Case 3: Meningitis Pathology Flashcards
How may microorganismenter the meninges?
Ears, nasopharynx (extension)
cranial injury (direct implantation)
Blood (haematological dissemination)
Peripheral nervous system
Name 4 major bacterial agents for meningitis?
Neisseria Mengitidis
Strep Pneumonia
Staph Aureus
Step gORUP b
Name 4 major viral causes of meningitis?
Enterovirus
Herpes
Mumps
HIV
Name 2 major fungal cause of meningitis
Crypt neoformans
candida Albicans
What is the gram status of H influenza?
Gram Negaive
What conditions is H. influenza most associated with?
OM and sinusitis
Where is H influenza commonly found?
The nasopharynx
When is strep pneumococcal the most common type of meningitis?
In patient with truama, ASSOCIATED WITH ALCOHLISM, MALUTRITION AND dm
What is the gram status of strep Pnemococcal
Gram Positive
What is the gram status of n. meningitides?
Gram Negative
hy is leiseria monocytogens so important?
High mortality rate
What changes in the pie-arachnoid space are observed in meningitis?
congestion of polymorphs and development of pus
brain become covered wit grey-green exudate
What changes int eh sub-arachnoid space are observed in viral meningitis?
lymphocytic inflammatory CSF reaction without pus formation
What is the difference between complicated and uncomplicated Hydrocephalus?
Complicated has an obstruction of CSF leading to coning, brain atrophy and widening of the ventricles
What are the 3 types of meningitis?
Acute pyogenic (bacterial)
Aseptic (acute or subacute viral)
Chronic (Tb, cryptococcus)
What is the leading cause of acute pyogenic meningitis in adolescents?
Neisseria meningitidis
What is th leading cause of meningitis in elderly?
Strep pneumonia and listeria monocytogens
What is waterhouse-friderichsen syndrome?
Septicaemai secondary to meningitis
Haemorrhagic infection of the adrenal glands
Cutaneous petechiae
(seen in meningococcal infeciton
How does CSF appear in acute pyogenic meninigitis?
Clouding, increased pressure, increased neutrophils, increased protein and decreased glucose
What is aseptic meningitis?
What there are the manifestations of meningitis without positive bacterial culture (usually is viral)
How does the CSF appear in aseptic meningitis?
Lymphocytic pleocytosis, increased pressure, increased neutrophils, moderate protein and normal glucose
What is a brain abscess?
Discrete lesions with liquiefactive necrosis surrounded by brain swelling
Granulation tissue at the outer margin
What predisposes to brain abscess?
Bacterial endocarditis Congenital heart disease Loss of pul filtration of organisms Pul sepsis Immunosuppression
Whatis subdural empyema
This is an infection of the subdural tissue, bacteria proliferate in the subdural tissue
Whatis the Munro Kellie hypothesis of Intra-cranial Pressure
he Volume of the brain, CSF and blood is constant because th skull creates a confined space
How is cerebral perfusion pressure calculated
Mean arterial pressure - ICP
Why do vasalva manoeuvres worsen headaches?
Increase ICP
What are the 3 types of herniation
Trantentorial (temporal lobe below the tentorium cerebella), tonsils (cerebella tonsils) and subfalcine (falx cerebri)
What can raise ICP?
Mass lesions
Disturbance of CSF circulation
Diffuse brain oedema
Idiopathic
Where is the pathology in non-communicated hydrocephalus?
Blockage within the ventricular system, proximal to arachnoid granulations
What can cause non-communicating hydrocephalus?
Aqueduct stenosis
What are the MRI findings on non-communicating hydrocephalus?
Ventricular enlargement, sulcal effacement, reduced visibility of tissue
What is the pathology of communicating Hydrocephalus
Can’t properly reabsorb the CSF
What are the presentations of acute hydrocephalus?
acutely elevated ICP
What is the presentation of chronic hydrocephalus? (AID)
Apriaxia
Incontinenc
Dementia
