The case presents a 75 year old patient, requests a psychiatric evaluation due to the recent onset (three days) of visual and auditory hallucinations, with attention disorder. The psychiatrist classifies the patient’s symptoms as delirium and recommends a cardiologic evaluation, due to breathlessness at mild efforts. Clinical examination reveals lip and extremities cyanosis, voluminous varices on the legs, with an increase in volume of the right calf, tricuspid systolic murmur, stasis hepatomegaly and hepatojugulary reflux. The biochemical and hematological explorations were within normal limits, except for D-dimers and pulse oximetry. The echocardiography reveals pulmonary hypertension; vascular echography shows an old, right-calf venous thrombosis. Corroboration of clinical and paraclinical data leads to the repetitive pulmonary thromboembolism diagnosis. The patient’s evolution has been favorable, during therapy with anticoagulants; his cardiovascular symptoms and signs have improved and the delirium has disappeared after two days of medical therapy.