Rare diseases · Sign or symptom
Infectious encephalitis
Brain inflammation
HP:0002383
What it means
A disorder of the brain caused by an infectious agent that presents with fever, headache, and an altered level of consciousness. There may also be focal or multifocal neurologic deficits, and focal or generalized seizure activity.
Rare diseases that can present with this42
Very common80–99%
6Sometimes5–29%
20- Alexander disease
- Bacterial toxic-shock syndrome
- Behçet disease
- Cerebral visual impairment
- Congenital enterovirus infection
- Crigler-Najjar syndrome
- Familial hemophagocytic lymphohistiocytosis
- Hartnup disease
and 12 more in this range
Rare1–4%
13- American trypanosomiasis
- Aspergillosis
- Avian influenza
- Brucellosis
- Chikungunya
- Cysticercosis
- Listeriosis
- Microsporidiosis
and 5 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions, and Orphanet separately records 1 disease where this sign is specifically absent. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Tracking symptoms like this for someone? Eleplan keeps symptoms, diagnoses, medications and every specialist in one plan.
Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.