Meningitis is an inflammation of the protective membranes covering the brain and spinal cord which is caused by bacteria or viruses.
Bacterial Meningitis a.k.a. Septic Meningitis
Bacterial meningitis, which is caused by bacteria (most commonly Streptococcus Pneumoniae and Meningococcus) in the blood stream, is also referred to as septic meningitis.
Factors which increase the risk of bacterial meningitis include:
- Cigarette smoking and viral upper respiratory infections – cause an increase in droplet production.
- Otitis media – inflammation or infection in the middle ear resulting from a cold, sore throat or respiratory infection; bacteria from otitis media can cross the epithelial membrane and enter the subarachnoid space, causing meningitis.
- Mastoiditis – a serious bacterial infection which affects the mastoid bone located behind the ear, commonly occurring in children; bacteria from mastoiditis can cross the epithelial membrane and enter the subarachnoid space, causing meningitis.
- Immune system deficiencies – increases risk for development of bacterial meningitis; this is why in oncology wards, wearing of PPEs is emphasised so the risk of infection in immuno-compromised patients is minimised as much as possible.
Viral Meningitis a.k.a. Aseptic Meningitis
Aseptic meningitis is usually caused by viruses, though at times the cause may also be fungal or parasitic. It can also be secondary to lymphoma, leukaemia, or human immunodeficiency virus (HIV).
Meningitis Pathophysiology
- A meningeal infection originates either through the bloodstream resulting from another infection, or by direct spread eg. following trauma to the facial bones or secondary to invasive procedures.
- The causative organism crosses the blood-brain barrier and starts to proliferate (multiply) in the CSF.
- The immune system stimulates the release of cell wall fragments and lipopolysaccharides, which facilitate inflammation of the subarachnoid and the pia mater. Due to lack of space in the cranial vault, this inflammation may cause intracranial pressure (ICP).
- Prognosis may include adrenal damage, circulatory (cardiac or peripheral) collapse, and Waterhouse-Friderichsen Syndrome (rare life-threatening disorder associated with bilateral adrenal haemorrhage, resulting from endothelial damage and vascular necrosis caused by the bacteria).
- Bacterial meningitis outcome depends on the causative organism, infection severity and treatment timeline.
- Resulting complications include visual impairment, deafness, seizures, paralysis, hydrocephalus (build-up of fluid in the brain), and septic shock (significant drop in blood pressure that may cause respiratory or heart failure, stroke, organ dysfunction, and mortality).
Meningitis Clinical Manifestations
- Headache
- Fever
- Disorientation
- Seizures
- Speech difficulties (slurred speech)
- Sluggish pupillary reaction
- Neck rigidity – attempts of head flexion prove to be difficult due to spasms in the muscles of the neck
- Visual disturbance
- Photophobia – extreme sensitivity to light
- Rash – feature of Neisseria Meningitis infection
- Skin Lesions – features only in bacterial meningitis: petechial rash with purpuric (bloody) lesions to large areas of ecchymosis (bruising).
- Intracranial Pressure ICP – increased pressure in the brain caused by the inflammation; signs of ICP include a decreased level of consciousness, and focal motor deficits; uncontrolled ICP leads to brain stem herniation – a life threatening situation which causes cranial nerve dysfunction and depression of the vital function centers, including the medulla
- Motor and sensory dysfunction
- Cranial nerve deficits eg. facial droop, dysfunction in the arm/leg of one side of the body (as happens with a CVA)
- Hydrocephalus – seen in children up to 2 years of age in which cranial bones are not yet fused well together, leading to enlargement of the head
- Positive Kernig’s Sign – inability to extend leg of patient when lying down with thigh flexed on the abdomen
- Positive Brudzinski’s Sign – after ruling out cervical trauma or injury, patient’s neck is flexed, followed by the flexion of knees and hips; passively flexing the lower extremity of one side may produce an involuntary movement in the opposite extremity – positive sign indicating meningeal irritation (better diagnostic method than Kernig’s).
- Lethargy, unresponsiveness and coma may develop with illness progression.
Meningitis Diagnosis
- CT Scan or MRI – performed with the aim of detecting a shift in brain contents that can lead to herniation
- Bacterial Culture and Gram Staining of CSF and blood following lumbar puncture
- CSF with low glucose level, high protein level, and high white blood cell count are indicative of meningitis
- Gram staining allows rapid identification of causative bacteria, leading to exact diagnosis and appropriate antibiotic therapy
Meningitis Prevention
- Meningococcal Conjugate Vaccine – administered to adolescents attending high school, and college freshmen living in dormitories
- Education – providing information about meningitis prevention availability so as to promote informed decision-making
- Prophylactic Treatment – Antimicrobial Chemoprophylaxis eg. Rifampin (Rifadin), Ciprofloxacin Hydrochloride (Cipro), or Ceftriaxone Sodium (Rocephin) is to be administered to people in close contact with patients diagnosed with meningococcal meningitis; treatment should be started within 24 hours following initial exposure; vaccination should also be considered as an adjunct
- H. influenzae and S. pneumoniae Vaccination – should be encouraged for children and high-risk adults
Meningitis Medical Management
- Early administration of an antibiotic that can cross the blood-brain barrier into the subarachnoid space and halt bacterial proliferation
- IV administration of Vancomycin Hydrochloride with Cephalosporins (eg. Ceftriaxone Sodium, Cefotaxime Sodium)
- Dexamethasone (Decadron) steroidal therapy administered 15-20 minutes prior to the first antibiotic dose and every 6 hours for the following 4 days as adjunct therapy for acute bacterial meningitis and pneumococcal meningitis
- Fluid Volume Expanders are administered for the treatment of dehydration and shock
- Phenytoin (Dilantin) may be administered in case of seizures
- Increased ICP is to be treated as necessary
Meningitis Nursing Care
- Provide reassurance to reduce anxiety; providing frequent orientation information may help
- Assess neurologic status
- Assess vital signs
- Assist in the reduction and control of body temperature
- Encourage bed rest in a quiet, non-stressful environment so as to avoid extra activity, pain and anxiety from increasing blood pressure leading to an increase in ICP; keep room quiet, limit visitors, and speak calmly
- Pulse Oximetry and ABGs provide early identification the need for respiratory support if ICP compromises the brain stem
- Maintain adequate tissue oxygenation – insertion of a cuffed endotracheal tube or tracheotomy, and mechanical ventilation, may be required for continuous oxygenation maintenance
- Avoid opioids as these may increase the risk of respiratory distress and alter responsiveness
- Blood pressure monitoring is required to assess for incipient shock, which precedes cardiac or respiratory failure
- IV fluids may be prescribed for fluid replacement, however, care should be taken so as to avoid fluid overload
- Provide the patient with protection from secondary injury following seizures or altered level of consciousness eg. pull up side rails, place patient close to the nursing station for close monitoring, use padded side rails or/and wrap patient’s hands in mitts to protect from self injury and dislodging of IV lines; Make sure there are no items eg. sharps close to the patient especially in the case of altered level of consciousness, so as to avoid further injuries; If possible, avoid restraints as these may increase anxiety and stress, leading to further injuries and worsening of ICP
- Monitor daily body weight (serum electrolytes and urine volume, specific gravity and osmolality (concentration of dissolved particles of chemicals and minerals) if SIADH is suspected (a condition in which the body makes too much antidiuretic hormone ADH, causing the body to retain excessive water)
- Apply preventative measures in relation to pressure ulcer formation (provide adequate skin care and change nappy frequently if patient is incontinent to avoid sacral area ulcer formation) and pneumonia (elevate head of bed to 30% to avoid aspiration; this also promotes venous drainage from the patient’s head in the case of patient having ICP)
- Apply infection control precautions until 24 hours following the initiation of antibiotic therapy
- Provide information as part of meningitis nursing care to the patient’s family about the patient’s condition due to the critical nature of meningitis; support the patient’s relatives and assist them in identifying other supportive individuals to help them cope with the situation; provide information about hygiene practices at home eg. frequent handwashing; provide information on antimicrobial chemoprophylaxis including possible side effects (eg. vertigo, nausea and headache) and frequency – prophylactic therapy should be started within 24 hours following exposure to meningitis (delay limits effectiveness of prophylaxis); consider vaccination possibility as an adjunct to chemoprophylaxis (refer to Meningitis Prevention section further up)
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