Neurology Book


HSV Encephalitis

Aka: HSV Encephalitis, Herpes Simplex Encephalitis
  1. See Also
    1. Neonatal HSV
    2. Encephalitis
  2. Epidemiology
    1. Most common cause of sporadic focal Encephalitis (1 per 250,000)
    2. HSV is responsible for 10% of Encephalitis cases
    3. Newborns: Onset 2-30 days after delivery
    4. Bimodal distribution of onset
      1. Age under 20 years old (33% of cases)
      2. Age over 50 years old (>50% of cases)
  3. Etiology
    1. Adults
      1. Herpes Simplex Virus Type I
      2. Herpes Simplex Virus Type II (rare)
    2. Neonates
      1. See Neonatal HSV
      2. Perinatal Herpes Simplex Virus Type II transmission
  4. Pathophysiology
    1. Encephalitis (brain inflammation)
    2. HSV Encephalitis causes inflammation, Hemorrhage and edema
    3. Results in brain necrosis and liquefaction
    4. Destructive lesions by HSV infection
      1. Inferior Frontal Lobe
      2. Anterior Temporal Lobe
  5. Precautions
    1. Fever, Headache and neurologic abnormalities should prompt evaluation for Encephalitis
    2. Worse outcomes with delayed diagnosis
    3. Cryptic presentations
      1. Skin vessicles may be absent
      2. Nuchal Rigidity may be absent
      3. Fever alone may be only presenting finding
      4. Neurologic changes may be subtle (mild behavior change or mild cognitive deficits)
  6. Symptoms
    1. Fever
    2. Headache
    3. Irritability and decreased feeding in newborns
    4. Lethargy
    5. Tremors
    6. Focal Seizures
    7. Ataxia
    8. Vomiting
    9. Dysphagia
    10. Altered Mental Status
      1. Behavioral changes
      2. Memory changes
      3. Personality Changes
  7. Labs
    1. See Encephalitis
    2. Lumbar Puncture for CSF
      1. CSF PCR for HSV (gold standard)
        1. Test Sensitivity: 95%
        2. False Negatives occur in first 12 hours and after 10 days
      2. CSF Cell Count
        1. Test Sensitivity: 95% for Pleocytosis at 10-200 cells
        2. Predominantly Lymphocytosis or monocytosis
        3. Xanthochromia and Red Blood Cells may be present
      3. CSF Protein
        1. Increased to 100 mg/dl in 80% of cases
      4. CSF Glucose
        1. Normal to low
  8. Diagnosis
    1. MRI Head imaging
      1. MRI is preferred over CT Head (CT Head is typically normal in first 5 days)
      2. Diffuse edema
      3. Medial temporal and inferior Frontal Lobe necrotic changes on imaging
        1. T1 weighted images - hypointensity
        2. T2 weighted images - hyperintensity
    2. Electroencephalogram (EEG)
      1. Findings localize to frontal and Temporal Lobe
      2. Periodic sharp wave activity temporally
      3. Background of focal or diffuse slowing
  9. Management
    1. See Encephalitis
    2. Acyclovir
      1. Dose (adjust for decreased Renal Function)
        1. Age under 12 years: 20 mg/kg IV every 8 hours
        2. Age over 12 years: 12.5 mg/kg IV every 8 hours
      2. Duration: 14-21 days (or until HSV Encephalitis is excluded)
      3. Directions: Give dose over 60 minutes
      4. Start early, empirically, as soon as diagnosis is considered possible, to maximize best possible outcome
        1. Initially, Acyclovir is also added to Meningitis antibiotic regimen until HSV Encephalitis is excluded
  10. Complications
    1. Dementia
    2. Personality Disorder
    3. Memory Loss
    4. Aphasia
  11. Prognosis
    1. Mortality: 10-40%
      1. Acyclovir has reduced mortality from >70% to <20%
    2. High risk of severe residual neurologic deficit
  12. References
    1. Claudius in Majoewsky (2012) EM:Rap 12(11): 7-8
    2. Fuchs and Yamamoto (2012) APLS, Jones and Bartlett, Burlington, p. 180-3
    3. Herbert and Jhun in Herbert (2014) EM:Rap 14(12):12

Herpes encephalitis (C0276226)

Definition (NCI) A serious viral disorder characterized by infection of the brain by herpes simplex virus type 1 or 2. Herpes simplex virus type 1 affects adults, whereas herpes simplex virus type 2 affects newborns. Signs and symptoms include fever, headaches, vomiting, seizures and psychiatric manifestations.
Definition (MSH) An acute (or rarely chronic) inflammatory process of the brain caused by SIMPLEXVIRUS infections which may be fatal. The majority of infections are caused by human herpesvirus 1 (HERPESVIRUS 1, HUMAN) and less often by human herpesvirus 2 (HERPESVIRUS 2, HUMAN). Clinical manifestations include FEVER; HEADACHE; SEIZURES; HALLUCINATIONS; behavioral alterations; APHASIA; hemiparesis; and COMA. Pathologically, the condition is marked by a hemorrhagic necrosis involving the medial and inferior TEMPORAL LOBE and orbital regions of the FRONTAL LOBE. (From Adams et al., Principles of Neurology, 6th ed, pp751-4)
Concepts Disease or Syndrome (T047)
MSH D020803
ICD10 B00.4
SnomedCT 428638009, 79450003, 192688003, 266100001
English HERPES SIMPLEX ENCEPHALITIS, Herpes encephalitis, HSE - Herpes simplex encephal, HSE - Herpes simplex encephalitis, Herpetic encephalitis, Herpesviral encephalitis, HERPETIC ENCEPH, HERPES ENCEPH, ENCEPH HERPES SIMPLEX, HERPES SIMPLEX ENCEPH, Encephalitis due to Herpesvirus (disorder), Encephalitis due to Herpesviridae, Encephalitis due to Herpesvirus, Herpes simplex encephalitis (diagnosis), Encephalitis, Herpes, Herpes Encephalitis, Encephalitides, Herpes Simplex, Encephalitis, Herpes Simplex, Herpes Simplex Encephalitides, Herpes Simplex Encephalitis, Encephalitides, Herpetic, Encephalitis, Herpetic, Herpetic Encephalitides, Herpetic Encephalitis, Encephalitis, Herpes Simplex [Disease/Finding], encephalitis hsv, herpes simplex encephalitis, hsv encephalitis, encephalitis herpes, herpes encephalitis, herpetic encephalitis, Herpes simplex encephalitis, Herpes encephalitis (disorder), Herpes simplex encephalitis (disorder), Encephalitis herpes, Herpes simplex encephalitis [Ambiguous]
Swedish Hjärninflammation, herpes simplex
Czech encefalitida - herpes simplex, Encefalitida způsobená virem herpes simplex, Herpetická encefalitida
Spanish Encefalitis por Herpes Simplex, Encefalitis por Herpes Simple, encefalitis herpética, encefalitis por virus herpes, encefalitis herpética (trastorno), Encefalitis por herpes simplex, Encefalitis herpética, Meningoencefalitis por el Simplex Virus del Herpes, Meningoencefalitis por el Virus Herpes Simplex
Finnish Herpes simplex -enkefaliitti
Italian Encefalite erpetica, Encefalite da herpes, Encefalite da herpes simplex
German Enzephalitis durch Herpesviren, Herpes simplex-Enzephalitis, Herpes-Enzephalitis, Enzephalitis, Herpes simplex, Herpes-simplex-Enzephalitis
Japanese 単純ヘルペス髄膜脳炎, 脳炎-ヘルペス性急性壊死性, ヘルペス性急性壊死性脳炎, 単純ヘルペス脳炎, 髄膜脳炎-単純ヘルペス, 脳炎-単純ヘルペス, タンジュンヘルペスノウエン, ヘルペス脳炎, ヘルペスノウエン
Korean 헤르페스바이러스 뇌염
Polish Zapalenie mózgu wywołane opryszczką zwykłą, Zapalenie mózgu opryszczkowe
Norwegian Herpeshjernebetennelse, Herpetisk encefalitt, Herpesencefalitt, Encefalitt, Herpes simplex
Dutch herpes-simplex-encefalitis, herpesencefalitis, Encefalitis door Herpesvirus, Encefalitis, herpes simplex, Herpes-simplexencefalitis
French Encéphalite à Herpès simplex, Encéphalite herpétique, Encéphalite à herpès simplex
Hungarian Herpes simplex encephalitis, herpes encephalitis
Portuguese Encefalite de herpes simples, Encefalite herpética, Encefalite Causada pelo Vírus Herpes Simples, Encefalite por Herpes Simples
Derived from the NIH UMLS (Unified Medical Language System)

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