Intracranial empyemas
Dariusz J. Jaskólski
An intracranial empyema is a sub- or epidural collection of pus. Subdural empyema comes frequently as a sequela of ENT infections, meningitis or neurosurgical procedures, and rarely as a result of hematogenous spread, whereas epidural one usually coexists with osteomyelitic flap in patients after surgery. A typical clinical picture consists of fever, meningeal irritation, symptoms of raised intracranial pressure including somnolence or coma, neurological deficit and seizures. Establishing the diagnosis requires radiological studies, preferably MRI including diffusion weighted images. Surgical treatment allows drainage of pus and obtaining samples for Gram stain and culture assessment. Craniectomy relieves raised intracranial pressure. Up-to-date there has been no randomised controlled clinical trial comparing three applicable methods of surgery: burr hole aspiration, craniotomy and craniectomy. Currently, the average mortality rate in subdural empyema is 10–20%, however, it does not exceed 5% in patients in good general condition on admission, reaching up to 75% in unconscious ones. Delayed diagnosis and treatment brings about a significant risk of permanent neurological deficit. Possible complications involve: herniation, ischaemic stroke, venous sinus thrombosis, cranial osteomyelitis, cerebral abscess, septic shock, hydrocephalus and epilepsy. The last-named has been reported in as many as 42% of patients after subdural empyema.