A 54-year-old African-Canadian female is admitted to the hospital for intravenous heparin therapy for a deep-vein thrombosis of her leg. She had previously been very healthy. Shortly after admission she begins to experience profound orthostatic hypotension and gastrointestinal distress. Serial hemoglobin tests are stable, but serum sodium and bicarbonate levels are low. Her potassium level is slightly elevated.
Which one of the following tests would most quickly determine if she has suffered from acute adrenal cortex insufficiency (Addison’s disease)?
Correct Answer A:
Destruction of the adrenal cortex by acute causes (infarction, hemorrhage, infection) or chronic ones (granulomatous disease, immune destruction) results in a loss of circulating levels of cortisol and aldosterone. The effects of this deficiency can include electrolyte disturbances such as those seen in this patient, gastrointestinal distress (including “acute abdomen,” diarrhea, nausea, etc.), orthostatic hypotension, and patient fatigue. If the process is gradual, ACTH levels will increase, resulting in a darkened skin tone. Measuring serum levels of ACTH may be helpful in determining the cause of decreased cortisol levels, but is not a good first test of adrenal cortex function. The dexamethasone suppression test is used to evaluate glucocorticoid excess.
The cosyntropin stimulation test does assess adrenal cortex function. This test involves injecting cosyntropin, 250 µg intra-muscularly or intravenously, and measuring cortisol levels 60 minutes later. If the result shows an inadequate response (cortisol level < 495 nmol/L), adrenal cortical function is proven to be at least 90% diminished.
Which of the following scenarios best describes otosclerosis?
Correct Answer B:
Otosclerosis is a disease of the bone of the otic capsule that produces an abnormal accumulation of new bone within the oval window.
In otosclerosis, the new bone traps and restricts the movement of the stapes, causing conductive hearing loss. Otosclerosis also may produce a sensorineural hearing loss, particularly when the foci of otosclerotic bone are adjacent to the scala media. Half of all cases are inherited. The measles virus may play an inciting role in patients with a genetic predisposition for otosclerosis.
Although about 10% of white adults have some otosclerosis (compared with 1% of blacks), only about 10% of affected people develop conductive hearing loss. Hearing loss from otosclerosis may manifest as early as age 7 or 8, but most cases do not become evident until the late teen or early adult years, when slowly progressive, asymmetric hearing loss is diagnosed. Fixation of the stapes may progress rapidly during pregnancy.
A hearing aid may restore hearing. Alternatively, microsurgery to remove some or all of the stapes and to replace it with a prosthesis may be beneficial.
A patient previously diagnosed with Huntington chorea (HC) comes for a family planning consult with his wife. He states that his father had the disease and his mother was unaffected.
They ask you "what is the likelihood having a son with this condition"?
Huntington chorea (HC), is an inherited disease characterized by choreiform movements and progressive dementia. It is inherited as an autosomal dominant disorder. There is a 50% chance of the man passing the disease to his child. There is a 50% chance of having a son. 0.5x0.5=0.25 = 25% Therefore, there is a 25% chance of the man passing the disease to his son.
What is the chance of having offspring affected by Duchenne Muscular Dystrophy (DMD), if the father is affected and the mother is not (not a carrier)?
Duchenne muscular dystrophy is inherited in an X-linked recessive pattern. The following figure illustrates the outcomes for an affected male with a normal female:
and following figure an affected female with a normal male:
In first scenario (concerning this question), the affected male mates with a normal female. The female offspring will be carriers and the male offspring will be normal. No offspring will be affected.
In the second scenario, a normal male mates with an affected female resulting in male offspring that are affected and female offspring that are carriers.
Which of the following is associated with streptococcal pharyngitis?
Streptococci are gram-positive aerobic organisms that cause many disorders, including pharyngitis, pneumonia, wound and skin infections, sepsis, and endocarditis. Symptoms vary with the organ infected. Sequelae include rheumatic fever and glomerulonephritis. Clinical diagnoses are confirmed by Gram stain and culture.
Strep throat (Streptococcal pharyngitis) is a form of Group A streptococcal infection that affects the pharynx. Symptoms include: severe sore throat, yellow and white patches in the throat, difficulty swallowing, tender cervical lymphadenopathy, red and enlarged tonsils, halitosis, fever of 38°C (101F) or greater, rash and absence of cough.
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