Meningitis - Acute, Bacterial Differential Diagnosis

Differential Diagnosis

The following diseases should be ruled out in the diagnosis of acute bacterial meningitis:  

• Viral meningitis, if the CSF exam may reveal a polymorphonuclear response of ≤60%
• Rocky Mountain spotted fever, if CSF cell counts >100/μL (>70% polymorphonuclear)
• Acute subarachnoid hemorrhage, when a more abrupt onset is noted without a prodromal fever and the presence of subarachnoid blood on CT scan or CSF examination
• Neuroleptic malignant syndrome, if with the presence of markedly elevated creatine kinase level
• Non-infectious diseases such as Henoch-Schönlein purpura, acute hemorrhagic edema of infancy, idiopathic thrombocytopenic purpura, collagen vascular disease, and neoplastic processes