Exam 2: [CNS Infectious Diseases] Flashcards
(135 cards)
Routes by which Infection can get into the CNS
1) Haematogenous (Bacteremia, Virema)
2) Directly from Local Infection
3) Penetrating injuries (Cribiform Plate or Ear Fractures provide pathway to the cranium)
Primary Infections of the MENINGES [CNS] List
1) Acute Bacterial (suppurative meningitis)
2) Acute Viral Meningitis
3) Chronic Meningitis: tuberculosis, cryptococcidiosis
Acute Bacterial (Suppurative) Meningitis : Site of Infection, Components Increased/Decreased:
- Infection is in Leptomeningitis
- CSF shows increased pressure
- Contains: organisms, increased protein decreased glucose, neutrophils (pus) so CSF looks cloudy
- Type of organism varies depending on pt. Age
Acute Bacterial (Suppurative) Meningitis: Organisms in Different Age Groups
Neonates/Infants: group B strep, E. Coli, Listeria
6 mo-5yrs (FORMER): H. Influenzae strain B
6 mo-5yrs (CURRENT): Streptococcus pneumonia
5yrs-Young Adult: Neisseria Meningitidis
Older Adults: S. Pneumoniae & Gram Negatives
Acute Bacterial (Suppurative) Meningitis: Pathology
- Meninges Congested & Inflamed
- Neutrophils & Fibrin Present
- Bacteria are Obvious on CSF Smear
- Culture Gives Sensitivities
Acute Bacterial (Suppurative) Meningitis: Clinical Features
- Fever, Headaches, Stiff Neck, Altered Mental Status, Kernig’s Sign, Brudzinski’s Sign
- May have symptoms of the previous infection
Acute Bacterial (Suppurative) Meningitis: Treatment & Progression
- Progresses Very Rapidly
- Medical Emergency
- Prognosis related to rapidity of treatment
What should be suspected from an adult who was previously well and may resent as part of an epidemic?
N. Meningitidis
Acute Bacterial (Suppurative) Meningitis: Complications
1) Epilepsy, Hydrocephalus, Neuro Deficits (mental retardation, CN palsies of CNII & CNVIII, spinal nerve neuropathies)
2) Significant Mortality Rate
Meningococcus Complications
1) DIC (Disseminated Intravascular Coagulation) abnormal blood clotting
2) Septic Shock
3) Waterhouse-Friedrichsen Syndrome
Neurosyphilis: Caused by what Organism, Symptoms occur when? Infiltrate & what + Test?
- Cause by organism Treponema Pallidum
- Symptoms may occur years after infection
- 2/3 yrs after infection Meninges have Lymphocytic Infiltrate and a (+) VDRL Test (cure=penicillin)
When does Meningovascular Syphillis Occur?
- 3 Years following infection
- Chronic inflammation of meninges -> cranial nerve palsies
- Some cases have “Gummas” that act as space-occupying lesions
Neurosyphillis: After 10 years
- “Parenchymous Syphillis” at this Stage
- General Paresis (dementia & paralysis)
- Tabes Dorsalis
What Symptoms does Tabis Dorsalis Have?
- In spinal cord (lightning pains, sensory loss, hypotonia, areflexia)
- Argyll-Robinson Pupils
- Charcots Joints
What Does General Paresis show?
Progressive dementia & psychosis with cerebral atrophy
Causative Agents of Viral Meningitis
1) Coxsackievirus B
2) Mumps
3) EBV
4) Echovirus
Viral Meningitis Features
- Produces Aseptic Meningitis (No Bacteria)
- Benign, Self-Limiting
- May spread to Encephalitis
- CSF is clear
- Cells = Lymphocytes
- Protein moderately raised, Glucose is Normal
Chronic Meningitis Causative Agents
1) Mycobacterium Tuberculosis
2) Cryptococcus
3) Brucella Species
4) Treponema Pallidum
Meningeal Appearance in Chronic Meningitis
- Thick Meninges (all 3)
- Fibrinous Exudate in the Subarachnoid Space
Chronic Meningitis Leads To:
Fibrous Adhesions Causing Obstructive Hydrocephalus
Chronic Meningitis Cellular Components
[In CSF]
- Increased # of Mononuclear Cells
- Increased Protein
- Decreased Glucose
Chronic Meningitis: Signs/Symptoms & Prognosis
- Insidious Onset & Less Marked than in the Acute Forms
- Poor Prognosis
Different Ways Viruses can Affect the Brain
- From Systemic Infection
- Direct Target of the Brain
- Specific areas of Brain OR All-Over
- Specifically target Neurons
- Specifically Target Neuroglia
- Healthy OR Immunocompromised Individuals
Viral Encephaltis: Pathological Features
- Perivascular Cuffing of Mononuclear Cells
(Lymphocytes, plasma cells, monocytes) - Microglial Nodules often Present
- Neuronophagia if Neuron has Dies
- Inclusion Bodies in Neurons