Endocrinology Practice Questions

Q: A 20-year-old male is admitted to the ICU for diabetic ketoacidosis (DKA). His mother reports increased thirst and frequent urination recently. He has no prior diabetes diagnosis and no family history of diabetes. His BMI is 42 kg/m2. Anti-GAD antibodies and anti-islet cell antibodies (ICA) are not detected. Which of the following statements is true regarding this patient?

The patient has type 2 diabetes mellitus.. ### Explanation The correct answer is **D. The patient has type 2 diabetes mellitus.** This patient presents with **Ketosis-Prone Type 2 Diabetes (KPD)**, also known as "Flatbush Diabetes." While DKA is classically associated with Type 1 Diabetes (T1DM), it is increasingly seen in patients with Type 2 Diabetes (T2DM), particularly those with obesity [1]. **Why Option D is correct:** The diagnosis of T2DM is supported by the patient’s **high BMI (42 kg/m²)** and the **absence of pancreatic autoantibodies** (Anti-GAD and ICA). In KPD, patients present with acute insulin deficiency (leading to DKA), often triggered by glucose toxicity which suppresses beta-cell function [1]. With treatment, they later regain significant beta-cell function and can often be managed with oral hypoglycemic agents rather than lifelong insulin [1]. **Why other options are incorrect:** * **Option A & B:** While young age and DKA are "textbook" features of T1DM [2], the presence of morbid obesity and negative autoantibodies strongly point toward T2DM. DKA is no longer considered pathognomonic for T1DM [1]. * **Option C:** Maturity-Onset Diabetes of the Young (MODY) typically presents in non-obese individuals with a strong autosomal dominant family history [3]. This patient has no family history and a high BMI, making MODY unlikely. ### Clinical Pearls for NEET-PG: * **Antibody Testing:** Negative Anti-GAD, ICA, and IA-2 antibodies in a patient with DKA should raise suspicion for Ketosis-Prone T2DM. * **AB Classification:** KPD is often classified using the "Aβ" system (A: Autoantibodies; β: Beta-cell function). This patient fits the **A-β+** category (Antibody negative, preserved beta-cell function). * **Management:** After resolving the initial DKA with insulin, these patients should be re-evaluated for transition to oral drugs (like Metformin) once glucose toxicity resolves [1].

Q: Malignancy associated hypercalcemia is most commonly due to which of the following mechanisms?

Parathyroid hormone-related peptide production. **Explanation:** Hypercalcemia of malignancy (HCM) is the most common cause of hypercalcemia in hospitalized patients. It occurs via four distinct mechanisms, but the most frequent is **Humoral Hypercalcemia of Malignancy (HHM)**. **Why Option B is Correct:** Approximately **80% of cases** of HCM are caused by the secretion of **Parathyroid Hormone-related Peptide (PTHrP)** by tumor cells [2]. PTHrP mimics the action of PTH by binding to the PTH-1 receptor in bones (increasing osteoclast activity) and kidneys (increasing calcium reabsorption) [1]. It is most commonly associated with **Squamous cell carcinomas** (lung, head, and neck), renal, and breast cancers [3]. Unlike true hyperparathyroidism, PTH levels in these patients are suppressed [3]. **Why Other Options are Incorrect:** * **Option A (Tumor Lysis Syndrome):** This typically causes **hypocalcemia** (due to phosphate release binding with calcium) and hyperuricemia, not hypercalcemia. * **Option C (IL-7):** While cytokines like IL-1, IL-6, and TNF-alpha (Osteoclast Activating Factors) contribute to local osteolytic hypercalcemia (common in Multiple Myeloma), IL-7 is not a primary mediator of malignancy-associated hypercalcemia. * **Option D (IGF-BP):** These proteins regulate growth factor activity but do not play a direct role in calcium homeostasis or the pathogenesis of HCM. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common mechanism:** PTHrP production (80%). 2. **Second most common mechanism:** Local osteolytic hypercalcemia (20%), seen in Multiple Myeloma and breast cancer bone metastases. 3. **Rare mechanism:** 1,25-dihydroxyvitamin D production (seen in Lymphomas) [3]. 4. **Laboratory findings in HHM:** High Calcium, Low PTH, Low 1,25-(OH)₂D (usually), and High PTHrP. 5. **Treatment of choice:** Aggressive IV hydration (Normal Saline) followed by IV Bisphosphonates (e.g., Zoledronic acid).

Q: A 30-year-old female presents with a need to progressively buy larger and wider shoes and cannot wear any of her rings because they are too small. A physical examination shows a prominent brow, protruding lower jaw, and spaces between all of her teeth. This woman may have a tumor in which one of the following organs or tissues?

Hypothalamus. ### Explanation **Correct Option: A (Hypothalamus)** The clinical presentation describes classic **Acromegaly**, characterized by acral enlargement (increased shoe/ring size), frontal bossing (prominent brow), macrognathia (protruding jaw), and teeth spacing (diastema). While most cases of acromegaly are caused by a Growth Hormone (GH)-secreting pituitary adenoma [1], the question asks for the source of a tumor that could cause this syndrome. In rare instances, **ectopic secretion of Growth Hormone-Releasing Hormone (GHRH)** can lead to somatotroph hyperplasia and secondary acromegaly [3]. The **hypothalamus** is a primary site for GHRH production [2]. A hypothalamic gangliocytoma or hamartoma secreting GHRH can result in the clinical features described. **Analysis of Incorrect Options:** * **B. Bone marrow:** Bone marrow disorders (like multiple myeloma or leukemias) do not cause soft tissue or bony overgrowth characteristic of GH excess. * **C. Adrenal glands:** Adrenal tumors typically present with Cushing’s syndrome (cortisol), Conn’s syndrome (aldosterone), or virilization (androgens), none of which cause acral enlargement [4]. * **D. Pancreas:** While pancreatic neuroendocrine tumors (NETs) can rarely secrete ectopic GHRH or GH, the hypothalamus is a more direct physiological source of GHRH in the context of neuroendocrine regulation. **NEET-PG High-Yield Pearls:** * **Best Initial Test:** Serum IGF-1 levels (more stable than GH) [1]. * **Gold Standard/Confirmatory Test:** Oral Glucose Tolerance Test (OGTT) with GH measurement; failure to suppress GH <1 ng/mL is diagnostic [1]. * **Most Common Cause:** Pituitary Adenoma (Somatotroph adenoma) [3]. * **Ectopic GHRH Sources:** Hypothalamic tumors, Bronchial carcinoid, and Pancreatic NETs. * **Associated Conditions:** Often associated with MEN-1 syndrome (Pituitary, Parathyroid, Pancreas).

Q: What condition is caused by neurotensinoma?

None of the above. A **neurotensinoma** is an extremely rare functional pancreatic neuroendocrine tumor (pNET) that secretes excessive amounts of the peptide **neurotensin**. While neurotensin has several physiological effects, most neurotensinomas are clinically "silent" because the peptide does not produce a distinct, consistent clinical syndrome in humans. [1] **Why "None of the above" is correct:** The primary clinical features associated with neurotensinoma (when present) are **weight loss, diarrhea, and skin flushing**. None of the symptoms listed in the options (cyanosis, hypertension, or hyperkalemia) are characteristic of this tumor. **Analysis of Incorrect Options:** * **A. Cyanosis:** Neurotensinomas may cause flushing (redness), but they do not cause cyanosis (bluish discoloration), which is typically related to deoxygenated hemoglobin or shunting. * **B. Hypertension:** Neurotensin actually acts as a **vasodilator**; therefore, it is more likely to cause hypotension (low blood pressure) rather than hypertension. * **C. Hyperkalemia:** There is no established link between neurotensin and elevated potassium levels. In fact, some pNETs (like VIPomas) are famously associated with *hypokalemia*. **NEET-PG High-Yield Pearls:** * **Diagnosis:** Elevated plasma neurotensin levels (often >250 pmol/L). * **Location:** Most neurotensinomas are found in the **head of the pancreas** and are often large and metastatic at the time of diagnosis. [1] * **Association:** They can occur sporadically or as part of **MEN-1 syndrome**. * **Differential:** If a question mentions "Watery Diarrhea, Hypokalemia, and Achlorhydria (WDHA)," think **VIPoma** (Verner-Morrison Syndrome), not neurotensinoma.

Q: Cushing's disease typically presents with which of the following hormonal changes?

Increased ACTH and increased cortisol. **Explanation:** **Cushing’s Disease** specifically refers to hypercortisolism caused by a **pituitary adenoma** (usually a microadenoma) that hypersecretes Adrenocorticotropic Hormone (ACTH) [1]. 1. **Why Option A is correct:** In Cushing’s disease, the primary pathology is in the anterior pituitary [2]. The adenoma secretes excessive **ACTH**, which chronically stimulates the adrenal cortex to produce and release high levels of **cortisol**. Unlike normal physiological states, the pituitary tumor is relatively resistant to the negative feedback inhibition usually exerted by high cortisol levels, leading to a state where both hormones are elevated [1]. 2. **Why other options are incorrect:** * **Option B:** Decreased ACTH and cortisol characterize **Addison’s disease** (primary adrenal insufficiency) or secondary adrenal insufficiency. * **Option C:** Increased ACTH with decreased cortisol is seen in **Primary Adrenal Insufficiency** (Addison’s), where the pituitary tries to compensate for low cortisol by producing more ACTH. * **Option D:** Increased catecholamines are the hallmark of **Pheochromocytoma**, not Cushing’s disease. **High-Yield Clinical Pearls for NEET-PG:** * **Cushing’s Syndrome vs. Disease:** "Syndrome" is the clinical state of excess cortisol (most common cause is exogenous steroids). "Disease" is specifically the pituitary-dependent cause [2]. * **Screening Tests:** Overnight Dexamethasone Suppression Test (ONDST) or 24-hour urinary free cortisol [3]. * **Localization:** High-dose dexamethasone suppression test (8mg) typically suppresses cortisol by >50% in Cushing’s **Disease**, but fails to suppress it in **Ectopic ACTH syndrome** (e.g., Small Cell Lung Cancer). Once presence is confirmed, measurement of plasma ACTH is key for differential diagnosis [1]. * **Gold Standard for Localization:** Inferior Petrosal Sinus Sampling (IPSS).

Q: Necrobiosis lipoidica is seen in which condition?

Diabetes mellitus. **Explanation:** **Necrobiosis Lipoidica (NL)**, historically known as Necrobiosis Lipoidica Diabeticorum, is a chronic granulomatous skin disorder. While its exact pathogenesis is idiopathic, it is strongly associated with **Diabetes Mellitus (Option C)** [2]. It is estimated that approximately 0.3% of diabetic patients develop NL, and conversely, over 60% of patients with NL have underlying diabetes. The condition is characterized by collagen degeneration (necrobiosis), a granulomatous response, and thickening of blood vessel walls. **Analysis of Options:** * **Dermatomyositis (Option A):** This is an inflammatory myopathy characterized by Gottron papules, Heliotrope rash, and proximal muscle weakness [1], not NL. * **Lyme Disease (Option B):** Caused by *Borrelia burgdorferi*, it typically presents with Erythema Chronicum Migrans (a "bull's eye" rash) [3]. * **Symmonds Disease (Option D):** This refers to panhypopituitarism (often due to pituitary necrosis). It does not have a primary association with necrobiotic skin lesions. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Classically presents as well-demarcated, yellowish-brown, atrophic plaques with a "glazed" or "porcelain" appearance and prominent **telangiectasia**, usually on the **pretibial area** (shins). * **Correlation with Glycemic Control:** Importantly, the severity or progression of NL does **not** correlate with blood glucose levels or HbA1c control. * **Differential Diagnosis:** Must be distinguished from *Granuloma Annulare*, which also involves collagen necrobiosis but lacks the atrophy and telangiectasia seen in NL. * **Complication:** Though rare, squamous cell carcinoma can develop within chronic NL scars.

Q: Which of the following is not seen in Secondary Adrenal insufficiency?

Hyperpigmentation. In **Secondary Adrenal Insufficiency (SAI)**, the pathology lies in the pituitary gland (decreased ACTH) or hypothalamus (decreased CRH), rather than the adrenal cortex itself [2]. ### Why Hyperpigmentation is NOT seen: Hyperpigmentation is a hallmark of **Primary Adrenal Insufficiency (Addison’s Disease)** [1]. In Primary AI, the lack of cortisol feedback causes a massive compensatory increase in **ACTH** and its precursor, **Pro-opiomelanocortin (POMC)**. POMC is cleaved into ACTH and **Melanocyte-Stimulating Hormone (MSH)**; high levels of these hormones stimulate melanocytes, leading to skin and mucosal darkening. In SAI, ACTH levels are low or inappropriately normal, so hyperpigmentation does not occur. ### Analysis of Incorrect Options: * **Postural Hypotension:** While more severe in Primary AI (due to mineralocorticoid deficiency), it can still occur in SAI due to decreased vascular tone and reduced cardiac output resulting from cortisol deficiency. * **Hypoglycemia:** Cortisol is a counter-regulatory hormone that promotes gluconeogenesis. Its absence in SAI leads to impaired glucose production, especially during fasting or stress. * **Lassitude:** General fatigue, weakness, and lethargy are universal symptoms of glucocorticoid deficiency regardless of the site of the lesion [4]. ### NEET-PG High-Yield Pearls: 1. **Mineralocorticoids:** In SAI, the Renin-Angiotensin-Aldosterone System (RAAS) remains intact. Therefore, **hyperkalemia is absent** in SAI (a common "except" question) [2]. 2. **Aldosterone:** Is preserved in SAI but lost in Primary AI. 3. **Most Common Cause:** The most common cause of SAI is the **abrupt withdrawal of long-term exogenous steroid therapy**. 4. **Cosyntropin Test:** Used to differentiate; in SAI, the adrenals may be "atrophied" and fail to respond to an acute ACTH bolus [3].

Question 1

A 20-year-old male is admitted to the ICU for diabetic ketoacidosis (DKA). His mother reports increased thirst and frequent urination recently. He has no prior diabetes diagnosis and no family history of diabetes. His BMI is 42 kg/m2. Anti-GAD antibodies and anti-islet cell antibodies (ICA) are not detected. Which of the following statements is true regarding this patient?

Accepted Answer

The patient has type 2 diabetes mellitus.

Answer

Due to the young age of onset, type 1 diabetes is suspected.

Answer

Because of the presentation with diabetic ketoacidosis, type 1 diabetes is suspected.

Answer

The patient has maturity-onset diabetes of the young.

Question 2

Malignancy associated hypercalcemia is most commonly due to which of the following mechanisms?

Accepted Answer

Parathyroid hormone-related peptide production

Answer

Tumor lysis syndrome

Answer

Interleukin-7 (IL-7) production

Answer

Insulin-like growth factor binding protein (IGF-BP) production

Question 3

A 30-year-old female presents with a need to progressively buy larger and wider shoes and cannot wear any of her rings because they are too small. A physical examination shows a prominent brow, protruding lower jaw, and spaces between all of her teeth. This woman may have a tumor in which one of the following organs or tissues?

Accepted Answer

Hypothalamus

Answer

Bone marrow

Answer

Adrenal glands

Answer

Pancreas

Question 4

What condition is caused by neurotensinoma?

Accepted Answer

None of the above

Answer

Cyanosis

Answer

Hypertension

Answer

Hyperkalemia

Question 5

All of the following are associated with Primary aldosteronism EXCEPT?

Accepted Answer

Postural hypotension

Answer

Hypokalaemia

Answer

Hypernatremia

Answer

Metabolic alkalosis

Question 6

What is the most common cause of hyperparathyroidism?

Accepted Answer

Post-thyroid surgery

Answer

Di George syndrome

Answer

McCune-Albright syndrome

Answer

Parathyroid hypoplasia

Question 7

Cushing's disease typically presents with which of the following hormonal changes?

Accepted Answer

Increased ACTH and increased cortisol

Answer

Decreased ACTH and decreased cortisol

Answer

Increased ACTH and decreased cortisol

Answer

Increased catecholamines

Question 8

A 50-year-old obese female presents with recurrent candidal urinary infections and excessive thirst. She also reports frequent nighttime urination. What is the initial diagnostic test you would prefer for this patient?

Accepted Answer

Random plasma glucose level

Answer

HbA1c

Answer

Oral glucose tolerance test

Answer

Plasma C-peptide level

Question 9

Necrobiosis lipoidica is seen in which condition?

Accepted Answer

Diabetes mellitus

Answer

Dermatomyositis

Answer

Lyme disease

Answer

Symmonds disease

Question 10

Which of the following is not seen in Secondary Adrenal insufficiency?

Accepted Answer

Hyperpigmentation

Answer

Postural hypotension

Answer

Hypoglycemia

Answer

Lassitude

Endocrinology — MCQs

Endocrinology — MCQs

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