Leptomeningitis
Leptomeningitis, which is more commonly referred to as meningitis, represents inflammation of the subarachnoid space (i.e. arachnoid mater and pia mater) caused by an infectious or noninfectious process.
On this page:
Pathology
Etiology
Infective
-
pyogenic meningitis
- elderly
- Streptococcus pneumoniae
- Listeria monocytogenes
- Neisseria meningitidis
- Gram negative bacilli
- adults
- Streptococcus pneumoniae
- Neisseria meningitidis
- Group B streptococcus
- children
- Neisseria meningitidis
- infants
- Streptococcus pneumoniae
- Neisseria meningitidis
- neonates
- Group B streptococcus
- Escherichia coli
- Listeria monocytogenes
- elderly
-
viral meningitis
- Enterovirus
- JC virus meningitis
- mycobacterial meningitis
- Mycobacterium tuberculosis
- fungal meningitis
- Cryptococcus neoformans (in patients with AIDS)
- Coccidioides immitis
For a further discussion related to other etiological agents and other infective processes in the CNS, please refer to CNS infectious diseases.
Aseptic meningitis
- leptomeningeal carcinomatosis
- rheumatoid arthritis 2
- granulomatous
- iatrogenic
- postoperative 4
- hydrogel-coated aneurysm coils 3
Radiographic features
CT
- may be normal
- subtle hydrocephalus
- hyperdensity around basal cisterns (especially in tuberculosis)
- leptomeningeal enhancement
- complications or sources of the meningitis
MRI
- T1: may be normal; sulci may appear less hypointense than normal
- T1 C+ (Gd): leptomeningeal enhancement
- FLAIR: demonstrates hyperintense signal in CSF space, especially in the sulci
- FLAIR C+ (Gd): has shown to be more sensitive and specific than T1 C+ (Gd) sequence in spotting leptomeningeal enhancement 6
- MR angiography: arterial narrowing or occlusion
Treatment and prognosis
Complications
- hydrocephalus
- subdural empyema
- epidural empyema
- cerebritis and cerebral abscess
- infarction
- ventriculitis
- dural sinus thrombosis
The complications of meningitis can be remembered using the mnemonic HACTIVE.
See also
Related Radiopaedia articles
Infections of the central nervous system
-
CNS infections
- classification by etiology
- viral
- Eastern equine encephalitis
- enterovirus rhombencephalitis
- flavivirus encephalitis
- herpes virus family
- HIV CNS manifestations
- HTLV-1-associated myelopathy
- JC virus
- measles encephalitis
- Nipah virus (NiV) encephalitis
- rabies encephalitis
- bacterial
- CNS listeriosis (Listeria monocytogenes)
- CNS nocardiosis (Nocardia spp)
- CNS tuberculosis (Mycobacterium tuberculosis)
- Lyme disease (Borrelia burgdorferi)
- neurosyphilis (Treponema pallidum)
- Rocky Mountain spotted fever (Rickettsia rickettsii)
- fungal
- CNS aspergillosis (Aspergillus spp)
- CNS coccidioidomycosis (Coccidioides immitis)
- CNS cryptococcosis (Cryptococcus neoformans)
- CNS mucormycosis (order Mucorales)
- neurocandidiasis (Candida spp)
- parasitic
- cerebral amoebiasis
- primary amoebic meningoencephalitis (Naegleria fowleri)
- granulomatous amoebic encephalitis (Acanthamoeba spp, Balamuthia mandrillaris and Sappinia pedata)
- cerebral malaria (Plasmodium falciparum)
- cerebral sparganosis (Spirometra mansonoides)
- neurocysticercosis (Taenia solium)
- neurohydatidosis (Echinococcus spp)
- neurotoxoplasmosis (Toxoplasma gondii)
- cerebral amoebiasis
- prion
- others or those with possible infectious etiologies
- acute necrotizing encephalopathy of childhood
- encephalitis lethargica
- hemorrhagic shock and encephalopathy syndrome
- Mollaret meningitis (idiopathic recurrent meningitis)
- Rasmussen encephalitis
- viral
- classification by location
- extra-axial
- intra-axial
- classification by etiology
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