Bacterial meningitis


Meningitis is an acute bacterial infection of the meninges, which may affect the brain and lead to irreversible neurological damage and auditory impairment.

Bacterial meningitis is a medical emergency. The treatment is based on early parenteral administration of antibiotics that penetrates well into the cerebrospinal fluid. Empiric antibiotic therapy is administered if the pathogen cannot be identified or while waiting for laboratory results.


The main bacteria responsible vary depending on age and/or context:

– Meningitis in a non-epidemic context:
• Children 0 to 3 months:
Children ≤ 7 days: Gram-negative bacilli (Klebsiella sppE. coliS. marscesensPseudomona sppSalmonella spp) and group B streptococcus
Children > 7 days: S. pneumoniae accounts for 50% of all bacterial meningitis
L. monocytogenes is occasionally responsible for meningitis during this period.
• Children 3 months-5 years: S. pneumoniae, H. influenza B and N. meningitidis
• Children > 5 years and adults: S. pneumoniae and N. meningitidis

Special conditions:
• Immunodepressed patients (HIV, malnourished): high percentage of Gram- negative bacilli (specially Salmonella spp) and also M. tuberculosis.
• Sickle cell anaemia: Salmonella spp and Staphylococcus aureus are frequent causes.
• Meningitis may be related to S. aureus when associated with skin infection or skull fracture.

– Meningitis in an epidemic context:
In the Sahelian region (but not exclusively, e.g. Rwanda, Angola, Brazil), during the dry season, epidemics of meningococcal meningitis (Neisseria meningitidis A or C or W135) affect children from 6 months of age, adolescents and adults. In these regions, whether during epidemics or not, all the above pathogens can be found, especially in young children.

Clinical features

The clinical presentation depends on the patient's age.

Children over 1 year and adults

– Fever, severe headache, photophobia, neck stiffness
– Brudzinski's sign (neck flexion in a supine patient results in involuntary flexion of the knees) and Kernig's sign (attempts to extend the knee from the flexed-thigh position are met with strong passive resistance).
– Petechial or ecchymotic purpura (usually in meningococcal infections)
– In severe forms: coma, seizures, focal signs, purpura fulminans

Children under 1 year

The classic signs of meningitis are usually absent.

– The child is irritable, appears sick with fever or hypothermia, poor feeding or vomiting.
– Other features include: seizures, apnoea, altered consciousness, bulging fontanelle (when not crying); occasionally, neck stiffness and purpuric rash.

Laboratory

– Lumbar puncture (LP):
• Macroscopic examination of the cerebrospinal fluid (CSF): antibiotic therapy should be initiated immediately if the LP yields a turbid CSF.
• Microscopic examination: Gram stain (but a negative examination does not exclude the diagnosis) and white blood cell count (WBC).
• In an epidemic context, once the meningococcal aetiology has been confirmed, there is no need for routine LP for new cases.


Pressure

Aspect

WBC
(leucocytes/mm3)

Protein

Other tests

Normal CSF


Clear

< 5

Pandy–
< 40 mg/dl

Bacterial meningitis

++++

Cloudy, turbid

100-20 000
mainly neutrophiles

In neonates:
> 20

In immunocompromised,
the WBC may be < 100

Pandy+
100-500 mg/dl

Gram stain +

Viral meningitis

Normal to +

Clear

10-700
mainly lymphocytes

Pandy–

TB meningitis

+++

Clear or yellowish

< 500
mainly lymphocytes

Pandy+

AFB

Cryptococcal meningitis

++++

Clear

< 800
mainly lymphocytes

Pandy–

India ink

– Rapid test for detection of bacterial antigens.

Note: in an endemic area, it is essential to test for severe malaria (rapid test or thin/thick films).

Treatment in a non-epidemic context

Antibiotherapy

For the choice of antibiotic therapy and dosages according to age, see table below.


No associated skin infection Associated skin infection (including umbilical cord infection)


First line

Alternative

First line

Alternative

0 to 7 days
< 2 kg

ampicillin IV
100 mg/kg every 12 hours
+
cefotaxime IV
50 mg/kg every 12 hours

ampicillin IV
100 mg/kg every 12 hours
+
gentamicin IV
3 mg/kg once daily

cloxacillin IV
50 mg/kg every 12 hours
+
cefotaxime IV
50 mg/kg every 12 hours

cloxacillin IV
50 mg/kg every 12 hours
+
gentamicin IV
3 mg/kg once daily

0 to 7 days
≥ 2 kg

ampicillin IV
100 mg/kg every 8 hours
+
cefotaxime IV
50 mg/kg every 8 hours

ampicillin IV
100 mg/kg every 8 hours
+
gentamicin IV
5 mg/kg once daily

cloxacillin IV
50 mg/kg every 8 hours
+
cefotaxime IV
50 mg/kg every 8 hours

cloxacillin IV
50 mg/kg every 8 hours
+
gentamicin IV
5 mg/kg once daily

8 days to
< 1 month
≥ 2 kg

ampicillin IV
100 mg/kg every 8 hours
+
cefotaxime IV
50 mg/kg every 8 hours

ampicillin IV
100 mg/kg every 8 hours
+
gentamicin IV
5 mg/kg once daily

cloxacillin IV
50 mg/kg every 6 hours
+
cefotaxime IV
50 mg/kg every 8 hours

cloxacillin IV
50 mg/kg every 6 hours
+
gentamicin IV
5 mg/kg once daily

1 to 3 months

ampicillin IV
100 mg/kg every 8 hours
+
ceftriaxone IV 100 mg/kg on D1
then starting on D2: 100 mg/kg once daily or 50 mg/kg every 12 hours

ampicillin IV
100 mg/kg every 8 hours
+
gentamicin IV
2.5 mg/kg every 8 hours

cloxacillin IV
50 mg/kg every 6 hours
+
ceftriaxone IV 100 mg/kg on D1
then starting on D2: 100 mg/kg once daily or 50 mg/kg every 12 hours

cloxacillin IV
50 mg/kg every 6 hours
+
gentamicin IV
2.5 mg/kg every 8 hours

> 3 months

ceftriaxone IV
Children < 20 kg: 100 mg/kg on D1 then starting on D2: 100 mg/kg once daily or 50 mg/kg every 12 hours
Children ≥ 20 kg and adults: 2 g once daily

cloxacillin IV
Children < 40 kg: 50 mg/kg every 6 hours
Children ≥ 40 kg and adults: 2 g every 6 hours
+
ceftriaxone IV
Children < 20 kg: 100 mg/kg on D1 then starting on D2: 100 mg/kg once daily or 50 mg/kg every 12 hours
Children ≥ 20 kg and adults: 2 g once daily


Duration of antibiotherapy:

1) According to the pathogen:
• Haemophilus influenzae: 7 days
• Streptococcus pneumonia: 10-14 days
• Group B streptococcus and Listeria: 14-21 days
• Gram-negative bacilli: 21 days
• Neisseria meningitidis: see antibiotherapy in an epidemic context

2) If the pathogen is unknown:
Children < 3 months: 2 weeks beyond the first sterile CSF culture or 21 days
Children > 3 months and adults: 10 days. Consider extending treatment or alternative diagnoses if fever persists beyond 10 days. On the other hand, a 7-day course of ceftriaxone is sufficient in patients who are making an uncomplicated recovery.

Additional treatment

– Dexamethasone reduces the risk of hearing loss in patients with H. influenzae or S. pneumoniae.
Early administration in indicated in meningitis caused by these pathogens or when the pathogen is unknown, except in neonates (and in presumed meningococcal meningitis in an epidemic context).
dexamethasone IV
Children > 1 month and adults: 0.15 mg/kg (max. 10 mg) every 6 hours for 2 days
The treatment should be started before or with the first dose of antibiotic, otherwise, the treatment offers no benefit.

– Ensure that the patient is well fed and well hydrated (infusions or nasogastric tube if necessary).

– Seizures (Chapter 1).

– Coma: prevention of bed sores, care of the mouth and eyes, etc.

Treatment in an epidemic context

Antibiotherapy

In this context, N. meningitidis is the most likely pathogen.

Children under 2 months

ceftriaxone IV1 or IM2 for 7 days
100 mg/kg once daily

Children over 2 months and adults

ceftriaxone IV1 or IM2 for 5 days
Children 2 months to < 5 years: 100 mg/kg once daily (max. 2 g daily)
Children ≥ 5 years and adults: 2 g once daily

Note:
A short treatment with a single dose of ceftriaxone IM can be used in children 2 years and older, and in adults, if during a meningococcal meningitis epidemic confirmed by a reliable laboratory, the number of cases exceeds management capacities with the 5-day treatment. Check national recommendations. Nevertheless, it is essential to ensure a monitoring of cases after 24 hours.
ceftriaxone IM2
Children 2 to < 12 years: 100 mg/kg single dose
Children ≥ 12 years and adults: 4 g single dose
If there is no clinical improvement (fever > 38.5 °C, repeated seizures, appearance or aggravation of a reduced level of consciousness or of neurological signs) 24 hours after the injection, continue the treatment with ceftriaxone for 5 days.

Additional treatment

– Ensure that the patient is well fed and well hydrated (infusions or nasogastric tube if necessary).
– Seizures (Chapter 1).
– Coma: prevention of bed sores, care of the mouth and eyes, etc.
– Dexamethasone in not indicated.



Footnotes
Ref Notes
1 The solvent of ceftriaxone for IM injection contains lidocaine. Ceftriaxone reconstituted using this solvent must never be administered by IV route. For IV administration, water for injection must always be used. [ a b ]
2 For IM administration, divide the dose into 2 injections if needed, half-dose in each buttock. [ a b c ]