, enhancing renal distal tubule calcium reabsorption, and stimulating the synthesis of 1,25-dihydroxyvitamin D [1]. * **Option C:** Subperiosteal resorption, particularly on the radial aspect of the middle phalanges, is the **most specific radiographic sign** of hyperparathyroidism (Osteitis Fibrosa Cystica). * **Option D:** Although PTH increases renal calcium reabsorption, the massive filtered load of calcium (due to hypercalcemia) eventually overwhelms the tubules, leading to **hypercalciuria** (>250 mg/24h in females; >300 mg/24h in males). This distinguishes PHPT from Familial Hypocalciuric Hypercalcemia (FHH), where urinary calcium is low. **NEET-PG High-Yield Pearls:** * **Classic triad:** "Stones (renal), bones (aches/resorption), abdominal groans (peptic ulcers/pancreatitis), and psychic overtones" [3]. * **Biochemical hallmark:** High PTH, High Calcium, Low Phosphate, and High Alkaline Phosphatase (if bone disease is present) [2]. * **ECG finding:** Shortened QT interval due to hypercalcemia.

Q: A 25-year-old female presents with a 12-month history of palpitations, intermittent diarrhea, anxiety, and a 1-month history of "bulging of both eyes." What is the most likely cause of her symptoms?

Graves' disease. **Explanation:** The clinical presentation of palpitations, diarrhea, anxiety, and weight loss (implied by the systemic symptoms) points toward **Hyperthyroidism** [3]. The pathognomonic finding in this case is the **"bulging of both eyes" (Exophthalmos/Graves' Ophthalmopathy)** [2]. **1. Why Graves' Disease is Correct:** Graves' disease is an autoimmune disorder caused by **Thyroid Stimulating Immunoglobulins (TSI)** that bind to and activate the TSH receptor [1]. It is the most common cause of hyperthyroidism in young women [3]. It is characterized by a classic triad: Hyperthyroidism, Diffuse Goiter, and **Ophthalmopathy** [1]. The eye changes occur due to the activation of TSH receptors on orbital fibroblasts, leading to glycosaminoglycan accumulation and extraocular muscle edema—a feature **not** seen in other causes of hyperthyroidism [2]. **2. Why Other Options are Incorrect:** * **Hashimoto’s Thyroiditis:** Typically presents with features of *hypothyroidism* (weight gain, constipation, cold intolerance). While a transient "Hashitoxicosis" can occur, it does not cause ophthalmopathy. * **Multinodular Toxic Goiter (Plummer Disease):** Common in older age groups. While it causes hyperthyroidism, it is characterized by nodules and **lacks** the extrathyroidal manifestations like exophthalmos [2]. * **Papillary Carcinoma:** The most common thyroid malignancy; it usually presents as a painless, euthyroid cold nodule and does not typically cause hyperthyroidism or exophthalmos. **Clinical Pearls for NEET-PG:** * **Graves' Triad:** Hyperthyroidism, Exophthalmos, and Pretibial Myxedema (Dermopathy) [1]. * **Diagnosis:** Low TSH, High T3/T4, and **diffuse increased uptake** on Radioactive Iodine Uptake (RAIU) scan [3]. * **Specific Marker:** TSH Receptor Antibodies (TRAb/TSI) [1]. * **Smoking** is the most significant risk factor for the worsening of Graves' ophthalmopathy.

Q: Hypothyroidism caused by a viral infection of the thyroid gland is a pathologic condition associated with which of the following blood hormone levels?

High TSH. ### Explanation **1. Why the Correct Answer is Right:** Hypothyroidism caused by a viral infection refers to **Subacute Granulomatous Thyroiditis (De Quervain’s Thyroiditis)**. While this condition typically presents with a transient phase of hyperthyroidism (due to the release of preformed hormones), it is frequently followed by a **hypothyroid phase** as the gland's hormone stores are depleted and the follicular cells are recovering [2]. In any form of **primary hypothyroidism** (where the defect is in the thyroid gland itself), the low levels of circulating T3 and T4 remove the negative feedback on the anterior pituitary [1]. This results in a compensatory **increase in Thyroid Stimulating Hormone (TSH)** [1]. Therefore, high TSH is the hallmark biochemical marker of primary hypothyroidism. **2. Why the Incorrect Options are Wrong:** * **High Prolactin (PRL):** While severe primary hypothyroidism can cause hyperprolactinemia (because high TRH acts as a prolactin-releasing factor), it is not the primary diagnostic hormone level associated with viral-induced thyroiditis. * **High Cortisol:** Cortisol levels are typically unaffected by thyroiditis. High cortisol is associated with Cushing’s syndrome or acute stress, not hypothyroidism. * **Low Growth Hormone (GH):** While thyroid hormones are necessary for normal GH secretion in children (leading to growth retardation in cretinism), GH levels are not a standard diagnostic parameter for adult viral thyroiditis. **3. Clinical Pearls for NEET-PG:** * **De Quervain’s Thyroiditis:** Characterized by a **painful/tender thyroid gland**, often following an upper respiratory tract infection. * **ESR:** Typically very high (>50-100 mm/hr) [2]. * **Radioactive Iodine Uptake (RAIU):** Characteristically **low** during the thyrotoxic phase (due to follicular cell damage) [2]. * **Treatment:** NSAIDs for mild cases; Steroids for severe pain [2]. It is usually self-limiting.

Q: Which type of diabetes is characterized by impaired glucose-induced insulin secretion with preserved beta-cell mass?

Maturity-onset diabetes of the young (MODY). **Explanation:** The correct answer is **Maturity-onset diabetes of the young (MODY)**. **Why MODY is correct:** MODY is a group of monogenic disorders characterized by **functional defects** in beta-cell glucose sensing or insulin secretion, rather than the destruction of the cells themselves [2]. In MODY (especially MODY 2 and MODY 3), the **beta-cell mass remains preserved**, but there is a "blindness" to glucose or a defect in the stimulus-secretion coupling. For example, in MODY 2 (Glucokinase mutation), the "glucose sensor" has a higher threshold, requiring higher glucose levels to trigger insulin release. **Why other options are incorrect:** * **Type 1 Diabetes:** Characterized by autoimmune-mediated **destruction of beta-cells**, leading to an absolute deficiency of insulin and a significant loss of beta-cell mass [1]. * **LADA (Latent Autoimmune Diabetes in Adults):** Often called "Type 1.5," it involves a slow-progressing autoimmune attack. Like Type 1, it eventually leads to a **reduction in beta-cell mass**. * **Wolfram Syndrome (DIDMOAD):** A rare genetic neurodegenerative disorder (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness). The DM here is caused by progressive **beta-cell loss** due to endoplasmic reticulum stress (WFS1 gene mutation). **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** MODY follows an **Autosomal Dominant** pattern (look for 3 generations of early-onset DM in the history) [2]. * **Most Common Type:** **MODY 3** (HNF-1α mutation) is the most common globally; **MODY 2** (Glucokinase) is the second most common. * **Treatment:** Patients with MODY 3 are exquisitely sensitive to **Low-dose Sulfonylureas**, which bypass the glucose-sensing defect. * **Key Differentiator:** Unlike Type 1 DM, MODY is **Ketosis-negative** and **Autoantibody-negative** (GAD/ICA negative).

Q: Which of the following is not a characteristic feature of Multiple Endocrine Neoplasia type 1 (MEN1)?

Posterior pituitary tumors. **Explanation:** Multiple Endocrine Neoplasia type 1 (MEN1), also known as **Wermer’s Syndrome**, is an autosomal dominant disorder caused by a mutation in the *MEN1* gene (encoding the protein Menin). It is classically characterized by the **"3 Ps"**: Parathyroid, Pancreas, and Pituitary. **Why Option A is correct:** While pituitary adenomas are a hallmark of MEN1, they almost exclusively involve the **Anterior Pituitary** (adenohypophysis). Prolactinomas are the most common, followed by somatotropinomas (GH-secreting). The **Posterior Pituitary** (neurohypophysis) is not involved in the MEN1 syndrome, making this the "except" or incorrect feature. **Why other options are incorrect:** * **B. Foregut Carcinoids:** These are recognized components of MEN1. They include thymic, bronchial, and gastric carcinoids. Thymic carcinoids are particularly aggressive and are a significant cause of mortality in these patients. * **C. Parathyroid Hyperplasia:** This is the **most common** (95% of patients) and usually the earliest clinical manifestation of MEN1. It typically involves multiglandular hyperplasia rather than a single adenoma. * **D. Pancreatic Neuroendocrine Tumors (pNETs):** These occur in about 60-70% of patients. Gastrinomas (leading to Zollinger-Ellison Syndrome) are the most common symptomatic pNET, followed by Insulinomas. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Autosomal Dominant; Chromosome **11q13**. * **Most common feature:** Primary Hyperparathyroidism. * **Most common pituitary tumor:** Prolactinoma. * **Cutaneous markers:** Angiofibromas, collagenomas, and lipomas are frequently seen and can aid in early clinical diagnosis. * **Screening:** Annual biochemical screening (Calcium, PTH, Gastrin, Prolactin) is recommended for carriers starting in childhood.

Question 1

A 30-year-old female complains of palpitations, fatigue, and insomnia. On physical exam, her extremities are warm and she is tachycardic. There is diffuse thyroid gland enlargement and proptosis. There is a thickening of the skin in the pretibial area. Which of the following lab values would you expect in this patient?

Accepted Answer

Decreased TSH, increased total thyroxine

Answer

Increased TSH, total thyroxine, total T3

Answer

Increased T3 uptake, decreased T3

Answer

Decreased TSH, normal T4

Question 2

What is the most common presentation of hypoparathyroidism beyond the neonatal period?

Accepted Answer

Tingling of extremities

Answer

Syncope secondary to prolonged QT intervals

Answer

Seizure

Answer

Bronchospasm

Question 3

Which of the following is not typically seen in Cushing syndrome?

Accepted Answer

Hypotension

Answer

Peptic ulcer

Answer

Proximal myopathy

Answer

Glucose intolerance

Question 4

In patients with thyrotoxicosis, which condition is associated with the least radioiodine uptake?

Accepted Answer

Subacute thyroiditis

Answer

Toxic adenoma

Answer

Graves' disease

Answer

Multinodular goiter

Question 5

Which condition is characterized by the following clinical feature?

Accepted Answer

Graves disease

Answer

Hyperparathyroidism

Answer

Cushing disease

Answer

Addison disease

Question 6

Which of the following is NOT seen in hyperparathyroidism?

Accepted Answer

Increase in serum calcitonin

Answer

Increase in serum calcium

Answer

Subperiosteal resorption of phalanges

Answer

Increase in 24-hour urinary calcium excretion > 250 mg

Question 7

A 25-year-old female presents with a 12-month history of palpitations, intermittent diarrhea, anxiety, and a 1-month history of "bulging of both eyes." What is the most likely cause of her symptoms?

Accepted Answer

Graves' disease

Answer

Hashimoto's thyroiditis

Answer

Multinodular toxic goiter

Answer

Papillary carcinoma

Question 8

Hypothyroidism caused by a viral infection of the thyroid gland is a pathologic condition associated with which of the following blood hormone levels?

Accepted Answer

High TSH

Answer

High prolactin (PRL)

Answer

High cortisol

Answer

Low growth hormone (GH)

Question 9

Which type of diabetes is characterized by impaired glucose-induced insulin secretion with preserved beta-cell mass?

Accepted Answer

Maturity-onset diabetes of the young (MODY)

Answer

Wolfram syndrome

Answer

Type 1 diabetes

Answer

Latent autoimmune diabetes in adults (LADA)

Question 10

Which of the following is not a characteristic feature of Multiple Endocrine Neoplasia type 1 (MEN1)?

Accepted Answer

Posterior pituitary tumors

Answer

Foregut carcinoids

Answer

Parathyroid hyperplasia

Answer

Pancreatic neuroendocrine tumors

Endocrinology — MCQs

Endocrinology — MCQs

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