Bacterial & Viral Meningitis (1324-1326)
Inflammation caused by:
• Bacteria
• Viruses
• Fungi
• Chemicals (contrast media, blood in subarachnoid space)
CNS infections may occur via:
• The bloodstream
• By extension from a primary site
• Along cranial and spinal nerves
Rates – higher in older immunocompromised pts
• Some who recover have long-term neuro deficits (hearing loss)
Meningitis
• Acute inflammation of meningeal tissues surround the brain and spinal cord
• Usually occurs in fall, winter or early spring
o Related to viral respiratory disease
o Older adults and debilitated – affected more
• College students living in dorms and people living in institutions (prisoners) have higher
risk
Bacterial meningitis
• Etiology & pathophysiology
o Streptococcus pneumoniae and Neisseria meningitidis = leading cause
 N. M. has 13 subtypes with 5 of them causing most cases (A, B, C, Y, W)
 H. influenzae used to be the most common cause before flu vaccine
o Organisms gain entry to CNS through – URT or bloodstream
 May enter by direct extension from penetrating wounds of skull or
through fractured sinuses in basilar skull fractures
o Inflammatory response increases CSF production (w/ mod increase ICP)
 Purulent secretions quickly spread to other areas of brain through the
CSF & cover CN and other intracranial structures
 If this process extends into the brain parenchyma or if concurrent
encephalitis is present, cerebral edema and increased ICP become
bigger problem
• Clinical manifestations:
o Key signs:
 Fever
 Severe HA (becomes progressively worse; + vomiting & irritability)
 Nausea
 Vomiting
 Nuchal rigidity (neck stiffness)
o Photophobia, decreased LOC and signs of increased ICP may be present
o Coma (5-10% pts) = poor prognosis
o Seizures (1/3 of cases)
o Rash – if meningococcus is infecting organism
o Petechia – trunk, LE, mucous membranes
 Tumbler test – pressing base of drinking glass against the rash
 The rash does not blanch or fade under pressure
• Complications
o Most common = increased ICP
o Residual neuro dysfunction (involving many cranial nerves)
 Optic nerve (2) – papilledema and blindness
 3,4, 6 – ocular movements affected (pstosis, unequal pupils, diploplia)
 5- sensory losses and loss of corneal reflex
 7 – facial paresis
 8 – tinnitus, vertigo, deafness (usually disappears but hearing loss may be
permanent)
o Hemiparesis, dysphasia, and hemianopsia
o Acute cerebral edema may cause seizures, CN III palsy, bradycardia, hypertensive
coma, and death
o noncommunicating hydrocephalus – if exudate causes adhesions that prevent
normal flow of CSF from ventricles
o Waterhouse-Friderichsen syndrome
 petechiae, disseminated intravascular coagulation (DIC), adrenal
hemorrhage, and circulatory collapse
• Diagnostic studies:
o Suspected = Blood culture & CT
o To confirm diagnosis = LP w/ analysis of CSF
 LP done after CT scan has r/o obstruction in foramen magnum to prevent
fluid shift resulting in herniation
o Before starting abx – Culture CSF, sputum, and nasopharyngeal secretions
 Gram stain don’t to detect bacteria
 Abx started even before dx confirmed
 Predominant WBC in CSF w/ bacterial meningitis = neutrophils
o X-rays of skull may show infected sinuses
o CT and MRI may be normal in uncomplicated meningitis
 Other cases: CT may show increased ICP and hydrocephalus
Signs/Symptoms. Brudzinski & Kernig’s sign
• Kernig's is performed by having the supine patient, with hips and knees flexed, extend
the leg passively.
o The test is positive if the leg extension causes pain.
o Helps in the diagnosis of meningitis
• Brudzinski's sign is positive when passive forward flexion of the neck causes the patient
to involuntarily raise his knees or hips in flexion.
o Helps in the diagnosis of meningitis
•
Interprofessional Care Table 56-17
Diagnostic Assessment
• History and physical examination
• Analysis of CSF (for protein, WBC, and glucose), Gram stain, and culture
• CBC, coagulation profile, electrolyte levels, glucose, platelet count
• Blood culture
• CT scan, MRI, PET scan
• Skull x-ray studies
Management
• Rest
• IV fluid
• Hypothermia
Drug Therapy
• IV antibiotics
• ampicillin, penicillin
• cephalosporin (e.g., cefotaxime, ceftriaxone)
• codeine for headache
• dexamethasone
• acetaminophen or aspirin for temperature >100.4° F (38° C)
• phenytoin IV
• mannitol (Osmitrol) IV for diuresis
Transmission & Isolation
• Respiratory isolation until cultures are negative
o Meningococcal meningitis - Highly contagious
Prevention & Nursing Care
Prevention
• Pneumonia and flu vaccines – to prevent respiratory tract infections
• Meningococcal vaccines – protect against the serogroups that are most often seen in US
but do not prevent all cases
o 2 types:
 Meningococcal conjugate vaccines (MCV4) (Menactra, Menveo)
 Serogroup B meningococcal vaccines (Bexsero, Trumenba)
• Early tx of respiraotyr tract and ear infections is important
• Persons who have close contact with anyone who has bacterial meningitis should
receive prophylactic antibiotics.
Acute care
• Assess and record vital signs, neurologic status, fluid intake and output, skin, and lung
fields at regular intervals based on the patient’s condition.
o Bacterial meningitis = acutely ill
 High fever, severe head pain, possible seizures, change in mental
status/LOC
o Codeine – pain relief (head and neck pain)
o Position of comfort – curled up with head slightly flexed
o HOB slighlty elevated
o Darkened room and cool cloth over eyes (photphobia)
o Delirium – low lighting may decrease hallucinations
o Min. environmental stimuli
o Familiar person at bedside= calming effect
o Antiseizure drugs – phenytoin (Dilantin) or levetiracetam (Keppra)
o Fever vigorously treated (because it increases cerebral edema and risk seizures)
 Acetaminophen or aspirin or cooling blanket (tepid sponge baths)
o Assess dehydration and adequacy of fluid intake
Ambulatory care
• Adequate nutrition – high protein, high calorie in small, frequent feedings
• ROM exercises and warm baths – muscle rigidity may persist
• Assess vision, hearing, cognitive skills, and motor and sensory abilities after recovery,
with appropriate referrals as indicated.
Viral Meningitis
• Most common cause:
o Enteroviruses
 Spread through direct contact with respiratory secretions
o Arboviruses
o HIV & HSV
• Viral manifestations:
o headache
o fever (moderate or high)
o photophobia
o stiff neck
• diagnosis:
o Expert EV test
 Sample of CSF used to determine if enterovirus present
 Results available within hours of symptoms onset
•
o CSF can be clear or cloudy
 Typical finding: lymphocytosis
o Organisms not seen on gram stain or acid-fast smears
o PCR (polymerase chain reaction) – used to detect viral-specific DNA or RNA
 Sensitive method for dx CNS viral infections
o Antibiotics should be given after the LP while awaiting the results of the CSF
analysis.
 Antibiotics are the best defense for bacterial meningitis.
 We can easily discontinue them if the meningitis is found to be viral.
Management:
o Self – limiting disease (managed symptomatically)
o Full recovery expected
o Rare sequelae = persistent HA, mild mental impairment, incoordination