Meningitis

1-Meningitis could be occurred due to viral or bacterial or by any other causes of brain infection, so we can not really know the cause of meningitis by CT or MRI.

2-Meningitis needs contrast injection to be diagnosed, you will find the following:

-It causes the same effects as the rest of the brain infection.

*Cerebritis or encephalitis according to the type of organism.

*Brain abscess if the organism is bacterial.

*Epi dural / sub dural empyema.

*Hydrocephalus.

*Sinus thrombosis which could cause brain infarction.

*Ventriculitis. 

*Residual effect of meningitis is sub dural hygroma which is similar to sub dural empyema but without enhancement

D.D.of sub dural fluid collection are

Sub dural hematoma(old).

Sub dural empyema.

Sub dural hygroma(sterile sub dural fluid collection).

 

*Meningo-encephalitis when meningitis affect brain parenchyma causing encephalitis. 

3-Do not forget the clinical where the patient is suffering from  fever, neck retraction and so on.