6 - Neuro Manifestations of Infections Flashcards
1
Q
What is a CNS infection?
A
- Brain parenchyma, meninges, blood vessels can be invaded by any pathologic microorganism
- CNS infections classified by site of involvement (Meningitis, Encephalitis, Myelitis)
2
Q
What is meningitis?
A
An infection of the meninges
3
Q
What is encephalitis?
A
An infection of the brain
4
Q
What is myelitis?
A
An infection of the spinal cord
5
Q
What is the time period of a CNS infection?
A
Disease processes may be
- Acute
- Subacute
- Chronic
6
Q
Describe meningitis
A
- Invasion of meninges by pathologic microorganism
- Infection / inflammatory response mostly involves the pia mater, arachnoid mater, subarachnoid space (CSF)
- Secondary involvement blood vessels and brain parenchyma
7
Q
Describe the causes of meningitis
A
Aseptic Meningitis
- Unknown pathogen
Viral organisms
- Enteroviruses most common
- Usually self limiting / not life threatening
May be a complication of systemic viral infection
- Mumps
8
Q
Describe bacterial meningitis
A
- Brain not the primary site of infection
- Pathogen gains access to brain (hematologic or direct extension via ear, sinus, bone, etc.)
- Sporadic or Epidemic (Meningococcus)
9
Q
What are the signs and symptoms of meningitis?
A
- Chills, Fever, Headache
- Neck pain / stiffness –> “nuchal rigidity”
- Altered mental state
- Seizures
- Petechial rash (with meningococcus)
10
Q
Which organisms typically cause meningitis?
A
Neonate
- Group B streptococcus
- Escherichia coli
Children
- H. influenza ( decreased incidence with vaccine)
Adults
- Streptococcus pneumoniae (pneumococcus)
- Neisseria meningitidis (meningococcus)
- Listeria monocytogenes (also neonates)
1/3 - no organism cultured
11
Q
Describe the outcome of bacterial meningitis
A
- Fatality rate is still rather high
- Incidence is 1-2/100,000 so not that infrequent
12
Q
Describe the sequelae (consequences) of meningitis
A
- Focal neurologic deficits
- Cognitive loss
- Cranial nerve palsies (blindness, deafness, facial palsy)
- Seizures
- Hydrocephalous
- Myelopathy, radiculopathy
- Death
13
Q
How do you diagnose meningitis?
A
- Suspected on history and physical exam
- Confirmed on CSF analysis
- Get spinal tap before antibiotics
- Other tests (WBC, CT/MRI of brain, sinus x-ray, blood culture)
14
Q
What patients would you not want to do a spinal tap on?
A
Don’t do a spinal tap on an anticoagulated patient (warfarin) - they will bleed into the spinal canal and clot and then spinal deficits result
15
Q
Where do you do a spinal tap?
A
L2-3, L3-4 or L4-5
It is a very benign procedure - minimal risk
16
Q
Describe what you will see in the CSF in CNS infections
A
slide 19
17
Q
What is the treatment for bacterial meningitis?
A
Antibiotics
- Cephalosporins – Ceftriaxone, Cefotaxime
- Vancomycin
Supportive
- Hydration / metabolic support / CSF edema
- Ventilation
- Anticoagulation for DIC
Steroids / Anticonvulsants
Rehabilitation
Prophylaxis (Rifampin, Cephalosporins
18
Q
Describe tuberculous meningitis
A
- Generally subacute / secondary
- Rupture of tubercle into CSF
- Present with headaches, cognitive dysfunction, weight loss
19
Q
How do you diagnose tuberculous meningitis?
A
- Brain scan, CSF
- Brain / meningeal biopsy
20
Q
Describe a CNS abscess
A
- Can be found in the Brain, Spinal Cord, Epidural space
- Typically occur secondary to blood metastasis, direct extension from skin, sinus, etc. or a perforating wounds
- May contain anaerobic organisms
- May be aseptic
21
Q
What is myelitis again?
A
A direct infection of the spinal cord itself
22
Q
Describe leprosy
A
- Not a disease that has gone away
- Chronic infection of skin and peripheral nerves
- Granulomatous nerve deterioration occurs
- Caused by the pathogen mycobacterium leprae
23
Q
What are the signs and symptoms of leprosy?
A
Cutaneous and peripheral nerve manifestation
- Anesthesia
- Motor loss
- Joint, bone limb deformities
24
Q
How do you treat leprosy?
A
- Treated with Dapsone, Rifampin, Clofazimine
Chance of spreading from person to person is very small, so you do not need to seclude patients
25
What is encephalitis?
- Infection of brain parenchyma
| - Often secondary to viral infection
26
What do we call encephalitis with spinal cord involvement?
With spinal cord involvement – encephalo-myelitis
27
What do we call encephalitis with meningeal involvement?
With meningeal involvement – meningo-encephalitis (aseptic meningitis)
28
How do you diagnose encephalitis?
- Diagnosis suspected clinically
| - Confirmed with virus isolation in CSF / tissue
29
What is poliomyelitis?
Polio
- Starts out with a GI infection - Enterovirus (picovirus)
- First presents as an acute infection
- Later progresses to flaccid paralysis (due to attacks on α motor neurons)
- Occasional brain involvement occurs (stupor, seizures)
- Respiratory muscles or bulbar muscles (used to talk and swallow) dysfunciton can result
- Post-polio syndrome 30 – 40 years later (after infection)
- Not a reactivation of the virus, but a an effect on previously injured nerves
30
What is the arbovirus infection?
Transmitted by arthropod vectors (mosquitoes)
- Eastern Equine Encephalitis
- Western Equine Encephalitis
- St. Louis Encephalitis
- West Nile Encephalitis
1st acute infection
2nd confusion, seizures, focal neuro deficits, myelitis
- May progress to coma, death
- Recovery may be incomplete
31
Describe herpes simplex encephalitis
- Most significant sporadic encephalitis
- Endogenous reactivation of latent virus
- Abrupt onset with fever, headache, malaise (cognitive dysfunction, focal neuro deficits or seizures)
- Abnormal EEG/MRI scan
32
How do you treat herpes simplex encephalitis?
- Acyclovir
- Steroids
- Anticonvulsants
33
Describe AIDS
Clinical syndrome of multiple infections
- Secondary to HIV-I infection
- Targets immune system
Categorized by degree of immune system involvement
- CD4 lymphocyte counts
Neurotropic virus
- 70% with neurologic disease
CNS also affected by opportunistic infections
34
Describe HAART therapy
HAART therapy – highly active anti-retroviral
We don't see CNS manifestations of AIDS anymore due to these drugs
35
What is progressive multifocal leucoencephalopathy?
- Slowly progressive infection
- It is a demyelinating disease that leads to dementia
- Caused by the JC virus (which most people have inside them - 90%)
- It is typically benign until there are problems with the immune system
- PML involves an activation of this latent virus
36
What patient populations do we see PML in?
Seen in immuno-deficient states
- Lymphoma, AIDS
- ↑ case reports with Tysabri (Natalizumab)
37
Describe the fungal infections in the CNS
Cryptococcosis most common
- Subacute / Chronic
- Meningeal / Cognitive symptoms, Headache
Coccidiomycosis in southwest
- Valley fever
Candida Albicans (yeast) in immuno-compromised patients
38
Describe fungal meningitis secondary to contaminated steroid injections
CDC – 54 cases as of 10/22/12
- Exserohilum rostratum in 52 pts. and in unopened steroid vials
- About 14,000 patients exposed
- 25 deaths
Treatment
- Voriconazole, amphotericin B
39
What are two spirochete infections?
- Lyme Neuroborreliosis
| - Neurosyphilis
40
Describe Lyme Neuroborreliosis
- Secondary borrelia burgdorferi
- Tick vector
- Causes erythema migrans, facial nerve palsy, meningoencephalitis, neuropathy
41
Describe neurosyphilis
- Secondary to treponema pallidum
- Sexually transmitted disease
- Causes meningoencephalitis, tabes doralis (use Rhomberg sign to diagnose), general paresis
42
Describe cerebral cysticercosis
- Encystment with larvae of Taenia solium
- Multiple cysts / calcified lesions in brain and meninges
Mostly comes from meat or fish - lives in the muscle of pork
If you eat uncooked pork, it can infest inside of you and eventually get to the brain
43
How does cerebral cysticercosis present?
- Headaches
- Seizures
- Focal deficits
44
How do you treat cerebral cysticercosis?
- Ventricular shunts, surgery
- Anticonvulsants / steroids
- Albendazole
45
What are prion diseases?
Proteins that have the ability to get into an orgaism and use the DNA/RNA equiptment to reproduce themselves
Present with...
- Dementia
- Motor signs
- Seizures
- Death
46
Describe prions
Prion
- Protein units without nucleic acid
- Infectious / resistant to heat and radiation
47
Describe the transmission of prion diseases
- 90% sporadic
| - Can also be iatrogenic or familial forms
48
What are the CNS forms of prion diseases?
Transmissible Spongiform Encephalopathy
- Jakob-Creutzfeldt disease (and variant)
- Bovine Spongiform Encephalopathy (BSE) which is “Mad Cow” disease from food
49
Describe botulism
- Does not invade the CNS
- Works on the neuromuscular junction
- It is from a toxin of Clostridium Botulinum
- Typically acquired in food and wounds
50
What happens to patients with botulism poisonin?
Paralysis of motor and autonomic nerves (prominent cranial nerve involvement)
51
How do you diagnose botulism?
Confirmed with toxin / organism identification
52
What is the treatment with botulism?
Antitoxin and supportive
You have to prove you have botulism toxin before the CDC will send you the drug
