Intoxications/Infections Flashcards
Tetanus
Tetanospasmin binds to cortical, brainstem, and interneurons, preventing the release of GABA (glycine and gamma aminobutyric acid)
(2 weeks after exposure)
Symptoms: painful muscle spasms
-spread of exotoxin through the bloodstream produces diffuse muscle spasms and generalized convulsive seizures from cortical disinhibition
(trismus, risus sardonicus, opisthotonus)
-may impair swallowing and breathing
Botulism
improperly canned or contaminated food -exotoxin binds to presynaptic nerve terminals and prevents the release of acetylcholine from lower motor neurons and parasympathetic nerves (within 12 hours) Symptoms: initially 1. ptosis 2. diplopia 3. pupillary dialysis followed by: 4. dysphagia 5. facial and limb weakness 6. respiratory paralysis
guanidine helps facilitate release of acetylcholine
Lead Poisoning
Adults: peripheral neuropathy with focal neuropathies like wrist drop
children: encephalopathy and abdominal pain
Organic solvent
peripheral neuropathy or encephalopathy or both
glue
periphearl neuropahty
CO
headache vomiting and blurry vision–>coma, seizures, and cardiopulmonary arrest
survivors: deficits of memory or cognition or show signs of parkinsonism
illicit drugs and the brain
- intracranial hemorrhage from head trauma
- drug induced seizures
- drug induced vasoconstriction or hypertension leading to ischemic infarction or brain hemorrhage–>stroke syndrome in young healthy adult —>cocaine
- ischemic infarction from IV drug use from vasculitis-immune mediated vascular reaction to the drug or its filler material
acute alcohol toxicity
social disinhibition, impairment of consciousness, and cerebral dysfunction(dysarthria, dysmetria, nystagmus, and ataxia)
- head trauma secondarily
- very high levels coma and death
Alcohol withdrawal syndrome
Initially
Hypersympathetic stage-tremulous, sweating, tach, jitteriness
12 hours- 3-days
Cluster of generalized tonic-clonic seizures
3-4 days
Delirium tremens
-fluctuating motor and autonomic activity, confusion and hallucinations
-delirium tremens or any complications such as infections or head trauma may become fatal if untreated
What is the treatment for alcohol withdrawal?
- hydration and metabolic care (thiamine)
2. benzodiazepines provide sedation and seizure control*
Wernicke-Korsakoff syndrom
-deficiency of thiamine in patients with malnutrition or malabsorption-most described in alchololics
Wernicke’s encephalopathy
acute phase of the syndrome
- nystagmus
- ophthalmoplegia
- gait ataxia
- confusion
may resolve within hours to days of thiamine administration
Korsakoff’s psychosis
severe or recurrent thiamine deficiency
- chronic memory deficit
- amnestic syndrome
- confabulation
(tiny petechial hemorrhages and gliosis occur in the vicinity of the third and fourth ventricle and connecting aqueduct, involving mammillary bodies, fornix, and dorsomedial thalamus)
Alcoholic cerebellar degneration
anterior superior vermis–> ataxic gait and dysmetria of the lower limbs
central pontine myelinolysis
occurs in alcoholic who undergo rapid correction of severe hyponatremia
-demyelination of the corticospinal and corticobulbar tracts of the pons occur
Acute meningitis
Symptoms
Treatment
symptoms: fever, headache, nuchal rigidity( meningeal irritation and inflammation-Kernig or Brudzinski sign) malaise, lethargy, nausea and vomiting, lethargy to coma
- may be fatal
Treatment: ceftriaxone plus vanco
amp for elderly or neo for list
IV dexamethasone-given just before antibiotics reduces neurological complications such as deafness and cognitive deficits and lowers mortality
What can substantial amounts of purulent exudate lead to?
hydrocephalus by obstructing csf pathways
- pus in subarachnoid space may lead to inflammation and edema of cortex (meningoencephalitis) or cause infarction of the underlying brain or spinal cord when local superficial blood vessels become inflamed or thrombose
- young children may have deafness
Lumbar puncture bacterial meningitis
Polymorphonuclear WBC and low CSF glucose
Chronic meningitis
more subtle symptoms over weeks or months
-Tb, fungus, syphilis, parasites
Symptoms: confusion, low grade fever, mild headache, without obvious nuchal rigidity
-PCR CSF
Encephalitis
brain primary site of infection
symptoms: headache and fever, seizures, focal neurological deficits, behavior changes and impairment of consciousness
- patchy demyelination, edema, and tiny petechial hemorrhages
- neuronal destruction by proliferating microglia, perivascular lymphocytes, and viral inclusions within neurons
-arthropods(west-nile), viral infection (polio), rabies, herpes
What happens to patients with encephalitis
ICU-raised intracranial pressure and treatment with anticonvulsants and sedatives
Herpes simplex encephalitis
Location in brain it affects
Symptoms
Treatment
non epidemic, nonseasonal, high mortality when not treated
-inferior frontal and medial temporal lobes, often bilaterally and asymmetrically
Symptoms:
- aphasia
- behavioral changes
- memory deficits
Treatment: acyclovir
-treated on suspicion
West nile virus causing encephalitis
Location of CNS and pns
Symptoms
fever, headache, rash, significant weakness by affecting:
- peripheral nerves(similar to Guillain barre syndrome)
- anterior horn cells (similar to polio)
Polio
viral invasion and destruction of anterior horn cells and brain stem motor nuclei
- lower motor neuron sign asymmetrical
- post polio atrophy-gradual metabolic failure or burnout of lower motor neurons which collaterally sprouted to control the denervated fibers in polio-weakened muscles
Zoster or shingles
-chickenpox lays dormant in dorsal root ganglia
eruption of a vesicular rash with severe neuralgic pain along one or adjacent dermatomes on the torso or limbs
treatment: acyclovir
late AIDS
- chronic, painful neuropathy
- cognitive changes
- HIV dementia
- myelopathy similar to combined degeneration from B12
-direct viral invasion or indirect damage from cell lysis and inflammation or complications related to immuno deficient state
Primary cerebral lymphoma-
rare immune system tumor arising within the brain
Opportunistic infections in HIV
cerebral toxoplasmosis
cryptococcal meningitis
CMV retinitis or encephalitis
**Progressive multifocal leukoencephalopathy
What is PML?
JV virus
infect oligodendrocytes
patchy or spotty demyelination of CNS white matter occurs from destruction of the oligodendrocytes
no cure
abcess
localized, encapsulated infection within or outside the brain or spinal cord
-usually bacterial but may be fungal or parasitic in immunocompromised patients
symptoms: fever and headache and may be ill from serious systemic infection
- seizures and focal neurological signs depend on its location
- may create brain edema with mass effect and increased intracranial pressure
- ->rupture–>meningitis
prion
infectious proteins
- ->spongiform encephalopathies in human animals
- progressive aggregation of prions in neurons destroys them in the absence of any inflammation
Creutzfeldt Jakob dementia
often sporadic rather than transmitted
-rapidly progressive dementia with cerebellar, cortico spinal, lower motor neuron or extrapyramidal signs and symptoms
-myoclonus
- no cure
- cytoplasmic vacuoles in neurons and astrocytes and neuronal loss without inflammation
mad cow–>human–>variant of CJD-slower progression and more psych and behavioral symptoms
