Module 3

Multiple Sclerosis

• Areas commonly affected by MS include the optic nerve, corticobulbar tracts (speech and swallowing), corticospinal tracts (muscle strength), cerebellar tracts (gait and coordination), spinocerebellar tracts (balance), medial longitudinal fasciculus (conjugate gaze function of the extraocular eye muscles), and posterior cell columns of the spinal cord (position and vibratory sensation)
• Symptoms may include parathesias, optic neuritis, diplopia, or specific types of gaze paralysis, as well as abnormal gait, bladder and sexual dysfunction, vertigo, nystagmus, fatigue, and speech disturbance
• MS has four categories: Relapsing-remitting, secondary progressive, primary progressive, and progressive relapsing

Parkinson's Disease

• Degenerative disorder of basal ganglia function characterized by variable combinations of tremor, rigidity, akinesia/bradykinesia, and postural changes
• Mean onset is 57 years old
• People with Parkinson's disease often have excessive sweating, sebaceous gland secretion, and salivation due to the influence of the basal ganglia on the autonomic nervous system
• Cognitive dysfunction may also be present
• Treatment must be highly individualized, with no cure available, only symptom management

Brain Injury and Stroke

• Primary brain injuries are caused by impact, while secondary brain injuries result from subsequent complications
• Five main mechanisms of stroke subtypes include large artery thrombosis (20%), small penetrating artery thrombosis disease (25%), cardiogenic embolism (20%), cryptogenic stroke (30%), and other (5%)
• Hemorrhagic stroke is often fatal and commonly results from the spontaneous rupture of a cerebral blood vessel, especially in older adults with hypertension

Clinical Manifestations of Stroke

• Symptoms are determined by the affected cerebral artery, brain tissue supplied by the vessel, and collateral circulation
• Symptoms are always sudden in onset, focal, and usually one-sided, and may include facial droop, arm weakness, slurred speech, unilateral numbness, vision loss, language disturbance, and sudden unexplained imbalance or ataxia

Alzheimer's Disease

• Diagnosis can only be confirmed by microscopic examination of tissue obtained from a cerebral biopsy or at autopsy
• Diagnosis is based on clinical findings, with neuroimaging and metabolic screening used to exclude other conditions
• There is no curative treatment, but medications may slow progression and improve depression, agitation, or sleep disorders
• Cholinesterase inhibitors can slow disease progression by potentiating available acetylcholine and inhibiting acetylcholinesterase
• Two major goals of care are maintaining socialization and providing support for caregivers

Retinal Detachment

• Separation of the neurosensory retina from the pigment epithelium, occurring when traction on the inner sensory layer or a tear allows fluid to accumulate between the two layers
• Four types of retinal detachments: exudative, traction, rhegmatogenous, and combined traction/rhegmatogenous
• Intermittent retinal ischemia can accompany internal carotid or common carotid stenosis, and amaurosis fugax is characterized by transient episodes of monocular visual loss lasting 5-10 minutes

Otitis Media

• Acute onset of otalgia, fever, irritability, otorrhea, hearing loss, and evidence of middle ear inflammation and effusion
• Children older than 3 may experience rhinorrhea, vomiting, and diarrhea
• Ear pain increases as the effusion accumulates behind the tympanic membrane, and perforation may occur, allowing purulent material to drain into the external auditory canal
• Risk factors include smoking in the house, prematurity, daycare attendance, unimmunized status, bottle-feeding, and family history of otitis media
• Structural immaturity contributes to the increased risk in infants and young children

Metabolic Requirements of Nervous Tissue

• Nervous tissue has a high rate of metabolism, with the brain receiving 15% to 20% of the total resting cardiac output and consuming 20% of its oxygen.
• The brain cannot store oxygen or engage in anaerobic metabolism, making it susceptible to interruptions in blood or oxygen supply, leading to clinically observable signs and symptoms.

Somatosensory Function, Pain, Headache, and Temperature Regulation

• Acute pain is elicited by injury to body tissues and activation of nociceptive stimuli at the site of local tissue damage, and generally resolves when the underlying pathologic process has resolved.
• Chronic pain persists longer than might be reasonably expected after an inciting event and is sustained by factors that are both pathologically and physically remote from the originating cause.
• Types of pain include cutaneous pain (arising from superficial structures), deep somatic pain (originating in deep body structures), and visceral pain (originating in visceral organs).

Disorders of Neural Function

Multiple Sclerosis

• MS can affect areas such as the optic nerve, corticobulbar tracts, corticospinal tracts, cerebellar tracts, spinocerebellar tracts, medial longitudinal fasciculus, and posterior cell columns of the spinal cord.
• Symptoms may include parathesias, optic neuritis, diplopia, abnormal gait, bladder and sexual dysfunction, vertigo, nystagmus, fatigue, and speech disturbance.
• The disease can be categorized into four types: relapsing-remitting, secondary progressive, primary progressive, or progressive relapsing.

Parkinson's Disease

• Parkinson's disease is a degenerative disorder of basal ganglia function, characterized by variable combinations of tremor, rigidity, akinesia/bradykinesia, and postural changes.
• The disease results from progressive destruction of the nigrostriatal pathway, leading to a reduction in striatal concentrations of dopamine.
• Symptoms also include excessive sweating, sebaceous gland secretion, and salivation, as well as cognitive dysfunction.

Mechanisms of Brain Injury

• Primary brain injuries occur due to impact, and neuroimaging suggests several functional abnormalities, including loss of cortical gray matter, abnormal cortical thinning, and reduced numbers of synaptic structures on neurons.

Neurocognitive Disorders

• Mood disorders, such as depression, can be linked to ongoing inflammation in the body.
• Neuroimaging indicates smaller hippocampal volumes and hippocampal hypertrophy in people who have depression and have experienced early abuse.
• Dopamine plays a role in depression.

Disorders of Special Sensory Function

Disorders of Eye Movement

• Strabismus refers to any abnormality of eye coordination or alignment that results in loss of binocular vision.
• Amblyopia, also known as lazy eye, can result from retinal detachment or decreased perfusion pressure in the head region.

Disorders of Hearing and Vestibular Function

• Otitis media with effusion symptoms include intermittent ear pain, sensation of fullness in the ear, complaint of hearing loss, dizziness, and decreased tympanic membrane mobility.
• Risk factors for otitis media include smoking in the house, prematurity, daycare attendance, and a family history of otitis media.
• Structural immaturity contributes to the increased risk of otitis media in children.