Endocrine pathology

Endocrine pathology US Medical PG Question 1: A 21-year-old woman presents with irregular menses, acne, and increased body hair growth. She says her average menstrual cycle lasts 36 days and states that she has heavy menstrual bleeding. She had her menarche at the age of 13 years. Her blood pressure is 125/80 mm Hg, heart rate is 79/min, respiratory rate is 14/min, and temperature is 36.7°C (98.1°F). Her body weight is 101.0 kg (222.7 lb) and height is 170 cm (5 ft 7 in). Physical examination shows papular acne on her forehead and cheeks. There are dark hairs present on her upper lip, periareolar region, linea alba, and hips, as well as darkening of the skin on the axilla and posterior neck. Which of the following endocrine abnormalities would also most likely be found in this patient?

• A. Aldosterone hyperproduction
• B. Adrenaline hypersecretion
• C. Hypothyroidism
• D. Insulin resistance (Correct Answer)
• E. Hypoestrogenism

Endocrine pathology Explanation: ***Insulin resistance*** - The patient exhibits several features suggestive of **Polycystic Ovary Syndrome (PCOS)**, including **irregular menses (oligomenorrhea)**, **acne**, **hirsutism** (increased body hair), and **obesity** (BMI 34.9 kg/m2). - Insulin resistance is a central pathophysiological feature of PCOS, leading to **hyperinsulinemia** which stimulates ovarian androgen production, exacerbating symptoms like hirsutism and acne. *Aldosterone hyperproduction* - **Aldosterone hyperproduction**, as seen in primary hyperaldosteronism, primarily causes **hypertension** and **hypokalemia**, none of which are explicitly indicated in this patient's presentation. - The patient's blood pressure is within a normal range, and there are no symptoms or signs pointing to electrolyte imbalances. *Adrenaline hypersecretion* - **Adrenaline hypersecretion** (e.g., in pheochromocytoma) typically presents with paroxysmal **hypertension**, **tachycardia**, palpitations, and anxiety. - These signs are absent in the patient, whose vital signs are stable and blood pressure is normal. *Hypothyroidism* - **Hypothyroidism** can cause irregular menses and weight gain, but it is typically associated with **cold intolerance**, fatigue, and dry skin, not acne or hirsutism. - The patient's presentation of androgen excess (acne, hirsutism) is inconsistent with hypothyroidism. *Hypoestrogenism* - **Hypoestrogenism** would typically present with symptoms such as **hot flashes**, vaginal dryness, and bone loss, and it would usually lead to oligomenorrhea or amenorrhea. - In PCOS, while estrogen levels can be dynamic, the primary issue is **androgen excess**, and estrogen levels are often normal or even elevated due to peripheral conversion of androgens.

Endocrine pathology US Medical PG Question 2: A 28-year-old woman presents to her primary care physician complaining of intense thirst and frequent urination for the past 2 weeks. She says that she constantly feels the urge to drink water and is also going to the bathroom to urinate frequently throughout the day and multiple times at night. She was most recently hospitalized 1 month prior to presentation following a motor vehicle accident in which she suffered severe impact to her head. The physician obtains laboratory tests, with the results shown below: Serum: Na+: 149 mEq/L Cl-: 103 mEq/L K+: 3.5 mEq/L HCO3-: 24 mEq/L BUN: 20 mg/dL Glucose: 105 mg/dL Urine Osm: 250 mOsm/kg The patient’s condition is most likely caused by inadequate hormone secretion from which of the following locations?

• A. Adrenal cortex
• B. Anterior pituitary
• C. Preoptic nucleus of the hypothalamus
• D. Suprachiasmatic nucleus of the hypothalamus
• E. Posterior pituitary (Correct Answer)

Endocrine pathology Explanation: ***Posterior pituitary*** - The patient's symptoms of **polydipsia** and **polyuria**, coupled with **hypernatremia** and **low urine osmolality**, are classic signs of **diabetes insipidus (DI)**. - The **posterior pituitary gland** is responsible for releasing **antidiuretic hormone (ADH)**, which, when inadequately secreted (neurogenic DI), leads to these findings. The prior **head trauma** is a common cause of damage to this region. *Adrenal cortex* - The adrenal cortex produces **mineralocorticoids** (e.g., **aldosterone**), **glucocorticoids** (e.g., **cortisol**), and **androgens**. - Deficiencies or excesses of these hormones lead to conditions like **Addison's disease** (adrenal insufficiency) or **Cushing's syndrome**, which have different clinical presentations than those described. *Anterior pituitary* - The anterior pituitary produces hormones such as **GH, TSH, ACTH, FSH, LH**, and **prolactin**. - Dysfunction of the anterior pituitary would lead to a range of hormonal imbalances impacting growth, metabolism, and reproduction, but not directly cause diabetes insipidus. *Preoptic nucleus of the hypothalamus* - The **preoptic nucleus** is involved in **thermoregulation**, **sleep**, and **hypothalamic control** of reproduction. - While part of the hypothalamus, its primary functions do not directly involve ADH synthesis or release, thereby not causing diabetes insipidus. *Suprachiasmatic nucleus of the hypothalamus* - The **suprachiasmatic nucleus (SCN)** is the body's primary **circadian rhythm** pacemaker. - Damage to the SCN would disrupt the sleep-wake cycle and other circadian functions, but would not directly lead to symptoms of diabetes insipidus.

Endocrine pathology US Medical PG Question 3: A 60-year-old man comes to the emergency department because of recurrent episodes of fatigue, palpitations, nausea, and diaphoresis over the past 6 months. The episodes have become more frequent in the last 2 weeks and he has missed work several times because of them. His symptoms usually improve after he drinks some juice and rests. He has had a 2-kg (4.5-lb) weight gain in the past 6 months. He has a history of bipolar disorder, hypertension, and asthma. His sister has type 2 diabetes mellitus and his mother has a history of medullary thyroid carcinoma. His medications include lithium, hydrochlorothiazide, aspirin, and a budesonide inhaler. His temperature is 36.3°C (97.3°F), pulse is 92/min and regular, respirations are 20/min, and blood pressure is 118/65 mm Hg. Abdominal examination shows no abnormalities. Serum studies show: Na+ 145 mEq/L K+ 3.9 mEq/L Cl- 103 mEq/L Calcium 9.2 mg/dL Glucose 88 mg/dL Which of the following is the most appropriate next step in diagnosis?

• A. Corticotropin stimulation test
• B. Water deprivation test
• C. Oral glucose tolerance test
• D. 24-hour urine catecholamine test
• E. 72-hour fasting test (Correct Answer)

Endocrine pathology Explanation: **72-hour fasting test** - The patient's symptoms (fatigue, palpitations, nausea, diaphoresis) that improve with eating (drinking juice) are highly suggestive of **hypoglycemia**, fitting **Whipple's triad**. - A 72-hour fasting test is the gold standard for diagnosing **insulinoma**, a neuroendocrine tumor that causes endogenous hyperinsulinism and recurrent hypoglycemia. *Corticotropin stimulation test* - This test is used to diagnose **adrenal insufficiency** by evaluating the adrenal glands' response to ACTH. - The patient's symptoms are inconsistent with adrenal insufficiency, and his blood pressure is stable, arguing against a hypotensive crisis. *Water deprivation test* - This test is used to diagnose **diabetes insipidus** by assessing the kidney's ability to concentrate urine. - The patient's symptoms do not align with polyuria and polydipsia characteristic of diabetes insipidus. *Oral glucose tolerance test* - This test is primarily used to diagnose **diabetes mellitus** or impaired glucose tolerance. - While helpful for assessing glucose metabolism, it is not the initial test for recurrent symptomatic hypoglycemia that improves with sugar intake. *24-hour urine catecholamine test* - This test is used to diagnose **pheochromocytoma**, a tumor that causes excessive catecholamine release. - While palpitations and diaphoresis can occur, the improvement with glucose and lack of sustained hypertension make pheochromocytoma less likely.

Endocrine pathology US Medical PG Question 4: A 40-year-old man comes to the physician because of weight gain over the past 3 months. During this period, he has gained 10 kg (22 lb) unintentionally. He also reports decreased sexual desire, oily skin, and sleeping difficulties. There is no personal or family history of serious illness. He has smoked one pack of cigarettes daily for the past 10 years. The patient appears lethargic. His temperature is 37°C (98.6°F), pulse is 80/min, and blood pressure is 150/90 mm Hg. Physical examination shows central obesity, acne, and thin, easily bruisable skin with stretch marks on the abdomen. There is darkening of the mucous membranes and the skin creases. Examination of the muscles shows atrophy and weakness of proximal muscle groups. His serum glucose concentration is 240 mg/dL. Which of the following findings would most likely be present on imaging?

• A. Pituitary microadenoma (Correct Answer)
• B. Decreased thyroid size
• C. Multiple kidney cysts
• D. Kidney tumor
• E. Adrenal carcinoma

Endocrine pathology Explanation: ***Pituitary microadenoma*** * The patient's symptoms, including **weight gain, central obesity, oily skin, acne, thin and easily bruisable skin with stretch marks, proximal muscle weakness, hypertension, and hyperglycemia**, are classic for **Cushing's syndrome**. * A common cause of Cushing's syndrome is **Cushing's disease**, which is caused by an **ACTH-secreting pituitary adenoma** (often a microadenoma). *Decreased thyroid size* * **Decreased thyroid size** would be associated with conditions like **atrophic thyroiditis** or **iodine deficiency**, typically leading to **hypothyroidism**. * **Hypothyroidism** would present with **weight gain** and **fatigue**, but not with **hypertension, hyperglycemia, central obesity, skin bruising, or proximal muscle weakness** as seen in this patient. *Multiple kidney cysts* * **Multiple kidney cysts** are characteristic of **polycystic kidney disease**, which can cause **hypertension** and sometimes **renal failure**. * However, polycystic kidney disease does not typically cause **central obesity, skin changes (bruising, stretch marks, acne), proximal muscle weakness, or hyperglycemia** seen in this patient. *Kidney tumor* * A **kidney tumor** (e.g., **renal cell carcinoma**) can cause **hypertension** and **weight loss** but is not associated with the full spectrum of symptoms presented here like **central obesity, skin fragility, stretch marks, muscle atrophy, or hyperglycemia**. * Some kidney tumors can produce **erythropoietin** leading to **polycythemia**, but not the endocrine features of Cushing's syndrome. *Adrenal carcinoma* * While an **adrenal carcinoma** can cause Cushing's syndrome by directly producing **cortisol**, it is typically a **large tumor** visible on imaging and often presents with more rapid and severe symptom onset. * The presence of **skin darkening (hyperpigmentation)** in this patient, due to increased ACTH stimulation of melanocytes, suggests an **ACTH-dependent Cushing's syndrome**, making a pituitary adenoma more likely than a primary adrenal tumor which would suppress ACTH.

Endocrine pathology US Medical PG Question 5: An epidemiologist is evaluating the efficacy of Noxbinle in preventing HCC deaths at the population level. A clinical trial shows that over 5 years, the mortality rate from HCC was 25% in the control group and 15% in patients treated with Noxbinle 100 mg daily. Based on this data, how many patients need to be treated with Noxbinle 100 mg to prevent, on average, one death from HCC?

• A. 20
• B. 73
• C. 10 (Correct Answer)
• D. 50
• E. 100

Endocrine pathology Explanation: ***10*** - The **number needed to treat (NNT)** is calculated by first finding the **absolute risk reduction (ARR)**. - **ARR** = Risk in control group - Risk in treatment group = 25% - 15% = **10%** (or 0.10). - **NNT = 1 / ARR** = 1 / 0.10 = **10 patients**. - This means that **10 patients must be treated with Noxbinle to prevent one death from HCC** over 5 years. *20* - This would result from an ARR of 5% (1/0.05 = 20), which is not supported by the data. - May arise from miscalculating the risk difference or incorrectly halving the actual ARR. *73* - This value does not correspond to any standard calculation of NNT from the given mortality rates. - May result from confusion with other epidemiological measures or calculation error. *50* - This would correspond to an ARR of 2% (1/0.02 = 50), which significantly underestimates the actual risk reduction. - Could result from incorrectly calculating the difference as a proportion rather than absolute percentage points. *100* - This would correspond to an ARR of 1% (1/0.01 = 100), grossly underestimating the treatment benefit. - May result from confusing ARR with relative risk reduction or other calculation errors.

Endocrine pathology Flashcard 1 of 5

Question: What MSK pathology is characterized by a reduction in trabecular and cortical bone mass and interconnections? _____

Answer: Osteoporosis

Endocrine pathology Flashcard 2 of 5

Question: One cause of cretinism is _____ mediated maternal hypothyroidism

Answer: antibody

Endocrine pathology Flashcard 3 of 5

Question: A common cause of Addison disease is metastatic carcinoma, especially from the _____

Answer: lungs

Endocrine pathology Flashcard 4 of 5

Question: TTP and HUS present with _____ bleeding time

Answer: increased

Endocrine pathology Flashcard 5 of 5

Question: Thyroid _____ is a benign solitary growth of the thyroid

Answer: adenoma