Flashcards in Infections of CNS - bacterial meningitis and miscellaneous bacterial infections Deck (37)
how do bacteria reach the subarachnoid space?
- blood stream
what causes edema in bacterial meningitis?
- toxins from bacteria or from leukocytes
bacterial meningitis presentation
- change in alertness
- stiff neck resistant to flexion
how diagnose bacterial meningitis?
WBCs in bac meningitis
- usually 1000cells/cu mm or more and mostly PMNs
- early in disease WBC count can be low and can be mostly lymphocytes
protein and glucose in bac meningitis
high protein, low glucose
when start antibiotics in bac meningitis?
right away, it's an emergency, and LP will be good even if taken hours after starting antibiotics
most common pathogen in bac meningitis in neonates?
group B beta-hemolytic streptococci and enteric gram-negative bacilli are the most common pathogens, accounting for 60-70% of the cases of meningitis.
most common pathogen in bac meningitis in 2 month to ten year olds?
“Hemophilus influenzae, meningococci, or pneumococci.”
Excerpt From: “Disorders of the Nervous System.” iBooks.
what should we think about if there are unusual organisms?
treatment for group B-beta hemolytic strep
treatment for enteric gram negative bacilli
3rd gen cephalosporin
treatment for listeria
ampicillin or penicillin
treatment for H. influenza
treatment for meningococcal meningitis
amp or chloremphenicol
ten complications of acute bacterial meningitis
- Cerebral edema (may lead to herniation)
Cortical venous thrombosis (stroke, seizures)
Venous sinus thrombosis (increased intracranial pressure)
- Cranial nerve palsies
- Subdural effusion or empyema
- Disseminated intravascular clotting (purpura, cyanosis, pain, fever, and hypotension)
- Lactic acidosis
- Inappropriate ADH secretion (hyponatremia)
- Diabetes insipidus
- Residual findings
Cranial nerve palsies
causes of intracranial pressure in bac meningitis
- reduced resorption of CSF due to inflammation of the sinuses
- damage to arachnoid granulations
- in infants - subdural effusion
what causes DIC in bac meningitis?
vasculitis with intravascular deposition of fibrin
treatment of DIC in bac meningitis
- steroids in children
- possibly heparin
treatment of lactic acidosis in bac meningitis
presentation of bac meningitis in Lyme disease
- weeks after infection but often when rash is still present
- often accompanies damage to the facial nerve
array of presentations of neurosyphilis
- vasculitis and CNS infarction
- tertiary syphilis
two presentations of tertiary syphilis
- tabes dorsalis
- general paresis
symptoms of tabes dorsalis in tertiary syphilis
- inflammation of dorsal root ganglia
- loss of position and vibration sense
- loss of deep tendon reflex
- lightning pain to abdomen
- abdominal cramps and vomiting
- Argyll-Robertson pupil, small and irregular with no light reaction but with accommodation
- bladder dysfunction
symptoms of general paresis in tertiary syphilis
- infection of frontal lobes of cerebral cortex
- frontal lobe dementia
- pupillary changes, myoclonic jerks, tremor
what tests can be used to diagnose neurosyphilis?
- rapid plasma reagin (RPR)
- venereal disease research lab test (VDRL)
- fluorescent treponemal antibody test (FTA)
which test can confirm tertiary syphilis?
- only FTA
what spirochete is responsible for lyme disease?
what is a common misdiagnosis in lyme disease parenchymal lesions?
- the lesions can occur with a fluctuating corset