Test 15

Question 1

Botulism

Answer 1

Botulism is an acute, presynaptic, neuromuscular junction disorder caused by infection with Clostridium botulinum. Botulinum toxin inhibits release of acteylcholine into the synaptic cleft in both autonomic and somatic nervous systems. Clinically, patients develop acute bulbar and descending limb weakness with absent reflexes and autonomic dysfunction but preserved sensation.

Question 2

Peripartum depression

Answer 2

Patients with postpartum depression can be tx with antidepressants and continue breastfeeding. Sertraline and paroxetine are first-line drugs as they have the best safety record, and amounts secreted into breast milk are low or undetectable.

Question 3

Asthma

Answer 3

Glucocorticoid administration for less than 3 weeks does not typically cause significant suppression of the hypothalamic-pituitary-adrenal axis and can be stopped abruptly with minimal risk of adrenal insufficiency.

Question 4

Confounding, effect modification, bias, errors

Answer 4

Lead-time bias is a common bias seen with screening tests. It occurs when a test diagnoses a dx earlier than another test does. As a result, the time from diagnosis until death appears prolonged even though there is no actual improvement in survival.

Question 5

Patient confidentiality

Answer 5

Patient-physician email communication regarding simple, nonurgent health care issues is useful in clarifying instructions, improving rapport, and increasing patient satisfaction. Physicians should set clear parameters early on with patients regarding appropriate use of email.

Question 6

Otitis media

Answer 6

A persistent, unilateral middle ear effusion requires examination of the nasopharynx to look for a mass lesion (nasopharyngeal carcinoma) obstructing the eustachian tube orifice.

Question 7

Mitochondrial disorders

Answer 7

Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes is one of the most common mitochondrial myopathies and presents with stroke-like episodes, seizures, muscle weakness, hearing loss, and lactic acidosis. It is maternally inherited. As such, transmission occurs only through affected females and never through males.

Question 8

Thyroid cancer

Answer 8

Elevated calcitonin levels in patients with medullary thyroid cancer following total thyroidectomy indicate metastatic dx. CT scan of the neck and chest is recommended as the next step to look for metastatic dx. Medullary thyroid cancer cells do not take-up iodine; therefore, total body iodine scan is not useful.

Question 9

Acute diarrhea

Answer 9

Viral gastroenteritis commonly causes acute watery diarrhea in children, and excessive fruit juice consumption may exacerbate sx. Tx involves oral rehydration therapy and avoidance of fruit juice during illness.

Question 10

Colonic ischemia

Answer 10

Colonic ischemia most commonly occurs due to non occlusive dx in the setting of underlying atherosclerosis and a state of low blood flow. Patients typically have abdominal pain, bloody diarrhea, and fecal urgency as well as leukocytosis, lactic acidosis, and colonic distension or pneumatosis shown on abdominal x-rays.