Meningitis Flashcards
Inflammation of the Leptomeninges - Pia mater covering the Brain and CSF within
Subarachnoid space, usually caused by infection.
Meningitis
Pathogenesis of Meningitis
Direct implantation :
Hematogenous spread:
Local extension:
Axonal transport:
Direct implantation : Traumatic
Hematogenous spread: Arterial
Local extension: Established infection in an air sinus
Axonal transport: Peripheral nerves (Rabies and Herpes zoster)
Etiology Pathogens differ among groups in Bacterial Meningitis
Neonates:
Infants/Children:
Adolescents/young adults:
Elderly:
Neonate
- B – Streptococcus group B
- E – E. coli (IgM)
- L – Listeria monocytogenes
Infants/Children (IgG) 1st 2 m
- Haemophilus influenza (IgA)
- Streptococcus pneumoniae
- Neisseria meningitidis
Adolescents/young adults
- Neisseria meningitidis “severe” 1996-1.M case
Elderly
- S. Pneumoniae
- L. monocytogenes
Bacteria in subarachnoid space attract
Neutrophils
Clinical Manifestations of Bacterial Meningitis
- Fever
- Headache
- Photophobia
- Clouded sensorium
- Nuchal rigidity/torticollis
Risk Factors of Bacterial Meningitis
- Peak incidence: Children 75%
- Undernutrition, Otitis media
- Pneumonia
- Immunodeficiency
- Viral infection
- Sickle cell diseases
- Craniofacial abnormality
Spinal Tap Diagnosis of Bacterial Meningitis
1st tube:
2nd tube:
3rd tube:
4th tube:
1st tube: chemical or serologic tests
2nd tube: microbiologival tests including molecular diagnostics
3rd tube: microscopic examination, differential count
4th tube: cytological examination
Normal CSF Findings
Specific Fravity: Pressure: Protein: Glucose: Lactate: WBC count RBC count:
Gross Appearance Specific gravity= 1.006-1.009 Pressure = 8-20 mmHg Protein = 15-45 mg/dL Glucose = 40-80 mg/dL Lactate = <35mg/dL WBC count ✔Newborns: 30 microL ✔Infants: 19 microL ✔Adults:0.6 microL RBC Count = NONE
Laboratory FIndings in Bacterial Meningitis
- ) Protein
- )Leukocyte:
- ) Lactate:
- ) Glucose
✔ Increased CSF
- ) Protein >15-45 mg/dL
- )Leukocyte: Neutrophils
- ) Lactate: >35 mg/dL
✔ Decreased
3.) Glucose <40-80 mg/dL
Absence of bacterial culture in patient with manifestations of meningitis :
- ) Meningeal irritation
- ) Fever
- ) Alterations of consciousness (acute onset)
Viral Meningitis
Most Common cause of Viral Meningitis
Enterovirus – Coxsackievirus 80%
Route of Viral Meningitis
Oral-Fecal Route
Laboratory findings Viral Meningitis
1.) Moderate increased to normal CSF Protein: > Vessel Permeability
2.) Increased Total CSF Leukocyte count: Neutrophils 🡪 Lymphocytes in 24-48H
“Lymphocytic Pleocytosis”
3.) NORMAL CSF Glucose
- Maybe part of active disease elsewhere in the body or appear in isolation following seeding from silent lesion’s usually the lungs
- Primary complications of pulmonary tuberculosis caused by Mycobacterium tuberculosis
- It may affect the brain om the meninges and usually involved the base of the brain
Tuberculous meningitis
Clinical manifestations Tuberculous meningitis
- Headache
- Malaise
- Mental confusion
- Vomiting
Most common Tuberculous meningitis
Diffuse meningioencephalitis
Morphology of Tuberculous meningitis in subarachnoid
- ) Gelatinous/Fibrous exudate
2. ) Granulomas: at the Base encasing cranial nerves
Laboratory findings of Tuberculous meningitis
- MODERATE CSF mononuclear cells Pleocytosis predominant:
- Protein:
- Glucose
MODERATE CSF mononuclear cells Pleocytosis predominant: Lymphocytes
ELEVATED Protein
Moderately reduced or Normal Glucose
Complications of Tuberculous meningitis
- ) Hydrocephalus- arachnoid fibrosis
2. ) Infarction- Obliterative endarteritis
Etiology of Fungal Meningitis
Cryptococcus neoformans
Meningitis
- Not Contagious
- Hematogenous
- AIDS: fulminant/fatal 2 weeks, or chronic
- Poultry contacts
Fungal Meningitis
Morphology of Fungal Meningitis
soap bubbles
Direct Dx of Fungal Meningitis
- ) Direct CSF sample with india ink stain
2. ) Detection of Cryptococcus capsule antigens using assays
Laboratory findings of Fungal Meningitis
- ) Protein
- ) CSF Leukocytes
- ) Glucose
Increased 1.) Protein 2.) CSF Leukocytes: Lymphocytes Decreased 3.) Glucose
CSF Fndings of of Different Meningitis: Bacterial
- Differential Count
- CSF Glucose
- CSF Protein
- Gram Stain
- Total Cell count
- Differential Count: Neutrophils
- CSF Glucose: Decreased
- CSF Protein: Increased
- Gram Stain: 60-90% +
- Total Cell count: Increased
CSF Fndings of of Different Meningitis: Tuberculosis
- Differential Count
- CSF Glucose
- CSF Protein
- Gram Stain
- Total Cell count
- Differential Count: Lymphocytes
- CSF Glucose: Moderately Decreased to NORMAL
- CSF Protein: Increased
- Gram Stain: + until 2 months
- Total Cell count: Increased
CSF Fndings of of Different Meningitis: Viral
- Differential Count
- CSF Glucose
- CSF Protein
- Gram Stain
- Total Cell count
- Differential Count: 24-48 H: Neutrophils Lymphocytes after
- CSF Glucose: NORMAL
- CSF Protein: Moderately increased
- Gram Stain: —
- Total Cell count: NORMAL – slightly Increased
CSF Fndings of of Different Meningitis: Fungal
- Differential Count
- CSF Glucose
- CSF Protein
- Gram Stain
- Total Cell count
- Differential Count: Lymphocytes
- CSF Glucose: Decreased
- CSF Protein: Increased
- Gram Stain: +
- Total Cell count: NORMAL to slightly Increased
