Intoxications and Infections of the Nervous System

Question 1

Tetanus (demented monkeys)

Answer 1

• prevent release of inhibitory GABA
• prolonged painful muscle spasms
• localized vs generalized (diffuse mu spasms and generalized convulsive seizures from cortical disinhibition)

Question 2

painful muscle spasms of tetanus

Answer 2

• clenching lockjaw (trismus)
• grimacing smile (risus sardonicus)
• arching back (opisthotonus)

Question 3

Botulism (robots)

Answer 3

• improperly canned or contaminated food or in wound infections
• prevent release of ACh from LMN and parasympathetic nerves=paralysis of skeletal muscle, bowel, bladder, and salivary glands

Question 4

Guanidine

Answer 4

oral drug helps facilitate ACh release from motor nerve endings

Question 5

Environmental toxins

Answer 5

• lead poisoning: adults-peripheral neuropathy + focal neuropathy (wrist drop); kids-encephalopathy and abdo pain
• organic solvent/glues and adhesives: peripheral neuropathy +/or encephalopathy
• CO-HA, v, blurry vision…coma, sz, cardiopulm arrest. survivors: memory and cognition deficits, parkinsonism

Question 6

what should a stroke syndrome in a young, otherwise healthy, pt make you think of?

Answer 6

drug induced vasoconstriction or HTN leading to ischemic infarction or brain hemorrhage. **cocaine

Question 7

Alcohol withdrawal

Answer 7

1. hypersympathetic stage-tremulousness, sweating, tachy, jitters
2. 12hr-3d after last drink: cluster of generalized tonic-clonic seizures (d/t diffuse toxic effect on the brain)
3. 3-4d after last drink: DTs

Question 8

what provides sedation and seizure control for DTs

Answer 8

benzos

Question 9

Wernicke-Korsakoff syndrome

Answer 9

• B1 (thiamine) deficiency in pts with malnutrition or malabsorption
• acute phase: W’s encephalopathy=nystagmus, ophthalmoplegia, gait ataxia, and confusion (resolve in hours to days of thiamine administration)

Question 10

Korsakoff’s psychosis

Answer 10

• 2/2 persistent, severe, or recurrent thiamine deficiency

- chronic memory deficit or amnestic syndrome leading to confabulation

Question 11

pathology of Korsakoff

Answer 11

-tiny petechial hemorrhages and gliosis around 3rd and 4th ventricles and connecting aqueduct, involving mammilary bodies, fornix, and dorsomedial thalamus

Question 12

alcoholic cerebellar degeneration

Answer 12

-involves anterior-superior vermis=ataxic gait and dysmetria of the lower limbs

Question 13

central pontine myelinolysis

Answer 13

• 2/2 overly rapid correction of severe hyponatremia

- get demyelination of the corticospinal and corticobulbar tracts in the pons

Question 14

where can meningitis come from

Answer 14

-can directly spread form an infection in an area near (ex otitis or sinusitis) or f/m infectious organisms spread through the bloodstream from a remote infection (PNA)

Question 15

acute meningitis

Answer 15

• fever, HA, stiff neck, malaise, lethargy, n/v

- acute bacterial meningitis can be fatal!!

Question 16

what causes neck stiffness/nuchal rigidity?

Answer 16

• meningeal irritation or inflammation

- can cause signs of Kernig or Brudsinski

Question 17

what is initial Abx coverage for meningitis

Answer 17

ceftriaxone and vancomycin (add Ampicillin to cover for Listeria)

Question 18

role of iv dexamethasone (0.15mg/kg)

Answer 18

• reduces neuro complications
• lowers mortality
• give just before/with initial abx

Question 19

When substantial amt of purulent exudate or pus develops from bacterial meningitis what can it cause

Answer 19

hydrocephalus by obstructing CSF pathways

Question 20

meningoencephalitis

Answer 20

when pus accumulates over the cortical subarachnoid space and leads to inflammation and edema of the cortex itself…can also get infraction of underlying brain or SC when local superficial blood vessels become inflamed and thrombose

Question 21

what should young kids recovering from meningitis be observed for

Answer 21

subsequent deafness which may impede their ability to learn to talk

Question 22

LP

Answer 22

-perform asap in meningitis management

Question 23

reasons to delay an LP

Answer 23

• thrombocytopenia
• deficient clotting factors
• infection along skin of the back
• elevated ICP
• intracranial mass with edema (new onset sz, focal neuro deficit, h/o stroke, IC)

Question 24

what is the most typical profile for bacterial meningitis

Answer 24

PMN WBCs and low CSF glucose

Question 25

encephalitis primary site of infection and indllmation

Answer 25

THE BRAIN

Question 26

modes of infection by the causative virus of the encephalitis

Answer 26

- arthropods (ticks, mosquitoes) - ingestion (polio virus) - inoculation (Rabies from animal bites) - inhalation - reactivation (Herpes simplex)

Question 27

encephalitis microscopically

Answer 27

neuronal destruction by proliferating microglia, perivascular lymphocytes, and viral inclusions within neurons and glia

Question 28

are antiviral drugs useful in encephalitis

Answer 28

only herpes simpex wherein acyclovir is used

Question 29

HSE

Answer 29

- 2/2 HSV1 | - involves inferior frontal and medial temporal lobes, often b/l an asymmetric

Question 30

whatre s/s highly suggestive of HSE

Answer 30

- aphasia - behavioral changes - memory deficits

Question 31

polio

Answer 31

- viral invasion and destruction of anterior horn cells and BS motor nuclei - asymmetrical LMN signs - postpolio muscular atrophy in contra stronger limb

Question 32

Zoster or shingles

Answer 32

- eruption of a vesicular rash with severe neuralgic pain along 1 or 2 adjacent dermatomes on torso or limb - admin acyclovir - sequelae: post-herpetic neuralgia

Question 33

HIV1

Answer 33

destroys T4 helper lymphocytes

Question 34

later sequelae of AIDS

Answer 34

-chronic painful sensory neuropathy along with cognitive changes, HIV dementia and myelopathy

Question 35

AIDS and primary cerebral lymphoma

Answer 35

-PCL is a rare immune system tumor arising within the brain and most often occurs in AIDS pts

Question 36

common opportunistic infections in AIDS

Answer 36

- cerebral toxo (protozoal parasite) - cryptococcal meningitis (fungal) - CMV retinitis or encephalitis

Question 37

PML

Answer 37

- progressive multifocal leukoencephalopathy - most cases occur in AIDS pts - involves reactivation of latent JC virus (polyomavirus)--goes on to infect oligodendrocytes=patchy demyelination of CNS white matter=focal neuro deficits

Question 38

What is an abscess?

Answer 38

- a localized encapsulated infection within or outside (epidural or subdural) the brain or spinal cord - usually bacterial, but may be fungal or parasitic in IC pts - may be solitary or numerous

Question 39

How does an abscess develop

Answer 39

-f/m adjacent infection OR -through bloodstream from a distant infection

Question 40

cerebral abscess may cause...

Answer 40

- seizures and focal neurological signs dependent on its location - may create brain edema with mass effect and increased ICP - may rupture into ventricular system or subarachnoid space and produce meningitis

Question 41

how is the diagnosis of abscess confirmed

Answer 41

-CT or MRI brain scan with and without contrast

Question 42

Prion dz

Answer 42

-prions=infectious proteins that can cause transmissible spongiform encephalopathies in human and animals

Question 43

Creutzfeldt-Jakob dementia

Answer 43

- most common prion dz, sporadic - v. rapidly progressive dementia with cerebellar, corticospinal, LMN or EPS s/s - myoclonus is usually present

Question 44

EEG of CJD

Answer 44

periodic sharp wave discharges

Question 45

diagnostic brain bx of CJD

Answer 45

- spongiform changes which are cytoplasmic vacuoles in neurons and astrocytes - neuronal loss sans inflammation

Question 46

mad cow dz

Answer 46

bovine spongiform encephalopathy thats an epidemic prion dz in cattle

Question 47

HSV encephalitis

Answer 47

- affects mostly temporal lobe and may present acutely (<1wk duration) with focal neurological findings - csf: lymphocytic pleocytosis, inc erythrocytes, elevated protein - standard for diagnosis: HSV PCR analysis

Question 48

Creutzfeldt-Jakob dz probably diagnosis

Answer 48

- rapidly progressive dementia - two out of 4: - --myoclonus - --akinetic mutism - --cerebellar or visual disturbances - --pyramidal/extrapyramidal dysfunction (hypokinesia) - periodic sharp wave complexes on EEG and.or positive 14-3-3 CSF assay

Question 49

CJD definitive diagnosis (need 2/4 features) and

Answer 49

-brain biopsy (gold standard) or demonstrated PRNP gene mutations

Question 50

autonomic dysfunction

Answer 50

- postural hypotension - abnormal sweating - disturbance of bowel or bladder control - abnormal salivation or lacrimation - impotence - gastroparesis