1.

2. Infectious Diseases
Prepared
by
DR.SHERIF REDA
Prof. of Pediatrics
AL- AZHAR UNIVERSITY
CAIRO-EGYPT
3. Introduction
4. I.Meningitis
II. Encephalitis
III.Poliomyelitis
IV.Mumps
V. Tetanus Neonatorum
VI.Pertussis
5. I.Meningitis
The meninges are membranes that cover and protect the brain and spinal cord. There are 3 layers known as the:
Dura mater is the tough outer membrane
Arachnoid mater is the thin, delicate, web-like membrane
Pia mater is the innermost membrane
The arachnoid & pia mater are together known the as leptomeninges
Inflammation of the leptomeninges, caused by
Bacteria
Viruses
Or rarely, Fungi
The term ASEPTIC MENINGITIS refers principally to viral meningitis, but a similar picture may be seen with:
Other infectious organisms (Lyme disease, syphilis, tuberculosis)
Parameningeal infections (brain abscess, epidural abscess, venous sinus empyema)
Chemical exposure (nonsteroidal anti-inflammatory drug, IV immunoglobulin)
Autoimmune disorders
Alterations of host defense:(anatomic defects or immune deficits) increase the risk of meningitis from less common pathogens e.g. Pseudomonasaeruginosa, Staphylococcus aureus, Salmonella spp., and L. monocytogenes.
6. Cont.
Bacterial Causes of Meningitis
NB: Viral meningitis is caused principally by entero-viruses, including coxsackieviruses, echoviruses, and, in unvaccinated individuals, polioviruses
Mumps virus is a common cause of viral meningitis in unvaccinated children
7. Cont.
Mode of infection:
Bacterial meningitis is most commonly results from hematogenous dissemination of microorganisms from a distant site of infection
Clinical Manifestations:
The onset of acute bacterial meningitis has two predominant patterns:
The more dramatic and fortunately less common presentation is sudden onset with rapidly progressive manifestations of shock, purpura, DIC, unconsciousness, and frequently resulting in death within 24 hours.
More often, meningitis: is preceded by several days of fever with upper respiratory or gastrointestinal symptoms followed by nonspecific signs of CNS infection such as lethargy or irritability.
8. Cont.
1)Non specific findings:
Fever, anorexia, poor feeding, myalgia, arthralgia, tachycardia, hypotension and various cutaneous signs such as petechiae, purpura or an erythematous macular rush.
2)Signs of meningeal irritation:

Nuchal rigidity and back pain

9. Kernigs sign: flexion of the hip 90 degrees with subsequent pain with extension of the leg. 10. Brudzinski sign: involuntary flexion of the knees and hips after passive flexion of the neck while supine.3)Symptoms and Signs of increased ICP:
1- Headache and vomiting
2- Bulging fontanel or widening of the sutures
3- Cranial neuropathies.
4- Hypertension with bradycardia
5- Apnea or hyperventilation, stupor and coma.
4)Seizures:
(focal or generalized) due to, cerebritis, infarction or electrolyte disturbances. Seizures that occur on presentation or within the first 4 days of onset are usually of no prognostic significance
11. Cont.
Diagnosis:
Lumbar puncture for CSF analysis should be performed when bacterial meningitis is suspected:
1- Microorganisms on gram stain and culture.
2- Neutrophilpleocytosis (300 - 2000/mm3).
3- Elevated protein (100 - 500mg/dL)
4- Reduced glucose concentration (< 50% of serum glucose)
5- Physical manifestations (Turbid with elevated pressure,100 - 300 mm H2O).
Normal CSF shows:
Normal pressure (50 - 80 mm H2O), leucocytes (< 5/mm3), proteins (20 -45 mg/dl) and glucose (75 % of serum glucose)
12. Cont.
Treatment:
A)Initial Antibiotic Therapy:

Vancomycin 60 mg/kg/24hr given every 6 hr in combination

With either cefotaxime (200 mg/kg/24hr given every 6 hours) or ceftriaxone (100 mg/kg/24hr single dose or given every 12 hour). Patients allergic to - Lactam antibiotics can be treated with chloramphenicol, 100 mg/kg/24 hr given every 6 hr.
Duration of antibiotic therapy:At least for 7-14 days I.V.
B)Corticosteroids:
I.V dexamethasone 0.15 mg/kg/dose given every 6hr for 2 days in the treatment of children older than 6wk with acute bacterial meningitis caused by H. influenzae type b to decrease the permanent auditory nerve damage.
C)Supportive and symptomatic therapy:
- Good evaluation and monitoring are essential.
-Correction of dehydration and electrolyte disturbances and proper nutrition.
-Control of seizures
- Management of neurological complications
13. Cont.
Prevention:
Vaccination and antibiotic prophylaxis of susceptible at risk contacts:
Close contact:
Should be treated with RIFAMPIN 10mg/kg/dose every 12hr, for 2 days (in N. meningitides) and 20mg/kg/24for 4 days (in H. influenzae type b).
Meningococcal quadrivalent Vaccine:
Avaccine is recommended for high-risk children older than 2yr.
Also Vaccines for H. influenzae type b should be given to all children beginning at 2 mo of age 3 doses (2, 4, 6 months).
14. II.Encephalitis

Encephalitis is an inflammatory process of the brain parenchyma that usually is an acute infectious process, but may be a postinfectious encephalomyelitis, a chronic degenerative disease, or a slow viral infection.

15. Organisms cause encephalitis by one of two mechanisms: direct infection of the brain parenchyma
an apparent immune-mediated response in the CNS that usually begins several days after the appearance of extraneural manifestations of the infection

Encephalitis may be diffuse or localized

Etiology:

Viruses are the principal causes of acute infectious encephalitis.

16. The most common viral causes of encephalitis are the arboviruses (St. Louis, LaCrosse, California, West Nile encephalitis viruses), enteroviruses, and herpesviruses. 17. Encephalitis also may result from other types of infection, metabolic, toxic, and neoplastic disorders.