Massive Pulmonary Embolism in a Patient with Undiagnosed Homocystinuria

Background: Homocystinuria is an autosomal recessively inherited defect of methionine catabolism. This rare condition causes abnormal accumulation of homocysteine in the blood and urine that is not typically found in significant quantities. While elevated homocysteine levels can cause damage to multiple organ systems, they most often affect the cardiovascular, musculoskeletal, ocular, and central nervous systems. Nearly 20% of affected individuals who are untreated die from thrombotic complications before the age of 30. Case report: The authors present the case of a 54-year-old man with massive pulmonary emboli and severe pulmonary hypertension secondary to undiagnosed homocystinuria. Conclusion: When dealing with unexplained thrombophilia, it is important to include homocystinuria in the differential diagnosis in order to avoid delayed diagnosis which can be life threatening.