This document discusses central nervous system (CNS) infections, including: - Viral infections are more common than bacterial, which are more common than fungal/parasitic. Rickettsiae and Mycoplasma can also cause CNS infections. - There are three main types - meningitis, encephalitis, and meningioencephalitis. - Meningitis can be caused by bacteria, viruses, fungi or parasites. Presentation depends on age. Encephalitis has multiple viral and non-viral causes. Meningioencephalitis involves both meninges and brain tissue. Complications, diagnosis, and management are discussed for each type of infection.

1. CNS infection
Presented by Nancy Mohammed Alaa
Assistant lecturer of Pediatrics
Assiut university

2. 1-epidemiology
• In general, viral infections of the CNS are much
more common than bacterial infections, which, in
turn, are more common than fungal and parasitic
infections.
• Infections caused by rickettsiae (Rocky Mountain
• spotted fever, Ehrlichia) are relatively uncommon
but assume important roles under certain
epidemiologic circumstances.
• Mycoplasma spp. can also cause infections of the
CNS, although their precise contribution is often
difficult to determine

3. 2-types
• 1-meningitis
• 2-encephalitis
• 3-meningioencephalitis

4. 1-meningitis
• Etiology
• a-bacterial organisms are age-dependent
• b-viral can be seasonal
• c-fungal most common in immunocompromised
• d-tuberculosis
• e-parasite (rare

5. • A-Pyogenic meningitis
• Neonatal meningitis
• mostly reflect maternal GI and genitourinary flora E coli, Strep
pneumoniae, Salmonella species, Pseudomonas aeruginosa, Strep
fecalis, Staph aureus
• Beyond Neonatal period
• 2 month ‐2 years —
• • H. influenzae( 60‐70%)
• • S. pneumoniae
• • Neisseria meningitidis
• • Group B streptococcus (18 percent).
• 2 ‐18 years —
• N. meningitidis ‐ 59 percent of cases,
• S. pneumoniae (approximately 25 percent)
• Hib (approximately 8 percent).

10. Route of spread
• Hematogenous spread
• • Direct spread :
• ‐ Contiguous focus (eg, sinusitis, mastoiditis,
otitis media)
• ‐Through an injury, such as a skull fractures
and foreign body (ventricular shunt).

11. presentation
• A-Neonate
Bulging fontanelle
• Fever/ hypothermia
• Persistent vomiting
• Alternating irritability and drowsiness
• Refusal to feed
• Poor tone and cry
• Shock
• Seizure

12. :• B-child and adult
• 2 presentations:
•
1) Dramatically acute presentation:
Rapid progressive manifestations of shock, purpura,
DIC, altered sensorium, usually death within 24
hours

14. • 2) Acute presentation :
progress over several days
Nonspecific findings:
• Fever, Anorexia, lethargy, URI or GIT sx,
• Petechie/ purpura/ macular rash
• f/o shock
S/o meningeal irritation
f/o raised ICP: headache, vomiting, bulging AF,
hypertension, posturing, papillaedema
Focal neurological signs ( 10‐ 20%)
Altered mental status

16. 2-encephalitis
• encephalitis has been defined as encephalopathy
plus two or more of fever, seizure, focal neurological
findings, compatible electroencephalogram (EEG),
abnormal diagnostic imaging or CSF pleocytosis

17. • Etiology
•
Viral:
• Mumps, measles, rubella, enterovirus
• HSV, CMV, EBV, Varicella
• Japanese encephalitis, West Nile, Russian spring
summer, Equine virus
• Rabies
• Lymphocytic choriomeningitis
• Dengue
• Influenz

18. • Nonviral:
• Rickettsia
• Mycoplasma pneumoniae
• Bacterial: TB, Enteric fever, Shigella etc.
• Spirochetal
• Fungal
• Protozoal

19. Route of spread
• The majority of cases of herpes encephalitis are
caused by herpes simplex virus-1 (HSV-1), the
same virus that causes cold sores which is spread
through droplets, casual contact, and sometimes
sexual contact, though most infected people
never have cold sores.
• About 10% of cases of herpes encephalitis are due
to HSV-2, which is typically spread through sexual
contact.

20. • Clinical picture
• Acute onset
• High fever
• Rash±
• Headache
• Vomiting
• Altered sensorium
• Seizures
• Neurological deficits( HSV: focality +)
• H/o similar illness in the community

21. 3-meningioencephalitis
Organisms located in the subarachnoid space may spread
to the adjacent cortical mantle. When there are signs of
both meningeal and cerebrocortical involvement, the
term meningoencephalitis is appropriate

22. -prognosis
• 1-Bacterial infection: early recognition, diagnosis and
start of treatment are associated generally with better
outcomes. HIB, pneumococcal and meningococcal
vaccines decreases the incidence of meningitis
• 2-causes of Recurrent meningitis:
• • # of cribriform plate or sinuses, pilonidal sinus,
• congenital fistulae, immune deficiency dis

23. monitoring
• With appropriate treatment: CSF culture and
gram stain will become negative in 24-48
hours, glucose will normalize in 72 hrs. Cell
counts and proteins will take days to
normalize.
• Clinical symptoms: Fever and headaches may
persist for 7-10 days

24. diagnosis
Diagnostic criteria and tests
A-A complete and detailed history and physical examination
with details of length of illness and details of presenting
symptoms, preceding illness, past medical history. Also history
of exposure: travel, sick contact, insect bites, sexual activities,
animal contacts
.
B-Initial labs: CBC, CMP, CPR, UA, blood cultures; CSF: with
opening pressure, cultures, cytology, serology
C-Initial imaging: CT head without contrast to rule out space-
occupying lesions, hemorrhage or trauma.
MRI of brain and spine if concern for myelitis/encephalitis

27. complications
•
1-meningitis
• Inflammation of spinal roots/ Nerves
• Neuropathy of 2, 3, 7, 8 N:
•
Inflammation of cranial Nerves
• Hydrocephalus
• Communicating type:
Adhesive thickening of arachnoid villi around cisterns
of brain l/t interference with CSF absorption
• Obstructive type:
Fibrosis & gliosis of aqueduct / foramina of Magendie
& Luschka
Subdural effusion
• Increased permeability of BBB causing exudation of
albumin rich fluid in subdural space

28. • Immediate Complications
• Subdural effusion/ empyema
• Ventriculitis
• Arachnoiditis
• Brain abscess
• Hydrocephalus
• Shock
• ARDS
• Myocarditis
• SIADH
Late complications/ Sequelae
• Hemiplegia/ monoplegia
• SN deafness
• Blindness
• Aphasia
• Ocular palsies ( squint)
• Mental retardation
• Seizure disorder

31. 9-management
• Key emergency management steps
• ABC
• Management of fluid & electrolytes
• Management of raised ICP
• Management of seizures
• Care of back, bladder & bowel
• Nutrition
• Neuro assessment: airway protection for severe altered mental status (GCS
below 8). Take precautions for increased intracranial pressure during
intubation. Consider ICP monitoring for evidence of elevated ICP. Treat
seizure activity: 50% of patients who presented with seizures progress to
status epilepticus, which is hard to control and correlates with poor neuro
outcomes.
• Cardiovascular support as needed; cerebral perfusion pressure is directly
affected by mean blood pressure.
• Antibiotics early; do not withhold antibiotics awaiting lumbar puncture.
Start antiviral if high suspicion of herpes infection.

32. • Management points not to be missed
• Electrolyte and fluid derangements are common:
• Diabetes insipidus: monitor urine output and check
sodium level for spike in UOP (Na in the 150s-160s).
• SIADH: late onset of electrolyte derangements with
oliguria and relative hyponatremia (Na can be below
125), increased risk of seizure activity. Correct
hyponatremia acutely to bring Na level above 125 with
3% saline if necessary (seizure threshold), then slow
correction to normal level (Na 140-145) over the next
36-48 hrs.
• At risk of hypokalemia secondary to GI losses,
hemodilution, osmotherapy, diuretics, sepsis.
• At risk for cerebral edema

33. Specific therapy
• Meningitis
• Antibiotics:
• Hib, Meningococcal, Pneumococcal, Gm negative: IV
Ceftriaxone/ Cefotaxime
• Hib: Ampicillin + Chloremphenicol
• Listeria: Ampicillin + Aminoglycoside
• Staph: Methicillin /Vancomycin
• Pseudomonas: Ceftazidime + Amonoglycoside
Duration of Tt:
10 ‐14 days in uncomplicated cases
Staph: 3‐4 weeks
Steroids:
• IV dexamethasone 15 mg/kg/dose 6 hourly X 5 days
• 1st dose : 15 min. before antibiotics
• Useful in reducing incidence of sensorineural
deafness