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Volume 98, Number 1 >
Pp. 24-25
Derriford Hospital, Plymouth PL6 8DH, UK
Correspondence to: Dr K M Evans, c/o Dr Chong's secretary, Level 9, Derriford Hospital, Plymouth PL6 8DH, UK E-mail: kme{at}doctors.org.uk
Non-bacterial thrombotic endocarditis is a complication of acute disorders such as septicaemia and burns, but the most common underlying condition is malignant disease.
CASE HISTORY
A woman of 55 came to hospital after an acute confusional episode, preceeded by ten days of lethargy, anorexia and chest and abdominal pains. She had a history of hypothyroidism and vitiligo, and was taking thyroxine.
On examination she was alert and afebrile. The only noteworthy finding was mild suprapubic tenderness. Her neutrophil count was 12.2 x 102/L and C-reactive protein was high (299 mg/L). When ward urinalysis proved abnormal she was started on levofloxacin for a presumed urinary tract infection. Subsequently, the chest radiograph showed a right upper lobe wedge-shaped opacification, felt to be consistent with tumour, consolidation or infarction. CT of the thorax was therefore arranged. Forty-eight hours later she became feverish and confused and developed a dense left hemiparesis. CT of the head revealed two separate infarcts, in the right middle cerebral artery territory and the right cerebellar hemisphere. There were no features of cerebral metastases. When a transthoracic echocardiogram revealed no cardiac source of emboli, transoesophageal echocardiography was arranged, but two days later the patient deteriorated, with a fall in the level of consciousness and development of a right hemiparesis. Repeat CT of the head now revealed a third infarct, in the left middle cerebral artery territory. Total body CT showed extensive pulmonary consolidation of the right upper lobe, thrombus in both right and left pulmonary arteries, and multiple renal and splenic infarcts, but no evidence of malignancy.
The differential diagnosis included infective endocarditis with septic emboli and a systemic vasculitis. For the former possibility she was treated with intravenous benzylpenicillin and gentamicin, and for the latter she received three pulses of intravenous methylprednisolone. There was no neurological improvement and subsequent immunological investigations offered no support for diagnosis of a vasculitic process. Transoesophageal echocardiography revealed a 1.2 cm mobile non-calcified mass on a structurally normal mitral valve consistent with a vegetation. The patient remained febrile with a rising neutrophil count and C-reactive protein, but extensive microbiological investigations yielded no causal organism. Non-bacterial thrombotic endocarditis was considered the most likely diagnosis.
Over the next two weeks she was kept on intravenous antibiotics and anticoagulated, receiving enteral feeding and full supportive care. There was no neurological recovery over this time. A further embolic event occurred with development of an acutely ischaemic leg. After extensive discussion with her family and the specialists concerned (cardiology, neurology, haematology, microbiology) it was decided that further interventions (tunnelled intravenous access, percutaneous gastrostomy placement, mitral valve replacement) would not be in the patient's best interests. Treatment was withdrawn and she died soon afterwards. At necropsy the diagnosis of non-bacterial thrombotic endocarditis was confirmed, vegetations being present on the mitral and aortic valves. Embolic infarcts were found in brain, kidneys, spleen, lungs, heart and adrenals. Disseminated carcinomatosis was evident, with a mass in the right lung surrounded by an extensive area of infarcted lung parenychma accounting for the CT appearances. Histological examination showed this to be a poorly differentiated adenocarcinoma.
COMMENT
Non-bacterial thrombotic endocarditis, variously termed marantic, Libman–Sacks or verrucous endocarditis, typically occurs in the setting of malignancy, most commonly lung adenocarcinoma.1 It is also seen in other states of hypercoagulability, for example antiphospholipid syndrome,2 and in acute conditions such as burn injury.3 Antemortem diagnosis is rare, but in postmortem series of cancer patients the prevalence has been as high as 1.3%;1,4 even this may be an underestimate since the verrucae are friable and embolize easily, so that little of them may remain on the valves at postmortem.5
Clinical diagnosis is difficult, since there are no pathognomonic features and cardiac mumurs may be absent. Echocardiography is currently the most useful diagnostic investigation, to be followed by transoesophageal echocardiography if appearances are normal but clinical suspicion is high. The vegetations are predominantly left-sided masses situated on structurally normal valves.6 Cerebral embolic events are the most common manifestation,5 and imaging typically shows multiple disseminated strokes of heterogeneous sizes.7 Sometimes the condition is hard to distinguish from a vasculitic process. Treatment is directed at the underlying disease.
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