How is Meningitis Detected?

How Doctors Detect Meningitis

According to WHO, acute bacterial meningitis can have a case fatality rate of up to 10–20% even with treatment, and may reach 50% or higher if untreated, depending on the pathogen and setting. Approximately 10–20% of survivors of bacterial meningitis may experience long-term neurological sequelae such as hearing loss or cognitive impairment. Meningitis is known as inflammation of meninges, which is the layer surrounding the brain and spinal cord, which diagnostic tests can detect. Such tests may include imaging studies, blood tests, cultures, and a physical examination.

Read further to understand the diagnostic tests that help detect meningitis.

What are the Diagnostic Procedures to Detect Meningitis?

Meningitis can be diagnosed and detected through several procedures, such as:

Symptom Analysis

Doctors will look for symptoms of meningitis, such as high fever, severe headache, stiffness in the neck, nausea, light sensitivity, and changes in mental status. Infant symptoms include irritability, poor feeding, and a bulging skull.

Physical Examination

Testing for meningitis starts with a physical exam, in which the doctor measures the probability of meningitis. The doctor will ask about any present illnesses, all symptoms, and when the symptoms started. A few of such tests involve:

Brudzinski’s Sign

A doctor performs this test by flexing the patient's neck toward the chest when the patient is on their back. Brudzinski’s sign is positive when passive flexion of the neck causes involuntary flexion of the hips and knees, suggesting meningeal irritation.

Kernig’s Sign

This test involves lying down, and the doctor bends the knee toward the chest and tries to straighten the leg upward. If doing this hurts the patient or cannot be performed at all, the patient might have inflammation in the meninges, which is predicted to be meningitis.

Blood Tests and Culture

Some blood test results, like those for meningitis, show an extremely high white blood cell count, which can be used to diagnose a severe infection. A few of those tests include:

Lumbar Puncture (Spinal Tap)

It is the gold standard for meningitis diagnosis. Cerebrospinal fluid (CSF) is extracted and analyzed for:

• White blood cell count (Elevated in bacterial/viral meningitis)
• Glucose levels (Low in bacterial meningitis)
• Protein levels (High in bacterial meningitis)
• Gram stain & culture (Identifies bacterial cause)
• PCR tests (Detect viral DNA/RNA)

Blood Tests

The following blood tests diagnose meningitis:

• Complete blood count (CBC): High WBC indicates infection.
• Blood cultures: Detect bacteria in the bloodstream.
• CRP & procalcitonin: Markers of bacterial infection.

Imaging Tests

Before a lumbar puncture, CT (computed tomography) or MRI (magnetic resonance imaging) scans are performed if:

• There’s a risk of brain herniation
• Focal neurological deficits are present
• The patient has seizures or is immunocompromised.

Rapid Antigen Test

Rapid antigen tests (e.g., latex agglutination) can detect bacterial pathogens (Streptococcus pneumoniae, Neisseria meningitidis); however, they are less sensitive than cultures.

Early detection can save lives. Since meningitis can be fatal if left untreated, it is necessary to consult a healthcare provider for an accurate diagnosis and a personalized treatment plan.

Reader Information: The information provided in this article is intended for general educational purposes only. Symptoms, diagnostic procedures, and outcomes of meningitis can vary based on the individual, the causative organism, and clinical circumstances. Readers are strongly advised to consult a qualified healthcare professional for diagnosis, evaluation, and treatment.

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