19. Neurological Disorders Flashcards
What is amyotrophic lateral sclerosis (ALS)?
ALS is a progressive neurodegenerative disease of the upper and lower motor neurons due to degeneration of lateral cotricospinal tracts, which will eventually lead to muscle failure
How does ALS present?
Progressive muscle weakness, hyperreflexia (due to upper motor neuron involvement), muscle fasciculations (due to lower motor neuron involvement), and atrophy
Maxillofacial implications of ALS
Dysphagia (pharyngeal muscle weakness) leading to aspiration risk (bulbar nuclei involvement), tongue weakness with fasciculations, sialorrhea due to inability to handle secretions.
What is Alzheimer’s Disease?
A neurodegenerative disease characterized by the progressive loss of cortical neurons and the formation of amyloid plaques and intraneuronal neurofibrillary tangles
- Progressive loss of neurons eventually leads to a relative deficiency in cortical acetylcholine transmission (resulting from loss of neurons in the nucleus basalis)
Dose of sedative-hypnotics should be reduced by ___% in alzeheimer disease patients
30%
What is Parkinson’s Disease?
Neurodegenerative disease characterized by classic triad of bradykinesia, rigidity, and resting (pill-rolling tremor) caused by progressive loss of dopaminergic neurons in the pars compacta of the substantia nigra in the basal ganglia.
What is the pathophysiology of Parkinson’s disease?
Depletion of dopamine –> diminished inhibition of neurons in the extrapyramidal motor system –> unopposed stimulation by acetylcholine –> tremors of Parkinsonism.
Treatment of Parkinson’s disease
Goal to increase concentration of dopamine in the basal ganglia.
- Carbidopa-levodopa (Sinemet). Levodopa is a dopamine precursor that is combined with the decarboxylase inhibitor, carbidopa, which prevents peripheral conversion of levodopa to dopamine, thereby optimizing the amount of levodopa that can enter the CNS.
What drugs are used in early Parkinson’s disease that delay the need for levodopa treatment?
Selegiline, rasagiline (Type B Monoamine Oxidase Inhibitors) MAO-B inhibitors
Anticholinergics and antihistamines are also used to antagonize the effects of acetylcholine
What are the options for Parkinson’s patients who fail medical treatment?
Surgical treatment: thalamotomy, pallidotomy, or implantation of deep brain stimulator
What is Multiple Sclerosis?
MS is an inflammatory demyelinating disease of the CNS marked by discrete episodes of neurological dysfunction, termed relapses, followed by periods of remission.
- Demyelination preferentially occurs in the periventricular areas of the brain, due to autoimmune processes involving T and B autoreactive cells.
- Symptoms = visual disturbances, gait disturbance, ascending paresis, limb paresthesias, trigeminal neuralgia.
Diagnosis of MS
MRI with gadolinium (to demonstrate demyelination in the CNS)
CSF analysis will show increased intrathecal synthesis of IgG
What is a seizure?
A sudden onset of abnormal, highly synchronous discharges of neurons
Phases of seizures
Ictus (seizure itself)
Ictal phase (period of time during seizure)
Postictal phase (the time after the seizure)
Interictal phase (the time in between seizures)
What is epilepsy?
Epilepsy is a chronic disorder defined as recurrent seizures resulting from congenital or acquired factors in the cerebral cortex (e.g. cerebral scar, malformation, tumor, abnormal gene expression).
- Requires 2 separate unprovoked seizures
How are seizures classified
Partial vs. generalized (area of brain affected)
- Partial originate from single focus of cortical neurons
- Generalized involve diffuse activation of neurons in both hemispheres
Simple vs. complex (level of one’s consciousness)
- Simple = no loss of consciousness
- Complex = altered level of consciousness
Workup for seizures
MRI: the preferred method for studying brain structure in patients with epilepsy
EEG: (electroencephalography) - most important diagnostic test for seizures and epilepsy. Identify locations of seizure foci and characterize their electrical properties.
First-line agents for idiopathic generalized epilepsies
Valproate and lamotrigine
Fist-line agents for partial seizures
Carbamazepine, oxcarbazepine, topiramate, levetiracetem, lamotrigine, zonisamide
Most widely used anti-epileptic drug in the world because of low cost
Phenobarbital
What is status epilepticus?
A continuous episode of prolonged seizure activity or two or more occuring in sequence without recovery of consciousness between them.
- Life threatening medical emergency
- Most commonly caused by abrupt withdrawal of antiepileptic drugs
Treatment of status epilepticus
Activate EMS if no self-resolution in 5 minutes
ABCs, vitals, ECG, airway protection, supplemental O2
Establish venous access, consider benzodiazepines
- Midazolam 10mg for >40 kg, 5mg for 13-40 kg
- Lorazepam 0.1mg/kg/dose, max 4mg/dose
- Diazepam 0.15-0.2 mg/kg/dose, max 10mg/dose
Rule-out hypoglycemia
Routine glucose administration not indicated because hyperglycemia can exacerbate brain injury
Second-line therapy if seizure continues = phenobarbital, phenytoin, or anesthetic dose of propofol
What is neurogenic shock?
Can occur after spinal cord injury above T4-6, lasting 1-3 weeks.
- Hypotension (caused by loss of sympathetic tone and decrease in SVR
- Increase in venous capacitance and pooling
- Bradycardia and decreased ventricular function in lesions above T5 (sympathetic innervation to heart T1-T4)
What is autonomic hyperreflexia?
Neurogenic dysregulation which can lead to severe hypertension when stimulated below the level of the lesion. It is a medical emergency and occurs in 50-75% of patients with a lesion above T6
What is a cerebrovascular accident?
CVA (stroke) is a sudden onset of neurological deficits that occurs secondary to cerebral ischemia or cerebral hemorrhage
What is a transient ischemic attack?
TIA is a sudden onset of focal neurological deficits that resolve quickly (within 24 hours)
What is a reversible ischemic neurological deficit?
RIND is a neurological deficit that lasts >24 hours but resolves in <3 weeks
Treatment of ischemic stroke
IV thrombolytics (within 3 hour window)
- Tissue plasminogen activator (tPA)
Maintain adequate oxygenation
Endovascular thrombectomy
Maintain adequate BP (but not exceeding 185/110)
Normoglycemia
Airway management
Normothermia
DVT/PE prophylaxis
Treatment of hemorrhagic stroke
Discontinue and reverse all anticoagulants or antiplatelet drugs
FFP or prothrombin complex concentrate
Neurosurgery consult for possible external ventricular drain in setting of increased cerebral pressure
Mechanical hyperventilation to reduce ICP
Mannitol or hypertonic saline to manage elevated ICP
SCDs
