Primary pulmonary hypertension is uncommon and a diagnosis of exclusion. This patient’s occupational history provided the key to his diagnosis.
A 59-year-old male noted dyspnea while playing golf in 2001. He ultimately had a pre-syncopal episode associated with chest pressure at work in 2002. He was hospitalized and an echocardiogram revealed normal left ventricular function and a dilated right ventricle. He underwent left and right heart catheterization that showed a pulmonary artery pressure of 63/29 mmHg and a mean of 43 mmHg. His pulmonary capillary wedge pressure was 10 mmHg. He had no coronary artery disease. An extensive investigation as to the cause of his pulmonary hypertension was unrevealing. Spirometry and lung volumes were normal. However, he had a reduced diffusion capacity of 37% predicted. His radiographic evaluation included a negative ventilation/perfusion lung scan and a high-resolution chest computed tomogram was without evidence of parenchymal lung disease. Work-up for an underlying connective tissue disease was negative. Serologies for HIV and hepatitis were negative. A sleep study was normal. His past medical history was non-contributory. His occupational history was notable for heavy exposure to a laminate containing toluene. For 15 months he worked with this material in a small, poorly ventilated room. Visitors to his work site often commented on the strong fumes present. He observed a temporal relationship between his symptoms and working with the glue. He was diagnosed with pulmonary arterial hypertension (PAH) due to toluene exposure. Currently, he is being treated with bosentan, diltiazem, and coumadin. He requires oxygen therapy for exertional desaturations. His pulmonary arterial pressure remains elevated although his chronic sinus symptoms resolved when he left his work site. His exercise tolerance and echocardiographic findings have improved on bosentan and away from toluene.
This patient’s occupational history reveals important diagnostic clues about the cause of his PAH. He had heavy exposure to a laminate adhesive containing 5-15% toluene by weight. Review of the medical literature between 1966-2004 found no reports of PAH due to occupational toluene exposure. However, toxicologic information on toluene inhalation is available in the context of glue sniffing; these health effects are separated into acute and chronic toxicities. This patient’s history is consistent with both. Acutely the patient developed dyspnea while at work and this prompted his medical evaluation. Several reports of glue sniffers presenting with acute shortness of breath are published (Cronk 1985, Schikler 1984). An additional case report describes an infant who developed acute respiratory failure associated with echocardiographic pulmonary hypertension following ingestion of paint thinner containing toluene (Dauger 2003). This case is also consistent with chronic toxicity from glue inhalation. Eighteen adolescents who chronically abused adhesives containing toluene underwent extensive medical evaluations. Reduced diffusion capacity was seen in 33% (6 of 18 people) and right ventricular dilation on echocardiogram was noted in 28% (5 of 18 people) (Devathasan 1984). This patient manifests both these findings.
This is the first case of occupational-associated PAH due to toluene exposure reported in the literature. It underscores the necessity of obtaining a thorough occupational history when evaluating patients with pulmonary hypertension.
D.W. Ford, None.