Neurologic Infections, Seizures, Brain Injury, CVD Flashcards
What are the two locations of neurological infections?
- Within the brain tissue. 2. Within the Meninges and Spinal Cord
What is the meninges?
The meninges are the three membranes that envelop the brain and the spinal cord.
What are the three layers of the meninges?
Pia Mater: the innermost layer of the meninges. Arachnoid Mater: the middle layer. The Dura Mater: the outter most layer
What are the two classifications of nerological infections?
Viral or Bacterial
Name four different routes of entry for nerological infections?
- Microbe entry via compromised blood brain barrier.
- Fracture in the skull.
- Direct spread from adjoining area (middle ear extends to brain)
- Along an axon that goes into the brain. (cranial nerve)
What is bacterial meningitis?
Bacterial meninigitis is a bacterial inflammation of the meninges.
What are the causes of bacterial meningitis?
Any bacterium that is able to enter and infect the meningies. Some bacteria are more likely to cause meningies.
What are the three most common bacteria seen in meningitis? What age groups do they most commonly affect?
- Streptoccus pneumonia: most common in adults.
- Neisseria meningitides: causes meningococcal meningitis in youth.
- Haemophilus influenzae: cause in those less that 5 yrs old.
What are several predisposing factors of bacterial meningitis? (protals of entry).
Head trauma, infection in sinus or middle ear (congruent infection), post surgery infections, decreased immunity.
What is the pathophysiology of bacterial meningitis?
Once entry occurs, microbial prliferation and lysis occurs. Cell lysis releases inflammatory agents resulting in inflammation. Because there is inflammation, purulent exudate develops and gets into the CSF. Pus accumulates around the meningies, subarachnoid space, ventricles and blood vessels are all affected. The space needed by the exudate puts pressure on the brain surface and CSF.
What are the manifestations of bacterial meningitis?
There are several manifestations of bacterial meningitis.
Fever because of bacterial infections (Systemic manifestatons of infection), Headache/Neck/Back Pain, Nausea/Vomiting (centers in brain that regulate are affected), Nuchal Rigidity (nape of neck).
What are the two physical test we can conduct for bacterial meningitis diagnosis?
Brudzinski’s Sign and Kernig’s Sign. Both will be positive.
Brudzinski’s is raising the head, and the knees flex at the hip.
Kernig’s is extension of knee flexion at hip and results in back pain.
What is a diagnostic test we can complete for diagnosis of bacterial meningitis?
Body fluid collection and CSF. Purulent, proteins, neutrophils and decreased glucose will all show up in diagnostics due to inflammation. This will also allow for the indentification of microbes.
Why will tests show a decreased glucose level when diagnosing bacterial meningitis?
Bacteria will be using the glucose as an energy source.
What is the treatment for bacterial meningitis?
Indentify the bacteria and treat with antibiotics. Will also be given steroids to reduce inflammation (Anti-inflammatory)
What is viral meningitis?
Viral meningitis is usually a self limiting condition which is less severe than bacterial meningitis. Most cases are due to mumps virus. Complications can still be serious, such as intercranial pressure which must be treated.
What is the purpose of CSF tapping in viral meningitis?
CSF can tell us several different things: The presence of lymphocytes which come to fight viral infection. Moderately elevated levels of proteins which demonstrate inflammation, compromised brain/blood barrier, and autoimmunity. It will also show normal glucose levels.
Why will there be a normal glucose level in viral meningitis, but not bacterial?
Viruses do not utilize glucose for energy, so glucose levels will remain normal.
What is encephalitis?
Encephalitis is the inflammation of the brain or spinal cord parenchyma. It is usually caused by a virus.
What is parenchyma?
Parenchyma is the bulk of a substance. In the case of encephalitis we are speaking about the brain tissue, or spinal column.
What are several common viruses implicated in encephalitis?
- Arbovirus Encephalitis - virus from tics.
- Hepes Simplex 1 Virus Encephalitis - cold sore.
What is the pathophysiology of Encephalitis?
Initially localized damage like necrosis and hemorrhage becomes generalized inflammation leading to edema. Eventually, the cell bodies get destroyed. The course of encephalitis follows an unpredictable course.
What are the manifestations of Encephalitis?
Typically, several of the manifestations will present.
Neurological disturbances (lethargy, seizures, coma). Fever. Headache. Nuchal rigidity. Manifestations usually subside in about 2 weeks if Arbovirus. If caused by Herpes Simplex the manifestations are more serious and should be treated agressively. Antivirals like Acyclovir IV. Severe neuro impairment is possible. There is a 30% mortality rate and those that do survive may have neuro impairment like dementia or seizures.
What is a seizure?
A seizure is a sudden, uncontrolled neural discharge characterized by altered movements, sensation, and altered behaviour. Manifestations will vary according to the site of discharge.
