Cerebritis is a term that represents inflammation of the brain in the setting of infection, before the development of a cerebral abscess.
Cerebritis is essentially the same as encephalitis except that it is used to denote brain parenchymal inflammation secondary to infection with bacteria or other non-viral pathogens. In contrast, encephalitis usually is assumed to denote inflammation due to a virus or paraneoplastic/autoimmune process 1.
Cerebritis is divided into early and late phases and lasts typically 10-14 days depending on the virulence of the pathogen 3.
Early cerebritis is usually a relatively short-lived phenomenon (2-3 days), representing edema, vascular congestion and coagulative necrosis 1,2.
Late cerebritis represents progressive infection, such that areas of the brain undergo liquefactive necrosis. It occurs at approximately 1 week from initial infection.
Late cerebritis may progress and organize to form a cerebral abscess, where a capsule of granulation tissue lines a cavity containing purulent material 1,2. This may occur approximately 2 weeks from initial infection.
- may appear normal by CT
- poorly marginated cortical or subcortical hypodensity with mass effect, corresponding to edema
- little or absence of enhancement
- +/- small areas of hemorrhage
- more defined, but still irregular, rim-enhancing lesion with a hypodense center
MRI is more sensitive to the early changes of cerebritis and will demonstrate the signal changes expected for an area of inflammation 1:
- T1: iso- to hypointense
- T2/FLAIR: increased signal with surrounding vasogenic edema
- T1 C+: no or minimal heterogeneous enhancement
- DWI/ADC: restricted diffusion, may be patchy
- progressive, especially peripheral, enhancement (not well-defined vs abscess)
- progressive restricted diffusion
Treatment and prognosis
In most cases cerebritis has progressed to cerebral abscess by the time the diagnosis is made; however, if detected early enough, medical management with antibiotics can successfully treat cerebritis 2.
- 1. Scott W. Atlas. Magnetic Resonance Imaging of the Brain and Spine. (2016) ISBN: 9781469873268
- 2. Toshio Moritani, Sven Ekholm, Per-Lennart A. Westesson. Diffusion-Weighted MR Imaging of the Brain. (2009) ISBN: 9783540787853
- 3. Maximilian F Reiser, Wolfhard Semmler, Hedvig Hricak. Magnetic Resonance Tomography. (2007) ISBN: 9783540293552
Related Radiopaedia articles
Infections of the central nervous system
- classification by etiology
- Eastern equine encephalitis
- enterovirus rhombencephalitis
- flavivirus encephalitis
herpes virus family
- herpes simplex virus 1 (HSV-1) encephalitis
- herpes simplex virus 2 (HSV-2) encephalitis
- varicella zoster virus (VZV) encephalitis
- Epstein-Barr virus (EBV) encephalitis
- cytomegalovirus (CMV) encephalitis
- human herpesvirus 6 (HHV-6) encephalitis
- HIV CNS manifestations
- HTLV-1-associated myelopathy
- JC virus
- measles encephalitis
- Nipah virus (NiV) encephalitis
- rabies encephalitis
- 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)
- cerebral amoebiasis
- cerebral malaria (Plasmodium falciparum)
- cerebral sparganosis (Spirometra mansonoides)
- neurocysticercosis (Taenia solium)
- neurohydatidosis (Echinococcus spp)
- neurotoxoplasmosis (Toxoplasma gondii)
- others or those with possible infectious etiologies
- classification by location
- classification by etiology