USMLE® Step 1 style questions USMLE
USMLE® Step 2 style questions USMLE
A 39-year-old female comes to the office because of sudden pain in her fingers and color changes of the skin of her fingers when she is cold for the past 4 weeks. She has noted that the skin on her face and fingers “feel like she is wearing a tight mask and gloves". She additionally reports that she seems to have developed some lesions on the tips of her fingers. She was recently diagnosed with CREST syndrome. Examination is shown below. Which of the following cell types is most attributable to causing the pathophysiologic changes associated with this disease process?
CREST syndrome, also known as limited cutaneous systemic sclerosis, is an autoimmune condition, and its name is an acronym that stands for calcinosis, Raynaud’s phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasias.
Calcinosis is the deposition of calcium in the skin, Raynaud’s is spasm of the arteries in the fingers, esophageal dysmotility refers to difficulty swallowing, sclerodactyly is tightening of the skin over the fingers, and telangiectasias are small dilated blood vessels on the skin surface.
In addition to destroying the pathogen, they also present a fragment of the pathogen, called an antigen, to naive T cells.
They also release cytokines, like TGF-β, that tells fibroblasts to repair damaged tissue after the infection by laying down collagen.
The cause of CREST syndrome isn’t known exactly, but individuals in the first two years of the disease have a higher than normal number of T-helper cells in the skin on their hands and face, particularly near small blood vessels.
The T-helper cells release cytokines to attract other immune cells, like macrophages and neutrophils, which cause a lot of inflammation in the skin.
There is so much inflammation that the tissue dies, in a process called necrosis.
It’s not clear why it happens, but individuals with CREST often experience Raynaud’s phenomenon, which is an episodic, dramatic vasoconstriction of arterial blood vessels in the hands.
It’s not quite clear what is going on, but in CREST syndrome there is often difficulty in swallowing food, which we esophageal dysmotility.
This causes more damage to the skin, particularly in the hands and fingers.
The body tries to repair the damage by activating fibroblasts which lay down bundles of collagen.