[BNP elevation due to a subdural hematoma - misled by a biomarker].
METHODS
A 73-year-old man with a mechanical aortic valve and a history of congestive heart failure was admitted to our hospital with an unspecifically reduced general condition. Physical examination was normal according to age apart from mechanic valve closure tones and a 2/6 sytolic murmur at Erb's point.


METHODS
Inflammation markers were elevated (leukocytosis 22 100/μl, CRP 22 mg/dl ), there was mild anemia (hemoglobin 9.7 mg/dl) and digitoxin blood level was increased to 56 μg/l (therapeutic range 10-30 μg/l). Because NT-proBNP was highly elevated, further diagnostics focused on cardiac causes of BNP elevation despite missing clinical symptoms. Transesophageal echocardiography was inconspicuous and blood cultures were negative. Therefore an infection of unknown origin or an emerging endocarditis were presumed.


METHODS
Pragmatic treatment with antibiotics and diuretics as well as discontinuation of digitoxin led to normalization of leukocytes, CRP and digitoxin levels. But the patient's general condition deteriorated further, NT-proBNP rose to 37731 pg/ml and the patient became disoriented. On thorough questioning the patient's relatives stated that he had fallen 6 weeks previously. Computed tomography then revealed a large chronic subdural hematoma which had caused the NT-proBNP elevation. The patient was operated successful.


CONCLUSIONS
In patients with elevated BNP and atypical symptoms neurological causes should be considered.
Klinik für Kardiologie, Klinikum Oldenburg gGmbH.
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Elsässer
D000368:Aged; D015415:Biomarkers / Q000097:blood; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000517:prevention & control*; D005189:False Positive Reactions; D006408:Hematoma, Subdural / Q000097:blood* / Q000175:diagnosis*; D006801:Humans; D007249:Inflammation / Q000097:blood* / Q000175:diagnosis*; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*
D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain