Which clinical manifestation would the nurse associate with a patient experiencing meningitis?
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Acute bacterial meningitis is rapidly progressive bacterial infection of the meninges and subarachnoid space. Findings typically include headache, fever, and nuchal rigidity. Diagnosis is by cerebrospinal fluid (CSF) analysis. Treatment is with antibiotics and corticosteroids given as soon as possible. Show
Because white blood cells (WBCs), immunoglobulins, and complement are normally sparse or absent from cerebrospinal fluid (CSF), bacteria initially multiply without causing inflammation. Later, bacteria release endotoxins, teichoic acid, and other substances that trigger an inflammatory response with mediators such as WBCs and tumor necrosis factor (TNF). Typically in CSF, levels of protein increase, and because bacteria consume glucose and because less glucose is transported into the CSF, glucose levels decrease. Brain parenchyma is typically affected in acute bacterial meningitis. Inflammation in the subarachnoid space is accompanied by cortical encephalitis and ventriculitis. Complications of bacterial meningitis are common and may include
Likely causes of bacterial meningitis depend on
In older infants, children, and young adults, the most common causes of bacterial meningitis are
N. meningitidis meningitis occasionally causes death within hours. Sepsis caused by N. meningitidis sometimes results in coagulopathy and bilateral adrenal hemorrhagic infarction (Waterhouse-Friderichsen syndrome). Haemophilus influenzae type B, previously the most common cause of meningitis in children < 6 years and overall, is now a rare cause in the US and Western Europe, where the H. influenzae vaccine is widely used. However, in areas where the vaccine is not widely used, H. influenzae is still a common cause, particularly in children aged 2 months to 6 years. In middle-aged and in older adults, the most common cause of bacterial meningitis is
Less commonly, N. meningitidis causes meningitis in middle-aged and older adults. As host defenses decline with age, patients may develop meningitis due to L. monocytogenes or gram-negative bacteria. In people of all ages, Staphylococcus aureus occasionally causes meningitis.  Routes of entry include the following:
Having any of the above conditions increases the risk of acquiring meningitis. Overall, the most common causes of bacterial meningitis in immunocompromised patients are
But the most likely bacteria depend on the type of immune deficiency: In very young infants (particularly premature infants) and older adults, T-cell immunity may be weak; thus, these age groups are at risk of meningitis due to L. monocytogenes. Symptoms and Signs of Acute Bacterial MeningitisIn most cases, bacterial meningitis begins with 3 to 5 days of insidiously progressive nonspecific symptoms including malaise, fever, irritability, and vomiting. However, meningitis may be more rapid in onset and can be fulminant, making bacterial meningitis one of the few disorders in which a previously healthy young person may go to sleep with mild symptoms and never awaken. Typical symptoms and signs of meningitis include
However, fever, headache, and nuchal rigidity may be absent in neonates and infants (see Neonatal Bacterial Meningitis Symptoms and Signs Neonatal bacterial meningitis is inflammation of the meninges due to bacterial invasion. Signs are those of sepsis, central nervous system irritation (eg, lethargy, seizures, vomiting, irritability... read more ). So-called paradoxical irritability, in which cuddling and consoling by a parent irritates rather than comforts the neonate, suggests bacterial meningitis. Seizures occur early in up to 40% of children with acute bacterial meningitis and may occur in adults. Up to 12% of patients present in coma. Accompanying systemic infection by the organism may cause
Fever and nuchal rigidity may be absent or mild in immunocompromised or older patients and in alcoholics. Often, in older patients, the only sign is confusion in those who were previously alert or altered responsiveness in those who have dementia. In such patients, as in neonates, the threshold for doing lumbar puncture should be low. Brain imaging (MRI or, less optimally, CT) should be done if focal neurologic deficits are present or increased ICP is suspected. If bacterial meningitis develops after a neurosurgical procedure, symptoms often take days to develop.
As soon as acute bacterial meningitis is suspected, blood cultures and lumbar puncture for CSF analysis (unless contraindicated) are done. Blood should be analysed when lumbar puncture is done so that blood glucose levels can be compared with CSF glucose levels. Treatment should be started as follows:
Clinicians should suspect bacterial meningitis in patients with typical symptoms and signs, usually fever, changes in mental status, and nuchal rigidity. However, clinicians must be aware that symptoms and signs are different in neonates and infants and may be absent or initially mild in older patients, alcoholics, and immunocompromised patients. Diagnosis can be challenging in the following patients:
Because untreated bacterial meningitis is lethal, tests should be done if there is even a small chance of meningitis. Testing is particularly helpful in infants, older patients, alcoholics, immunocompromised patients, and patients who had neurosurgical procedure because symptoms may be atypical. If findings suggest acute bacterial meningitis, routine tests include
Contraindications to immediate lumbar puncture are signs suggesting markedly increased ICP or an intracranial mass effect (eg, due to edema, hemorrhage, or tumor); typically, these signs include
In such cases, lumbar puncture may cause brain herniation and thus is deferred until neuroimaging (typically CT or MRI) is done to check for increased ICP or a mass effect. When lumbar puncture is deferred, treatment is best begun immediately (after blood sampling for culture and before neuroimaging). After ICP, if increased, has been lowered or if no mass effect or obstructive hydrocephalus is detected, lumbar puncture can be done. CSF should be sent for analysis: cell count, protein, glucose, Gram staining, culture, PCR, and other tests as indicated clinically. A new multiplex film-array PCR panel can provide rapid screening for multiple bacteria and viruses plus Cryptococcus neoformans in a CSF sample. This test, which is not always available, is used to supplement, not replace, culture and traditional tests. Simultaneously, a blood sample should be drawn and sent to have the CSF:blood glucose ratio determined. CSF cell count should be determined as soon as possible because white blood cells (WBCs) may adhere to the walls of the collecting tube, resulting in a falsely low cell count; in extremely purulent CSF, WBCs may lyse. Typical CSF findings in bacterial meningitis include the following (see table CSF Findings in Meningitis ):
A CSF:blood glucose level of < 50% suggests possible meningitis. A CSF glucose level of ≤ 18 mg/dL or a CSF:blood glucose ratio of < 0.23 strongly suggests bacterial meningitis. However, changes in CSF glucose may lag 30 to 120 minutes behind changes in blood glucose. In acute bacterial meningitis, an elevated protein level (usually 100 to 500 mg/dL) indicates blood-brain barrier injury. CSF cell count and protein and glucose levels in patients with acute bacterial meningitis are not always typical. Atypical CSF findings may include
When initial CSF findings are equivocal, a repeat lumbar puncture 12 to 24 hours later can sometimes clarify which direction CSF changes are heading or whether there was a laboratory error. Identification of the causative bacteria in CSF involves Gram staining, culture, and, when available, PCR. Gram staining provides information rapidly, but the information is limited. For bacteria to be reliably detected with Gram stain, about 105 bacteria/mL must be present. Results may be falsely negative if any of the following occur:
If clinicians suspect an anaerobic infection or other unusual bacteria, they should tell the laboratory before samples are plated for cultures. Prior antibiotic therapy can reduce the yield from Gram staining and culture. PCR, if available, and latex agglutination tests to detect bacterial antigens may be a useful adjunctive tests, especially in patients who have already received antibiotics. Determination of antibiotic sensitivity requires bacterial culture. Until the cause of meningitis is confirmed, other tests using samples of CSF or blood may be done to check for other causes of meningitis, such as viruses (particularly herpes simplex), fungi, and cancer cells. Samples from other sites suspected of being infected (eg, urinary or respiratory tract) should also be cultured. With antibiotic treatment, the mortality rate for children < 19 years may be as low as 3% but is often higher; survivors may be deaf and neuropsychologically impaired. The mortality rate, even with antibiotic treatment, is about 17% for adults < 60 years but up to 37% in those > 60. Community-acquired meningitis due to S. aureus has a mortality rate of 43%. In general, mortality rate correlates with depth of obtundation or coma. Factors associated with a poor prognosis include
Seizures and a low CSF:serum glucose ratio may also indicate a poor prognosis.
Antibiotics are the mainstay of therapy for acute bacterial meningitis. In addition to antibiotics, treatment includes measures to decrease brain and cranial nerve inflammation and increased intracranial pressure (ICP). Most patients are admitted to an intensive care unit (ICU). Antibiotics must be bactericidal for the causative bacteria and must be able to penetrate the blood-brain barrier. If patients appear ill and findings suggest meningitis, antibiotics (see table
Initial Antibiotics for Acute Bacterial Meningitis
Initial Antibiotics for Acute Bacterial Meningitis Appropriate empiric antibiotics depend on the patient's age and immune status and route of infection (see table
Initial Antibiotics for Acute Bacterial Meningitis
Initial Antibiotics for Acute Bacterial Meningitis Commonly used antibiotics include
Dexamethasone is used to decrease cerebral and cranial nerve inflammation and edema; it should be given when therapy is started. Adults are given 10 mg IV; children are given 0.15 mg/kg IV. Dexamethasone is given immediately before or with the initial dose of antibiotics and every 6 hours for 4 days. Use of dexamethasone is best-established for patients with pneumococcal meningitis. The effectiveness of other measures is less well-proved. Patients presenting with papilledema or signs of impending brain herniation are treated for increased ICP:
Usually, adults are given mannitol 1 g/kg IV bolus over 30 minutes, repeated as needed every 3 to 4 hours or 0.25 g/kg every 2 to 3 hours, and children are given 0.5 to 2.0 g/kg over 30 minutes, repeated as needed. Additional measures can include
Use of vaccines for H. influenzae type B and, to a lesser extent, for N. meningitidis and S. pneumoniae has reduced the incidence of bacterial meningitis. Keeping patients in respiratory isolation (using droplet precautions) for the first 24 hours of therapy can help prevent meningitis from spreading. Gloves, masks, and gowns are used. Vaccination can prevent certain types of bacterial meningitis.
During a meningitis epidemic, the population at risk (eg, college students, a small town) must be identified, and its size must be determined before proceeding to mass vaccination. The effort is expensive and requires public education and support, but it saves lives and reduces morbidity. The meningococcal vaccine does not protect against serotype B meningococcal meningitis; this information should kept in mind when a vaccinated patient presents with symptoms of meningitis. Anyone who has prolonged face-to-face contact with a patient who has meningitis (eg, household or day care contacts, medical personnel and other people who are exposed to the patient's oral secretions) should be given postexposure chemoprophylaxis. For meningococcal meningitis, chemoprophylaxis consists of one of the following:
For meningitis due to H. influenzae type b, chemoprophylaxis is rifampin 20 mg/kg orally once a day (maximum: 600 mg/day) for 4 days. There is no consensus on whether children < 2 years require prophylaxis for exposure at day care. Chemoprophylaxis is not usually needed for contacts of patients with other types of bacterial meningitis.
The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
Click here for Patient Education Which assessment findings would the nurse associate with a diagnosis of acute aseptic meningitis?The key physical exam findings of aseptic meningitis may include fever, nuchal rigidity (neck stiffness) and photophobia. Altered mental status is rare and if present should increase suspicion for acute purulent meningitis or encephalitis.
Which signs and symptoms would the nurse find while assessing a patient with Graves disease?Signs and Symptoms of Grave's Disease. Weight loss (burning calories increased). Heat intolerance (feel extremely hot… sweaty). Tachycardia (sympathetic system in overdrive). Hypertension (sympathetic system in overdrive). Diarrhea (GI system working harder and faster). Irritable.. Smooth skin/hair (increase blood flow). Which disorder would the nurse associate with an obstruction of a blood vessel impeding blood flow to the brain?Stroke: Key points
A stroke happens when blood flow to your brain is stopped. It is an emergency situation. It can be caused by a narrowed blood vessel, bleeding, or a clot that blocks blood flow.
Which clinical manifestations are characteristics of Cushing's triad select all that apply?Cushing's triad refers to a set of signs that are indicative of increased intracranial pressure (ICP), or increased pressure in the brain. Cushing's triad consists of bradycardia (also known as a low heart rate), irregular respirations, and a widened pulse pressure.
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