The document provides a comprehensive overview of acute meningoencephalitis, detailing its definition, causes, risk factors, clinical features, and management approaches. It covers bacterial and viral causes, including specific conditions like tuberculosis meningitis and various complications such as septic shock and encephalitis. Therapeutic strategies include the need for early diagnosis, intensive supportive care, and appropriate antibiotic treatment based on the causative organism.

1. Acute Meningoencephalitis
Intern. Sunder Chapagain
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2. Acute Meningoencephalitis
• meningoencephalitis is an acute inflammatory
process involving the meninges and, to a variable
degree, brain tissue.
• Acute Bacterial Meningitis
• Acute Viral Meningoencephalitis
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4. Acute bacterial meningitis
• Etiology
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5. Aseptic meningitis
• Viral
– Enterovirus (Echovirus, Coxsackie virus, Polio)
– Herpes Simplex Virus-2
– Mumps: The commonest complication
– Lymphocytic choriomeningitis virus
• Fungal (in imuunocompromised)
– Cryptococcus neoformans
– Histoplasmosis, Candidiasis, Blastomyces
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6. • Parasitic
– Toxoplasmosis
– Cysticercosis
– Amoebiasis
• Miscellaneous
– SLE
– Leukemia
– Lymphoma
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7. Risk Factors
• Age
• Low socioeconomic status
• Head trauma
• Splenectomy
• Chronic diseases
• Children with facial cellulitis, periorbital cellulitis, sinusitis and
septic arthritis
• Maternal infection and pyrexia at the time of delivery.
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10. Clinical features
Newborn & Infants: non-specific
• Fever
• Irritability
• Lethargy
• Vacant stare
• Poor tone
• Poor feeding
• High pitched cry
• Bulging anterior fontanelle
• Convulsions
• Opisthotonus
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11. Older children
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12. • Seizures
• Alteration in mental status
• Hypotension, fever or Hypothermia,
Tachycardia (Septic shock)
• Bleeding, Renal dysfunction (DIC)
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13. Increased intracranial pressure (ICP)
• Papilledema
• Cushing’s triad
– Bradycardia
– Hypertension
– Cheyne-Stokes Breathing
• Projectile vomiting
• Headache

14. Physical examination
•Neck rigidity
•Focal neurological signs
•Ptosis
•Cranial nerve palsies
•Bulging fontanel

15. TB meningitis
• Children 6 months – 5 years
• Local microscopic granulomas on meninges
• Meningitis may present weeks to months after
primary pulmonary process
• CSF:
– Profoundly low glucose
– High protein
– Acid-fast bacteria (AFB stain)
– PCR
• Steroids + antitubercular agents
– (2HRZE+ 10 HR) WITH steroid for 4-6 weeks
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16. Stages
• Stage 1: stage of invasion
– Low grade fever, loss of appetite, vomiting,
headache, photophobia, irritable, restless
• Stage 2: Stage of meningitis
– Neck rigidity, focal neurological deficits, isolated
cranial nerve palsies, loss of sphincter control
• Stage 3: Stage of coma
– Loss of consciousness, altered respiratory pattern,
dilated pupils, ptosis, ophthalmoplegia, coma
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17. Neisseria meningitis
(Meningococcemia)
• Neisseria meningitidis: serotype Grp B
commonest
• Endotoxin causes vascular damage
vasodilatation, third spacing, severe shock
• Severe complication:
Waterhouse-Friderichsen syndrome: massive
haemorrhage of adrenal glands secondary to
sepsis: adrenal crisis-low B.P, shock, DIC,
purpura, adreno-cortical insufficiency
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18. Morbiliform, non blanching
petechiae to purpura
involving mostly extensor
surfaces Tumbler test 18

19. Investigations
• Complete blood count
• C- Reactive Protein
• Renal function test
• Serum glucose
• Blood culture and
sensitivity
• If tubercular suspected
– PCR
– Chest X-ray
– Mantoux test
• Arterial blood gas
• Fundoscopy
• CT scan
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20. CSF analysis
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21. Management
Medical emergency
• Early diagnosis essential
• Immediate optimum treatment
• Intensive supportive therapy
• Rehabilitation
• Prophylaxis to family
• Notification to Public Health
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22. Treatment
• Managed in Intensive Care Unit
• Manage airway, breathing and circulation first
• Management of raised ICP
• Fluid management
• Dexamethasone: only in Pneumococcal and H.
Influenzae B, given 1-2 hours before antibiotics
• Antibiotics
• Inotropes: increasing aortic diastolic pressure and
improving myocardial contractility
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23.  ICP treatment
• 3% NaCl, 5 cc/kg over ~20
minutes
• May utilize osmotherapy
(Mannitol) - if serum
osmolarity <320 mOsm/L
• Mild hyperventilation
– PaCO2 <28 may cause
regional ischemia
– Typically keep PaCO2 32-38
mm Hg
• Elevate head end of bed by
30o

24. Fluid management
• Restore intravascular volume & perfusion
• Monitor serum Na+ (osmolality, urine Na+):
– If serum Na+ <135 mEq/L then fluid restrict
(~2/3x), liberalize as Na+ improves
– If severely hyponatremic, give 3% NaCl
• SIADH
– 4 - 88% in bacterial meningitis
– 9 - 64% in viral meningitis
• Diabetes insipidus
• Cerebral salt wasting
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25. Antibiotics
• Best started within 60 min
• Empirical therapy
• Meningococcal meningitis
– Benzyl penicillin 400-500,000 units/kg/day q 4 hour
• Pneumococcus/ H. influenza
– Ampicillin (if penicillin susceptible) 300 mg/kg/day IV
q6 hour
– Ceftriaxone (if penicillin resistant) 100-150 mg/kg/day
q12 hour
– Cefotaxime 150-200 mg/kg/day q8 hour
– Vancomycin 60 mg/kg/day
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26. Meningitis - Treatment duration
• Gram negative organisms: 21 days
• Pneumococcal (ampiclox/ceftriaxone): 10-14 days
• H influenza: 7-10 days
• Meningococcal: 7 days
• No growth: 7-10 days
• The CSF should be sterile within 24–48 hr of
initiation of appropriate antibiotic therapy.
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27. Dexamethasone use in meningitis
• Consider if
– H. influenza & Streptococcus pneumoniae
– > 6 wks old
• Dose: 0.6 mg/kg/day in 4 divided doses for 2 days
• MOA:
–  local synthesis of TNF-, IL-1, PAF & prostaglandins resulting in  BBB
permeability,  meningeal irritation
•  incidence of hearing loss
• May adversely affect the penetration of antibiotics into CSF
• May decrease fever, giving false impression of improvement
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28. Prophylaxis
• Rifampicin:
– Children 5mg/kg bd x 2 days
– Adults: 600 mg bd x 2 days
• Pregnant contact:
– Cefuroxime IM x 1 dose
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29. Meningitis – Early complications
• Encephalitis
• Septic shock
• DIC
• Abscess
• SIADH
• Subdural effusion or
empyema ~30%
• Dural sinus
thrombophlebitis
• Stroke

30. Intermediate
• Hydrocephalus
• Cranial nerve palsy
Late
• Cerebral palsy
• Hearing loss
• Learning disability
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31. Acute Encephalitis
• Encephalitis is an acute inflammatory process
affecting the brain
• Viral infection is the most common and important
cause, with over 100 viruses implicated worldwide
• Symptoms
– Fever
– Headache
– Behavioral changes
– Altered level of consciousness
– Focal neurologic deficits
– Seizures
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32. Etiology
Non-Arbo viral
• Herpes viruses (sporadic)
– HSV-1, HSV-2
– varicella zoster virus
– cytomegalovirus
– Epstein-Barr virus
– human herpes virus 6
• Adenoviruses
• Influenza A
• Enteroviruses, poliovirus
• Mumps
• Rabies
Arbo-Viral (epidemic)
• Flaviviridae
– Japanese encephalitis
– St. Louis encephalitis
– West Nile
• Togaviridae
– Eastern equine encephalitis
– Western equine encephalitis
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33. – Herpes simplex virus (HSV)
• the most common etiology of acute sporadic
encephalitis
– Arboviruses – arthropod-borne virus
• outbreaks in summer time…mosquitos and ticks
– Varicella zoster virus (VZV)
• immunosuppressed patients
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34. Japanese encephalitis
• Most important cause of arboviral
encephalitis worldwide
• Transmitted by culex mosquito, which breeds
in rice fields
• Commonly involve Basal ganglia: Extra
pyradimal symptoms
• Post-immunization: Measles, Mumps
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35. Herpes Simplex Encephalitis
• Primary infection: On the mucosa of
oropharynx, mostly asymptomatic
• Following primary infection, a latent
infection in trigeminal ganglion
• Inflammation and necrotizing lesions in
– Inferior and medial temporal lobe
– Orbito-frontal lobe
– Limbic structures
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36. • Evolve over several days or acutely
• Fever, headache, confusion, stupor, coma,
seizures, status epilepticus
• Personality changes, irritability, delirium
• Temporal lobe seizures: Gustatory or olfactory
hallucinations, anosmia
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37. CSF Analysis
• Increases CSF pressure
• Cell count: 10-500 cells/mm3
• Lymphocyte predominance
• Erythrocytes (in 80% of the cases)
• Normal CSF findings in 10%
• Xanthochromia: Due to lysis of RBC
• Glucose (mg/dl): normal or low
• Protein (mg/dl): >50 mg/dl
• HSV PCR: For the first 24-48 hours, detecting HSV DNA
by PCR in CSF:
– specific (100%) and
– sensitive (75-98%)
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38. Neuroimaging
• Contrast Enhanced MRI
• Sensitive for early period HSV encephalitis
• Edema in orbitofrontal and temporal regions
• CT Scan
– Less sensitive than MRI
• EEG
– If seizures are the features
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39. Treatment
• If shock/hypotension exists, crystalloid
infusion
• If unconscious, provide airway/breathing
• Seizure, lorazepam 0.1 mg/kg, IV
• Acyclovir IV, 14 – 21 days
– Neonates and infant: 60 mg/kg/day in 3
divided doses
– Children: 30 mg/kg in 3 divided doses
• Reduce ICP: restrict fluid, hyperventilation
• Acute psychosis: Haloperidol 39

40. References
• Nelson Textbook of Pediatrics 20th edition
• Essential Pediatrics, OP Ghai, 8th Edition
• Harrisons textbook of Internal Medicine
• AAP Guidelines 2016
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41. Thank You
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