Neuro: CNS infections Flashcards
3 most common bugs that cause bacterial meningitis.
- S. pneumoniae
- N. meningitidis
- H. influenza (vaccine is decreasing cases)
What is Cushing’s reflex?
Physiological nervous system response to increased intracranial pressure (ICP) that results in Cushing’s triad:
- widening pulse pressure
- irregular breathing
- reduction of the heart rate
A sign of meningitis
What are the 3 major signs of meningitis?
- Nuchal Rigidity (unless a patient is comatose)
- Fever
- Headache
What is a defining feature used to diagnose infantile meningitis?
Bulging fontanelles
What is latex agglutination?
An antigen binding test that can be diagnostic for meningitis. Usually used to identify Strep. pneumo.
Symptom of Meningococcal Meningitis that is immediately observed on physical exam.
Petechial or hemorrhagic skin rash
N. meningitidis can be spread through respiratory droplets. What prophylactic treatment is given to friends and family of a patient with meningococcal meningitis?
Rifampin and Cipro
Name 3 complications of meningococcal meningitis.
- Disseminated Intravascular Coagulation (DIC): intense coagulation response of the whole body that leads to blockage of small capillaries to organs and tissues leading to necrosis.
- Adrenal Hemorrhage (Waterhouse Friderichsen syndrome)
- Circulatory Collapse
What 3 things can lead to a Haemophilus meningitis?
- Skull fracture
- otitis media
- sinusitis
What 3 conditions are linked to pneumococcal meningitis?
- Alcoholism
- Sickle Cell Disease (causes necrosis of the spleen)
- Asplenia (no ability to opsonize)
What is the treatment for bacterial meningitis?
Once it is suspected, immediately start on antibiotics. DON’T wait for spinal tap.
What are the two most common bugs that cause meningitis in newborns?
- E. coli
2. Strep. agalactiae (Group B)
Unique characteristics that define polio.
Unilateral flaccid paralysis
What are the two vaccines used for polio?
Sabin - live attenuated
Salk - killed
Main symptom that differentiates meningitis from encephalitis.
Seizures
How does HSV cause encephalitis and what are the symptoms of Herpes encephalitis?
Gains entry to the brain thru the Trigeminal ganglion or olfactory bulb.
Symptoms include seizure, headache, meningeal signs.
If it gain entry thru olfactory bulb, can affect frontal lobe leading to hallucination and personality changes.
If it gains entry tru CN V ganglion can lead to speech problems.
With most encephalitis conditions there is no increase in RBCs in the CSF. With herpes encephalitis the RBC count in CSF increases due to what?
HSV causes a hemorrhagic reaction
Treatment for Herpes encephalitis.
Acyclovir
Name 3 types of aseptic meningitis that lead to a decrease in glucose levels.
- Herpes Meningitis
- Mumps Meningitis
- Lymphocytic Choriomeningitis
Name two buzz words for Rabies infection and a treatment.
- Hydrophobia
- Negri bodies
Only treatment is prophylaxis after suspicious animal bite
Name the three mechanisms of brain abscess, the 3 causes in healthy people and 3 causes in immunocompromised people.
Spreading
- Direct Extenstion (ex. from ear infection)
- Tumor
- Trauma
Healthy:
- Staph
- Strep
- Anaerobes
Immunocompromised:
- Toxoplasmosis
- Fungus
- TB
What 6 mononeuropathies are most common in leprosy?
Superficial nerves
- CN V
- CN VII
- Great Auricular Nerve
- Ulnar
- Tibial
- Fibular
What are 3 general etiologies for epidural abscesses?
- Direct Extension
- Metastasis
- Trauma
(same as brain abscess)
Main causative agent of epidural abscesses and most common location.
Staph aureus
Thoracic region
How is epidural abscess differentiated from:
- Guillain Barre
- Meningitis
- Hyperreflexia in EA, arefelxia in GB
2. Peripheral nerve symptoms in EA (reflexes)
What diseases are associated with increased risk to contract Listeria m?
Chronic diseases: diabetes mellitus, alcoholism, renal disease, transplants
What is Mollaret Meningitis?
Recurrent Aseptic meningitis
What is Behcet Syndrome?
Immune mediated small vessel vasculitis associated with recurrent meningitis.
What are some symptoms of TB meningitis?
Slow progression, which is different than most meningitis cases.
Temperature increase, very high protein in CSF, lower glucose in CSF, and increased CSF lymphocytes.
Tend to form in basilar portion of brainstem, so cranial nerve symptoms arise.
What is neurosarcoidosis?
Formation of granulomas along the basilar portion of the brainstem leading to cranial nerve signs. Can also affect peripheral nerves.
CSF has increased protein, decreased glucose, increased lymphocytes.
How do you differentiate neurosarcoidosis from TB meningitis and how is each treated.
NS: treat with steroids
- increased ACE
- increased serum calcium
TB: treat with antibiotics and surgery
-acid fast stain
What is cyticercosis and what 3 conditions can it lead to?
Ingestion of Taenia solium (pork tapeworm) eggs which migrate to brain or muscle tissue and form cysts. Eventually they can rupture leading to inflammation. They can cause:
- Focal symptoms (depending on location in the brain)
- Hydrocephalus (if in ventricles)
- Meningitis (if rupture into CSF)
Who is at risk for Toxoplasmosis infection and where is the most common source?
AIDS patients (and other immunocompromised)
Comes from undercooked pork
How do patients with Toxo present?
Mono-like symptoms, masses in the CNS lead to focal like symptoms.
If a pregnant patient contracts Toxo, what can happen to the fetus?
Birth deformities: microcephaly, mental retardation.
Also seizure, eye findings, spasticity
What is a defining symptom to Creuztfeldt-Jakob disease?
Stimulus Sensitive Myoclonus: ex. overreaction to loud noises
What can indicate Cruezfeldt-Jakob disesase in the CSF?
14-3-3 protein
biopsy is most conclusive
How do patients present in Cryptococcosis and which populations are at highest risk?
Presentation: headaches, mental change, focal findings
Immunocompromised and chronic disease are at risk. (AIDS, lupus, leukemia, diabetes m. renal failure)
What are the best two tests to diagnose Cryptococcosis and what is the treatment?
- India Ink
- Crypto antigen
Treat: antifungals
What are symtoms of Tetanus?
trismus (lockjaw), opisthotonos (hyperextended body), risus saronicus (locked facial expression)
What is normal CSF:
- pressure
- WBC count
- Glucose level
- 50-200 mm H2O
- 0-5 lymphocytes
- 1/2 to 2/3 of serum level
What is Hypoglycorrhachia and what causes it?
Low glucose in CSF.
-mainly caused by infection in the CSF inhibiting the ability of cells to transfer glucose into the CSF
What are normal protein levels in CSF?
15-45 mg/dl
What are 4 indications for a spinal tap?
- Fever with or without meningeal signs
- Unexplained delirium or dementia
- Unexplained headache
- Diagnostic purposes: subarachnoid hemorrhage, multiple sclerosis, Guillain Barré syndrome, metastatic cancer, etc.
What are 3 contraindications for a spinal tap?
- Coagulopathy: low platelets, anticoagulation
- Focal skin infection
- Increased intracranial pressure with a mass lesion
(Papilledema itself is NOT a contraindication)
What 3 conditions are indicative of a traumatic tap?
- The CSF RBC/WBC ratio is similar to the peripheral blood RBC/WBC ratio
- The CSF differential is similar to the blood
- The CSF clears when spun down
What condition is indicative of a subarachnoid hemorrhage when blood appears in a spinal tap?
CSF tends to be yellowish/reddish when spun down
