Transient pulmonary hypertension mediated by vasoconstriction and hypoxia with over perfusion of certain regions of the pulmonary vascular bed is thought to contribute to the development of high altitude pulmonary edema (HAPE). Patients with pulmonary vascular abnormalities demonstrate an increased susceptibility to HAPE. We report a case of a woman who presented with fibrosing mediastinitis with complete occlusion of the left pulmonary artery and unilateral HAPE.
A 40 year-old woman with polycystic kidney disease, hypertension and mitral valve prolapse, flew to Colorado on vacation. She is originally from Indiana but move to Houston 10 years ago. Upon arrival to Denver, the patient experienced headache and nausea but continued to travel 5 hours by car to Aspen. Her symptoms persisted. She experienced an episode of dizziness, without loss of consciousness, lasting about 10 seconds. The following day, the patient went up to an elevation of 3000 meter. She became dyspneic at rest and had productive cough of pinkish sputum. The patient returned to the hotel where her symptoms improved, however her headache and nausea persisted, promptly returning to Houston. Her symptoms of nausea and dyspnea on exertion persisted, and sought medical attention. On admission, she was hypoxemic with an oxygen saturation of 94% on 4 liters at rest, and crackles in the right mid lung zone. Ultrasound was negative for DVT. Chest radiograph revealed a right lung alveolar infiltrate with left hilar calcification. Chest CT PA demonstrated abrupt termination of the left pulmonary artery at the level of the left hilum and densely calcified left hilar lymph nodes. No definite left pulmonary artery branches were identified. Alveolar opacities were noted throughout the right lung. Echocardiography was normal without evidence of pulmonary hypertension. A V/Q scan demonstrated lack of perfusion to the left lung with normal ventilation and a matched decreased perfusion and ventilation in the right upper lung without PE in the right lung.
This is a unique case of unilateral right-sided HAPE due to complete occlusion of the left pulmonary artery secondary to fibrosing mediastinitis probably caused by histoplasmosis. In 1997, a case report of a 5-year-old boy who developed unilateral HAPE with left pulmonary artery agenesis. More recently in 2009, a 35 year-old female with worsening headaches, shortness of breath and chest pain was found to have mediastinal fibrosis causing occlusion of the left pulmonary artery without HAPE. HAPE is a life-threatening form of non-cardiogenic pulmonary edema that occurs in healthy individuals at altitudes above 2500m, however, some cases have been reported at lower altitudes. HAPE is characterized by dyspnea secondary to non-cardiogenic pulmonary edema, frequently preceded by symptoms of headache, nausea and vomiting. The improvement in our patient’s symptoms on descent to lower altitude in the absence of therapeutic intervention, suggests a diagnosis of HAPE. Chronic forms of mediastinal fibrosis (MF) include Idiopathic Proliferative Fibrosing Mediastinitis (IPFM) and fibrosing mediastinitis most commonly due to Histoplasma capsulatum. MF is one of the more severe, late complications of infection with histoplasmosis. Post histoplasmosis MF is characterized by calcified fibrosis centered in lymph nodes, which may occlude major vessels or airways. With IPMF, the mass does not usually contain calcifications. Radiographic presence of calcification (greater than 1 cm) carries high specificity of FM due to histoplasmosis. Our patient’s calcification in the left hila was 2.2 cm × 1.2 cm of diameter. The mass in IPMF is usually bulkier and more diffuse than that of MF related to histoplasmosis.
This is a unique case of unilateral HAPE due to complete occlusion of the pulmonary artery secondary to granulomatous fibrosing mediastinitis.
Johan van Jaarsveld, No Financial Disclosure Information; No Product/Research Disclosure Information