8.1 Infections of the Nervous System

8.1.1 Bacterial infections

8.1.1.1 Bacterial Meningitis

Is a serious infection in which there are inflammations of the layers (meninges) covering the brain and spinal cord. Causative bacteria differs among different age groups

Diagnostic criteria

• Headache, high fever
• Confusion, convulsions, coma may occur.
• Photophobia
• Nausea and vomiting
• neck stiffness and other signs of meningeal irritations

Children

In infants under 1 year diagnosis is much more difficult therefore always think of it in a sick child if:

• Refusal to eat and or suckle, drowsiness and weak cry
• Focal or generalized convulsions
• Fever may be absent
• Irritability
• Hypotonia, neck is often not stiff
• Bulging fontanel

NOTE: A lumbar puncture for CSF analysis is essential to confirm diagnosis

Supportive therapy

• Control of fever and pain(refer fever and pain section)
• Control convulsions( see section convulsions)
• If unconscious, insert NGT for feeding and urethral catheter

Pharmacological Treatment

1. Where the organism is not known:

Adults:

B: Chloramphenicol 1000mg IV 6 hourly for 14 days

Plus

A: Benzyl penicillin 5MU IV 6 hourly for 14 days.

OR

A: Ceftriaxone IV 2 g 12 hourly for 14 days

OR

D:Cefotaxime 2 g IV 6 hourly for 10–14 days Plus

A: Ampicillin IV 2g 6 hourly for 10–14 days

Plus either

S: Cefepime 2 g IV every 8 hours 10–14 days OR

S: Meropenem 2 g IV every 8 hours 10 days

 

1. Where the organism is known:

• Meningococcal meningitis

Adults & children >2yrs

A: Ceftriaxone IM 100mg/kg as a single dose (divide into 2 injections if needed & inject half-dose in each buttock)

• Haemophilus influenza meningitis

Adults

A: Ceftriaxone IV 2g 12 hourly for 14 days

OR

D:Cefotaxime 2g IV 6 hourly for 10 days

OR

B: Chloramphenicol 1g IV 6 hourly for 7–10 days.

 

Children

C: Ampicillin 50–100 mg/kg 6 hourly for 10 days

OR

B: Chloramphenicol 50 mg/kg 6 hourly for 10 days

• Pneumococcal meningitis

A: Benzyl penicillin 5MU IV 6 hourly for 14 days

OR

B: Ceftriaxone IV 2 g 12 hourly for 14 days OR

D: Ceftriaxone + Salbactam (IV) 1.5mg twice daily for 14 days

OR

D: Cefotaxime 2g IV 6 hourly for 10 days

8.1.1.2 Tetanus

It is an acute, often fatal disease caused by an exotoxin produced by the anaerobic bacterium Clostridium tetani. It is acquired through wounds contaminated with spores of the bacteria and in the case of neonates, through the umbilical stump, resulting in neonatal tetanus

Diagnostic criteria

• Generalized spasms and rigidity of skeletal muscles
• Locked jaws
• Patients are usually fully conscious and aware.
• Dysphagia
• diaphoresis
• Local spasms may also occur

Supportive Therapy

• Nurse in dark, quiet room to avoid unnecessary external stimuli which can trigger spasms
• Protect the airway
• Thorough cleaning of the site of entry (wound/umbilicus), leaving it exposed without dressing
• Pain management with Paracetamol (via NGT) as the spasms can be very painful
• Maintenance of fluid balance and nutrition (via NGT)
• Avoid giving medications via IV/IM route as injections can trigger spasms
• Sedation (see below) and care as for unconscious patient

Pharmacological Treatment

Treatment is generally aimed at the following:

• For prevention of further absorption of toxin from the wound B: Human tetanus immunoglobulin; Adults give 3000IU stat

AND

A: Amoxicillin 500mg via NGT 8 hourly for 5 days

AND

A: Metronidazole 400mg 8 hourly for 5 days

• Control of spasms

Give a sedative cocktail of ALL the following via NGT:

A: Injection Diazepam10–30 mg 4–6 hourly Children: 0.5 mg/kg 6 hourly

AND

A: Injection Chlorpromazine100–200 mg 8 hourly

Children 2 mg/kg 6 hourly

AND

B: Injection Phenobarbitone 50–100 mg 12 hourly

Children 6 mg/kg 12 hourly

Table 8.1: Guidelines for dosage administration**

Time (Hours)	0	3	4	6	9	12	15	18	21	24
Diazepam	*			*		*		*		*
Chlorpromazine			*			*			*
Phenobarbitone		*					*

Prevention: Tetanus (toxoid) vaccine 0.5 ml IM; repeat after 4 weeks and after 6-12 months, then boost every 10 years thereafter

8.1.1.3 Brain Abscess

Brain abscess is a focal collection of pus/necrotic tissue within the brain parenchyma, which can arise as a complication of a variety of infections, trauma or surgery. The manifestations of brain abscess depends on the site, size and the immune status of the patient

Diagnostic Criteria

• Headache is the most common symptom
• Fevers
• Focal neurological deficit
• Vomiting and lethargy may progress to coma
• A ring enhancing lesion demonstrated by a CT scan of the brain.

Non-Pharmacological Treatment

Brain abscess is generally managed by:

• Controlling fever and pain with Paracetamol
• If unconscious, insert NGT for feeding and urethral catheter

Pharmacological Treatment:

Table 8.2: Management of Brain Abscess

Condition	Treatment	Duration
Brain abscess (unspecific bacterial)	B: Benzyl penicillin (I.V) 5 MU 6 hourly (children 125,000 IU/kg/24 hours) OR D: Cefotaxime 2 g IV 4 hourly OR B: Ceftriaxone 2 g IV 12 hourly Plus A: Metronidazole (IV) 500mg 8 hourly (children 7.5 mg/kg/day)	4-6weeks       4-6 weeks
Brain abscess (Staph aureus)	D: Vancomycin 1 g 12 hourly is used (with cefotaxime or ceftriaxone)	4-8 weeks

Note: Where the patient is allergic to penicillin, chloramphenicol 500 mg IV every 6 hours can be used instead

Surgery

All patient with a brain abscess should be referred to a neurosurgeon

8.1.2 Fungal infections

Cryptococcus meningitis

It develops in patients who are immune compromised e.g. HIV-positive patients with low CD4 cell count.

Diagnostic criteria

• Headache, fever, intolerance to light and sound, neck stiffness, vomiting, seizures, deafness and blindness
• In advanced stages it may present with confusion, altered consciousness and coma.

Non-Pharmacological Treatment

Refer to section on bacterial meningitis

Pharmacological Treatment: Treatment is in 3 phases:

Phase 1: Induction phase

D: Amphotericin B 0.7mg/kg/day IV

AND

D: 5 Flucytosine 100mg/kg/day administered orally for 14 days

OR

A: Fluconazole 1200mg IV/(PO) once daily for 14 days

Phase 2: Consolidation phase

A: Fluconazole 400mg day for 8 weeks or until CSF is sterile.

Phase 3: Suppressive phase

A: Fluconazole 200mg per day until CD₄ more than 350

Note:
	LP is done for diagnostic and therapeutic for cryptococal meningitis.
	Cryptococal antigen test should be done as there are cases of negative India ink results with cryptococal meningitis

8.1.3 Protozoa infections

Toxoplasmosis

Immunocompetent persons with primary infection are usually asymptomatic, but latent infection can persist for the life of the host. In immunosuppressed patients, especially patients with AIDS, the parasite can reactivate and cause disease, usually when the CD4 lymphocyte count falls below 100 cells/mm³.

Diagnostic Criteria

• Patients can present with focal paralysis or motor weakness depending on the brain area affected
• Neuro-psychiatric manifestations corresponding to the affected area in the brain, seizures or altered mental status.

Note: Diagnosis is predominantly based on clinical findings after exclusion of other common causes of neurological deficit. If available, a CT scan is very useful for confirmation. Toxoplasma serology has to be done for addition in diagnosis.

Supportive Therapy

Similar to bacterial meningitis

Pharmacological Treatment

Acute infection

D: Sulphadiazine 1 gm 6 hourly for 6 weeks

AND

D: Pyrimethamine 100mg loading dose then 50mg /day for 6 weeks

AND

D: Folinic acid tabs 10mg /day for 6 weeks.

After six weeks of treatment give prophylaxis therapy with Sulphadiazine tabs 500mg 6 hourly + Pyrimethamine tabs 25-50mg /day + Folinic acid tabs 10mg /day.

For those allergic to sulphur replace Sulphadiazine tabs with S: Clindamycin capsules 450mg 6 hourly for for 6 weeks.

8.1.4 Viral infections

In Tanzania, viral infections of the nervous system are mainly caused by Herpes simplex virus and HIV.

See section on viral infections and HIV

8.1.4.1 Rabies

Rabies is an acute viral infection of the central nervous system that affects all mammals and is transmitted to man by animal bites via infected secretions, usually saliva.

Diagnostic Criteria

• Early or prodromal clinical features of the disease include apprehensiveness, restlessness, fever, malaise and headache
• The late features of the disease are excessive motor activity and agitation, confusion, hallucinations, excessive salivation, convulsions and hydrophobia

Pharmacological Treatment

• Local wound therapy:-Wash wound thoroughly with water and soap and repeat process with 10% Povidone iodine; prevent secondary bacterial infection
• For Prophylactic wound therapy that has lasted less than 8 hours

A: Amoxicillin-clavulanic acid 500mg/125mg (PO) 8 hourly for 5 days

• For Infected wounds and wounds older than 24 hourly,

A: Amoxicillin-clavulanic acid 500mg/125mg (PO) 8 hourly for 5 days

AND

S: Clindamycin 150–300 mg every 6 hourly for 5 days

AND

A: Ciprofloxacin (adults) 500mg 12 hourly for 5 days

OR

A: Trimetroprim/Sulphamethoxazole (children) 120-480mg 12 hourly for

5 days

1. Passive Immunization

B: Anti-rabies human immunoglobulin 20 IU/kg half the dose given parenterally and the other half injected into and around the wound

1. Active Immunization

B: Human Diploid Cell Vaccine (HDCV) 1ml I.M on day 0, 3, 7, 14 and 28. In addition, patients should receive rabies immune globulin with the first dose (day 0)

• Tetanus toxoid vaccine see section on Tetanus

8.1.4.2 Herpes simplex encephalitis

The majority of cases in adults caused by HSV-1, a small number are caused by HSV-2 usually in immuno-suppression or in neonates. It causes inflammation and necrosis in the brain.

Diagnostic Criteria

• Early features are fever, headache & altered consciousness which may develop gradually over days or rapidly over hours
• The most common manifestations are personality change, dysphasia, behavioural disturbance and occasional psychotic features
• Focal or generalized seizures can occur
• On lumbar puncture, CSF is under increased pressure and may appear normal or show a mild-moderate lymphocytosis, a mild-moderate increase in protein and normal or mildly decreased glucose.

Note: The disease is easily missed in Tanzanian settings due to lack of diagnostic (HSV-1 and HSV-2 PCR) and should therefore be suspected in patients not responding to antibiotics/other treatment.

Supportive Therapy

Manage it as for unconscious patients (control seizures)

Pharmacological Treatment

B: Acyclovir IV/Oral (10–15 mg/kg every 8 hourly for 14–21 days