Classic triad of fever, neck stiffness and mental status changes occurs in approximately 44% of cases, but 95% of patients have 2 of 4 symptoms of fever, headache, neck stiffness or mental status change.
A worsening headache when the head is turned in the horizontal plane at 2-3 rotations per second has a 97% sensitivity for meningitis (jolt accentuation).
Meningitis can be classified as acute, subacute, or chronic.
With acute meningitis symptoms occur for up to five days, while those with subacute meningitis symptoms last for 6 to 30 days.
Chronic meningitis indicates that symptoms have lasted for more than 30 days.
Fever occurs in the majority of patients with meningitis and is the most sensitive of the classic triad of findings.
Impaired sensorium, hemodynamic instability, and respiratory compromise are life-threatening complications that require ICU monitoring.
Immunocompromised patients are patients with focal neurologic findings, seizures, obtundation, or papilledema should undergo a noncontrast head CT scan prior to lumbar puncture.
With suspected meningitis antibiotics are initiated a soon as possible, even prior to lumbar puncture, if the study is delayed.
Most common bacterial cause is S. pneumonia with about 3,000 cases each year with a incidence of 0.8-1.1 cases per 100,000 population.
32% of children two years of age and younger with meningitis had been given oral antibiotics more than two days before the meningitis is detected.
Gram stained and culture from blood and CSF are critical for diagnosis.
Gram stain has a sensitivity of 60-90% and specificity of over 97%.
CSF opening pressure is frequently elevated.
CSF markers include white blood cell count greater than 2000 cells put millimeter cubed, protein 2.2 g/L, glucose level less than 34 mg/dL and CSF to serum glucose ratio of 0.23 are present in 88% of bacterial meningitis cases.
In gram-negative bacillary meningitis 75% of cases are associated with a recent neurological procedure or head trauma, placement of a neurosurgical device of CSF leak.
Most cases present within negative Gram stain (88%) and is often considered to be due to it enterovirus with a benign clinical outcome.
Is often a diagnostic challenge because of its broad differential diagnosis and include some entities that require urgent therapy for cure and survival.
As many as 11% of cases have serious associated neurologic morbidity or mortality.
Risk stratification for adverse clinical outcome in patients with a negative CSF Gram stain is an age greater than 60 years, the presence of an abnormal neurologic examination such as an altered mental status, focal neurological deficit, or seizure and a CSF glucose of less than 45 mg per dL(Khoury NT et al).
Gram-negative organisms on CSF examination in the absence of predisposing factors should prompt a search for a urinary, gastrointestinal, sinus or oral infection as the source.
Recurrence of meningitis may be associated with intermittent meningeal symptoms, and spinal fluid abnormalities, followed by periods of normal clinical examination and CSF findings.
Bacterial and viral meningitides tend to produce a thin, linear pattern of leptomeningeal enhancement, where is fungal and neoplastic meningitides are often associated with thicker, nodular pattern of enhancement.
Recurrent meningitis may be associated with recurrent headaches, fever, nausea, nuchal rigidity, impaired mental status, seizures, focal neurologic abnormalities,papilledema and cranial nerve palsies.
Recurrent menigitis may have CSF pleocytosis, normal or elevated protein levels, variable glucose levels and opening pressure that is elevated, dependent on the cause.
Chronic meningitis is defined as meningitis with symptoms lasting longer than four weeks and with CSF pleocytosis and is most commonly caused by atypical bacteria, fungi, or a non-infectious process.
Symptoms of chronic meningitis include: headache, lethargy, mental status changes, and fever.
The above findings suggest the need for lumbar puncture to detect an inflammatory process in the CSF.
Cranial nerve abnormalities such as diplopia or hearing loss can be associated with chronic meningitis, as these nerves are affected in their course through the subarachnoid space.
About 40% of patients experience cognitive changes with chronic meningitis.
In some patients with chronic meningitis cognitive change maybe the sole presentation.
Chronic meningitis may be associated with the rapid onset of dementia, especially in those with a history of immunosuppression.
Nuclear rigidity is less common than in acute or subacute disease and even less common with non-infectious causes than with infectious causes.
The CSF cell count is elevated in chronic meningitis, except in persons with severe immunosuppression or in some forms of neoplastic meningitis.
The CSF in chronic meningitis generally has a lymphocyte predominant pleocytosis, however, tuberculous meningitis and other infections including norcardis, Brucella, and fungal infections may have persistent neutrophilic meningitis.
CSF protein is nearly always elevated in chronic meningitis and hypoglycorrhacia commonly accompanies infectious causes of meningitis including sarcoidosis and meningeal metastasis.
Hydrocephalus and elevated intracranial pressure may be associated with inflammatory leptomeninges of disease, particularly with cryptococcal meningitis.
Seizures or stroke like episodes occur as a result of infectious or inflammatory cerebral vasculitis.
Chronic meningitis may be characterized as infectious or non-infectious.
Cognitive alterations occur with chronic meningitis in approximately 40% of cases, and the incidence varies according to the underlying cause.
In the evaluation of a patient with chronic meningitis, geographic residence, travel history, immune status and information on other underlying illnesses is required.
Uveitis suggests sarcoidosis, lymphoma, Behcet’s disease, or idiopathic uveoimeningeal syndromes of chronic meningitis.
Rheumatoid arthritis and sarcoidosis can cause inflammatory reactions in the meninges, but can also predisposed to meningitis with opportunistic infections
Parameningeal Infections and inflammatory reactions can cause a sterile inflammatory response in the CSF and manifest as chronic meningitis.
IgG4 disease can manifest as chronic meningitis.
The systematic examination of the lungs, skin, liver, spleen, joints, eyes, and lymph nodes provide necessary information regarding inflammatory and granulomas this disease is that often underlying chronic meningitis.
Multiple causes exist for chronic meningitis and include infections with Tuberculosis, HIV, syphilis, listeriosis, brucellosis, fungal, parasitic, and other bacterial and viral etiologies.
Noninfectious causes of chronic meningitis include sarcoidosis, lupus erythematosus,
granulomatous angiitis, Sjogren’s syndrome and Behcet disease.
Neoplastic meningitis can result from hematologic cancers, metastatic solid tumors or rarely primary brain cancers.
The most common organisms are streptococcus pneumoniae, followed by neisseria meningitidis.
Immunocompromised individuals and those over age 50 are more susceptible to Listeria monocytogenes.
Empiric treatment includes antibiotics with vancomycin and a third-generation cephalosporin to cover the most common agents, including those resistant to beta-lactam antibiotics.
Ampicillin may be added for Listeria coverage.
Intravenous steroids administered with antibiotics may decrease mortality in streptococcus pneumoniae infections and is recommended in bacterial meningitis treatment guidelines.
Viral agents of the most common cause of meningitis, and typically produce a self-limiting and less severe infection
In Western countries, most common viral agents are enteroviruses, followed by herpes simplex virus-2,varicella zoster virus, and arboviruses in order of preference.
Enteroviruses are the most commonly identified viral pathogens and have a seasonal distribution with the highest incidence in summer and autumn, and they are transmitted from person to person by the fecal-oral route.
CSF in viral meningitis usually reveals mild to moderate lymphocytic pleocytosis with 100-1000 cells per millimeter cubed, moderately elevated protein, and normal glucose.
PCR can help identify common viruses, but in many cases the pathogenic agent of viral meningitis remains unknown.
Treatment of viral meningitis is mostly supportive.
The efficacy of acycloviir in herpes Symplex virus meningitis is unclear.