Lesson 1, Topic 1
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Neurodegenerative Diseases and Disorders

April 11, 2024

Neurodegenerative Diseases and Disorders

Learning Objective: Examine neurodegenerative diseases and disorders, including the signs, symptoms, etiology, diagnostic procedures, and treatments.

Neurodegenerative diseases affect a person’s ability to move, talk, and breathe. These diseases can also affect a person’s balance and heart function. The etiology may be genetic, related to a medical condition (e.g., tumor, stroke), or caused by a virus or toxin. With some diseases, the etiology is unknown.

Neurologic Diseases and Disorders

Common signs and symptoms of neurologic diseases and disorders include the following:

• Neuralgia, paresthesia (feelings of prickling, burning, or numbness)
• Lack of coordination, muscle rigidity, spasms (involuntary muscle contractions, such as stuttering and tics), seizures, and tremors (rhythmic, purposeless muscle movements)
• Recurrent headache, amnesia (memory loss), difficulty speaking or finding the right word, slurred speech
• Loss of sight or double vision
• Confusion, disorientation, or loss of consciousness

FIGURE 22.8  Neuron and synapse (inset). From Shiland B: Mastering healthcare terminology, ed 5, St. Louis, 2016, Mosby.

Amyotrophic Lateral Sclerosis

Learning Objective: Describe amyotrophic lateral sclerosis, including the signs, symptoms, etiology, diagnostic procedures, and treatments.

Amyotrophic lateral sclerosis (ALS), or Lou Gehrig disease, is a progressive neurologic disorder that attacks the motor neurons in the brain and spinal cord. ALS usually affects adults between 40 and 60 years of age.
There is no known etiology (cause) for ALS, though there is a genetic component to the disease in up to 10% of the cases. Early signs and symptoms include mild muscle problems, including trouble walking, running, writing, swallowing (dysphagia), and speaking. The muscle weakness starts in the hands and feet and spreads throughout the body, leading to an inability to move the legs and arms. Eventually, the person has difficulty eating, speaking, and breathing. Some people experience memory issues and dementia.
The provider will do an examination that will show abnormal reflexes, weakness, twitching, and difficulty moving. Tests may be done to rule out other conditions, including blood tests, computed tomography (CT), magnetic resonance imaging (MRI), electromyography, and lumbar puncture. Breathing tests may be done to assess the lung muscles. Riluzole (Rilutek) may be prescribed to slow symptoms, and other medications may be given to help with the symptoms. Physical therapy and assistive devices (e.g., wheelchair, braces) may be used. A feeding tube may help with the nutritional status. Assistance with breathing may also be needed. There is no cure for ALS.

Alzheimer Disease

Learning Objective: Discuss Alzheimer disease, including the signs, symptoms, etiology, diagnostic procedures, and treatments.

Alzheimer disease (AD) is a degenerative disease of the brain. It is characterized by disorientation, memory failure, speech disturbance, and a loss of mental capacity. It is the most common cause of dementia. AD causes an increased amount of microscopic neurofibrillary tangles and amyloid plaques in the cerebral cortex and the loss of neurons.
Usually, AD begins after age 60, and the risk increases with age. The risk also increases if family members have AD. Researchers feel that AD is caused by a combination of lifestyle, genetics, and environmental factors that affect the brain. Some research suggests a link between herpes simplex virus type 1 and AD. The causes are not fully understood. The signs and symptoms of AD begin slowly; initially, there is difficulty remembering recent activities or the names of people the person knows. AD affects thinking, reasoning, making judgments and decisions, memory, performing familiar tasks, personality, and behavior. Over time, the symptoms worsen, affecting a person’s ability to speak, read, write, or remember family members. Personality changes, aggression, and wandering away from home can occur.
The provider will do a medical history and physical exam. There is no specific test for AD. Neurologic tests, CT, MRI, positron emission tomography (PET), psychiatric evaluation, and cognitive and neuropsychological tests may be done. Laboratory tests are done to rule out other conditions. A lumbar puncture may be done, and the cerebrospinal fluid may be examined for biomarkers that indicate AD. Current treatments may only keep symptoms from worsening for a limited time; no cure is available. The following medications can be used to treat cognitive symptoms:

• Cholinesterase inhibitors: Boost the acetylcholine in the brain, which is depleted with AD. Common medications include donepezil (Aricept), rivastigmine (Exelon), and galantamine (Razadyne).
• Memantine (Namenda) is used for moderate to severe AD.

Dementia

Several diseases and disorders, such as a stroke or Alzheimer disease (AD), cause dementia, though dementia is not a disease. It is a name for a group of symptoms that affect the brain. Symptoms of dementia include being unable to do normal activities of living (e.g., eating, dressing, grooming), solve problems, and control emotions. To be diagnosed with dementia, a person needs to have at least two or more problems with brain function (e.g., memory, language). AD is the leading cause of dementia.

Huntington Disease

Learning Objective: Describe Huntington disease, including the signs, symptoms, etiology, diagnostic procedures, and treatments.

Huntington disease (HD), also called Huntington chorea, is a progressive neurodegenerative disorder. There are two forms of HD:

• Early-onset HD: Begins during childhood or in the teen years; affects a small number of people.
• Adult-onset HD: Symptoms usually start in the 30s or 40s; most common form of HD.

Usually, people with HD die within 15 to 20 years.
HD is caused by a genetic defect. If the gene is inherited from one parent, the child has a 50% chance of getting the disease. As the gene is passed through families, the disease develops at an earlier age. Behavior issues are usually seen first, including behavioral disturbances, hallucinations, moodiness, irritability, restlessness, psychosis, and paranoia. Abnormal movements can also occur, including facial grimacing, jerky movements, slow and uncontrolled movements, or a prancing gait. Dementia also occurs and affects the memory and speech.
The provider will do an examination and order additional tests, including psychological testing, head CT or MRI, and a PET scan of the brain. There is no cure for HD. The goal of the treatment is to slow the symptoms. Medications such as dopamine blockers help reduce abnormal movements and behaviors, and amantadine may help control extra movements.

Multiple Sclerosis

Learning Objective: Describe multiple sclerosis, including the signs, symptoms, etiology, diagnostic procedures, and treatments.

Multiple sclerosis (MS) is an autoimmune neurodegenerative disorder that affects the brain and spinal cord. The myelin sheath is damaged, leading to slowed or blocked messages to the brain. MS often occurs between the ages of 20 to 40 and affects females more than males. The disease can be mild, but some people may not be able to write, walk, or speak. There are four types of MS:

• Clinically isolated syndrome (CIS): A person has an MS-like episode but does not meet the criteria for an MS diagnosis.
• Relapsing-remitting MS (RRMS): Most common form; a person experiences relapses of the neurologic symptoms, followed by periods of partial or complete remission (recovery).
• Secondary progressive MS (SPMS): Follows the initial relapsing-remitting course; most people will eventually have worsening symptoms.
• Primary progressive MS (PPMS): Symptoms worsen from the onset. The person does not experience early relapses or remissions.

The etiology is unknown, though the disorder is an autoimmune disease. The immune system destroys the myelin sheath. Some risk factors include a family history, infection with the Epstein-Barr virus, and a history of thyroid disease, type 1 diabetes, or inflammatory bowel disease. Signs and symptoms include tingling, numbness, or weakness in the extremities, partial or complete loss of vision, double vision, slurred speech, fatigue, and lack of coordination.
The provider will perform an examination and evaluate the person’s mental and language functions, along with movement and coordination. Vision and other senses will be evaluated. There are no blood tests to diagnose MS. The provider may order an MRI, cerebrospinal fluid analysis, and an evoked potential test. There is no cure for MS, though the goal of treatment is to slow the progression of the disease and speed up recovery time from attacks. Corticosteroid medications may be given to reduce nerve inflammation. Ocrelizumab (Ocrevus) may be used in some cases of MS.

Parkinson Disease

Learning Objective: Describe Parkinson disease, including the signs, symptoms, etiology, diagnostic procedures, and treatments.

Parkinson disease (PD) is a progressive neurodegenerative disorder that affects movement. With PD, the dopamine-producing neurons in the brain gradually die. The dopamine levels decrease in the brain, leading to the symptoms. PD usually begins around age 60 and is more common in males.
The cause of PD is unknown, but genetics and environmental triggers (e.g., exposure to certain toxins) can increase the risk of the disease. Signs and symptoms of PD include the following:

• Tremors and pill-rolling tremors (thumb and forefinger are rubbed back and forth)
• Bradykinesia (slow movement), shuffling gait, rigid muscles, impaired balance and posture, stooping, and writing changes
• Loss of automatic movements (e.g., blinking, smiling), masked face (facial appearance of depression or anger), and speech changes (e.g., slurring, soft voice)
• Loss of sense of smell, trouble sleeping, dizziness, and constipation
• Excessive sweating or very little sweating, and drooling

There are no specific tests for PD. The provider will do a neurologic examination, and with the history of symptoms, the diagnosis can be made. Additional tests may be done to rule out other diseases. The following medications can be used to manage the symptoms:

• Carbidopa-levodopa (Sinemet): Used to increase the dopamine in the brain.
• Dopamine agonist: Used to mimic dopamine’s effect in the brain. Examples include pramipexole (Mirapex), ropinirole (Requip), and rotigotine (Neupro).
• MAO-B inhibitors: Prevent the breakdown of dopamine. Examples include safinamide (Xadago) and selegiline (Eldepryl, Zelapar).

Deep brain stimulation (DBS) may also be done. This treatment requires a generator to be implanted, and electrodes from it send impulses to the brain, which decrease the symptoms.

Restless Legs Syndrome

Learning Objective: Discuss restless legs syndrome, including the signs, symptoms, etiology, diagnostic procedures, and treatments.

Restless legs syndrome (RLS) is also known as restless legs syndrome/Willis-Ekbom disease (RLS/WED). RLS causes a creeping, tingling, or burning sensation in the legs when the person is lying down or sitting. Moving the legs helps reduce the sensations for a short period of time. RLS can affect a person’s quality of sleep. Most people with RLS also have periodic limb movement disorder (PLMD), which causes the legs or arms to twitch or jerk uncontrollably in sleep. RLS can occur at any age and can worsen with age.
In many situations, there is no known cause for RLS. For some people, RLS is caused by a condition (e.g., pregnancy, anemia) or a medication. Caffeine, alcohol, and tobacco can worsen the symptoms. Researchers believe that RLS may be related to a dopamine imbalance in the brain. There also may be a genetic cause if the condition appears before age 40. Associated risk factors for RLS include peripheral neuropathy, iron deficiency, kidney failure, and spinal cord lesions. The signs and symptoms include abnormal sensations in the legs and feet that begin after rest (often at night) and decrease with movement. The abnormal sensations can be described as itching, electric, aching, throbbing, pulling, crawling, or creeping. The symptoms may disappear for a while and then come back.
Besides an examination, the provider may order blood tests and a sleep study. Treatments include exercise and massage of the legs, stress reduction activities, and decreased caffeine and tobacco use. Medication therapy may include iron for anemia and medications to increase the dopamine in the brain, including ropinirole (Requip), pramipexole (Mirapex), and rotigotine (Neupro). Opioids and anticonvulsants, such as gabapentin (Neurontin, Horizant), pregabalin (Lyrica), and clonazepam (Klonopin), may be used. RLS is a lifelong condition with no cure.