Question:

A 42-year-old woman comes to the office with a 4-month history of heartburn. She describes a periodic "sticking sensation" in her chest during meals. In addition, the patient has recently been unable to participate in her normal exercise routine due to dyspnea on exertion and joint pain in her hands and feet. She does not use tobacco, alcohol, or illicit drugs. Lung examination reveals bilateral end-inspiratory crackles. Endoscopic evaluation shows mild hyperemia in the distal esophagus. Esophageal manometry shows lack of peristaltic waves in the lower two-thirds of the esophagus and a significant decrease in lower esophageal sphincter tone. Which of the following is the most likely mechanism responsible for this patient's manometric findings?

Dysfunctional impairment of inhibitory neurons

Eosinophilic infiltration of esophageal mucosa

Loss of intramural neurons

Smooth muscle atrophy and fibrosis

Striated muscle inflammation

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Systemic sclerosis
Pathogenesis	Progressive tissue fibrosis Vascular dysfunction
Clinical features	Skin: telangiectasia, sclerodactyly, digital ulcer, calcinosis cutis Extremities: arthralgia, myalgia, contracture Gastrointestinal tract: esophageal dysmotility, dysphagia, acid reflux Lungs: dyspnea, dry cough Vascular system: Raynaud phenomenon
Autoantibodies	Antinuclear Anti–topoisomerase type I (anti–Scl-70) (diffuse SSc) Anticentromere (limited SSc)
Complications	Lungs: interstitial lung disease, pulmonary arterial HTN Kidneys: HTN, scleroderma renal crisis (severe HTN, AKI, MAHA) Heart: myocardial fibrosis, pericarditis, pericardial effusion
AKI = acute kidney injury; HTN = hypertension; MAHA = microangiopathic hemolytic anemia; SSc = systemic sclerosis.

This patient has a number of findings (eg, esophageal dysmotility, fibrotic lung disease, arthralgias) consistent with extradermal manifestations of systemic sclerosis (SSc). Classic early skin manifestations of SSc include thickening or hardening, edema, and pruritus. However, if skin symptoms are mild, patients may first seek attention due to gastrointestinal (GI), joint, or respiratory disease.

GI complications are common in SSc and primarily affect the esophagus. SSc causes smooth muscle atrophy and fibrosis in the lower esophagus; the upper third of the esophagus is made of striated muscle and seldom affected by SSc. Common symptoms include dysphagia, choking, heartburn, and hoarseness. Esophageal manometry in affected patients typically shows hypomotility and incompetence of the lower esophageal sphincter (LES).

(Choice A) Dysfunction of inhibitory neurons causes diffuse esophageal spasm and presents with chest pain and dysphagia rather than heartburn. Manometry is characterized by periodic, high-amplitude, non-peristaltic contractions.

(Choice B) Eosinophilic esophagitis is characterized by heartburn that does not respond to standard medications for gastroesophageal reflux disease. Manometry most often shows esophageal hypercontractility.

(Choice C) Achalasia presents with dysphagia and regurgitation of undigested food. As in SSc, manometry shows aperistalsis in the distal esophagus. However, achalasia causes increased LES pressure and incomplete LES relaxation, whereas SSc causes decreased LES pressure.

(Choice E) Esophageal involvement may occur in polymyositis. It can involve both the upper and lower esophagus and is characterized by dysphagia, regurgitation, and aspiration. Manometry results are often functionally similar to SSc, but most patients will have symmetric proximal muscle weakness, not distal arthralgias.

Educational objective:
Systemic sclerosis can cause atrophy and fibrosis of the smooth muscle in the lower esophagus. This leads to decreased peristalsis and decreased tone in the lower esophageal sphincter. Typical symptoms include heartburn and dysphagia.