Clin Med 2

• CNS protective functions


  • Blood brain barrier
  • Cerebrospinal fluid

  
• Immune system protection of CNS

  • Reticuloendothelial system removes bacteria & viruses
  • Glial cells (microglia) respond to infectious pathogens
  • Reduced immune protection in CSF due to low antibody and WBC levels
  • No lymphatic system to protect the brain
• Infectious CNS/PNS pathologies

  • Encephalitis
  • Meningitis
  • Poliomyelitis
  • Botulism
  • Tetanus
  • Rabies
  • Shingles
• Infectious CNS disorders can affect children, but more often affect adults or immunocompromised individuals
• What is the first sign of an infectious CNS pathogen?

  • Seizures
• Encephalitis


  Acute inflammation of brain tissue (parenchyma), mostly gray matter, leading to neuronal death, cerebral edema, and vascular damage
• Encephalitis


  • Etiology: viruses (mosquitos/ticks), complications from chicken pox, measles or mumps, herpes simplex
  • Symptoms: headache, nausea & vomiting, elevated temperature, lethargy, stiff neck, agitation, confusion & coma, focal signs and paralysis, seizure activity
  • Diagnosed by lumbar puncture, MRI & EEG changes
  • Treated with antivirals, antibiotics (IV), possible corticosteroids, surgical decompression
  • High mortality rate with only 10-50% recovery, dependent on pathogen
• Meningitis

  • Etiology: bacteria, virus, fungus, toxins
  • Some forms are contagious
  • Pathogens attack after inner ear, sinus or URI
  • Sudden onset of symptoms: high fever, headache, photophobia, nucal rigidity, drowsiness, stupor, seizures
  • Diagnosed by lumbar puncture, Kernig's sign, Brudzinski's sign
  • Treated with vaccines for bacterial, medications, quiet dark environment
  • Prognosis: Bacterial is a medical emergency - can be fatal in infants & elderly; Viral has to run its course

  
• Diagnostic tests can identify dural tension due to meningeal inflammation

  
• Poliomyelitis


  Viral infection affecting lower motor neurons in brainstem & spinal cord
• Poliomyelitis


  • 3 infection mechanisms: asymptomatic, symptomatic/flu-like, symptomatic with paralysis
  • Symptoms: muscle weakness of upper/lower extremities, neck stiffness, muscle atrophy, nausea & vomiting, respiratory system paralysis
  • Diagnosed by culture
  • Treated with braces, respiratory support
  • Post-polio syndrome occurs 20-30 years later with new muscle weakness & fatigue
• Zika virus


  Single strand RNA virus transmitted via mosquito bite, also spread mother to baby, sex, blood transfusion
• Zika virus


  • 80% asymptomatic, can cause fever, headache, joint pain, rash (mild)
  • Causes microcephaly in fetus/unborn children
  • Causes apoptosis and inhibition of neural cell differentiation leading to cortical thinning and microcephaly in mouse models
  • No cure, treatment is mosquito eradication, recommended safe sex/abstinence post traveling to high transmission area
• Botulism


  Neuromuscular poisoning resulting from bacterial invasion by Clostridium botulinum
• Botulism


  • Etiology: food borne, wound borne, infant (bacteria grows in intestines)
  • Symptoms: double vision, blurred vision, droopy eyelids, slurred speech, difficulty swallowing, dry mouth, respiratory decline, progressive muscle weakness
  • Mortality rate 60-70% if untreated immediately
  • Treatment: heat to destroy toxins, induce vomiting, close respiratory monitoring, antitoxin from CDC
• Tetanus


  Acute infectious disease characterized by convulsions and intermittent spasm of voluntary muscles
• Tetanus


  • Bacterial infection - Clostridium tetani found in soil and animal feces
  • Produces a toxin (tetanospasmin) which blocks release of inhibitory neurotransmitters
  • Transmission: acquired from open wound infection
  • Cardinal symptoms: contractions of muscles of mastication (lock-jaw), general muscle spasms
  • Treatment: life supporting procedures, wound debridement, antibiotics
  • Preventable with tetanus shots, need booster every 10 years
• Rabies


  Acute infectious disease of mammals characterized by CNS irritation followed by paralysis and death
• Rabies


  • Virus carried in saliva of infected animals - dogs, raccoons, squirrels, cats, skunks
  • Causes encephalomyelitis (neuro and muscular system inflammation)
  • Symptoms: incubation period of 3-10 days followed by fever, pain, paralysis, convulsions, rage, muscle spasm especially of swallowing (foaming of the mouth), hydrophobia
  • Treatment: immediately wash wound, anti-rabies injections (Ig) before virus spreads to brain, confine & treat or destroy the biting animal
  • Prognosis - can be fatal if untreated ASAP
• Shingles (Herpes Zoster)


  Acute CNS infection involving the dorsal root ganglia resulting in vesicular eruptions and severe pain along the cutaneous areas supplied by the nerve root
• Shingles (Herpes Zoster)


  • Etiology: caused by varicella zoster virus, may be dormant for years and reactivated
  • Prevalence: 1 out of 3 persons who have had chicken pox, increases with age over 60
  • Symptoms: itching, sharp stabbing pain, red rash with pustules along the path of a sensory nerve (dermatome)
  • Treated with antivirals (acyclovir), analgesics, meds for itching, isolation precautions
  • Ramsey-Hunt variant affects facial nerves (paralysis, possible hearing loss)
  • Prognosis - may recur anytime immune system is depressed or stressed, may develop post-herpetic neuralgia
• Brain abscess


  Space-occupying lesion of local infection with effects similar to a brain tumor

  
• Brain abscess


  • Affects individuals with compromised immune system, persons with systemic illnesses (HIV)
  • Etiology: bacteria, fungi, parasites, sinusitis, mastoiditis, infections from heart/lungs, cranial osteomyelitis
  • Presentation: evolves over 1-14 days, capsule of necrotic tissue develops from inflammatory process
  • Symptoms: may not have fever or increased WBC, headache, disturbed consciousness, nuchal rigidity, nausea & vomiting, seizures, visual disturbance, dysarthria, hemiparesis, sepsis
  • Diagnosed by MRI, treated with antibiotics, surgical drainage or excision of capsule
  • Outcomes - 50% left with neurologic sequelae, mortality increases if hemorrhage

  
• Prion disease


  Family of encephalopathies including Creutzfeldt-Jakob disease, kuru, & mad cow disease
• Prion disease


  • Prion is a protein that can replicate in the nervous system and results in neuronal cell death
  • Etiology: ingested from infected beef or protein products containing infected material
  • No known treatment - only symptom management
  • Clinical presentation & prognosis: abnormal movement, ataxia, progressive, usually fatal
• Implications for physical therapy

  • Recognize and observe isolation precautions
  • Monitor vital signs, changes in consciousness, typical evolution of each pathology
  • Be aware infectious pathologies may present like stroke, brain tumor, degenerative disease
  • Expect behavioral changes with diffuse brain disorders
  • Anticipate and monitor sensory and motor dysfunction
  • Implement motor learning approaches as many functions will be lost and have to be relearned