A 31-year-old man comes to the office due to progressive dyspnea over the past several months. The patient states that the shortness of breath improved initially with supine positioning, but lately, it is present even on recumbency and during minimal exertion. He reports recurrent episodes of nosebleeds since childhood but has no other medical conditions. Temperature is 36.7 C (98.1 F), blood pressure is 110/50 mm Hg, pulse is 102/min, and respirations are 20/min. Oxygen saturation is 96% on room air. Cardiac examination reveals an accentuated S2 over the upper left sternal border. The lungs are clear to auscultation. There is digital clubbing. Skin examination findings are shown in the exhibit. Which of the following is the most likely underlying cause of this patient's dyspnea?

Question

A 31-year-old man comes to the office due to progressive dyspnea over the past several months.  The patient states that the shortness of breath improved initially with supine positioning, but lately, it is present even on recumbency and during minimal exertion.  He reports recurrent episodes of nosebleeds since childhood but has no other medical conditions.  Temperature is 36.7 C (98.1 F), blood pressure is 110/50 mm Hg, pulse is 102/min, and respirations are 20/min.  Oxygen saturation is 96% on room air.  Cardiac examination reveals an accentuated S2 over the upper left sternal border.  The lungs are clear to auscultation.  There is digital clubbing.  Skin examination findings are shown in the exhibit.  Which of the following is the most likely underlying cause of this patient's dyspnea?

Quizplus · Accepted Answer

11ec160b_3b2f_eb29_9249_85e261273786_MD0001_00 This young adult has a history of recurrent epistaxis, cutaneous telangiectasias, and signs of pulmonary vascular disease. These findings are consistent with hereditary hemorrhagic telangiectasia (HHT) (Rendu-Osler-Weber syndrome). HHT is caused by autosomal dominant mutations of genes involved in angiogenesis (eg, ENG, ACVRL1), leading to multiorgan arteriovenous malformations (AVMs). In the lungs, HHT is associated with pulmonary AVMs, which may present with cyanosis, digital clubbing, hemoptysis, and platypnea (dyspnea aggravated by upright posture). The mechanism of platypnea is a gravitational increase in perfusion through the arteriovenous (AV) communications in the lower lung, worsening V/Q mismatch. HHT can induce pulmonary hypertension (progressive dyspnea, loud P2 [pulmonic component of S2]) in some patients. This is usually due to extensive systemic AVMs (eg, hepatic) provoking chronic, high-output heart failure (widened pulse pressure, tachycardia) that elevates mean pulmonary arterial pressure. HHT vascular gene mutations can also induce hypertrophic remodeling, leading to occlusion of the small precapillary pulmonary arteries, contributing to development of pulmonary hypertension. (Choice A) Obstructive airway disease (cystic fibrosis, bronchiectasis, chronic obstructive airway disease) may cause digital clubbing and a loud P2 (pulmonary hypertension due to lung disease). However, lung examination would be abnormal (eg, wheezing, decreased air movement). Furthermore, this patient's recurrent epistaxis, cutaneous angiomas, and platypnea are more suggestive of HHT. (Choices B and D) Infective endocarditis may cause digital clubbing and cutaneous lesions. Dermal findings include Osler nodes, Janeway lesions, and splinter hemorrhages. Involvement of the aortic valve can cause aortic regurgitation, resulting in widened pulse pressure and heart failure. However, recurrent epistaxis, telangiectasias, and platypnea are more consistent with HHT. (Choice C) Pulmonary fibrosis can cause progressive dyspnea, digital clubbing, and a loud P2 (pulmonary hypertension due to lung disease). However, idiopathic pulmonary fibrosis affects individuals in late adulthood, and lung examination would reveal inspiratory crackles. Educational objective: Hereditary hemorrhagic telangiectasia presents with mucocutaneous telangiectasias, epistaxis, and visceral arteriovenous malformations (AVMs) (eg, liver, lung, brain). Lung involvement includes pulmonary AVMs (eg, digital clubbing, platypnea) and pulmonary hypertension (eg, a loud P2) due to high-output heart failure from underlying systemic AVMs.

A 31-Year-Old Man Comes to the Office Due to Progressive