Pediatric Primary Care (112 page)

3.  Prophylaxis for certain exposures.

4.  Support and coordination of comprehensive services may be needed.

II.  ENCEPHALITIS

A.  Inflammation of the brain due to a viral infection.

B.  Etiology.

1.  Primary form: direct viral infection of the brain and spinal cord.

2.  Secondary form: viral infection that first occurs elsewhere in the body and travels to the brain.

3.  Exposure to viruses through:

a.  Breathing in respiratory droplets from infected person.

b.  Contaminated food or drink.

c.  Insect bites or animal bites (rabies).

d.  Specific viruses:

•  Arboviruses–most common cause, carried by mosquitoes or ticks.

•  Enteroviruses–coxsackievirus, echovirus, poliovirus.

•  Others: herpes simplex encephalitis (most common and worst prognosis–10-40% mortality).

•  Eastern equine: 70-90% mortality.

•  Western equine.

•  St.  Louis encephalitis: 30% mortality.

•  West Nile.

•  California and Venezuela equine.

4.  Allergic reaction to vaccinations (extremely rare).

5.  Effects of cancer and treatments.

6.  Autoimmune or immune response problems (immunocompromised, HIV).

C.  Occurrence.

1.  Seasonal: more common summer and fall.

2.  Age: more prevalent or severe in young children and elderly.

3.  Higher in those with weakened immune system.

4.  Geographic: higher in areas where mosquito-borne viruses are common.

5.  Outdoor activities increase risk.

D.  Clinical manifestations.

1.  Headache.

2.  Nausea.

3.  Lethargy.

4.  Behavioral changes–confusion, disorientation, irritability, personality changes.

5.  Joint pain, stiff neck.

E.  Physical findings.

1.  Fever.

2.  Positive Brudzinski's sign or Kernig's sign.

3.  Abnormal reflexes.

4.  Rash.

5.  Emergency symptoms:

a.  Low level of consciousness (LOC), poor responsiveness.

b.  Muscle weakness or paralysis.

c.  Seizure.

d.  Sudden change in mental functions.

e.  Bulging fontanel.

F.  Diagnostic tests.

1.  LP with CSF exam may show hemorrhagic component and increase WBC.

2.  Electroencephalogram (EEG)–periodic sharp waves at 2- to 3-second intervals on a background of diffuse or lateralized slowing if characteristic but nonspecific.

3.  MRI–often abnormal, showing limited or massive areas of inflammation and necrosis.

4.  PCR and blood antibodies–can show positive DNA for viruses.

5.  CBC, toxicology screen.

G.  Differential diagnosis.

H.  Treatment.

1.  Antiviral medications.

a.  Acyclovir–herpes encephalitis or varicella zoster virus.

b.  Ganciclovir–cytomegalovirus (CMV).

2.  Antibiotics if bacterial cause.

3.  Seizure medications as needed.

4.  Steroids to reduce swelling.

5.  Acetaminophen for fever and headache.

6.  Rest and fluids.

I.  Complications.

1.  Acute phase lasts 1-2 weeks, may take several months to fully recover.

2.  Permanent brain damage can occur in severe cases–can affect hearing, memory, muscle control, sensation, speech, vision.

3.  Outcomes vary–high recovery (Rocky Mountain spotted fever), high morbidity (herpes encephalitis) definite mortality, especially if untreated (rabies).

J.  Follow up.

1.  Emergency for sudden fever or other symptoms of encephalitis.

2.  Call for decline in neurological condition.

3.  2-4 weeks to assess for sequelae.  

K.  Education.

1.  Importance of vaccinations: measles-mumps-rubella (MMR), varicella, meningococcal.

2.  Immunizations specific for foreign travel.

3.  Take steps to prevent genital herpes.

4.  Avoidance of mosquitoes.

a.  Apply DEET products, not on face, hands, or infants younger than 2 months.

b.  Remove sources of standing water.

c.  Wear long-sleeve shirts and pants when outside, especially at dusk.

5.  Avoidance of ticks.

a.  Avoid woods, clear brush in yard, and keep grass mowed.

b.  Inspect body after return inside.

c.  Avoid contact with vector/host animals.

6.  Thoroughly cook meat and wash fruits/vegetables, especially in endemic areas.

III.  HEAD INJURY

A.  Any trauma that leads to injury to scalp, skull, or brain.

B.  Etiology.

1.  Trauma from motor vehicle accident (MVA), physical assaults, falls, accidents at home, work, outdoors, or while playing sports.

2.  Common causes include biking, skating, skateboarding, and contact sports.

3.  Types.

a.  Closed head–did not break the skull, more common.

b.  Penetrating or open–break in skull where objects enter brain (50% mortality rate).

c.  Focal brain injury–acute epidural, subdural, or subarachnoid hemorrhage.

C.  Occurrence.

1.  1.7 million people sustain traumatic brain injury (TBI) annually.  Majority are concussions or other forms of mild traumatic brain injury.

2.  Contributes to substantial number of deaths and causes of permanent disability.

3.  Range from mild with brief change in mental status or consciousness to severe with extended period of unconsciousness.

4.  Falls cause 50% of TBI in children age 0 to 14 years.

5.  Strike by moving or stationary object causes 25% of TBI in children ages 0 to 14 years.

6.  Males more often sustain TBI (59%).

7.  High-risk age groups–0 to 4 years and 15 to 19 years.

D.  Clinical manifestations.

1.  Occur immediately or over several hours to days.

2.  Minor head injury symptoms:

a.  Headache.