Infections of the Nervous System II

A Lecture Outline

© Hanuš Rozsypal
Aseptic meningitis | Acute encephalitis | Guillain-Barré syndrome | Lyme borreliosis


(ACUTE) ASEPTIC MENINGITIS
Meningitis serosa

Incidence: 10/100.000

Etiology:

  1. Viruses
    • Enteroviruses
    • Arboviruses (TBE virus)
    • Mumps
    • Herpesviruses (associated with primary genital infection with HSV-2)
    • Virus influenzae and other respiratory viruses
    • Human immunodeficiency virus (HIV-1)
    • Lymphocytic choriomeningitis virus (LCM)
  2. Bacteria
    • Borrelia burgdorferi
    • Leptospira spp.
    • Mycoplasma pneumoniae
  3. Unknown

Pathogenesis:

     during the viremia, the viral agent invades the CNS

Clinical manifestations:

Symptoms:
  • headache
  • fever
Signs:
  • meningeal signs
Tests:
  • ESR, hematologic and biochemical parameters: nonspecific

Course: acute, often biphasic

Diagnosis:

     Exposure history: suspicion of a tick-transmitted disease
     Clinical manifestations: suspicion of meningitis
     CSF: lymphocytic pleocytosis
     Serologic tests: antibody against causative agents

Complications and sequelae: occur rare

Differential diagnosis:

     Other forms of meningitis (bacterial, tuberculous, mycotic)
     Systemic illnessis with fever and meningeal irritation
     Subarachnoid hemorrhage
     Cervicocranial syndrome

Prognosis: good

Therapy:

  • Confinement to bed
  • Mannitol
  • Corticosteroids
  • Antipyretics
  • Antiemetics
  • Vitamins
Prevention

     Prevention from tick-bite
     Vaccination against mumps, exanthematic diseases etc.
     Vaccination or immunoglobulin against TBE (FSME Bulin, FSME-Immun, Encepur)
          post-exposure prophylaxis (after tick-bite)
          pre-exposure prophylaxis of the people, who will live in endemic area

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ACUTE ENCEPHALITIS
Encephalitis acuta

Incidence: 10/100.000

Etiology:

  1. Viruses
    • Arboviruses (TBE virus)
    • Virus influenzae and other respiratory viruses, measles virus
    • Enteroviruses
    • Herpesviruses (HSV-1, HSV-2, VZ virus, EBV, CMV etc.)
    • Rabies virus
    • Human immunodeficiency virus (HIV)
  2. Bacteria
    • Borrelia burgdorferi
    • Rickettsia rickettsii
    • Chlamydia psittaci
    • Chlamydia pneumoniae
    • Mycoplasma pneumoniae
  3. Parasitic agents
    • Trypanosoma spp.
    • Acanthamoeba
    • Naegleria spp.
    • Toxoplasma gondii
    • Plasmodium spp.
  4. Immunisation
    • Vaccine against measles, mumps, etc.

Pathogenesis:

Encephalitis
  • primary - direct invasion of causative agent
  • postinfectious and parainfectious - immunopathologic mechanisms

Clinical manifestations:

General symptoms and signs
  • fever
  • headache
  • decreased consciousness
  • movement disorders (pareses, dyskinesis, ataxia)
  • cranial nerve defects
  • tremor
  • seizures
Specific forms of encephalitis
  • herpes simplex encephalitis (necrozing encephalitis)
  • cerebellitis (acute cerebellar ataxia, gait disturbances) - chicken pox
  • brain stem encephalitis (life-threatening symptoms and signs)
  • focal encephalitis (focal seizures, hemiparesis, aphasia)
  • poliomyelitis anterior acuta
  • rabies
Course: Acute, often a biphasic course

Diagnosis:

     Exposure history: tick-bite
     Clinical manifestations: many neurologic symptoms and signs
     CSF: mild lymphocytic pleocytosis
     EEG: diffuse slowing
     CT: normal or diffuse brain edema
     Serologic tests: antibody against causative agents
     Virologic tests: isolation of viral agent, nucleic acid techniques
     Other microbiologic tests: detection of infectious agent

Differential diagnosis:
  • Metabolic diseases (uremic encephalopathy, hepatic encephalopathy, etc.)
  • Toxic disorders (drug intoxication)
  • Mass laesions (tumor or abscess)
  • Acute demyelinating disorders (acute multiple sclerosis, acute haemorrhagic leukoencephalitis)
  • Status epilepticus (especially non-convulsive status epilepticus, complex-partial status, absence status)
  • Toxoinfectious encephalopathies (Reye´s syndrome, malaria, etc.)
  • Thrombophlebitis of venous sinus
  • Rare: SSPE, PML, Jacob-Creutzfeldt´s disease

Prognosis:
          generally: good
          herpetic necrosing encephalitis: life-threatening
          rabies: fatal

Therapy:

Causal: acyclovir 3x 10mg/kg/day i.v.
Supportive and symptom-based:
  • Confinement to bed
  • Mannitol
  • Corticosteroids
  • Antipyretics
  • Antiemetics
  • Anticonvulsants
  • Nootropic agents
  • Vitamins

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GUILLAIN-BARRÉ SYNDROME
Polyradiculoneuritis acuta

Incidence:1/100.000

Etiology:
  1. Infection:
    • viral (EBV, CMV, HIV, HAV, HBV, TBE virus)
    • bacterial (Campylobacter jejuni)
  2. Systemic disease:
    • SLE
    • Hodkin´s disease
    • sarcoidosis
    • HIV infection
  3. Unknown
Pathogenesis:

     Autoimmune mechanisms - demyelination - conduction block - paresthesias, pain and weakness.

Clinical manifestations:

Symptoms:
  • prodromal influenza-like or diarrheal illness
  • fine parestesias to pain in the toes or fingertips
  • progressive weakness in both legs, then both arms follows (lead to walking and climbing stairs difficult)

Signs:
  • cranial-nerve involvement
    • bilateral weakness of facial muscles
    • ophthalmoplegia
  • weakness
    • relative symmetric
    • acral maximum
    • lower extremity > upper extremity
    • diminished tendon reflexes to areflexia
  • mild sensory loss
  • autonomic dysfunctions
    • difficulty swallowing
    • hypoventilation
    • constipation
Tests:
  • ESR, BC, CRP: nonspecific
  • CSF: proteinocytologic dissociation (lymphocytes < 50/3, protein level >0,8 g/l)
  • EMG: typical feature

Course:

     Weakness
          - stops advancing in one to three weeks
          - slowly improves after a plateau lasting several weeks

Clinical variants:

     Fischer´s syndrome (which involves ophthalmoplegia, ataxia, and areflexia)
     Chronic inflammatory demyelinating polyneuropathy (tends to progress for more than four weeks, relapsing course)

Complications:

     ARDS
     Pulmonary embolism
     Cardiac arrest

Sequelae: residual motoric or sensory deficit

Diagnosis:

     Clinical manifestations, CSF feature, EMG feature

Differential diagnosis:

  • Spinal cord compression
  • Transverse myelitis
  • Myasthenia gravis
  • Basilar-artery occlusion
  • Myopathies
  • Neuropathies
  • Botulism
  • Bannwarth´s syndrome
  • Tick paralysis
Prognosis:

     Usually: recovery over a period of weeks or months
     Mortality: 5%

Therapy:

  • Immunoglobulins (0.4g/kg/day x 5 days)
  • Plasma exchange
  • Corticosteroids - recently concluded studies have found no benefit
  • Chest physical therapy to mechanical ventilation
  • Anticoagulants (prevent from pulmonary embolism)
  • Rehabilitation

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LYME BORRELIOSIS

Geographical distribution: worldwide

Incidence: 20-40/100.000

Etiology:

     Borrelia burgdorferi sensu lato includes 3 genogroups:
  • Borrelia burgdorferi sensu stricto (USA)
  • Borrelia garinii (neuroborreliosis in Europe)
  • Borrelia afzelii (cutaneous and joint forms in Europe)

Epidemiology:

     Source: rodents, deers
     Transmission: vector - tick, particularly Ixodes ricinus

Ixodes ricinus

Pathogenesis:

  • presence of the spirochetes in tissue
  • vasculitic changes
  • autoimmune mechanisms

Incubation period: 3 to 32 days

Clinical presentation:

Manifestations Early localized infection Early disseminated infection Late disseminated infection Chronic infection (lasting >1 year)
Non-specific mild flu-like symptoms malaise, fatigue malaise, fatigue fatigue, neuropsychiatric symptoms
Cutaneous erythema chronicum migrans additional ECM lesions borrelial lymphocytoma acrodermatitis chronica atrophicans
Neurologic - headache, meningism, Bell´s palsy acute aseptic meningitis, acute encephalitis, Bell´s palsy, Bannwarth syndrome, peripheral neuropathy chronic (meningo)encephalitis, CNS vasculitis, peripheral neuropathy
Musculo-skeletal - arthralgias, myalgias arthritis arthritis
Others - lymphadenopathy, conjunctivitis, hepatopathy AV block, myo(peri)carditis -


Diagnosis of neuroborreliosis:

     Exposure history: tick-bite
     Clinical manifestations: many neurologic symptoms and signs
     Tests and imaging: often nonspecific
     Detection of Borrelia in CSF or blood (EM, PCR, culture)
     Serologic tests: antibody against B. burgdorferi

Therapy of neuroborreliosis:

  1. Specific treatment - antibiotics:
         PNS involvement:
    • Doxycycline
    • Amoxicillin
    • Macrolids
         CNS involvement:
    • Ceftriaxone
    • Penicillin G
  2. Immunomodulants:
    • T factor
  3. Symptom-based therapy:
    • Analgesics
    • Antirheumatics
    • Reduction of intracranial pressure
    • Vitamins
  4. Psychologic support

Prevention:

  • Tick control (applying acaricides, reducing and managing deer population)
  • Personal protection from tick bites
  • Preventive antibiotic treatment (generally is not recommended)
  • Vaccine for Lyme borreliosis: Lymerix (USA)


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© H. Rozsypal
The page was last updated June-30-2002