Infections of the central nervous and locomotor systems

1. Lecture №
Infections of the
central nervous
and locomotor
systems

2. Infections of the central nervous system
caused by:
trauma leading to breach of integuments of
C.N.S.
via blood from infective focus.
Meningitis inflammation of the membranes
( meninges ) that cover the brain and spinal
cord.
Bacterial meningitis (pyogenic)
More sever than viral type.
Clinical features. Symptoms of sever headache,
fever, vomiting, photophobia and convulsions
leading to unconsciousness.
Signs of meningeal irritation ,i.e. neck and
spinal stiffness, and kernig ‘s sign ( pain and

3. The common causative agents of bacterial
meningitis
Neisseria meningitidis - common in children
and young adults.
Haemophilus influenzae - meningitis mostly
seen in children between 1 months and 4 years
old.
Streptococcus pneumoniae – in old patients.
Mycobacterium tuberculosis.
Meningitis spread quickly in close household
contacts.
Avoiding overcrowding in living and working
conditions.
Chemoprophylaxis with antibiotics e.g.

4. Rarely causing meningitis organisms:
Listeria monocytogenes, Leptospira interrogans
and Cryptococcus neoformans.
Laboratory diagnosis:
Examination of C.S.F (lumbar puncture).
C.S.F centrifuged and the deposit Gram-stained
and cultured.
Treatment: dictated by the causative organism
and its sensivity; empirical therapy with two or
three antibiotic drugs is given immediately.

5. Viral meningitis (aseptic meningitis)
Benign, self-limited, resolves in 1-2 weeks
and requires only symptomatic treatment.
The major route of entry are respiratory and
gastrointestinal tracts and from these ports
spread to C.N.S by direct migration via
olfactory nerves or indirectly via blood.
The major causes of viral meningitis ( aseptic
meningitis) and/or encephalitis
1. Mumps virus 2. Coxsackievirus
3. Herpes simplex virus 4. Adenovirus
5. Measles virus 6. Influenza virus
7. Varicella-zoster virus
Susceptible persons (the most affected) :
Children

6. Encephalitis
Infection of the brain substance and patient
often show signs and symptoms of meningitis
and encephalitis at the same time.
Occurs after childhood illness such as
measles, chickenpox and rubella, and rarely
after immunization with vaccines such as
pertussis.
Patients often die or have debilitating
sequelae.
Very serious disease needs prompt and
intravenous antiviral treatment.

7. Poliomyelitis
Caused by poliovirus types 1-3.
The port of entry – mouth and the virus
multiply in lymphoid tissue of the pharynx and
intestine. Then enters the blood stream and
causes viraemia, spread into C.N.S and
causes neurological disease.
The disease is an influenza-like illness, with
meningitis and encephalitis.
In some, damage of the anterior horn cells of
the spinal cord leads to: 1. respiratory failure.
2. or permanent lower neuron weakness and
paralytic poliomyelitis. Two types of Polio

8. Cerebral abscess
infection reach the brain through blood or by
direct extension of sinus infection caused by
oral bacteria or, rarely, as complication of acute
or chronic dental infection.
also flow traumatic injury to the maxillofacial
region.
infection mostly polymicrobial (mixed) -
streptococci, staphylococci, anaerobic cocci
and coliforms.
treatment is surgical.

9. Tetanus Clostridium tetani (drum-stick bacillus).
After I.P. (5-15 days) exotoxins cause sever
painful muscle spasm:
masseter muscles - lockjaw
facial muscles – risus sardonicus (facial
grimace)
Extensor muscles - opisthotonos (arched body)
Pathogenesis
Contamination of wound with spores from dust,
soil or rusty objects results in spore
germination and release of tetanospasmin and
tetanolysin.
The bacteria remain localized at the site of
infection, but the exotoxins absorbed at the
motor nerve endings, diffuse towards the

10. Epidemiology
Main source is animal faeces.
Tetanus is commonly associated with deep
penetrating wounds, but it can result from
superficial abrasions e.g. thorn pricks.
Infection of umbilical stump - neonatal tetanus.
Diagnosis
Mainly clinical.
Treatment
1. Supportive: muscle relaxants, sedation and
artificial ventilation.
2. Antitoxin: I.V in large dose.
3.Antibiotics: penicillin or tetracycline to
prevent further toxin production.
4. Debridement: excision and cleaning of the
wound.

11. Prevention
Active immunization with toxoid in childhood,
during
the first year of life and before school entry.

12. Prophylaxis of wounded patients
 If the patient is immune, a booster dose of
toxoid should be given if the primary course
(or booster dose) was given more than 10 years
previously, and human antitetanus
immunoglobulin (ATS) should be given if the
wound is dirty and more than 24 h old.
 If the patient non-immune, human antitetanus
immunoglobulin should be given, followed by a
full course of tetanus toxoid by injection.
 Penicillin – to prevent tetanus and to avoid
pyogenic infection.
 Booster doses of toxoid 10 years after primary
course and again 10 years later maintain

13. Infection of the locomotor system
(bones and joints)
Natural defenses
1. macrophages in synovial membranes of
joints.
2. mononuclear cells, complement and
lysozyme of synovial fluid.
Acute septic arthritis
Can be caused by S. aureus, H. influenzae, S.
pneumoniae and other streptococci, N.
gonorrhoeae
and non-sporing anaerobes such as Bacteroids
spp.
Others infrequent agents are M.tuberculosis,

14. Acute septic arthritis may result from:
1. Traumatic injury through the joint capsule.
2. Haematogenous spread, usually as a
complication
of septicaemia.
3. Extension of osteomyelitis or spread of
infection
from an adjacent septic focus.
4. Infection of joint prosthesis. source of
infection
for artificial joints may patient, operating team
or
theatre air.
Clinical features:
Limitation of movement, swelling, redness and

15. Reactive arthritis
Acute arthritis mediated by immunological
mechanism.
Genetic predisposition present.
Affecting one or more joints.
Develops 1-4 weeks after infection of genital
(post-sexual reactive arthritis) or
gastrointestinal tract (post-dysenteric arthritis).
Post-sexual reactive arthritis caused by
Chlamydia trachomatis and almost all patients
are men.
Post-dysenteric arthritis follow infection with
Salmonella, Shigella, Yersinia or
Campylobacter.

16. Osteomyelitis
Acute osteomyelitis
• usually occurs in children under 10 years old.
• mostly caused by S. aureus ; H. influenzae, S.
pyogenes, S. pneumoniae, Salmonella,
Brucella, and non-sporing anaerobes.
Chronic osteomyelitis
• common in adults.
• mostly caused by S. aureus. Salmonella,
Brucella, Mycobacterium tuberculosis.

17. Osteomyelitis of the jaws
• uncommon due to high vascularity of the jaws,
especially maxilla.
• Predisposing factors such as bone disease
such as osteopetrosis, bone tumors and
irradiation.
Laboratory diagnosis
Blood culture, culture of pus from the bony
focus – pus obtained by needle aspiration or by
open surgery and by specimens from the
infective focus e.g. “ cold abscess ” pus in
tuberculosis.
Treatment

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