Determining the Cause

Management

May indicate meningitis, encephalitis, or sepsis.

Key principle: Don't delay antibiotics and acyclovir while waiting for diagnostic tests. Early treatment saves lives and prevents complications.

1. Bacterial meningitis is a medical emergency

It can progress rapidly to sepsis, brain injury, or death.
Delays in treatment, even by 1–2 hours, increase mortality.
Treat first and confirm later.

2. Start empiric antibiotics as soon as bacterial meningitis is suspected

This means:

Do NOT wait for lumbar puncture (LP) if doing so will delay antibiotics.
Blood cultures can be drawn first if possible, but antibiotics should not be delayed.

3. Also give adjunct corticosteroids

Dexamethasone is often given before or with the first dose of antibiotics to reduce inflammation and neurological complications (especially in S. pneumoniae).

For suspected or confirmed bacterial meningitis, the recommended dexamethasone dose is:

Adults
- 10 mg IV every 6 hours for 4 days
- Give the first dose before or with the first dose of antibiotics, ideally 10–20 minutes prior.
Children
- 0.15 mg/kg IV every 6 hours for 2–4 days
- Also given before or with the first antibiotic dose.
Key points
- Proven benefit mainly in pneumococcal (Streptococcus pneumoniae) meningitis in adults.
- It reduces mortality and neurologic complications such as hearing loss.
- Stop dexamethasone if CSF studies show:
  - Not consistent with bacterial meningitis, or
  - A non–S. pneumoniae organism is identified where steroids don't help (e.g., N. meningitidis).
[If you want, I can also give you the full empiric antibiotic regimen based on age group.
]

4. Antibiotics depend on age and risk

Empiric regimens generally include:

Adults < 50 years:
Ceftriaxone (or cefotaxime) + vancomycin
Adults > 50 or immunocompromised:
Ceftriaxone + vancomycin + ampicillin (for Listeria)
Neonates, infants, special conditions → different regimens.

5. Viral meningitis

Antibiotics can be stopped once testing confirms the cause is viral and the patient is stable.

Bottom line

If meningitis is suspected, give antibiotics immediately.
Confirm the diagnosis afterward with LP, cultures, and imaging as needed.

If you'd like, I can also give:

A step-by-step ER algorithm
Differences in treatment between bacterial, viral, fungal, TB meningitis
Red-flag symptoms that trigger empiric therapy

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Initial Assessment

Immediate priorities:

Assess airway, breathing, circulation (ABCs)
Vital signs: temperature, blood pressure, heart rate, respiratory rate, oxygen saturation
Blood glucose check (hypoglycemia can cause confusion)
Brief neurological examination (Glasgow Coma Scale, pupillary response, focal deficits)
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History Taking

Onset and duration of symptoms
Recent infections, travel, sick contacts
Immunization status
Immunocompromised state (HIV, chemotherapy, steroids)
Medications, substance use
Headache, neck stiffness, photophobia, rash
Recent head trauma

Physical Examination

Meningeal signs: Neck stiffness, Kernig's sign, Brudzinski's sign
Skin: Petechial or purpuric rash (meningococcemia)
Neurological: Level of consciousness, focal deficits, seizure activity
Signs of infection: Respiratory, urinary, abdominal sources

Investigations

Blood cultures (before antibiotics if possible)
Complete blood count, electrolytes, renal and liver function
Urinalysis and urine culture
Chest X-ray
Lumbar puncture (if no contraindications like raised intracranial pressure)
CT head (if focal signs, seizures, or papilledema present before LP)
Consider: Blood smear for malaria if travel history

Immediate Management

If meningitis/encephalitis suspected:

Empirical antibiotics immediately (don't delay for LP if unstable)
- Ceftriaxone or cefotaxime
- Add ampicillin if >50 years or immunocompromised (for Listeria)
- Add vancomycin if suspected resistant pneumococcus
Acyclovir if viral encephalitis possible
Dexamethasone (with or before first antibiotic dose for bacterial meningitis)

Supportive care:

IV fluids for hydration
Antipyretics (acetaminophen/paracetamol)
Seizure precautions
Monitor closely in appropriate setting (ICU if severe)

Differential Diagnoses to Consider

Bacterial meningitis
Viral encephalitis (HSV, arbovirus)
Cerebral malaria
Sepsis with encephalopathy
CNS abscess
Urinary tract infection (especially elderly)
Pneumonia with delirium
Drug intoxication/withdrawal