Endocrinology (diabetes, thyroid disorders) US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Endocrinology (diabetes, thyroid disorders). These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Endocrinology (diabetes, thyroid disorders) US Medical PG Question 1: A 62-year-old man presents to the emergency department with confusion. The patient’s wife states that her husband has become more somnolent over the past several days and now is very confused. The patient has no complaints himself, but is answering questions inappropriately. The patient has a past medical history of diabetes and hypertension. His temperature is 98.3°F (36.8°C), blood pressure is 127/85 mmHg, pulse is 138/min, respirations are 14/min, and oxygen saturation is 99% on room air. Physical exam is notable for a confused man with dry mucous membranes. Initial laboratory studies are ordered as seen below.
Serum:
Na+: 135 mEq/L
Cl-: 100 mEq/L
K+: 3.0 mEq/L
HCO3-: 23 mEq/L
BUN: 30 mg/dL
Glucose: 1,299 mg/dL
Creatinine: 1.5 mg/dL
Ca2+: 10.2 mg/dL
Which of the following is the most appropriate initial treatment for this patient?
- A. Insulin, normal saline, and potassium (Correct Answer)
- B. Normal saline and potassium
- C. Insulin and potassium
- D. Insulin
- E. Insulin and normal saline
Endocrinology (diabetes, thyroid disorders) Explanation: ***Insulin, normal saline, and potassium***
- This patient is presenting with **hyperosmolar hyperglycemic state (HHS)**, characterized by severe hyperglycemia (glucose 1299 mg/dL), dehydration (dry mucous membranes, high BUN and creatinine), and altered mental status. The initial treatment involves intravenous fluids to correct dehydration, insulin to lower blood glucose, and potassium supplementation due to potential shifts as insulin is administered.
- **Normal saline** addresses the severe dehydration, **insulin** corrects hyperglycemia, and **potassium supplementation** prevents hypokalemia, which is common during HHS treatment as glucose and potassium shift intracellularly.
*Normal saline and potassium*
- While **normal saline** and **potassium** are crucial for rehydration and electrolyte balance, omitting **insulin** would fail to address the core problem of severe hyperglycemia in HHS.
- Without insulin, blood glucose levels will remain dangerously high, leading to persistent osmotic diuresis and worsening dehydration.
*Insulin and potassium*
- Administering **insulin** without addressing the profound **dehydration** with intravenous fluids can lead to **hypovolemic shock** as insulin further drives glucose and water into cells.
- Rehydration is the priority in HHS management before or concurrent with insulin administration.
*Insulin*
- Giving only **insulin** would be detrimental, as the patient is severely dehydrated and hypokalemic (K+ 3.0 mEq/L, and will drop further with insulin).
- This approach would exacerbate dehydration and could cause life-threatening arrhythmias due to severe hypokalemia.
*Insulin and normal saline*
- While addressing hyperglycemia and dehydration, omitting **potassium supplementation** is dangerous because insulin drives potassium into cells, potentially causing severe **hypokalemia** and cardiac arrhythmias.
- The patient already has a low-normal potassium level, which will likely drop further with insulin treatment.
Endocrinology (diabetes, thyroid disorders) US Medical PG Question 2: A 19-year-old man with a history of type 1 diabetes presents to the emergency department for the evaluation of a blood glucose level of 492 mg/dL. Laboratory examination revealed a serum bicarbonate level of 13 mEq/L, serum sodium level of 122 mEq/L, and ketonuria. Arterial blood gas demonstrated a pH of 6.9. He is admitted to the hospital and given bicarbonate and then started on an insulin drip and intravenous fluid. Seven hours later when his nurse is making rounds, he is confused and complaining of a severe headache. Repeat sodium levels are unchanged, although his glucose level has improved. His vital signs include a temperature of 36.6°C (98.0°F), pulse 50/min, respiratory rate 13/min and irregular, and blood pressure 177/95 mm Hg. What other examination findings would be expected in this patient?
- A. Hypoglycemia
- B. Pupillary constriction
- C. Papilledema (Correct Answer)
- D. Pancreatitis
- E. Peripheral edema
Endocrinology (diabetes, thyroid disorders) Explanation: ***Papilledema***
- This patient's symptoms (confusion, severe headache, bradycardia, irregular respiration, hypertension) following treatment for **diabetic ketoacidosis (DKA)** are highly suggestive of **cerebral edema**.
- **Papilledema** is a retinal finding resulting from increased intracranial pressure (ICP), which is a characteristic sign of cerebral edema.
*Hypoglycemia*
- While the patient's glucose level has improved, it is not described as being low enough to cause hypoglycemia, and the symptoms are more consistent with **increased ICP**.
- Symptoms of hypoglycemia (e.g., tremors, sweating, hunger, anxiety) are different from the patient's current presentation of confusion and severe headache.
*Pupillary constriction*
- **Pupillary constriction** (miosis) is typically not associated with cerebral edema; instead, **pupillary dilation** (mydriasis) can occur with severe increase in ICP due to uncal herniation.
- The combination of bradycardia, irregular respiration, and hypertension (Cushing's triad) is indicative of increased ICP, which would likely cause pupillary changes related to brainstem compression.
*Pancreatitis*
- Pancreatitis is a known complication of DKA, but it typically presents with **severe abdominal pain**, nausea, and vomiting, rather than cerebral symptoms.
- Although the patient had DKA, the current neurological symptoms point directly to an intracranial process rather than an abdominal issue.
*Peripheral edema*
- **Peripheral edema** results from fluid accumulation in peripheral tissues and is not a direct consequence or expected finding in cerebral edema.
- While fluid administration can cause some peripheral fluid retention, it typically does not lead to the acute neurological deterioration seen in this patient.
Endocrinology (diabetes, thyroid disorders) US Medical PG Question 3: A 45-year-old woman comes to the emergency department with recurrent episodes of shaking, sweating, and palpitations. The patient is confused and complains of hunger. One week ago, she had similar symptoms that improved after eating. She has hypertension and a history of biliary pancreatitis. She underwent cholecystectomy 1 year ago. She works as a nurse aide in a nursing care facility. She does not smoke or drink alcohol. She does not exercise. Her temperature is 36.7°C (98°F), pulse is 104/min, respirations are 20/min, and blood pressure is 135/88 mm Hg. Examination shows tremors and diaphoresis. Laboratory studies show:
Blood glucose 50 mg/dL
Thyroid-stimulating hormone 1 mU/L
C-peptide 0.50 ng/mL (N=0.8–3.1)
Abdominal ultrasound reveals a 1-cm anechoic lesion in the head of the pancreas. Which of the following is the most likely cause of this patient's symptoms?
- A. Pancreatic neoplasm
- B. Pancreatic pseudocyst
- C. Graves' disease
- D. Surreptitious insulin use (Correct Answer)
- E. Type 1 diabetes mellitus
Endocrinology (diabetes, thyroid disorders) Explanation: ***Surreptitious insulin use***
- The patient's symptoms of **hypoglycemia** (shaking, sweating, palpitations, confusion, hunger) combined with a **low C-peptide level** (0.50 ng/mL) and a normal TSH strongly suggest **exogenous insulin administration**.
- As a nurse aide, she has access to insulin, and the normal pancreatic ultrasound (1 cm anechoic lesion is non-specific and unlikely to cause these symptoms) rules out an **insulinoma**, which would present with high C-peptide.
*Pancreatic neoplasm*
- While a pancreatic neoplasm can cause various symptoms, an **insulinoma** (a type of pancreatic neuroendocrine tumor) would present with **hypoglycemia** but typically with **elevated C-peptide levels**, as it produces endogenous insulin.
- The ultrasound finding of a 1-cm anechoic lesion is **non-specific** and not definitively indicative of an insulinoma or any other functional neoplasm causing these specific symptoms.
*Pancreatic pseudocyst*
- Pancreatic pseudocysts are collections of fluid that can occur after **pancreatitis** or trauma, and while this patient has a history of biliary pancreatitis, pseudocysts generally cause symptoms like **abdominal pain, distension, and early satiety**, not hypoglycemia.
- They also do not explain the **low C-peptide** and recurrent episodes of neuroglycopenic symptoms.
*Graves' disease*
- Graves' disease is an **autoimmune hyperthyroid condition** that causes symptoms like palpitations, sweating, and tremors, but it is characterized by **low TSH** with elevated free T3/T4 due to negative feedback, not hypoglycemia or low C-peptide.
- The patient's **normal TSH** (1 mU/L) rules out Graves' disease as the cause of her current symptoms.
*Type 1 diabetes mellitus*
- Type 1 diabetes is characterized by **insulin deficiency** due to autoimmune destruction of pancreatic beta cells, leading to **hyperglycemia**, not hypoglycemia.
- While patients with type 1 diabetes may experience hypoglycemia if they administer too much insulin, the underlying disease itself causes high blood glucose, and the C-peptide would be very low or undetectable in a new diagnosis, but not as the cause of recurrent spontaneous hypoglycemia.
Endocrinology (diabetes, thyroid disorders) US Medical PG Question 4: A 49-year-old woman presents to the office because of tremors for 2 months. She says that her hands have been shaking a lot, especially when she feels stressed. In addition, she has been sweating more than usual and has lost 8 kg (17.6 lb) in the last 2 months. She has a past medical history of vitiligo. Her vital signs are a heart rate of 98/min, a respiratory rate of 14/min, a temperature of 37.6°C (99.7°F), and a blood pressure of 115/75 mm Hg. Physical examination shows a fine, bilateral hand tremor and a diffuse goiter. Which of the following hormonal imbalances is most likely present?
- A. Low TSH, high free T4, and high free T3 (Correct Answer)
- B. High TSH, high free T4, and high free T3
- C. High TSH, normal free T4, and normal free T3
- D. Low TSH, normal free T4, and normal free T3
- E. High TSH, low free T4, and low free T3
Endocrinology (diabetes, thyroid disorders) Explanation: ***Low TSH, high free T4, and high free T3***
- The patient's symptoms (tremors, sweating, weight loss, tachycardia, goiter) are classic for **hyperthyroidism**, which is typically characterized by **low TSH** due to negative feedback and **elevated free T4 and T3** levels.
- Her history of **vitiligo**, an autoimmune condition, further supports an autoimmune thyroid disorder like **Graves' disease**, a common cause of hyperthyroidism.
*High TSH, high free T4, and high free T3*
- This pattern would indicate **secondary hyperthyroidism**, caused by a TSH-secreting pituitary adenoma.
- While TSH would be high, it is a much rarer cause of hyperthyroidism compared to primary causes.
*High TSH, normal free T4, and normal free T3*
- This hormonal profile is characteristic of **subclinical hypothyroidism** or a **compensated primary hypothyroidism** early in its course.
- The patient's symptoms are inconsistent with hypothyroidism.
*Low TSH, normal free T4, and normal free T3*
- This suggests **subclinical hyperthyroidism**, where TSH is suppressed but thyroid hormone levels are still within the normal range.
- The patient's prominent and severe symptoms (tremors, significant weight loss, goiter) indicate overt hyperthyroidism, not subclinical disease.
*High TSH, low free T4, and low free T3*
- This is the classic hormonal profile for **primary hypothyroidism**, where the thyroid gland is failing to produce sufficient hormones, leading to elevated TSH.
- The patient's symptoms of nervousness, weight loss, and tremors are directly opposite to those seen in hypothyroidism.
Endocrinology (diabetes, thyroid disorders) US Medical PG Question 5: A 40-year-old woman visits her physician’s office with her husband. Her husband says that she has been complaining of recurring headaches over the past few months. A year ago she was diagnosed with diabetes and is currently on treatment for it. About 6 months ago, she was diagnosed with high blood pressure and is also taking medication for it. Her husband is concerned about the short span during which she has been getting all these symptoms. He also says that she occasionally complains of changes and blurring in her vision. In addition to all these complaints, he has observed changes in her appearance, more prominently her face. Her forehead and chin seem to be protruding more than usual. Suspecting a hormonal imbalance, which of the following initial tests would the physician order to indicate a possible diagnosis?
- A. Chest X-ray
- B. Pituitary magnetic resonance image (MRI)
- C. Serum growth hormone
- D. Glucose suppression test
- E. Serum insulin-like growth factor-1 (IGF-1) (Correct Answer)
Endocrinology (diabetes, thyroid disorders) Explanation: ***Serum insulin-like growth factor-1 (IGF-1)***
- Elevated **serum IGF-1 levels** are the most sensitive and reliable initial screening test for **acromegaly**, reflecting sustained growth hormone excess.
- The clinical presentation with **new-onset diabetes**, **hypertension**, **headaches**, **visual changes**, and **facial prognathism** strongly suggests acromegaly, a condition caused by excessive growth hormone (GH) secretion.
*Chest X-ray*
- A chest X-ray is primarily used to evaluate **pulmonary or cardiac conditions** and would not directly screen for hormonal imbalances like acromegaly.
- While acromegaly can lead to **cardiomegaly** or **sleep apnea**, a chest X-ray is not the initial diagnostic test for growth hormone excess itself.
*Pituitary magnetic resonance image (MRI)*
- A **pituitary MRI** is the imaging study of choice to confirm the presence of a **pituitary adenoma** after biochemical confirmation of acromegaly, not an initial screening test.
- It visualizes the pituitary gland and helps locate the tumor but is ordered *after* biochemical tests indicate GH excess.
*Serum growth hormone*
- A single random **serum growth hormone (GH) level** can be misleading because GH secretion is pulsatile, making a single measurement unreliable for diagnosing acromegaly.
- While acromegaly involves elevated GH, a random sample is not the optimal initial diagnostic test due to its **fluctuating levels**.
*Glucose suppression test*
- The **oral glucose tolerance test (OGTT)** with GH measurement is the confirmatory test for acromegaly, used to demonstrate **failure of GH suppression** after glucose load.
- This is a diagnostic procedure performed *after* an elevated IGF-1 level suggests acromegaly, not an initial screening test.
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