LG 2.1 Pathology of Secondary Headaches Central Nervous System Infections Flashcards
What is meningitis?
Inflammation of the meninges caused by viral or bacterial infection and marked by intense headache and fever, sensitivity to light, and muscular rigidity, leading (in severe cases) to convulsions, delirium, and death.
What is leptomeningitis?
Infection of the inner two meninges, the arachnoid and the pia mater, between which circulates the cerebrospinal fluid.
What is pachymeningitis?
Thickening of the intracranial dura mater, when associated with an infectious, malignant, or rheumatic systematic disease and inflammation is restricted to its outer surface
Where do Cryptococcus grow in the brain?
Grow in the leptomeninges
Where do Aspergillus grow in the brain?
Aggressively induces cerebral parenchymal abscesses
Where does polio virus grow in the brain?
Selects the motor neurons of the spinal cord and bulbar area
Where does HSV localizes in the brain?
In the temporal lobes
Where do Treponema grow in the brain?
Gains access to the CNS through the bloodstream with prolonged residency in neural tissues, causing infection, sensory abnormalities and dementia.
What does RMSF target in the brain?
Cerebral Endothelial cells
What are the most common viral causative agents of meningitis?
- Enteroviruses including Coxsackie B
- Mumps virus
- Epstein-Barr Virus (Infectious Mono)
- Echovirus
- Herpesvirus
What is the most common causative agent of bacterial meningitis in neonates?
E. Coli and Group B Strep
What is the most common causative agent of bacterial meningitis in infant (3 months to 3 years)?
H. Influenza
What is the most common causative agent of bacterial meningitis in adults?
Strep pneumococcus
What is the most common causative agent of bacterial meningitis in military barracks?
N. meningitidis
What are the defining features of tuberculous meningitis?
- Found meninges at base of brain around chasm
- Can cause meningeal fibrosis leading to communicating hydrocephalus
- Lead to artheritis and parenchymal infarcts
What meningitis are defined by having lymphocytes?
Hallmark of meningitis caused by tuberculosis, viral meningitides, and chronic fungal infections (Cryptococcal meningitis)
What is the most common immune cell found in bacterial meningitis?
Neutrophils
What are defining features of bacterial meningitis?
- Decreased glucose.
- Exudate passes between intraspinal/subarachnoid spaces freely
- Opacified arachnoid (creamy gray or white appearance)
Which meningitis is most common?
Viral
What are the pathologic features of viral meningitis?
- Normally a benign condition in children and young adults
- Sudden febrile illness and headache
- CSF contains excess lymphocytes, protein, no decrease of glucose
What are clinical signs/symptoms of bacterial meningitis?
- Headache, vomiting, fever, convulsions, coma, death (if untreated)
- Cervical rigidity
- Head retraction
What is the Kernig Sign?
Pain in the knee when the hip is flexed
What is the Brudzinski Sign?
Flexion of the knees and hips when the neck is flexed
What is a tuberculoma?
- Parenchymal involvement by TB produces a tuberculoma, a solitary, spherical mass with a central area of caseous necrosis. The tubercle bacillus gain access to the brain by hematogenous dissemination.
- Solitary, spherical mass with central area of caseous necrosis
How does Tubercle bacillus gain access to the brain?
- Tubercle bacillus gain acess to the brain by hematogenous dissemination.
What is Potts Disease?
- TB of the spine
- Produces epidural granulomatous
- Cause destruction of the spine with spinal cord compression
What is the defining features of viral encephalitis?
- The classic hallmark of viral infections of the CNS is the presence of perivascular cuffs of lymphocytes involving small arteries and arterioles.
What are the diagnostic features of viral encephalitis?
-A more diagnostic feature of viral infections of the brain is the formation of intranuclear or intracytoplasmic inclusion bodies, but are not present in all viral infections.
Where does polio cause viral encephalitis?
Polio affects motor neurons of the S. cord
Where does rabies cause viral encephalitis?
- Rabies affects the brainstem.
- Rabies: Cytoplasmic “Negri bodies”.
Where does Herpes Simplex cause viral encephalitis?
- Herpes simplex affects the temporal lobes
- H. simplex and zoster: small, eosinophilic intranuclear inclusions
Where does SSPE and PML cause viral encephalitis?
SSPE and PML affects the cerebral hemispheres
What is SSPE?
•Subacute Sclerosing Panencephalitis (SSPE): have basophilic intranuclear inclusions (lethal disease caused by measles virus)
Where does CMV cause viral encephalitis?
CMV: basophilic, intranuclear inclusions
What is PML?
- Progressive Multifocal Leukoencephalopathy (PML): intranuclear inclusions with a ground glass appearance to the nucleus.(destructive multifocal disease of oligodendrocytes, caused by the JC virus)
What is the pathogenesis of Cryptococcal meningitis?
- Fungus that acts opportunistic in immunocompromised
- C. neoformans enter the human host by the inhalation of contaminated particulates.
- Birds are major reservoir, inhaled feces initiates a pneumonia, then fungi enter the bloodstream to the brain.
- Lesions are widely disseminated in the meninges, ependymal, and choroid plexus
- Appear grossly as discrete, white nodules
How do you stain cyptococcal?
• Organisms encapsulated spheres with gelatinous capsule that shows a clear halo with India Ink stain.
How can you detect Cyptococcal in serum?
• Caspule sheds specific antigens that can be detected in the CSF by latex cryptococcal agglutination test.
What is the morphology of cerebral abscess?
- Cerebral cortex/subjacent white matter contain the richest capillary beds
- Bacteria lodge preferentially in this site causing a localized area of infection.
- Replicated and elicit an acute inflammatory reaction called cerebritis, an irregular, soft, gelatinous area, that after several days, liquefies and coverts the leasion to an expanding abscess.
What type of inclusions does the H. simplex and zoster cause?
- Small, eosinophilic intranuclear inclusions
What type of inclusions does Rabies cause?
Cytoplasmic “Negri Bodies”
What type of inclusions does CMV cause?
Basophillic, intranuclear inclusions
What type of inclusion bodies does Subacute Sclerosing Panencephalitis (SSPE) cause?
Basophillic intranuclear inclusions (lethal disease caused by measles virus)
What type of inclusion bodies does Progressive Multifocal Leukoencephalopathy (PML) cause?
Intranuclear inclusions with a ground glass appearance to the nucleus.(destructive multifocal disease of oligodendrocytes, caused by the JC virus)
