Endocrinology Practice Questions

Q: Which of the following is NOT true about congenital hypothyroidism?

Females are more often affected. **Explanation:** Congenital Hypothyroidism (CH) is the most common preventable cause of intellectual disability worldwide. **Analysis of the Options:** * **Option A (Correct Answer):** This statement is actually **TRUE**, not false. In cases of thyroid dysgenesis (the most common cause of CH), there is a significant female preponderance, with a female-to-male ratio of approximately **2:1**. Since the question asks for the statement that is "NOT true," and all other options are technically accurate descriptions of the disease, this question likely contains a technical error in its framing or key. However, in the context of NEET-PG, **Option C** is the most medically "false" statement regarding the primary etiology of CH. * **Option B:** Most infants have **no signs at birth** because of the transplacental transfer of maternal T4, which protects the fetal brain. Clinical features (prolonged jaundice, large fontanelle, umbilical hernia) usually appear after a few weeks. * **Option C:** This is **FALSE**. CH is most commonly caused by **Thyroid Dysgenesis** (85% - ectopy, aplasia, or hypoplasia) or **Dysmorgonogenesis** (15%). Antibodies against thyroid peroxidase (TPO) are associated with Hashimoto’s thyroiditis (acquired), not congenital hypothyroidism. * **Option D:** The worldwide incidence is approximately **1:3000 to 1:4000** live births. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Thyroid Dysgenesis (specifically Ectopic thyroid). * **Most common cause of Goitrous CH:** Dyshormonogenesis (TPO defect). * **Screening:** Done at **48–72 hours** of life to avoid the physiological TSH surge. * **Treatment:** Levothyroxine (10–15 μg/kg/day) should be started immediately to prevent permanent neurodevelopmental delay. * **Radiology:** Absence of the **distal femoral epiphysis** at birth is a sign of intrauterine hypothyroidism.

Q: Late onset of puberty in the male is defined as:

Puberty onset after 16 years. **Explanation:** The definition of delayed puberty (Late onset of puberty) is based on the statistical upper limit of normal for the onset of secondary sexual characteristics. In males, puberty is considered delayed if there is **no evidence of testicular enlargement (volume < 4 ml or length < 2.5 cm) by the age of 14 years.** However, in the context of clinical milestones and specific academic definitions often tested in exams like NEET-PG, the **complete absence of any signs of puberty by age 16** is the definitive threshold for "Late onset." **Analysis of Options:** * **Option A (Correct):** By age 16, 99% of healthy males have entered puberty. Failure to do so indicates a pathological delay or a significant constitutional delay requiring investigation. * **Options B, C, and D:** These ages (17, 18, and 21) are well beyond the standard physiological window. While a patient might present at these ages, the clinical diagnosis of "delayed puberty" would have been established much earlier (at age 14 or 16). **High-Yield Clinical Pearls for NEET-PG:** * **First sign of puberty in males:** Testicular enlargement (due to growth of seminiferous tubules under FSH influence). * **Most common cause:** Constitutional Delay of Growth and Puberty (CDGP) – often associated with a positive family history and delayed bone age. * **Prader-Willi Syndrome:** A common syndromic cause of hypogonadotropic hypogonadism. * **Kallmann Syndrome:** Delayed puberty associated with anosmia (failure of GnRH neuron migration). * **Precocious Puberty (Male):** Onset of secondary sexual characters before **9 years** of age.

Q: Which of the following effects is NOT seen in primary hyperaldosteronism?

Hyperkalemia. **Explanation:** Primary hyperaldosteronism (Conn’s Syndrome) is characterized by the autonomous overproduction of aldosterone from the adrenal cortex. To understand the clinical manifestations, one must recall the action of aldosterone on the **principal cells** and **alpha-intercalated cells** of the renal collecting duct. **Why Hyperkalemia is the Correct Answer:** Aldosterone increases the activity of ENaC (epithelial sodium channels) and the Na+/K+ ATPase pump. This leads to increased sodium reabsorption in exchange for **potassium secretion** into the tubular lumen. Consequently, primary hyperaldosteronism causes **hypokalemia**, not hyperkalemia. Therefore, Option C is the "except" or incorrect effect. **Analysis of Incorrect Options:** * **Hypertension (Option A):** Increased sodium reabsorption leads to water retention, increasing peripheral resistance and cardiac output, resulting in hypertension. * **Metabolic Alkalosis (Option B):** Aldosterone stimulates the H+-ATPase pump in alpha-intercalated cells, leading to increased secretion of hydrogen ions into the urine. The loss of H+ ions results in systemic metabolic alkalosis. * **Expansion of ECF and Plasma Volume (Option C):** Sodium and water retention lead to volume expansion. However, clinical edema is rarely seen due to the **"Aldosterone Escape"** phenomenon (where increased ANP levels cause pressure natriuresis). **High-Yield Clinical Pearls for NEET-PG:** * **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). * **Aldosterone Escape:** Explains why patients with primary hyperaldosteronism have hypertension and hypernatremia but **no edema**. * **Muscle Weakness:** A common presenting symptom due to profound hypokalemia.

Q: Growth hormone (GH) deficiency is diagnosed by which of the following findings?

Bone age less than chronological age. In Growth Hormone (GH) deficiency, the primary clinical hallmark is **short stature with delayed skeletal maturation**. ### **Explanation of the Correct Answer** **Option A (Bone age < Chronological age):** Growth hormone is essential for the linear growth of long bones and the maturation of epiphyses. In GH deficiency, there is a significant delay in the appearance and fusion of ossification centers. Consequently, the **Bone Age (BA)**—determined by an X-ray of the left hand and wrist—is significantly lagging behind the **Chronological Age (CA)**. This delay is usually more than 2 standard deviations below the mean. ### **Analysis of Incorrect Options** * **Option B:** Bone age greater than chronological age (Advanced Bone Age) is seen in conditions with excess sex steroids, such as **Precocious Puberty** or **Congenital Adrenal Hyperplasia (CAH)**. * **Option C:** Bone age equal to chronological age is characteristic of **Genetic (Familial) Short Stature**, where the child is short but maturing at a normal rate. * **Option D:** An increased upper-to-lower segment ratio (disproportionate short stature) is typical of **Hypothyroidism** or skeletal dysplasias like **Achondroplasia**. In GH deficiency, the body proportions remain normal (proportionate short stature). ### **High-Yield Clinical Pearls for NEET-PG** * **Gold Standard Diagnosis:** GH deficiency is diagnosed using **GH Stimulation Tests** (using Insulin, Arginine, or Clonidine). A peak GH level **<10 ng/mL** is diagnostic. * **Screening Test:** Measurement of **IGF-1** and **IGFBP-3** levels (more stable than pulsatile GH). * **Clinical Features:** "Cherubic" appearance (doll-like face), truncal obesity, high-pitched voice, and micropenis (if associated with gonadotropin deficiency). * **Constitutional Delay of Growth and Puberty (CDGP):** Also shows BA < CA, but unlike GH deficiency, these children eventually achieve their target height.

Q: A 15-year-old boy with cystic fibrosis presents with a 3-6 kg weight loss over the past month, unaccompanied by changes in his pulmonary and gastrointestinal symptoms. Which of the following is most suspected?

Diabetes mellitus. ### Explanation **Correct Option: D. Diabetes Mellitus** The most likely diagnosis is **Cystic Fibrosis-Related Diabetes (CFRD)**. In Cystic Fibrosis (CF), thick secretions lead to progressive scarring and destruction of the pancreatic islet cells, causing a deficiency in insulin secretion. * **Why it fits:** Weight loss in a CF patient who is otherwise stable (no increase in cough, sputum, or malabsorption) is a classic red flag for CFRD. As insulin is an anabolic hormone, its deficiency leads to catabolism and weight loss despite adequate caloric intake. CFRD is the most common extra-pulmonary complication of CF, affecting nearly 20% of adolescents and 40-50% of adults. **Analysis of Incorrect Options:** * **A. Bronchogenic Carcinoma:** While CF increases the risk of certain malignancies, lung cancer is rare in a 15-year-old. Furthermore, weight loss from malignancy would typically be accompanied by worsening pulmonary symptoms. * **B. Eating Disorder:** While possible in any adolescent, the physiological link between CF and pancreatic endocrine failure makes CFRD a much more high-yield and likely clinical suspicion. * **C. Biliary Cirrhosis:** While CF-associated liver disease occurs, it usually presents with hepatosplenomegaly, jaundice, or portal hypertension rather than isolated rapid weight loss without GI distress. **NEET-PG High-Yield Pearls:** * **Screening:** Annual screening for CFRD using the **Oral Glucose Tolerance Test (OGTT)** should begin at **age 10** for all CF patients. * **Pathophysiology:** It is a unique entity—not Type 1 (not autoimmune) and not Type 2 (primarily insulin deficiency, not resistance). * **Treatment:** **Insulin** is the only recommended treatment. Oral hypoglycemic agents are generally not effective. * **Clinical Clue:** Unexplained decline in pulmonary function or weight loss in a CF patient is the most common presentation of CFRD.

Q: Rickets in the neonatal period and early infancy present as all EXCEPT:

Bow legs. The clinical presentation of rickets is highly dependent on the **age of the child** and the **mechanical stresses** acting on the skeleton at that time. ### **Explanation of the Correct Answer** **D. Bow legs (Genu Varum):** This is the correct answer because it is **not** seen in neonates or early infants. Bowing of the legs is a weight-bearing deformity. It occurs only after the child begins to stand or walk (typically after 1 year of age), as the softened, unmineralized osteoid in the lower limbs bends under the effect of gravity and body weight. ### **Explanation of Incorrect Options** * **A. Craniotabes:** This is the **earliest sign of rickets**, often seen in infants under 6 months. It refers to the softening of the skull bones (especially the occiput and parietal bones), which feel like a "ping-pong ball" when pressed. * **B. Widened fontanel:** Rickets causes a delay in the closure of the anterior fontanel and widening of the sutures due to impaired mineralization of the skull bones. * **C. Rachitic Rosary:** This is a classic early sign caused by the expansion of the osteochondral junctions of the ribs. It is palpable (and sometimes visible) as bead-like prominences on the chest wall. ### **NEET-PG High-Yield Pearls** * **Earliest Sign:** Craniotabes (though it can be physiological in newborns, its persistence suggests rickets). * **Earliest Radiological Sign:** Cupping and splaying of the distal ends of long bones (best seen at the **distal ulna**). * **Sequence of Deformities:** * *Infancy:* Craniotabes, Rachitic Rosary, Harrison’s Sulcus. * *Toddler (Weight-bearing):* Genu Varum (Bow legs). * *Older Children:* Genu Valgum (Knock knees). * **Biochemical Hallmark:** Elevated **Alkaline Phosphatase (ALP)** is the most sensitive marker for active rickets.

Question 1

Which of the following is NOT true about congenital hypothyroidism?

Accepted Answer

Females are more often affected

Answer

No signs at birth

Answer

Occurs due to antibodies against thyroid peroxisomes

Answer

Seen in 1:4000 live births

Question 2

A 2-week-old infant presents with feeding difficulties, somnolence, failure to thrive, and constipation. Blood studies reveal low T4 and high TSH. If appropriate therapy is not promptly instituted, which of the following complications would most likely occur?

Accepted Answer

Mental retardation

Answer

Bronchiectasis

Answer

Gigantism

Answer

Hepatic cirrhosis

Question 3

A cherry red spot is seen in which of the following conditions?

Accepted Answer

Tay-Sachs disease

Answer

Batten-Mayou disease

Answer

von Gierke's disease

Answer

Mucopolysaccharidosis

Question 4

Late onset of puberty in the male is defined as:

Accepted Answer

Puberty onset after 16 years

Answer

Puberty onset after 17 years

Answer

Puberty onset after 18 years

Answer

Puberty onset after 21 years

Question 5

Which of the following effects is NOT seen in primary hyperaldosteronism?

Accepted Answer

Hyperkalemia

Answer

Hypertension

Answer

Metabolic alkalosis

Answer

Expansion of extracellular and plasma volume

Question 6

Growth hormone (GH) deficiency is diagnosed by which of the following findings?

Accepted Answer

Bone age less than chronological age

Answer

Bone age more than chronological age

Answer

Bone age equal to chronological age

Answer

Ratio of upper to lower segment of body is increased

Question 7

A 15-year-old boy with cystic fibrosis presents with a 3-6 kg weight loss over the past month, unaccompanied by changes in his pulmonary and gastrointestinal symptoms. Which of the following is most suspected?

Accepted Answer

Diabetes mellitus

Answer

Bronchogenic carcinoma

Answer

Eating disorder

Answer

Biliary cirrhosis

Question 8

Pseudohypoparathyroidism is characterized by which of the following laboratory findings?

Accepted Answer

Decreased serum calcium and increased serum parathyroid hormone

Answer

Normal serum calcium and decreased serum parathyroid hormone

Answer

Decreased serum calcium and decreased serum parathyroid hormone

Answer

Normal serum calcium and increased serum parathyroid hormone

Question 9

Rickets in the neonatal period and early infancy present as all EXCEPT:

Accepted Answer

Bow legs

Answer

Craniotabes

Answer

Widened fontanel

Answer

Rachitic Rosary

Question 10

A 15-day-old male neonate presented with failure to thrive, recurrent vomiting, and symptoms of shock. On examination, severe dehydration is noted. He has normal genitalia along with precocious development of pubic hair, phallic enlargement, and accelerated skeletal maturation. The child's blood pressure was normal. Lab findings revealed hyponatremia and hypokalemia, increased serum 17-hydroxyprogesterone, and increased urinary pregnanetriol. A biopsy from the adrenal gland was taken. Which of the following is the most likely enzyme deficiency in this patient?

Accepted Answer

21-hydroxylase deficiency

Answer

11-hydroxylase deficiency

Answer

3-beta-hydroxysteroid dehydrogenase deficiency

Answer

17-hydroxylase deficiency

Endocrinology — MCQs

Endocrinology — MCQs

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