Amyotrophic lateral sclerosis medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Medical Therapy
No cure has yet been found for ALS. However, the Food and Drug Administration (FDA) has approved the first drug treatment for the disease: Riluzole (Rilutek). Riluzole is believed to reduce damage to motor neurons by decreasing the release of glutamate. Clinical trials with ALS patients showed that riluzole prolongs survival by several months, and may have a greater survival benefit for those with a bulbar onset. The drug also extends the time before a patient needs ventilation support. Riluzole does not reverse the damage already done to motor neurons, and patients taking the drug must be monitored for liver damage and other possible side effects. However, this first disease-specific therapy offers hope that the progression of ALS may one day be slowed by new medications or combinations of drugs.
Other treatments for ALS are designed to relieve symptoms and improve the quality of life for patients. This supportive care is best provided by multidisciplinary teams of health care professionals such as physicians; pharmacists; physical, occupational, and speech therapists; nutritionists; social workers; and home care and hospice nurses. Working with patients and caregivers, these teams can design an individualized plan of medical and physical therapy and provide special equipment aimed at keeping patients as mobile and comfortable as possible.
Physicians can prescribe medications to help reduce fatigue, ease muscle cramps, control spasticity, and reduce excess saliva and phlegm. Drugs also are available to help patients with pain, depression, sleep disturbances, and constipation. Pharmacists can give advice on the proper use of medications and monitor a patient's prescriptions to avoid risks of drug interactions.
Physical therapy and special equipment can enhance patients' independence and safety throughout the course of ALS. Gentle, low-impact aerobic exercise such as walking, swimming, and stationary bicycling can strengthen unaffected muscles, improve cardiovascular health, and help patients fight fatigue and depression. Range of motion and stretching exercises can help prevent painful spasticity and shortening (contracture) of muscles. Physical therapists can recommend exercises that provide these benefits without overworking muscles. Occupational therapists can suggest devices such as ramps, braces, walkers, and wheelchairs that help patients remain mobile.
ALS patients who have difficulty speaking may benefit from working with a speech-language pathologist. These health professionals can teach patients adaptive strategies such as techniques to help them speak louder and more clearly. As ALS progresses, speech-language pathologists can recommend the use of augmentative and alternative communication such as voice amplifiers, speech-generating devices (or voice output communication devices) and/or low tech communication techniques such as alphabet boards or yes/no signals. These methods and devices help patients communicate when they can no longer speak or produce vocal sounds. With the help of occupational therapists, speech-generating devices can be activated by switches or mouse emulation techniques controlled by small physical movements of, for example, the head, finger or eyes.
Patients and caregivers can learn from speech-language pathologists and nutritionists how to plan and prepare numerous small meals throughout the day that provide enough calories, fiber, and fluid and how to avoid foods that are difficult to swallow. Patients may begin using suction devices to remove excess fluids or saliva and prevent choking. When patients can no longer get enough nourishment from eating, doctors may advise inserting a feeding tube into the stomach. The use of a feeding tube also reduces the risk of choking and pneumonia that can result from inhaling liquids into the lungs. The tube is not painful and does not prevent patients from eating food orally if they wish.
When the muscles that assist in breathing weaken, use of nocturnal ventilatory assistance (intermittent positive pressure ventilation (IPPV) or bilevel positive airway pressure (BIPAP)) may be used to aid breathing during sleep. Such devices artificially inflate the patient's lungs from various external sources that are applied directly to the face or body. When muscles are no longer able to maintain oxygen and carbon dioxide levels, these devices may be used full-time.
Patients may eventually consider forms of mechanical ventilation (respirators) in which a machine inflates and deflates the lungs. To be effective, this may require a tube that passes from the nose or mouth to the windpipe (trachea) and for long-term use, an operation such as a tracheotomy, in which a plastic breathing tube is inserted directly in the patient's windpipe through an opening in the neck. Patients and their families should consider several factors when deciding whether and when to use one of these options. Ventilation devices differ in their effect on the patient's quality of life and in cost. Although ventilation support can ease problems with breathing and prolong survival, it does not affect the progression of ALS. Patients need to be fully informed about these considerations and the long-term effects of life without movement before they make decisions about ventilation support. It must be pointed out that some patients under long-term tracheostomy intermittent positive pressure ventilation with deflated cuffs or cuffless tracheostomy tubes (leak ventilation) are able to speak. This technique preserves speech in some patients with long-term mechanical ventilation.
Social workers and home care and hospice nurses help patients, families, and caregivers with the medical, emotional, and financial challenges of coping with ALS, particularly during the final stages of the disease. Social workers provide support such as assistance in obtaining financial aid, arranging durable power of attorney, preparing a living will, and finding support groups for patients and caregivers. Home nurses are available not only to provide medical care but also to teach caregivers about tasks such as maintaining respirators, giving feedings, and moving patients to avoid painful skin problems and contractures. Home hospice nurses work in consultation with physicians to ensure proper medication, pain control, and other care affecting the quality of life of patients who wish to remain at home. The home hospice team can also counsel patients and caregivers about end-of-life issues.
Both animal and human research suggest calorie restriction (CR) may be contraindicated for those with ALS. Research on a transgenic mouse model of ALS demonstrates that CR may hasten the onset of death in ALS. [1] In that study, Hamadeh et al also note two human studies[2][3] that they indicate show "low energy intake correlates with death in people with ALS." However, in the first study, Slowie, Paige, and Antel state: "The reduction in energy intake by ALS patients did not correlate with the proximity of death but rather was a consistent aspect of the illness." They go on to conclude: "We conclude that ALS patients have a chronically deficient intake of energy and recommended augmentation of energy intake." (PMID 8604660)
Previously, Pedersen and Mattson also found that in the ALS mouse model, CR "accelerates the clinical course" of the disease and had no benefits.[4] Suggesting that a calorically dense diet may slow ALS, a ketogenic diet in the ALS mouse model has been shown to slow the progress of disease.[5]
The new discovery of RNAi has some promise in treating ALS. In recent studies, RNAi has been used in lab rats to shut off specific genes that lead to ALS. Cytrx Corporation has sponsored ALS research utilizing RNAi gene silencing technology targeted at the mutant SOD1 gene. The mutant SOD1 gene is responsible for causing ALS in a subset of the 10% of all ALS patients who suffer from the familial, or genetic, form of the disease. Cytrx's orally-administered drug Arimoclomol is currently in clinical evaluation as a therapeutic treatment for ALS.
Insulin-like growth factor 1 has also been studied as treatment for ALS. Cephalon and Chiron conducted two pivotal clinical studies of IGF-1 for ALS, and although one study demonstrated efficacy, the second was equivocal, and the product has never been approved by the FDA. In January of 2007, the Italian Ministry of Health has requested INSMED corporation's drug, IPLEX, which is a recombinant IGF-1 with Binding Protein 3(IGF1BP3) to be used in a clinical trial for ALS patients in Italy.
References
- ↑ Hamadeh MJ, Rodriguez MC, Kaczor JJ, Tarnopolsky MA. Caloric restriction transiently improves motor performance but hastens clinical onset of disease in the Cu/Zn-superoxide dismutase mutant G93A mouse. Muscle Nerve. 2005 Feb;31(2):214-20. PMID 15625688.
- ↑ Kasarskis EJ, Berryman S, Vanderleest JG, Schneider AR, McClain CJ. Nutritional status of patients with amyotrophic lateral sclerosis: relation to the proximity of death. Am J Clin Nutr. 1996 Jan;63(1):130-7. PMID 8604660.
- ↑ Slowie LA, Paige MS, Antel JP. Nutritional considerations in the management of patients with amyotrophic lateral sclerosis (ALS). J Am Diet Assoc. 1983 Jul;83(1):44-7. PMID 6863783
- ↑ Pedersen WA, Mattson MP. No benefit of dietary restriction on disease onset or progression in amyotrophic lateral sclerosis Cu/Zn-superoxide dismutase mutant mice. Brain Res. 1999 Jun 26;833(1):117-20. PMID 10375685.
- ↑ Zhao Z, Lange DJ , Voustianiouk A, et al. A ketogenic diet as a potential novel therapeutic intervention in amyotrophic lateral sclerosis. BMC Neuroscience 2006, 7:29. (PMID 16584562). Media report on Zhao et al.