Episode 57: The Audio PANCE and PANRE Board Review Podcast

Answer: D. Metformin

The patient in this vignette most likely has type II diabetes. Of the given treatments, only metformin is weight neutral in the majority of cases (i.e. it does not cause significant weight gain/loss). Metformin is a first-line treatment for type II DM in most patients. Although the exact mechanism is unknown, it appears to decrease gluconeogenesis and increase insulin sensitivity. There is no risk of hypoglycemia or weight gain (though some patients even lose weight). The most high yield side effect involves lactic acidosis, particularly in patients with renal insufficiency. 

A. Glargine, a long-acting insulin, can cause weight gain.
B. Glyburide, a second-generation sulfonylurea, can cause weight gain.
C. Actos, a thiazolidinedione, can cause weight gain.
E. Glipizide, a second-generation sulfonylurea, can cause weight gain.

Answer: C. a fine needle biopsy

Fine needle aspiration (FNA) is the first step in the evaluation of a solitary nodule with a normal TSH level. FNA has a high level of accuracy in diagnosing benign versus malignant nodules in this setting.

A. Measurement of T4 and T3 levels would not be of benefit in the evaluation of a solitary thyroid nodule with a normal TSH level.
B. A thyroid scan would be the next step if there were a low TSH level.
D. Surgical excision would be the final step after determination of malignancy or suspicion of malignancy by FNA.

Answer: B. Decreased total body potassium

This type I diabetic is presenting with signs and symptoms of diabetic ketoacidosis (DKA). In DKA, total body potassium stores are generally decreased due to osmotic diuresis. DKA is a life-threatening emergency that may occur in either type I or type II diabetics but is significantly more common in patients with type I. The pathogenesis is related to insulin deficiency resulting in hyperglycemia that leads to osmotic diuresis and hypovolemia. The inability of the body to use the available glucose for ATP production results in ketone formation and eventually an anion gap metabolic acidosis. Serum potassium levels may be low, normal, or elevated, but total body stores are generally low and require repletion. Common precipitating factors include infection, trauma, myocardial infarction, sepsis and, of course, inadequate insulin administration. Patients may present with nausea, vomiting, abdominal pain, Kussmaul respirations (rapid, deep breaths), dehydration, polydipsia, polyuria and may eventually progress to altered mental status.

A. Patients with DKA more often present with hyponatremia. Remember that serum sodium decreases 1.6 mEq/L for every 100 mg/dL increase in glucose.
C. DKA requires hyperglycemia by definition. Hypoglycemia can be a complication of treatment if glucose is not monitored closely.
D. Ketones, such as Beta-OH-Butyrate, are commonly found in patients with DKA since ketogenesis is a normal response to starvation caused by the inadequate transit of serum glucose into cells.
E. Patients with DKA present with an anion-gap metabolic acidosis secondary to ketoacids.

Answer: A. Addison’s disease

Addison’s disease (adrenal insufficiency) would account for all her symptoms, the hypotension, and the hyperpigmentation of the skin.

B. Cushing’s disease, the presence of an ACTH-producing adenoma, is characterized by central obesity, hypertension, moon facies, purple striae, and glucose intolerance.
C. Anorexia nervosa may explain the weakness, weight loss, hypotension, and syncope, however, a normal pulse rate would be an unexpected finding along with the hyperpigmentation.
D. Porphyria presents acutely with anxiety, depression, disorientation, and insomnia.

Answer: D. A pituitary tumor 

A pituitary tumor would account for the headaches and the loss of the peripheral vision in both visual fields. As the tumor grows, the optic chiasm will be compressed by the tumor.

A. An aneurysm involving the circle of Willis would result in CN III palsy. This would be a rare finding.
B. Although a migraine headache may produce visual field defects, these defects would remit upon resolution of the migraine. It would also be unusual to have the scotomas occur bilaterally.
C. Optic neuritis associated with multiple sclerosis presents with decreased visual acuity, dimness, or color desaturation in the central visual field. It would not affect the periphery.

Answer:  A. Grave’s disease.

Radioactive iodine is an excellent method to destroy overactive thyroid tissue of Grave’s disease.

B. Radioactive iodine is ineffective in subacute thyroiditis due to the thyroid’s low uptake of iodine.
C. Radioiodine uptake is low in Hashimoto’s thyroiditis and is often transient.
D. Papillary thyroid carcinoma is a common thyroid malignancy and must be treated by a thyroidectomy.

Answer: B. Thyroid hormone replacement 

This scenario is consistent with congenital hypothyroidism. Measurement of TSH or T4 would confirm this and T4 should be given.

C. Hepatitis and sepsis may account for the presence of jaundice, feeding problems, and hypotonia, but would not result in an enlarged tongue.
D. A deficiency in vitamin B6 may lead to glossitis but would not account for or any of the other signs.

Answer: B. Acarbose (Precose)

Alpha-glucosidase inhibitors, such as acarbose, reduce glucose by delaying glucose absorption.

A. Metformin, a biguanide, lowers glucose by decreasing hepatic glucose production and increased glucose utilization.
C. Glipizide and other sulfonylureas work by increasing insulin secretion.
D. Pioglitazone is a thiazolidinedione and decreases insulin resistance and increases glucose utilization.c

Answer: A. Adrenal adenoma

Excessive secretion of aldosterone from an adrenal adenoma will lead to sodium retention and the secretion of potassium in the distal tubule of the kidney, eventually leading to hypokalemia.

B. Hypoparathyroidism and hyperthyroidism should not have any effect on potassium levels.
D. Adrenal insufficiency would lead to hyperkalemia.

Answer: C. the Somogyi effect.

This refers to nocturnal hypoglycemia, which stimulates counter-regulatory hormone release resulting in rebound hyperglycemia.

A. Nightmares and night sweats are not associated with growth spurts.
B. With this limited history, it is impossible to label the child as emotionally unstable.
D. This refers to an early morning rise in plasma glucose due to reduced tissue sensitivity to insulin between 5 AM and 8 AM. It is not associated with nightmares and night sweats.