Encephalitis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Common encephalidites include:

### Viral encephalitis[edit | edit source]

* Herpes simplex encephalitis
* VZV encephalitis
* Nipah virus encephalitis

### Vector-borne encephalitis[edit | edit source]

* Tick-borne encephalitis
* California encephalitis
* Eastern equine encephalitis
* Western equine encephalitis
* Japanese encephalitis
* Venezuelan equine encephalitis
* West Nile encephalitis
* La Crosse encephalitis
* St. Louis encephalitis

### Fungal encephalitis[edit | edit source]

### Protozoan encephalitis[edit | edit source]

* Granulomatous amebic encephalitis
* Toxoplasmic encephalitis

### Bacterial encephalitis[edit | edit source]

## Differential diagnosis[edit | edit source]

Encephalitis must be differentiated from other causes of headache, seizures and loss of consciousness.

Diseases | Symptoms  | Physical Examination | Past medical history | Diagnostic tests | Other Findings

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Headache | ↓LOC | Motor weakness | Abnormal sensory | Motor Deficit | Sensory deficit | Speech difficulty | Gait abnormality | Cranial nerves | CT /MRI | CSF Findings | Gold standard test
Meningitis | \+  | \-  | \-  | \-  | \-  | \+  | \+  | \-  | \-  | History of fever and malaise | \-  | ↑ Leukocytes,

↑ Protein

↓ Glucose

| CSF analysis[1] | Fever, neck

rigidity

Encephalitis | \+  | \+  | +/-  | +/-  | \-  | \-  | \+  | +/-  | \+  | History of fever and malaise | \+  | ↑ Leukocytes, ↓ Glucose  | CSF PCR | Fever, seizures, focal neurologic abnormalities
Brain tumor[2] | \+  | \-  | \-  | \-  | \+  | \+  | \+  | \-  | \+  | Weight loss, fatigue | \+  | Cancer cells[3] | MRI  | Cachexia, gradual progression of symptoms
Hemorrhagic stroke | \+  | \+  | \+  | \+  | \+  | \+  | \+  | \+  | \-  | Hypertension | \+  | \-  | CT scan without contrast[4][5] | Neck stiffness
Subdural hemorrhage | \+  | \+  | \+  | \+  | \+  | \-  | \-  | \-  | \+  | Trauma, fall  | \+  | Xanthochromia[6] | CT scan without contrast[4][5] | Confusion, dizziness, nausea, vomiting
Neurosyphilis[7][8] | \+  | \-  | \+  | \+  | \+  | \+  | \-  | \+  | \-  | STIs  | \+  | ↑ Leukocytes and protein | CSF VDRL-specifc

CSF FTA-Ab -sensitive[9]

| Blindness, confusion, depression,

Abnormal gait

Complex or atypical migraine | \+  | \-  | \+  | \+  | \-  | \-  | \+  | \-  | \-  | Family history of migraine | \-  | \-  | Clinical assesment  | Presence of aura, nausea, vomiting
Hypertensive encephalopathy | \+  | \+  | \-  | \-  | \-  | \-  | \+  | \+  | \-  | Hypertension | \+  | \-  | Clinical assesment  | Delirium, cortical blindness, cerebral edema, seizure
Wernicke’s encephalopathy | \-  | \+  | \-  | \-  | \-  | \+  | \+  | \+  | \+  | History of alcohal abuse  | \-  | \-  | Clinical assesment and lab findings  | Ophthalmoplegia, confusion
CNS abscess | \+  | \+  | \-  | \-  | \+  | \+  | \+  | \-  | \-  | History of drug abuse, endocarditis, immunosupression | \+  | ↑ leukocytes, ↓ glucose and ↑ protien  | MRI is more sensitive and specific  | High grade fever, fatigue,nausea, vomiting
Drug toxicity | \-  | \+  | \-  | \+  | \+  | \+  | \-  | \+  | \-  | \-  | \-  | \-  | Drug screen test  | Lithium, Sedatives, phenytoin, carbamazepine
Conversion disorder | \+  | \+  | \+  | \+  | \+  | \+  | \+  | \+  |  | History of emotional stress | \-  | \-  | Diagnosis of exclusion  | Tremors, blindness, difficulty swallowing
Metabolic disturbances (electrolyte imbalance, hypoglycemia)  | \-  | \+  | \+  | \+  | \+  | \+  | \-  | \-  | \+  | \-  | \-  | Hypoglycemia, hypo and hypernatremia, hypo and hyperkalemia | Depends on the cause  | Confusion, seizure, palpitations, sweating, dizziness, hypoglycemia
Multiple sclerosis exacerbation  | \-  | \-  | \+  | \+  | \-  | \+  | \+  | \+  | \+  | History of relapses and remissions  | \+  | ↑ CSF IgG levels

(monoclonal bands)

| Clinical assesment and MRI [10] | Blurry vision, urinary incontinence, fatigue
Seizure | \+  | \+  | \-  | \-  | \+  | \+  | \-  | \-  | \+  | Previous history of seizures | \-  | Mass lesion  | Clinical assesment and EEG [11] | Confusion, apathy, irritability,

## Comprehensive List of Causes of Encephalitis & Encephalopathy[edit | edit source]

Cardiovascular | Kawasaki disease

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Chemical / poisoning | Arsenic, heavy metal toxicity, icaridin, organophosphate poisoning, poison hemlock, thallium
Dermatologic | Behcet disease, systemic lupus erythematosus, Vogt-Koyanagi-Harada syndrome
Drug Side Effect | Acyclovir, interferon, kynurenic acid, levodopa, methamphetamine, trimethobenzamide, zanamivir
Ear Nose Throat | Cholesteatoma, labyrinthitis, sinusitis
Endocrine | Myasthenia gravis
Environmental | No underlying causes
Gastroenterologic | Porphyria, Reye's syndrome
Genetic | Aicardi-Goutières syndrome, biotinidase deficiency, familial histiocytic reticulosis, hemophagocytic reticulosis, ornithine transcarbamylase deficiency, porphyria, Smith disease, Tourette syndrome
Hematologic | Familial histiocytic reticulosis, hemophagocytic reticulosis, lymphoproliferative syndrome, porphyria, x-linked agammaglobulinemia
Iatrogenic | No underlying causes
Infectious Disease | alkhurma virus, Borrelia burgdorferi, botulism, brome mosaic virus, California encephalitis virus, campylobacter fetus, capnocytophaga canimorsus, cardiovirus, cat scratch disease, cercopithecine herpesvirus 1, Chagas disease, chandipura virus, chicken pox, coccidioides spp, Colorado tick fever, congenital herpes simplex, congenital rubella syndrome, congenital syphilis, coxiella burnetii , coxsackievirus, Creutzfeldt-Jakob disease, cryptococcosis, cryptococcus neoformans, cysticercosis, cytomegalovirus, dengue fever, diphtheria, duvenhage virus, Eastern equine encephalitis virus, Ebstein-Barr virus, ehrlichia chaffeensis, ehrlichiosis, elizabethkingia meningoseptica, enterobacter sakazakii, enterovirus 70, enterovirus 71, enteroviruses, escherichia coli, feline viral rhinotracheitis, fetal parainfluenza virus type 3, flavivirus infections, flu, gnathostoma hispidum infection, gnathostoma spinigerum, gnathostoma spinigerum infection, gnathostomiasis, streptococcus, group B, haemophilus influenzae, hand-foot-and-mouth disease, hantavirosis , hemorrhagic fever, hendra virus, henipavirus, hepatitis E virus, herpes B virus, herpes simplex virus, histoplasma capsulatum, HIV, human granulocytotrophic ehrlichiosis, human herpesvirus 6, human monocytotrophic ehrlichiosis, immunosuppressive measles encephalitis, infectious canine hepatitis, influenza virus, Japanese encephalitis, JC virus, klebsiella, kumlinge virus encephalitis, kunjin virus, La Crosse encephalitis, labyrinthitis, lassa fever, listeria monocytogenes, listeriosis , louping ill, Lyme disease, lymphocytic choriomeningitis, lyssavirus, malaria, measles, mokola virus, mononucleosis , mumps , mumps virus, Murray Valley encephalitis virus, mycobacterium avium-intracellulare, mycobacterium tuberculosis, mycoplasma pneumoniae, naegleria fowleri, neisseria meningiditis, neonatal herpes, nipah virus, nocardia, pertussis, phlebovirus, pneumococcus, poliomyelitis, pontiac fever, Powassan virus, poxviridae disease, primary amoebic meningoencephalitis , primary encephalitis, progressive multifocal leukoencephalopathy, pseudomonas aeruginosa, psittacosis, Q fever, Queensland tick typhus, rabies, Rasmussen's encephalitis, rickettsiae, Rift Valley fever, rocio encephalitis, Rocky Mountain spotted fever, rubella, salmonella typhi, schistosoma japonicum, secondary encephalitis, shingles, Simian B virus infection, sinusitis, St. Louis encephalitis, staphylococcus aureus, streptococcus pneumoniae, streptococcus suis, subacute sclerosing panencephalitis, taenia solium, tick-borne encephalitis, togaviridae disease, TORCH syndrome, toxocariasis, toxoplasma gondii, toxoplasmosis, trench fever, treponema pallidum, trichinella, trichinosis, tropheryma whipplei, trypanosoma brucei gambiense, trypanosomiasis, typhoid fever, vaccinia, varicella zoster, varicella zoster virus, Venezuelan equine encephalitis, viral encephalitis, visna virus, West Nile fever, Western equine encephalitis, whooping cough, yersinia pestis
Musculoskeletal / Ortho | Metabolic myopathies, multiple sclerosis, skull fracture
Neurologic | Aicardi-Goutières syndrome, amyotrophic lateral sclerosis, aseptic meningitis, cauda equina syndrome, cerebral palsy, chronic inflammatory demyelinating polyneuropathy, conus medullaris, Creutzfeldt-Jakob disease, Lennox-Gastaut syndrome, multiple sclerosis, opsoclonus myoclonus syndrome, paraneoplastic neurologic disorders, poliomyelitis, progressive multifocal leukoencephalopathy, Rasmussen syndrome, Schilder's disease, St. Louis encephalitis, status epilepticus, subacute sclerosing panencephalitis, temporal lobe epilepsy, Tourette syndrome, tourettism, Vogt-Koyanagi-Harada syndrome
Nutritional / Metabolic | Biotinidase deficiency, metabolic myopathies, ornithine transcarbamylase deficiency
Obstetric/Gynecologic | TORCH syndrome
Oncologic | Paraneoplastic neurologic disorders
Opthalmologic | Vogt-Koyanagi-Harada syndrome
Overdose / Toxicity | Heavy metal toxicity, Reye's syndrome
Psychiatric | Progressive multifocal leukoencephalopathy, shaken baby syndrome, Tourette syndrome
Pulmonary | Flu, pertussis, whooping cough
Renal / Electrolyte | Systemic lupus erythematosus
Rheum / Immune / Allergy | Behcet disease, chronic inflammatory demyelinating polyneuropathy, multiple sclerosis, systemic lupus erythematosus, x-linked agammaglobulinemia
Sexual | No underlying causes
Trauma | Cauda equina syndrome, shaken baby syndrome, skull fracture
Urologic | No underlying causes
Miscellaneous | Porphyria

1. ↑ Carbonnelle E (2009). "[Laboratory diagnosis of bacterial meningitis: usefulness of various tests for the determination of the etiological agent]". Med Mal Infect. 39 (7–8): 581–605. doi:10.1016/j.medmal.2009.02.017. PMID 19398286.
2. ↑ Morgenstern LB, Frankowski RF (1999). "Brain tumor masquerading as stroke". J Neurooncol. 44 (1): 47–52. PMID 10582668.
3. ↑ Weston CL, Glantz MJ, Connor JR (2011). "Detection of cancer cells in the cerebrospinal fluid: current methods and future directions". Fluids Barriers CNS. 8 (1): 14. doi:10.1186/2045-8118-8-14. PMC 3059292. PMID 21371327.CS1 maint: Multiple names: authors list (link)
4. ↑ 4.0 4.1 Birenbaum D, Bancroft LW, Felsberg GJ (2011). "Imaging in acute stroke". West J Emerg Med. 12 (1): 67–76. PMC 3088377. PMID 21694755.CS1 maint: Multiple names: authors list (link)
5. ↑ 5.0 5.1 DeLaPaz RL, Wippold FJ, Cornelius RS, Amin-Hanjani S, Angtuaco EJ, Broderick DF; et al. (2011). "ACR Appropriateness Criteria® on cerebrovascular disease". J Am Coll Radiol. 8 (8): 532–8. doi:10.1016/j.jacr.2011.05.010. PMID 21807345.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link)
6. ↑ Lee MC, Heaney LM, Jacobson RL, Klassen AC (1975). "Cerebrospinal fluid in cerebral hemorrhage and infarction". Stroke. 6 (6): 638–41. PMID 1198628.CS1 maint: Multiple names: authors list (link)
7. ↑ Liu LL, Zheng WH, Tong ML, Liu GL, Zhang HL, Fu ZG; et al. (2012). "Ischemic stroke as a primary symptom of neurosyphilis among HIV-negative emergency patients". J Neurol Sci. 317 (1–2): 35–9. doi:10.1016/j.jns.2012.03.003. PMID 22482824.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link)
8. ↑ Berger JR, Dean D (2014). "Neurosyphilis". Handb Clin Neurol. 121: 1461–72. doi:10.1016/B978-0-7020-4088-7.00098-5. PMID 24365430.
9. ↑ Ho EL, Marra CM (2012). "Treponemal tests for neurosyphilis--less accurate than what we thought?". Sex Transm Dis. 39 (4): 298–9. doi:10.1097/OLQ.0b013e31824ee574. PMC 3746559. PMID 22421697.
10. ↑ Giang DW, Grow VM, Mooney C, Mushlin AI, Goodman AD, Mattson DH; et al. (1994). "Clinical diagnosis of multiple sclerosis. The impact of magnetic resonance imaging and ancillary testing. Rochester-Toronto Magnetic Resonance Study Group". Arch Neurol. 51 (1): 61–6. PMID 8274111.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link)
11. ↑ Manford M (2001). "Assessment and investigation of possible epileptic seizures". J Neurol Neurosurg Psychiatry. 70 Suppl 2: II3–8. PMC 1765557. PMID 11385043.