Meningitis (mechanism of disease)

This is a flowchart on meningitis, covering the etiologies, pathophysiology, and manifestations.

ADDITIONAL TAGS:
Head trauma
Neurosurgery
Common causes:
Risk factors / SDOH
Cell / tissue damage
Structural factors
Meningitis
Medicine / iatrogenic
Infectious / microbial
Biochem / organic chem
Immunology / inflammation
Signs / symptoms
Tests / imaging / labs
Environmental / toxins
Neoplasm / cancer
Flow physiology
Pathophysiology
Etiology
Manifestations
Infection / inflammation of the meninges (membranes surrounding the brain)
CSF leak causing direct infection
Contiguous spread from nose, eyes, ears
Sinusitis
Otitis media
Hematogenous dissemination
Maternal Group B Strep infection during birth
Sepsis
Retrograde transport along/within nerves
Risk factors:
Crowded occupational or living conditions
College dorms
Military barracks
Retirement homes
Kindergartens
Immunocompromised
AIDS
Asplenia
Heavy alcohol use
Chronic illness
Cancer
Sickle cell
Old age
Pregnancy
H flu B
Listeria
S pneumo
Gram(-) bacilli (E coli, Salmonella)
Basilar skull fracture
Penetrating injury
H flu B
GAS
S pneumo
S aureus
Coag(-) Staph (epi)
Aerobic gram(-); Pseudom.
GBS
E. coli
Listeria
S. pneumo
Neisseria m.
GBS
H flu B
S. pneumo
Neisseria m.
S. pneumo
E. coli
Listeria
H flu B
Neisseria m.
GBS
1 month
1mo - 2yr
2-50 yrs
50 yrs
Viral: enterovirus (coxsackie, echo); herpes (HSV1,2; VZV), mumps, measles, flu
Fungal: Coccidioides, Candida, Aspergillus
Sarcoidosis
Tumor mets
NSAIDs, sulfa drugs
Fever
Headache
Altered mental status
Neck stiffness
Photophobia
Bacterial etiologies by age
Classic triad
Malaise, fatigue
Nausea, vomiting
+/- CN palsies
Seizures
Photophobia
Myalgias
Petechial, purpuric rash
In case of N. meningitidis
DIC
Hemorrhagic necrosis of adrenals
Adrenal insuff.
Waterhouse-Friderichsen
Flu-like prodrome
Low-grade fever
Sore throat
Myalgias
Herpangina
Pharyngitis
Viral rash
Viral symptoms
Encephalitis
Inflammation
Hypotension
Tachycardia
Fever
Papilledema
↑ ICP
Physical exam
Brudzinski, Kernig signs
Neonatal
presentation:
early: → late:
Lethargy
Irritability
Muscle hypotonia
Dysthermia
Poor appetite
Dyspnea
Fontanelle bulging
High- pitched crying
Seizures
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↓ Downwards Arrow 25
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← Leftwards Arrow 27
↔ Left-Right Arrow 29
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