Clinical History
A 71-year-old male patient developed infective endocarditis, which required immediate surgical intervention. He also developed neurological signs postoperatively. An emergency CT of his brain was
performed for further investigation.
Imaging Findings
The patient, who was diagnosed two years ago with asymptomatic mitral valve incompetence, was admitted to the hospital in an acute confused state, which progressed rapidly to septic shock. Blood
cultures grew staphylococcus aureus. A trans-oesophageal echocardiogram was taken, which demonstrated mitral valve vegetations. The patient underwent emergency mitral and aortic valve replacements,
the latter owing to an abscess associated with the aortic valve. For a few days post-operatively he had a fluctuating level of consciousness, generalized weakness but no definite focal neurological
signs. Over the next two weeks, his condition was felt to be slowly improving and he continued to have no definite neurological signs. His medication at this time included broad spectrum antibiotics
and heparin. His heparin was in the accepted treatment range. He then, over a course of a few hours, became increasingly drowsy and developed a left third cranial nerve palsy. An emergency CT scan of
the head was performed. The unenhanced CT demonstrated the presence of a large mass in the right fronto-parietal lobe, which had a fluid–fluid level with acute haemorrhage layering posteriorly.
Some surrounding cerebral oedema and mass effect with midline shift to the right was noted. Blood was also seen in the posterior horn of the left lateral ventricle. The differential diagnosis for the
appearances includes haemorrhage into a cystic neoplasm or haemorrhage into a cerebral abscess – particularly given the clinical history. No neurosurgical intervention was performed and he died
the next day. A postmortem confirmed the presence of a cerebral abscess with haemorrhage. There was a left temporal lobe cavity filled with clotted blood and a focus of organizing purulent material.
The focus contained colonies of gram positive cocci. The white matter lining the cavity was granular and haemorrhagic.
Discussion
Haemorrhage into an abscess cavity or the wall of the cavity is extremely rare and may cause confusion in the diagnosis. However, haemorrhage into the wall of a cystic neoplasm is not uncommon. MRI
may help in the diagnosis. In haemorrhagic cystic neoplasms, there may be mixed stages of haematoma, tumour tissue, an absent or very irregular low signal ring and persistent peripheral high signal.
However, these signs are non-specific and clinical history is essential. The wall of an abscess contains newly formed thin vessels and it is possible that with increasing intra-cranial pressure these
ruptures might cause the haemorrhage. Therefore, although haemorrhage into a brain abscess is rare, the diagnosis should be considered in appropriate clinical settings.
Differential Diagnosis List
Brain abscess with haemorrhagic transformation.
Final Diagnosis
Brain abscess with haemorrhagic transformation.
