AssessmentsVasculitis: Pathology review
USMLE® Step 1 style questions USMLE
A 52-year-old man comes to the clinic due to fatigue, joint pain, and recent appearance of skin lesions on his legs. His medical history is noncontributory except for a car accident as a child which required hospitalization and multiple blood transfusions. He has not seen a physician in more than 10 years. The patient does not use tobacco, alcohol or illicit drugs. He is monogamous with one sexual partner. Temperature is 37.0°C (98.6°F), pulse is 75/min, and blood pressure is 130/85 mmHg. Physical exam shows purpuric papules covering the lower extremities that do not blanch with pressure. The rest of the physical examination is unremarkable. Laboratory tests are obtained and shown below:
Urinalysis is unremarkable. Serum protein electrophoresis and immunofixation reveals polyclonal IgG and monoclonal IgM bands. Testing for cryoglobulins shows no precipitation after 24 hours. Which of the following tests is most likely to reveal this patient's underlying condition?
At the clinic, two very different people with very different symptoms showed up. Novakova is a 60 year old woman from Czech Republic who’s been having a headache by the right temple, progressive jaw pain during chewing, and shoulder and hip stiffness, particularly in the morning. Her ESR levels are elevated, and she is beginning to develop vision loss in the right eye. The other person is Hikaru, a cute 3-year-old Japanese boy brought by his mother. He has a red, swollen tongue, unilateral neck swelling, a desquamating rash, and a fever for the past 6 days. An ECG reveals elevation of the ST segment, and an echocardiogram shows evidence of a coronary artery aneurysm.
At first glance, you’d think Novakova and Hikaru symptoms have nothing in common. But the fact is, they both have different forms of vasculitis. The majority of vasculitides are caused by some form of immune-mediated damage. Some are type III hypersensitivities caused by immune complexes that deposit in vessels and cause damage. They could also be triggered by autoantibodies, like anti-neutrophil cytoplasmic antibodies, or ANCA. Lastly, they might be caused by cell-mediated immunity due to monocytes, macrophages or lymphocytes.
Whatever the cause, immune cells c