Each week, Osmosis shares a USMLE® Step 1-style practice question to test your knowledge of medical topics. Today’s case involves a 56-year-old woman with asthma and notable skin tightening over the face, hands, and forearms. Can you figure it out?
A 56-year-old woman comes to her primary care physician for evaluation of acid reflux that began four months ago. The patient has tried ranitidine and pantoprazole; however, her symptoms have remained poorly controlled. Past medical history is notable for asthma, for which she is currently using an albuterol inhaler. Her temperature is 37.5°C (99.5°F) and her blood pressure is 118/67 mmHg. Physical examination is notable for skin tightening over the face, hands, and forearms. Several ulcers are observed at the fingertips. Which of the following is the most likely explanation of the patient’s presentation?
A. Pathological collagen deposition
B. Herniation of gastroesophageal junction
C. Cholesterol deposition in peripheral blood vessels
D. Pathological keratin deposition
E. Gram-negative bacterial infection
Scroll down to find the answer!
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The correct answer to today’s USMLE® Step 1 Question is…
A. Pathological collagen deposition
Before we get to the Main Explanation, let’s look at the incorrect answer explanations. Skip to the bottom if you want to see the correct answer right away!
Incorrect answer explanations
The incorrect answers to today’s USMLE® Step 1 Question are…
B. Herniation of gastroesophageal junction
Incorrect: This describes a hiatal hernia, which is a common cause of gastroesophageal reflux disease (GERD) that is refractory to medical treatment. Although a hiatal hernia may explain the patient’s GERD, it would not explain the skin tightening or fingertip ulcerations.
C. Cholesterol deposition in peripheral blood vessels
Incorrect: Severe atherosclerosis can reduce blood flow to the extremities and cause tissue necrosis. This may present with ulcers. However, ulcers secondary to atherosclerosis/peripheral artery disease are most often found in the lower extremities. Moreover, atherosclerosis would not explain skin tightening or treatment-resistant acid reflux.
D. Pathological keratin deposition
Incorrect: This describes hyperkeratosis, which may be seen in vitamin A deficiency or dermatomyositis. The condition causes skin thickening and discomfort. However, it would be atypical for hyperkeratosis to present with fingertip ulcers or severe acid reflux.
E. Gram-negative bacterial infection
Incorrect: Infection by gram-negative bacteria, such as Helicobacter pylori (H. pylori), can cause gastric acid overproduction. This can result in peptic ulcer formation and potentially contribute to the development of acid reflux. However, infection by H.pylori or other gram-negative pathogens would not account for the patient’s skin changes.
Main explanation
This patient has scleroderma (also termed systemic sclerosis), an autoimmune disorder characterized by the replacement of normal tissue by collagen. Scleroderma most often affects women over 50 years old.
The condition can be divided into two subtypes: diffuse cutaneous and limited cutaneous systemic scleroderma. Both cause thickening and tightening of the skin. In addition, both types can cause gastroesophageal reflux disease (GERD) secondary to replacement of the esophageal sphincter muscles by collagen.
However, diffuse scleroderma is characterized by severe visceral organ involvement (e.g., renal injury, malabsorption, restrictive cardiomyopathy) and diffuse skin involvement. In contrast, limited scleroderma is characterized by mild visceral organ involvement and affects only the skin of the face and distal extremities. Of note, the patient in this vignette most likely has limited scleroderma, as she presents with skin findings localized to the face and distal upper extremities.
The pathology of this condition is not completely understood. However, it’s believed that some individuals have a genetic predisposition to scleroderma, which is triggered by external factors. These triggers include viral infection by cytomegalovirus and parvovirus B19; exposure to silica dust, organic solvents, vinyl chloride; and medication like cocaine, bleomycin, and pentazocine.
Major Takeaway
Scleroderma is characterized by excess collagen deposition. The condition can be divided into two types: diffuse scleroderma and limited scleroderma. Diffuse scleroderma affects skin throughout the body and has severe visceral organ involvement. Limited sclerosis affects only skin of the face and distal extremities and has mild visceral organ involvement.
References
Adigun, R., Goyal, A., Bansal, P., Hariz, A. (2020) Systemic sclerosis (CREST syndrome). StatPearls [Internet].
Badri, T., Hariz, A. (2020) “Scleroderma (Systemic Sclerosis)”. StatPearls [Internet].
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The United States Medical Licensing Examination (USMLE®) is a joint program of the Federation of State Medical Boards (FSMB®) and National Board of Medical Examiners (NBME®). Osmosis is not affiliated with NBME nor FSMB.
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