Endocrinology Practice Questions

Q: Diabetes mellitus is diagnosed if fasting blood glucose is?

>126 mg/dL. The diagnosis of Diabetes Mellitus (DM) is based on standardized glycemic thresholds established by the American Diabetes Association (ADA) and WHO. [1] ### **Explanation of the Correct Answer** **Option B (>126 mg/dL)** is the correct diagnostic threshold for fasting plasma glucose (FPG). Fasting is defined as no caloric intake for at least 8 hours. A value of **≥126 mg/dL (7.0 mmol/L)** on two separate occasions (unless symptomatic with random glucose ≥200 mg/dL) confirms the diagnosis of Diabetes Mellitus. [1] This specific cutoff is used because it correlates with a significantly increased risk of developing microvascular complications, particularly diabetic retinopathy. [1] ### **Analysis of Incorrect Options** * **Option A (>100 mg/dL):** 100 mg/dL is the upper limit of "Normal." Values between **100–125 mg/dL** are classified as **Impaired Fasting Glucose (IFG)**, a state of pre-diabetes. [1] * **Options C & D:** These values (110 and 116 mg/dL) fall within the range of Impaired Fasting Glucose (Pre-diabetes) and do not meet the criteria for a definitive diagnosis of Diabetes Mellitus. [1] ### **NEET-PG High-Yield Pearls** To excel in NEET-PG, remember the four diagnostic criteria for Diabetes: 1. **Fasting Plasma Glucose (FPG):** ≥126 mg/dL. [1] 2. **2-hour Post-Prandial (75g OGTT):** ≥200 mg/dL. 3. **HbA1c:** ≥6.5% (using a standardized assay). 4. **Random Plasma Glucose:** ≥200 mg/dL in a patient with classic symptoms of hyperglycemia (polyuria, polydipsia, weight loss). [1] **Note:** For **Gestational Diabetes (GDM)**, the O'Sullivan criteria or IADPSG criteria (Fasting ≥92 mg/dL) are used, which differ from the standard adult diagnostic thresholds.

Q: Which of the following is considered a silent thyroiditis?

Postpartum thyroiditis. **Explanation:** **Postpartum thyroiditis (Option D)** is a variant of **painless (silent) thyroiditis**. It is an autoimmune-mediated destructive thyroiditis occurring within one year of delivery. Pathologically, it is characterized by a lymphocytic infiltration similar to Hashimoto’s, but clinically it presents with a transient thyrotoxic phase (due to the release of preformed hormones) followed by a hypothyroid phase, eventually returning to euthyroidism in most cases. It is "silent" because it lacks the thyroid pain and tenderness seen in inflammatory types. **Why other options are incorrect:** * **Acute thyroiditis (Option A):** Also known as Suppurative Thyroiditis, it is usually bacterial (e.g., *S. aureus*). It presents with high fever, redness, and severe localized pain. * **Subacute thyroiditis (Option B):** Also known as **De Quervain’s thyroiditis**, it is typically post-viral [1]. It is the most common cause of a **painful** thyroid gland. * **Hashimoto thyroiditis (Option C):** While it is an autoimmune lymphocytic thyroiditis, it typically presents as a chronic, progressive goitrous hypothyroidism rather than the transient, self-limiting "silent" episodes characteristic of postpartum or sporadic painless thyroiditis. **High-Yield Clinical Pearls for NEET-PG:** * **Radioactive Iodine Uptake (RAIU):** In the thyrotoxic phase of silent/postpartum thyroiditis, **RAIU is low** (distinguishing it from Graves' disease where RAIU is high) [1]. * **ESR:** Markedly elevated in Subacute (De Quervain’s) thyroiditis but usually normal or mildly elevated in silent thyroiditis [1]. * **Treatment:** Since the thyrotoxicosis is due to "leakage" and not overproduction, **Propranolol** is used for symptom control; Antithyroid drugs (PTU/Methimazole) have no role [1].

Q: Edema of the feet is not a feature of which of the following conditions?

Conn syndrome. **Explanation:** The correct answer is **Conn Syndrome** (Primary Hyperaldosteronism). **1. Why Conn Syndrome is the correct answer:** In Conn syndrome, there is an overproduction of aldosterone, which leads to sodium and water retention. While this initially increases extracellular fluid volume, it does not result in clinical edema due to a phenomenon known as **"Aldosterone Escape."** When the volume expands, the body compensates by increasing the secretion of **Atrial Natriuretic Peptide (ANP)** and increasing the pressure natriuresis in the kidneys. This leads to the excretion of excess sodium and water, preventing the formation of edema while maintaining hypertension. **2. Why the other options are incorrect:** * **Hypothyroidism:** Characteristically causes **Myxedema** (non-pitting edema) due to the accumulation of glycosaminoglycans (hyaluronic acid) in the interstitial space, which traps water. * **Congestive Heart Failure (CHF):** Causes pitting edema due to increased capillary hydrostatic pressure resulting from venous congestion and reduced cardiac output. * **Nephrotic Syndrome:** Leads to severe generalized edema (Anasarca) due to decreased plasma oncotic pressure (hypoalbuminemia) and secondary activation of the Renin-Angiotensin-Aldosterone System (RAAS). **Clinical Pearls for NEET-PG:** * **Aldosterone Escape:** This is the hallmark reason why patients with Primary Hyperaldosteronism have hypertension and hypokalemia but **no edema**. * **Triad of Conn Syndrome:** Hypertension, Hypokalemia, and Metabolic Alkalosis. * **Screening Test:** Plasma Aldosterone Concentration (PAC) to Plasma Renin Activity (PRA) ratio. A ratio >20-30 is suggestive. * **Confirmatory Test:** Saline infusion test or Oral salt loading test (failure to suppress aldosterone).

Q: Cushing syndrome is characterized by all of the following except?

Hypoglycemia. **Explanation:** Cushing syndrome results from chronic exposure to excessive levels of glucocorticoids (cortisol). To identify the correct answer, one must understand the metabolic and physiological actions of cortisol. **Why Hypoglycemia is the correct answer:** Cortisol is a "stress hormone" that acts as a **counter-regulatory hormone** to insulin. It stimulates gluconeogenesis in the liver and decreases peripheral glucose uptake in muscles and adipose tissue. Therefore, Cushing syndrome leads to **Hyperglycemia** (or impaired glucose tolerance/Diabetes Mellitus), not hypoglycemia. **Analysis of incorrect options:** * **Hypertension:** Cortisol causes hypertension through several mechanisms: mineralocorticoid activity (sodium and water retention), increased sensitivity to catecholamines, and activation of the Renin-Angiotensin-Aldosterone System (RAAS). * **Proximal Myopathy:** Excess cortisol has a catabolic effect on proteins. It causes muscle wasting, particularly in the proximal limb muscles (shoulders and hips), leading to difficulty climbing stairs or rising from a chair [1]. * **Centripetal Obesity:** Cortisol redistributes fat from the extremities to the trunk and face [1]. This results in the classic "Cushingoid" habitus: moon facies, buffalo hump (suvaclavicular/dorsocervical fat pads), and truncal obesity with thin extremities. **NEET-PG High-Yield Pearls:** * **Most common cause overall:** Iatrogenic (exogenous steroid use) [4]. * **Most common endogenous cause:** Cushing’s Disease (ACTH-secreting pituitary adenoma) [1], [4]. * **Electrolyte profile:** Hypokalemic metabolic alkalosis (due to mineralocorticoid effects, especially common in ectopic ACTH syndrome). * **Screening tests:** 24-hour urinary free cortisol, Low-dose dexamethasone suppression test (LDDST), or Late-night salivary cortisol [2], [3].

Q: All of the following forms of porphyria are associated with peripheral neuropathy except?

Porphyria cutanea tarda. **Explanation:** Porphyrias are metabolic disorders caused by deficiencies in the enzymes of the heme biosynthetic pathway [2]. They are broadly classified into **Acute Porphyrias** (neurovisceral symptoms) and **Cutaneous Porphyrias** (photosensitivity). **1. Why Porphyria Cutanea Tarda (PCT) is the correct answer:** PCT is the most common form of porphyria and is strictly a **cutaneous porphyria** [2]. It is caused by a deficiency of *uroporphyrinogen decarboxylase*. Unlike the acute forms, PCT presents with skin fragility, blistering, and hypertrichosis on sun-exposed areas [3]. It **does not** involve the accumulation of neurotoxic precursors like delta-aminolevulinic acid (ALA); therefore, it is **never associated with peripheral neuropathy** or acute abdominal pain [3]. **2. Why the other options are incorrect:** Options A, B, and D are the **Acute Porphyrias**. These are characterized by life-threatening "acute attacks" triggered by drugs, fasting, or hormones [1]. * **Acute Intermittent Porphyria (AIP):** The most severe acute form; lacks skin findings. * **Hereditary Coproporphyria (HCP) & Variegate Porphyria (VP):** These are "mixed" porphyrias, presenting with both neurovisceral attacks and skin photosensitivity [3]. All three involve the elevation of **ALA and PBG**, which are neurotoxic. The resulting neuropathy is typically a progressive, symmetric **motor neuropathy** (often involving the proximal muscles or cranial nerves) that can mimic Guillain-Barré Syndrome [1]. **NEET-PG High-Yield Pearls:** * **The "3 Ps" of Acute Porphyria:** **P**ain (Abdominal), **P**olyneuropathy, and **P**sychosis [1]. * **Urine finding:** In AIP, urine turns "port-wine" colored upon standing due to the oxidation of porphobilinogen. * **Enzyme Deficiencies:** AIP (*PBG Deaminase*); PCT (*uroporphyrinogen decarboxylase*). * **Treatment:** Acute attacks are managed with **IV Hemin** and **Glucose** (which inhibits ALA synthase).

Question 1

Diabetes mellitus is diagnosed if fasting blood glucose is?

Accepted Answer

>126 mg/dL

Answer

>100 mg/dL

Answer

>110 mg/dL

Answer

>116 mg/dL

Question 2

A patient presents with intermittent headache. On examination, there is hypertension and a thyroid nodule. Which of the following steps is to be taken next?

Accepted Answer

Urine VMA and aspiration of the thyroid nodule

Answer

Urine HIAA levels

Answer

Ultrasound abdomen

Answer

Echocardiography

Question 3

Which of the following is considered a silent thyroiditis?

Accepted Answer

Postpartum thyroiditis

Answer

Acute thyroiditis

Answer

Subacute thyroiditis

Answer

Hashimoto thyroiditis

Question 4

Hyperparathyroidism is characterized by the following except?

Accepted Answer

Osteosclerosis

Answer

Generalised osteoporosis

Answer

Renal calculi

Answer

Hypercalcemia

Question 5

A 30-year-old female presents with visual defects, breast engorgement, and amenorrhea. What is the investigation of choice?

Accepted Answer

Serum prolactin

Answer

CT brain

Answer

Biopsy

Answer

MR angiography

Question 6

A 43-year-old woman with chronic alcoholism presents with shortness of breath and edema. On examination, her blood pressure is 100/60 mm Hg, pulse 110/min, JVP is 8 cm, the cardiac apex is displaced and enlarged, there are bilateral inspiratory crackles, and there is pedal edema. For this patient with a potential vitamin deficiency, what is the most likely diagnosis?

Accepted Answer

Thiamine deficiency

Answer

Niacin deficiency

Answer

Pyridoxine deficiency

Answer

Vitamin C deficiency

Question 7

Which of the following does NOT precipitate ulcers in diabetes?

Accepted Answer

Microangiopathic changes in blood vessels

Answer

Neuropathy

Answer

Trophic ulcers

Answer

Macroangiopathy

Question 8

Edema of the feet is not a feature of which of the following conditions?

Accepted Answer

Conn syndrome

Answer

Hypothyroidism

Answer

Congestive Heart Failure (CHF)

Answer

Nephrotic syndrome

Question 9

Cushing syndrome is characterized by all of the following except?

Accepted Answer

Hypoglycemia

Answer

Hypertension

Answer

Proximal myopathy

Answer

Centripetal obesity

Question 10

All of the following forms of porphyria are associated with peripheral neuropathy except?

Accepted Answer

Porphyria cutanea tarda

Answer

Acute intermittent porphyria

Answer

Hereditary coproporphyria

Answer

Variegate porphyria

Endocrinology — MCQs

Endocrinology — MCQs

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