Bacteria in the Median Sulcus: Neurological Catastrophe

The median sulcus (interhemispheric/longitudinal fissure) separates the cerebral hemispheres, housing the falx cerebri and superior sagittal sinus. It is not a normal site for bacterial colonization.

When bacteria access this space—via hematogenous spread, direct extension from sinusitis/otitis, trauma, or neurosurgery—catastrophic complications follow:

1. Meningitis

Leptomeningeal infection → CSF pleocytosis, sepsis, cranial nerve palsies, infarcts, hydrocephalus. Mortality 15–30% despite antibiotics.

2. Encephalitis / Cerebritis

Parenchymal invasion → edema, seizures, focal deficits, coma. Bacterial suppurative encephalitis possible.

3. Subdural / Epidural Empyema

Pus between dura and arachnoid (subdural) or dura and skull (epidural). Mass effect, venous infarction from cortical vein thrombosis. Requires surgical drainage + IV antibiotics.

4. Brain Abscess

Encapsulated intracerebral pus. Ring-enhancing lesion on MRI. Stereotactic aspiration/excision + 6–8 weeks IV antibiotics.

5. Septic Sagittal Sinus Thrombosis

Infection spreads to superior sagittal sinus → venous hypertension, bilateral hemorrhagic infarcts, cranial neuropathies. High mortality.

6. Global Neurological Decline

Persistent inflammation, seizures, hydrocephalus → cognitive impairment, dementia.

Immediate neurosurgical + infectious disease consultation is mandatory. Empiric IV vancomycin + ceftriaxone + metronidazole ± acyclovir pending cultures.