Pathophysiology Exam 2- Pathologies

Which of the following can be used as a substrate for the process of gluconeogenesis?

a. Glycogen b. Alanine c. Lactate d. A and B e. B and C Answer: E.

What are some PT interventions for Post-Polio Syndrome?

● PRE's --be conscious of pt's fatigue ● Electrical stimulation to either strengthen, offer re-education to weakened muscles, or relieve myofascial pain ● Trigger point release ● Therapeutic stretching ● Hydrotherapy ● Orthotics ● Education on energy conservation methods

What is the definition of Post-Polio Syndrome?

-A condition that affects polio survivors years after recovery from an initial, attack of the poliomyelitis. Most often, polio survivors start to experience gradual new weakening in muscles that were previously affected by the polio infection. -Neurological disorder characterized by new and progressive muscular weakness, pain and fatigue many years after the acute paralytic polio [average 30-40 years after initial presentation].

What is the definition of Mitochondrial Myopathies?

A cell with mitochondrial disease might be compared to a car that's only running on three cylinders. No matter how much gas you put into the car, without a fully operating engine it's not going to go over 25 miles per hour - Mitochondrial disease includes a group of neuromuscular diseases caused by damage to intracellular structures that produce energy, the mitochondria; disease symptoms usually involve muscle contractions that are weak or spontaneous. Nerve cells in the brain and muscles require a great deal of energy, and thus appear to be particularly damaged when mitochondrial dysfunction occurs. Some of the more common mitochondrial myopathies include Kearns-Sayre syndrome, myoclonus epilepsy with ragged-red fibers, and mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes.

What is the definition of Muscular Dystrophy?

A group of diseases that cause progressive weakness and loss of muscle mass

What are some PT interventions for Mitochondrial Myopathies?

Exercise has been shown to improve functional capacity in pts with mm. It can greatly improve quality of life and prevent complications from developing such as heart disease and diabetes. Exercise can: improve energy production in the body by increasing the numbers of healthy mitochondria in the cells; improve the ability to walk; reduce lactate production; prevent problems arising from inactivity and disuse. Inactivity can lead to a loss of motivation, energy and mobility, all of which may reduce independence. "reduces lactate production" is not really true - lactate goes up with exercise; rather, it increases the amount of exercise you can do before the lactate is produced. By increase in muscular strengthening, satellite cells within the muscle cell can increase aerobically and perpetuate healthy cells, as opposed to those mutated Exercise Examples: Low impact, lots of stretching emphasized Walking (many communities have walking programs) Swimming/pool therapy (especially in a warm pool) Gentle stretching Tai chi Wii fit yoga Supplements may help make energy in the cells. These may include: • Creatine • Carnitine Coenzyme Q10

How does a typical patient with a Mitochondrial Myopathy present?

In some individuals, weakness is most prominent in muscles that control movements of the eyes and eyelids. Two common consequences are the gradual paralysis of eye movements, called progressive external ophthalmoplegia (PEO), and drooping of the upper eyelids, called ptosis. Often, people automatically compensate for PEO by moving their heads to look in different directions, and might not even notice any visual problems. Mitochondrial myopathies also can cause weakness and wasting in other muscles of the face and neck, which can lead to slurred speech and difficulty with swallowing. In these instances, speech therapy or changing the diet to easier-to-swallow foods can be useful. Sometimes, people with mitochondrial myopathies experience loss of muscle strength in the arms or legs, and might need braces or a wheelchair to get around.

What is the pathophysiology of Mitochondrial Myopathies?

Mitochondrial myopathies are caused by mutations, or changes, in genes — the cells' blueprint for making proteins. They are inheritable, although they can occur with no family history, and they often affect members of the same family in different ways.

What is the definition of Myasthenia Gravis?

Myasthenia gravis is an autoimmune disorder characterized by weakness and fatigability of skeletal muscles. It is caused by a breakdown in the normal communication between nerves and muscles.

Consider two identical runners who are about to run a marathon. Marathoner A has a good amount of glycogen stored in his liver and muscle while Marathoner B's glycogen stores are mostly depleted. All else being equal (i.e., running pace, aerobic fitness, lactate threshold, running economy, etc.), which of the following is most likely going to be true?

a. Marathoner B will most likely "hit the wall" sooner in the race than Marathoner A. b. Marathoner A will likely report higher RPE scores throughout the duration of the race compared to Marathoner B c. Marathoner A will shift to burning primarily fats earlier in the race compared to Marathoner B d. None of the above; depleted glycogen stores do not affect marathon performance Answer: A.

How does a typical patient with Myasthenia Gravis present?

● Weakness in eye muscles, drooping of eyelids and blurred/double vision ○ Only 16% stays in eyes, most progresses to the rest of the body within 13 months of onset ● Difficulty with swallowing, speech and breathing ● Works down to weakness in trunk and limb muscles ● Most severe: feeding tube and mechanical ventilation are necessary ● Unstable or waddling gait ● A change in facial expression ● Weakness in the arms, hands, fingers, legs, and neck ● Symptoms are proximal and symmetric ● Deep tendon reflexes are normal ● Pain is least in the morning, progresses throughout the day ● With treatment they can improve muscle weakness ● Some cases may go into remission

What is the pathophysiology of Muscular Dystrophy?

Abnormal genes (mutations) interfere with the production of proteins needed to form healthy muscle. There are many forms of muscular dystrophy, each form is caused by a genetic mutation particular to that type of disease. The basis underlying all MD is the defect in the genetic code for dystrophin(Dp427) a skeletal muscle protein. These defects result in various manifestations such as weakness and pseudohypertrophy. Dystrophin in also found in the brain which accounts for slight mental retardation associated with the disease.

What is the pathophysiology of Myasthenia Gravis?

An autoimmune disorder in which the thymus gland produces autoantibodies that are either directed to the muscle acetylcholine receptor (AChR) or to the muscle-specific tyrosine kinase (MuSK). These autoantibodies define two subforms of the disease: AChR-MG and MuSK-MG. Both forms cause obstruction at postsynaptic membrane of the neuromuscular junction, the region of the muscle that receives and processes the signals from the motor neuron. These autoantibodies bind to the receptors on the postsynaptic membrane, impeding the binding of neurotransmitters, therefore inhibiting the cascade of events that are required for a normal muscle contraction. This inhibition leads to impaired neuromuscular transmission and muscle weakness. This disease is associated with thymic hyperplasia of a lympho-proliferative origin and the development of thymomas.

What are some PT interventions for Myasthenia Gravis?

Disease progression ● Eyes, throat, neck, limbs ● SP, OT, nutritionist ● Track disease progression (MMT, CP) ● Whole body maintenance ● Should only involve stable patients Education ● Support ● Energy conservation ○ "dollar a day" Exercises ● Avoid excessive stress, fatigue, heat ● Peak energy levels of patient ● ADLs (esp. above shoulder level) ● Large muscle groups ● Short sessions only to moderate intensity ● HR limit (30 bpm increase) Consistent exercise increases baseline functional capacity and diminishes the effect of MG exacerbations.

How does a typical patient with Post-Polio Syndrome present?

Presentation: ● It can occur suddenly after a period of trauma or illness ● It can occur gradually over time Symptoms: ● Progressive muscle and joint weakness and pain ● Balance issues ● General fatigue and exhaustion with minimal activity ● Muscle atrophy ● Breathing or swallowing problems ● Sleep-related breathing disorders, such as sleep apnea ● Decreased tolerance of cold temperatures Complications: ● Falls - due to muscle weakness and balance issues ● Malnutrition, dehydration and pneumonia - due to difficulty chewing, swallowing ● Acute respiratory failure - due to difficulty using respiratory muscles to take deep breaths ● Osteoporosis - due to inactivity Prognosis: No known cure, but there are many ways to treat the symptoms of Post-Polio Syndrome ● Energy Conservation Techniques ● Retraining of muscles and movements

What are some PT interventions for Muscular Dystrophy?

Passive and active stretching. Physical therapists will the patient in increasing joint flexibility (range of motion) and preventing or delaying the development of contractures. Passive stretching should not be painful. ● Maintaining strength. Physical therapists will teach the patient exercises to maintain muscle and trunk strength and to use good posture and body mechanics throughout the lifespan. As the patient grows, the therapist will identify new games and activities to reduce the risk of obesity, and increase heart health. Overexercising can damage muscles, so patients are encouraged to seek physical therapy services early. ● Exercises for breathing. Physical therapists may provide a program to maintain good respiratory strength, or may work with respiratory therapists or speech therapists in designing such a program. ● Improving developmental skills. Physical therapists will help the patient learn to master motor skills, such as crawling, getting up to standing, walking, and jumping. Therapists will provide an individualized plan of care that is appropriate based on the patient's developmental level and motor needs. ● Foster physical fitness and activity. Physical therapists will assist in determining the specific exercises, diet, and community involvement that will promote good health. When needed, mobility aids, such as wheelchairs, splints and braces, and home devices may be prescribed to help maintain mobility.

How does a typical patient with Muscular Dystrophy present?

Signs and symptoms begin at different ages depending on the type of muscle dystrophy Duchenne Muscular Dystrophy: symptoms typically appear between ages 2 and 5 and typically affects boys ● Frequent falls ● Difficulty getting up from a lying or sitting position ● Waddling gait ● Walking on the toes ● Muscle pain and stiffness ● Progressive muscle weakness ● Large calf muscles ● Learning disabilities ● Trouble running or jumping Becker Muscular Dystrophy: symptoms are similar to Duchenne but are typically milder and progress more slowly, generally begin in teens, mid-20's, or later Other types include... ● Myotonic: most common adult form of MD ○ Long thin faces, drooping eyelids, and a swan-like neck ● Facioscapulohumeral (FSHD): usually begins in teenage years ○ Progressive weakness in muscles of the face, arms, legs, and around the shoulders and chest ● Congenital: affects boys and girls and is apparent at birth ○ Slowly progressing forms cause mild disability ○ Rapidly progressing forms can cause severe impairments ● Limb-girdle: usually begins in childhood or teenage years ○ Hip and shoulder muscles are usually the first affected ○ Difficulty lifting the front part of the foot, causing them to trip frequently

What is the pathophysiology of Post-Polio Syndrome?

They to have paralytic poliomyelitis first and then the individual has a period of partial or complete functional recovery after acute paralytic poliomyelitis it is the followed by a period of stable neuromuscular function. Poliomyelitis is caused by a virus, and is one of three polioviruses. It gains entry in the mouth and multiplies in the pharynx and GI tract gaining access to the circulatory and nervous systems. The virus is caused by small single stranded RNA virus surrounded by a protein capsid without a lipid envelope which is what makes it resistant to lipid solvents and is stable at low pH. Once the polio virus enters the nervous system it causes infection of the nervous system involving the precentral gyrus thalamus, hypothalamus, motor nuclei of the brainstem, surrounding reticular formation, vestibular nuclei, cerebellar nuclei, and neurons of the anterior and intermediate columns of the spinal cord. The nerve cells undergo central chromatolysis along with an inflammatory reaction. The virus multiplies which precedes the onset of paralysis. Paralysis or atrophy appears when fewer than 10% of the neurons survive in the corresponding cord segments. One possible cause of post-polio syndrome (PPS) is decompensation of a chronic denervation and reinnervation process to the extent that the remaining healthy motor neurons can no longer maintain new sprouts; thus, denervation exceeds reinnervation. A second possible mechanism for PPS is motor neuronal loss due to reactivation of a persistent latent virus. In addition to muscle atrophy and denervation, foci of perivascular and interstitial inflammatory cells have been found on 50% of biopsies of patients with PPS. Activated T cells and immunoglobulin M and immunoglobulin G antibodies specific for gangliosides also have been found.

Consider the major events that occur inside the muscle fiber to lead to a contraction. Of the four events listed below, which event must occur first?

a. Calcium binds to troponin b. Crossbridges are formed c. Binding sites on actin are revealed d. The action potential travels down the t-tubule to the region of contact between the t-tubule and the sarcoplasmic reticulum (SR) Answer: D.

A patient with Duchenne Muscular Dystrophy is at increased risk for _______ because they have reduced concentrations of _______ in the muscle.

a. Rigor, sarcoplasmic reticulum b. Muscle damage, dystrophin c. Ca2+ toxicity, actin d. Muscle soreness, H+ Answer: B.

Another name for the plasma membrane of a skeletal muscle cell is the:

a. Sarcolemma b. Sarcoplasmic reticulum c. Sarcomere d. Terminal cisternae Answer: A.

Calcium ions are required for the normal activation of all muscle types. Which statement below most closely describes the role of calcium ions in the control of skeletal muscle contraction?

a. The binding of calcium ions to regulatory proteins on the thin filaments removes the inhibition of actin-myosin interaction. b. The binding of calcium ions to the thick filament regulatory proteins activates the enzymatic activity of the myosin molecules. c. Calcium ions serve as a direct chemical inhibitor of the interaction between actin and myosin. d. A high concentration of calcium ions in the myofilament space is required to maintain muscle in a relaxed state. e. A very low concentration of calcium ions in the myofilament space is required to maintain Answer: A.

If the internal calcium-pumping mechanisms of a skeletal muscle cell were disrupted (as by a drug), what would be the functional consequence(s)?

a. The cell would be quickly depleted of calcium. b. The velocity of contraction would be markedly increased. c. Mechanical relaxation would be impaired. d. The surface membrane would quickly become depolarized. e. The muscle would become highly distensible. Answer: C.

In our bodies, fat is stored primarily as:

a. Triglycerides b. Amino acids c. Glycogen d. Lactate Answer: A.

Skeletal muscle is described as _________.

a. Visceral & voluntary b. Visceral & involuntary c. Striated & voluntary d. Striated & involuntary Answer: C.

When an isolated skeletal muscle is stretched beyond its optimal length (but not to the point where damage occurs), there is a reduction in isometric contractile force. This is due to

a. lengthening of the myofilaments, so that cross-bridges become spaced farther apart and can interact less readily. b. the inability of the cell membrane to depolarize when stretched. c. the thinning of the muscle, which reduces its cross-sectional area and, hence, the force that it can produce. d. a proportional reduction in the amount of calcium released from the sarcoplasmic reticulum. e. decreased overlap between thick and thin filaments, which reduces the number of crossbridges that can interact. Answer: E.