Meningitis is a clinical syndrome characterized by inflammation of the meninges, the three layers of membranes that enclose the brain and spinal cord.
What is Meningitis?
Infections of the central nervous system (CNS) can be divided into two broad categories: those primarily involving the meninges (meningitis; see the image below) and those primarily confined to the parenchyma (encephalitis).
Meningitis is a clinical syndrome characterized by inflammation of the meninges, the three layers of membranes that enclose the brain and spinal cord. These layers consist of the following:
- Dura – A tough outer membrane.
- Arachnoid – A lacy, weblike middle membrane.
- Subarachnoid space – A delicate, fibrous inner layer that contains many of the blood vessels that feed the brain and spinal cord.
Anatomically, meningitis can be divided into inflammation of the dura (sometimes referred to as pachymeningitis), which is less common, and leptomeningitis, which is more common and is defined as inflammation of the arachnoid tissue and subarachnoid space.
Most cases of meningitis are caused by an infectious agent that has colonized or established a localized infection elsewhere in the host.
- The organism invades the submucosa at these sites by circumventing host defenses (eg, physical barriers, local immunity, and phagocytes or macrophages).
- Invasion of the bloodstream and subsequent seeding is the most common mode of spread for most agents.
- Meningeal seeding may also occur with a direct bacterial inoculate during trauma, neurosurgery, or instrumentation.
- The blood-brain barrier can become disrupted; once bacteria or other organisms have found their way to the brain, they are somewhat isolated from the immune system and can spread.
- When the body tries to fight the infection, the problem can worsen; blood vessels become leaky and allow fluid, WBCs, and other infection-fighting particles to enter the meninges and brain;this process, in turn, causes brain swelling and can eventually result in decreasing blood flow to parts of the brain, worsening the symptoms of infection.
- Replicating bacteria, increasing numbers of inflammatory cells, cytokine-induced disruptions in membrane transport, and increased vascular and membrane permeability perpetuate the infectious process in bacterial meningitis.
Statistics and Incidences
The incidence of meningitis varies according to the specific etiologic agent, as well as in conjunction with a nation’s medical resources.
- With almost 4100 cases and 500 deaths occurring annually in the United States, bacterial meningitis continues to be a significant source of morbidity and mortality; the annual incidence in the United States is 1.33 cases per 100,000 population.
- The incidence of neonatal bacterial meningitis is 0.25-1 case per 1000 live births.
- In addition, the incidence is 0.15 case per 1000 full-term births and 2.5 cases per 1000 premature births.
- N meningitidis causes approximately 4 cases per 100,000 children aged 1-23 months.
- The risk of secondary meningitis is 1% for family contacts and 0.1% for daycare contacts.
- The rate of meningitis caused by S pneumoniae is 6.5 cases per 100,000 children aged 1-23 months.
- Newborns are at highest risk for acute bacterial meningitis.
- After the first month of life, the peak incidence is in infants aged 3-8 months.
- Bacteria. S pneumoniae, a gram-positive coccus, is the most common bacterial cause of meningitis.
- Viruses. Enteroviruses account for of the majority of cases of aseptic meningitis in children; the nonpolio enteroviruses (NPEVs) account for approximately 90% of cases of viral meningitis in which a specific pathogen can be identified; the mumps virus is the most common cause of aseptic meningitis in unimmunized populations, occurring in 30% of all patients with mumps.
- Fungi. Cryptococcus neoformans is an encapsulated, yeast like fungus that is ubiquitous; Coccidioides immitis is a soil-based, dimorphic fungus that exists in mycelial and yeast (spherule) forms; blastomyces dermatitidis is a dimorphic fungus that has been reported to be endemic in North America (eg, in the Mississippi and Ohio River basins).
- Parasite. Angiostrongylus cantonensis, the rat lungworm, can cause eosinophilic meningitis (pleocytosis with more than 10% eosinophils) in humans; Gnathostoma spinigerum, a GI parasite of wild and domestic dogs and cats, may cause eosinophilic meningoencephalitis; Gnathostoma spinigerum, a GI parasite of wild and domestic dogs and cats, may cause eosinophilic meningoencephalitis.
Only about 44% of adults with bacterial meningitis exhibit the classic triad of fever, headache, and neck stiffness.
- Fever. The patient presents with fever at first, which ultimately grow worse.
- Seizures. As bacterial meningitis progresses, patients of any age may have seizures (30% of adults and children; 40% of newborns and infants).
- Neck stiffness. The patient feels stiffness of the neck as part of the triad of symptoms.
- Positive Kernig’s sign. When the patient is lying with the thigh flexed on the abdomen, the leg cannot be completely extended.
- Positive Brudzinski’s sign. When the patient’s neck is flexed, flexion of the knees and hips is produced; when the lower extremity of one side is passively flexed, a similar movement is seen in the opposite extremity.
- Neurologic symptoms. Patients with subacute bacterial meningitis and most patients with viral meningitis present with neurologic symptoms developing over 1-7 days.
- High-pitched cry. Infants may present with high-pitched crying.
- Lethargy. An infant may appear only to be slow or inactive, or be irritable.
- Photalgia (photophobia). Discomfort when the patient looks into bright lights.
Assessment and Diagnostic Findings
The diagnostic tests in patients with clinical findings of meningitis are as follows:
- Lumbar puncture. In general, whenever the diagnosis of meningitis is strongly considered, a lumbar puncture should be promptly performed; examination of the cerebrospinal fluid (CSF) is the cornerstone of the diagnosis.
- CT scan. A screening computed tomography (CT) scan of the head may be performed before LP to determine the risk of herniation.
- Blood studies. In patients with bacterial meningitis, a complete blood count (CBC) with differential will demonstrate polymorphonuclear leukocytosis with a left shift.
- Chest radiography. As many as 50% of patients with pneumococcal meningitis also have evidence of pneumonia on initial chest radiography.
- Cultures and bacterial antigen testing. The utility of cultures is most evident when LP is delayed until head imaging can rule out the risk of brain herniation, in which cases antimicrobial therapy is rightfully initiated before CSF samples can be obtained.
- Serum procalcitonin testing. increasing data suggest that serum procalcitonin (PCT) levels can be used as a guide to distinguish between bacterial and aseptic meningitis in children.
Management of the patient includes:
- Crystalloid infusion. If the patient is in shock or hypotensive, crystalloid should be infused until euvolemia is achieved.
- Seizure precautions. If the patient’s mental status is altered, seizure precautions should be considered, seizures should be treated according to the usual protocol, and airway protection should be considered.
- IVT and oxygen administration. If the patient is alert and in stable condition with normal vital signs, oxygen should be administered, intravenous (IV) access established, and rapid transport to the emergency department (ED) initiated.
Begin empiric antibiotic coverage according to age and presence of overriding physical conditions.
- Sulfonamides. Trimethoprim and sulfamethoxazole work together to inhibit bacterial synthesis of tetrahydrofolic acid.
- Tetracyclines. Tetracyclines inhibit protein synthesis and, therefore, bacterial growth by binding with 30S and possibly 50S ribosomal subunits of susceptible bacteria.
- Carbapenems. Carbapenems inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins; carbapenems, including meropenem, can be used for the treatment of meningitis.
- Fluoroquinolones. Fluoroquinolones inhibit bacterial DNA synthesis and, consequently, growth by inhibiting DNA gyrase and topoisomerases, which are required for replication, transcription, and translation of genetic material.
- Glycopeptides. Vancomycin inhibits bacterial cell wall synthesis by blocking glycopeptide polymerization; it is indicated for many infections caused by gram-positive bacteria.
- Aminoglycosides. Aminoglycosides primarily act by binding to 16S ribosomal RNA within the 30S ribosomal subunit; they have mainly bactericidal activity against susceptible aerobic gram-negative bacilli.
- Cephalosporins, 3rd generation. Third-generation cephalosporins are less active against gram-positive organisms than first-generation cephalosporins are; they are highly active against Enterobacteriaceae, Neisseria, and H influenzae.
- Antivirals. Antiviral agents interfere with viral replication; they weaken or abolish viral activity; they can be used in viral meningitis.
- Systematic antifungals. Antifungal agents are used in the management of infectious diseases caused by fungi.
- Vaccines, inactivated. Inactivated bacterial vaccines are used to induce active immunity against pathogens responsible for meningitis.
- Corticosteroids. The use of steroids has been shown to improve overall outcome for patients with certain types of bacterial meningitis, such as H influenzae, tuberculous, and pneumococcal meningitis.
- Osmotic diuretics. Mannitol may reduce subarachnoid-space pressure by creating an osmotic gradient between CSF in the arachnoid space and plasma.
- Loop diuretics. Furosemide is a loop diuretic that increases the excretion of water by interfering with the chloride-binding cotransport system, which, in turn, inhibits sodium and chloride reabsorption in the ascending loop of Henle and distal renal tubule.
- Anticonvulsants. Anticonvulsants are used to help aggressively control seizures (if present) in acute meningitis, because seizure activity increases ICP.
Nursing management of the patient with meningitis include the following:
Assessment of the patient with bacterial meningitis include.
- Neurologic status. Neurologic status and vital signs are continually assessed.
- Pulse oximetry and arterial blood gas values. These values are used to quickly identify the need for respiratory support.
Based on the assessment data, major nursing diagnoses include:
- Risk for Infection related to contagious nature of organism.
- Acute Pain related to headache, fever, neck pain secondary to meningeal irritation.
- Impaired Physical Mobility related to intravenous infusion, nuchal rigidity and restraining devices.
- Activity Intolerance related to fatigue and malaise secondary to infection.
- Risk for Impaired Skin Integrity related to immobility, dehydration, and diaphoresis.
- Risk for Injury related to restlessness and disorientation secondary to meningeal irritation.
- Interrupted Family Process related to critical nature of situation and uncertain prognosis.
- Anxiety related to treatment and risk of death.
- Risk for Ineffective Therapeutic Regimen Management
Nursing Care Planning & Goals
Main Article: 7 Meningitis Nursing Care Plans
Goals for a patient with bacterial meningitis include:
- Protection against injury.
- Prevention of infection.
- Restoring normal cognitive functions.
- Prevention of complications.
Important components of nursing care include the following measures:
- Assess neurologic status and vital signs constantly. Determine oxygenation from arterial blood gas values and pulse oximetry.
- Insert cuffed endotracheal tube (or tracheostomy), and position patient on mechanical ventilation as prescribed.
- Assess blood pressure. (usually monitored using an arterial line) for incipient shock, which precedes cardiac or respiratory failure.
- Rapid IV fluid replacement may be prescribed, but take care not to overhydrate patient because of risk of cerebral edema.
- Reduce high fever to decrease load on heart and brain from oxygen demands.
- Protect the patient from injury secondary to seizure activity or altered level of consciousness (LOC).
- Monitor daily body weight; serum electrolytes; and urine volume, specific gravity, and osmolality, especially if syndrome of inappropriate antidiuretic hormone (SIADH) is suspected.
- Prevent complications associated with immobility, such as pressure and pneumonia.
- Institute infection control precautions until 24 hours after initiation of antibiotic therapy (oral and nasal discharge is considered infectious).
- Inform family about patient’s condition and permit family to see patient at appropriate intervals.
Expected patient outcomes include:
- Avoidance of injury.
- Avoidance of infection.
- Restoration of normal cognitive functions.
- Prevention of complications.
Discharge and Home Care Guidelines
After hospitalization, the patient at home should:
- Activities. Alternate rest and activity to conserve energy.
- Diet. Consume safe, clean, and healthy foods.
- Asepsis. Promote simple infection control procedures at home.
- Infectious process. Identify signs and symptoms of an infectious process and report to the physician promptly.
The focus of documentation in patients with bacterial meningitis are:
- Client’s description of response to pain.
- Acceptable level of pain.
- Prior medication use.
- Current physical findings.
- Client’s understanding of individual risks and safety concerns.
- Availability and use of resources.
- Current and previous level of function.
- Effect on independence and lifestyle.
- Results of laboratory and diagnostic tests.
- Mental status pr cognitive evaluation results.
- Plan of care.
- Teaching plan.
- Response to interventions, teaching, and actions performed.
- Attainment or progress towards desired outcomes.
- Modifications to plan of care.
Practice Quiz: Meningitis
1. Tiffany is diagnosed with increased intracranial pressure (ICP); which of the following if stated by her parents would indicate a need for Nurse Charlie to reexplain the purpose for elevating the head of the bed at a 10 to 20-degree angle?
A. Help alleviate headache
B. Increase intrathoracic pressure
C. Maintain neutral position
D. Reduce intra-abdominal pressure.
1. Answer: B. Increase intrathoracic pressure
- B: Head elevation decreases, not increases, intrathoracic pressure.
- A, C, and D: Elevating the head of the bed in a child with increased ICP helps to alleviate headache, maintain neutral position, and reduce intra-abdominal pressure, which may contribute to increased ICP.
2. During assessment, the nurse knows that well-recognized signs common to all types of meningitis include:
A. Positive Kernig’s sign
B. Positive Brudzinski’s sign
D. Negative Kernig’s sign
2. Answer: D. Negative Kernig’s sign.
- D: A patient with meningitis exhibits a positive and not a negative Kernig’s sign.
- A, B, and C: These are symptoms of bacterial meningitis.
3. The most severe form of meningitis is considered to be:
3. Answer: A. Bacterial.
- A: Bacterial meningitis is the most severe form of meningitis.
4. Meningitis alters intracranial physiology, causing:
A. Cerebral edema
B. Increased permeability of the blood-brain barrier
C. Raised intracranial pressure
D. All of the above changes
4. Answer: D. All of the above changes.
- D: All of the options listed above are caused by meningitis.
- A: Cerebral edema is caused by bacterial meningitis.
- B: Increased permeability of the blood-brain barrier is caused by meningitis.
- C: Raised intracranial pressure is caused by meningitis.
5. In diagnosing seizure, which of the following is the most beneficial?
A. Skull radiographs
C. Brain scan
D. Lumbar puncture
5. Answer: B. EEG
- B: The EEG recognizes abnormal electrical activity in the brain. The pattern of multiple spikes can assist in the diagnosis of particular seizure disorders.
- A: Skull radiographs can distinguish fractures and structural abnormalities.
- C: Brain scans confirm space-occupying lesions.
- D: Lumbar puncture confirms problems related to cerebrospinal fluid infection or trauma.