Pneumococcal meningitis is a bacterial inflammation of the meninges. It is potentially fatal with increased incidence of mortality in the very young and in the elderly. Individuals who survive this infection are at risk of developing sequelae like deafness, neurological deficits and growth retardation. Diagnosis is based on the analysis of cerebrospinal fluid and neuroimaging.
Pneumococcal meningitis (PM) is caused by the Gram-positive bacteria, Streptococcus pneumoniae, which is also called the pneumococcus bacteria. A majority of adult cases of community-acquired bacterial meningitis are caused by this bacteria  . PM became the leading cause of meningitis after the Haemophilus influenzae type b vaccine was introduced . Young children, the elderly, patients with chronic diseases, and immunocompromised individuals are at the greatest risk of developing PM   . Despite medical advances, the fatality rates for PM range from approximately 2% in children to 25% in adults  . Survivors frequently have neurological sequelae like deafness or cognitive deficits    .
The clinical signs and symptoms of PM depend on the age of the patient. Young babies may present with poor feeding, irritability, lethargy, vomiting, fever, and a bulging anterior fontanel . Children and adults classically have a fever, severe headache, photophobia, neck stiffness, vomiting, confusion, delirium, and seizures, while elderly patients may have atypical features like altered mental status and confusion  .
The diagnosis of PM depends on obtaining a detailed medical history, including a history of the patient's immunization status, physical examination, and cerebrospinal fluid (CSF) analysis. Clinically it is difficult to differentiate between bacterial and viral causes of meningitis. During the physical examination, vital signs and a complete neurological assessment should be performed. Neck stiffness is usually seen in a majority of the adults but may be present in only 30% of the children  . Although a petechial rash is a common feature of meningococcal meningitis, a majority of patients with other forms of bacterial meningitis also develop a rash within 24 hours of onset of the initial symptoms  . There may be evidence of a primary source of infection e.g. otitis media, sinusitis, or pneumonia. Meningeal signs and papilledema can be noted in most of the patients while babies may have a bulging anterior fontanel indicative of raised intracranial pressure.
A computed tomogram of the head should be performed prior to lumbar puncture in cases with neurological deficits, papilledema, and altered sensorium to exclude intracranial abscesses, tumors, or edema . Magnetic resonance imaging (MRI) is performed to diagnose complications associated with the condition and findings include brain infarction, cerebral edema, and hydrocephalus in cases of PM .
CSF analysis helps to differentiate between bacterial and viral etiology while CSF culture detects the causative bacteria. Typically in bacterial meningitis, the CSF pressure is elevated with polymorphonuclear leukocytosis, and reduced glucose levels relative to the serum glucose. Inflammatory markers such as serum C-reactive protein (CRP) levels are elevated in bacterial meningitis . Polymerase chain reaction (PCR) test can be performed, if available, as it is more sensitive than microbiological tests in detecting bacterial versus viral DNA. It is also useful in diagnosing a bacterial cause of meningitis in patients who have been treated with antibiotics .