Tag Archives: Weakness

Limb-Girdle Muscular Dystrophy

What is limb-girdle muscular dystrophy?
Limb-girdle muscular dystrophy is a term for a group of diseases that cause weakness and wasting of the muscles in the arms and legs. The muscles most affected are those closest to the body (proximal muscles), specifically the muscles of the shoulders, upper arms, pelvic area, and thighs.

The severity, age of onset, and features of limb-girdle muscle dystrophy vary among the many subtypes of this condition and may be inconsistent even within the same family. Signs and symptoms may first appear at any age and generally worsen with time, although in some cases they remain mild.

In the early stages of limb-girdle muscular dystrophy, affected individuals may have an unusual walking gait, such as waddling or walking on the balls of their feet, and may also have difficulty running. They may need to use their arms to press themselves up from a squatting position because of their weak thigh muscles. As the condition progresses, people with limb-girdle muscular dystrophy may eventually require wheelchair assistance.

Muscle wasting may cause changes in posture or in the appearance of the shoulder, back, and arm. In particular, weak shoulder muscles tend to make the shoulder blades (scapulae) “stick out” from the back, a sign known as scapular winging. Affected individuals may also have an abnormally curved lower back (lordosis) or a spine that curves to the side (scoliosis). Some develop joint stiffness (contractures) that can restrict movement in their hips, knees, ankles, or elbows. Overgrowth (hypertrophy) of the calf muscles occurs in some people with limb-girdle muscular dystrophy.

Weakening of the heart muscle (cardiomyopathy) occurs in some forms of limb-girdle muscular dystrophy. Some affected individuals experience mild to severe breathing problems related to the weakness of muscles needed for breathing.

Intelligence is generally unaffected in limb-girdle muscular dystrophy; however, developmental delay and intellectual disability have been reported in rare forms of the disorder.

How common is limb-girdle muscular dystrophy?
It is difficult to determine the prevalence of limb-girdle muscular dystrophy because its features vary and overlap with those of other muscle disorders. Prevalence estimates range from 1 in 14,500 to 1 in 123,000 individuals.

Steinert’s Disease/Myotonic Dystrophy

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What is myotonic dystrophy?
Myotonic dystrophy is an autosomal dominant inherited disease characterized by wasting of the muscles (muscular dystrophy), myotonia and multisystemic conditions. Myotonic dystrophy is one of the most common neuromuscular diseases in adults. Its prevalence rate is five cases out of 100,000 inhabitants.

What are the clinical signs?
Two major clinical forms can be distinguished, although both due to defects of the same gene.

The common form in adults, which combines:

Progressive muscular dystrophy (weakness and atrophy);
Myotonia: delayed relaxation of a muscle after an initial contraction (for example difficulty to release grip after shaking hands);
Defects in other organs: eye (cataracts in nearly all patients aged 40 and more), nervous system (sleep, cognitive function, or mood disorders), heart (heart rhythm disorders and/or conduction disturbances sometimes causing sudden death), respiratory system (pneumopathies), digestive system, endocrinal glands.

The severity of the disease depends upon the age of onset, clinical signs and progression.

The congenital form combines a clinical picture of neonatal hypotonia and severe acute respiratory distress. If the child survives, the disease progresses to become a disabling condition, especially at the intellectual level. Its exclusive maternal transmission pattern is still not clearly understood.

What is the cause?
Myotonic dystrophy is an autosomal dominant inherited disease. There is a 50-50 chance that affected parents will transmit the disease to any of their children. The myotonic dystrophy gene has now been located and identified precisely (chromosome 19). It codes for a protein kinase called myotonine, the function of which remains unclear. The peculiar type of the genetic defect may partially explain the anticipation phenomenon; the severity of symptoms increases as the disease is passed on to the next generation.

Complex Regional Pain Syndrome (CRPS)

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Signs and symptoms of complex regional pain syndrome include:

Continuous burning or throbbing pain, usually in your arm, leg, hand or foot
Sensitivity to touch or cold
Swelling of the painful area
Changes in skin temperature — at times your skin may be sweaty; at other times it may be cold
Changes in skin color, which can range from white and mottled to red or blue
Changes in skin texture, which may become tender, thin or shiny in the affected area
Changes in hair and nail growth
Joint stiffness, swelling and damage
Muscle spasms, weakness and loss (atrophy)
Decreased ability to move the affected body part

Symptoms may change over time and vary from person to person. Most commonly, pain, swelling, redness, noticeable changes in temperature and hypersensitivity (particularly to cold and touch) occur first.

Over time, the affected limb can become cold and pale and undergo skin and nail changes as well as muscle spasms and tightening. Once these changes occur, the condition is often irreversible.

Complex regional pain syndrome occasionally may spread from its source to elsewhere in your body, such as the opposite limb. The pain may be worsened by emotional stress.

In some people, signs and symptoms of complex regional pain syndrome go away on their own. In others, signs and symptoms may persist for months to years. Treatment is likely to be most effective when started early in the course of the illness.

Leigh Syndrome

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What is Leigh syndrome?
Leigh syndrome is a severe neurological disorder that typically arises in the first year of life. This condition is characterized by progressive loss of mental and movement abilities (psychomotor regression) and typically results in death within a couple of years, usually due to respiratory failure. A small number of individuals develop symptoms in adulthood or have symptoms that worsen more slowly.

The first signs of Leigh syndrome seen in infancy are usually vomiting, diarrhea, and difficulty swallowing (dysphagia) that leads to eating problems. These problems often result in an inability to grow and gain weight at the expected rate (failure to thrive). Severe muscle and movement problems are common in Leigh syndrome. Affected individuals may develop weak muscle tone (hypotonia), involuntary muscle contractions (dystonia), and problems with movement and balance (ataxia). Loss of sensation and weakness in the limbs (peripheral neuropathy), common in people with Leigh syndrome, may also make movement difficult.

Several other symptoms may occur in people with Leigh syndrome. Many affected individuals develop weakness or paralysis of the muscles that move the eyes (ophthalmoparesis); rapid, involuntary eye movements (nystagmus); or degeneration of the nerves that carry information from the eyes to the brain (optic atrophy). Severe breathing problems are common in people with Leigh syndrome, and these problems can worsen until they cause acute respiratory failure. Some affected individuals develop hypertrophic cardiomyopathy, which is a thickening of the heart muscle that forces the heart to work harder to pump blood. In addition, a substance called lactate can build up in the body, and excessive amounts are often found in the blood, cerebrospinal fluid, or urine of people with Leigh syndrome.

The signs and symptoms of Leigh syndrome are caused in part by patches of damaged tissue (lesions) that develop in the brains of people with this condition. A procedure called magnetic resonance imaging (MRI) reveals characteristic lesions in certain regions of the brain and the brainstem (the part of the brain that is connected to the spinal cord). These regions include the basal ganglia, which help control movement; the cerebellum, which controls the ability to balance and coordinates movement; and the brainstem, which controls functions such as swallowing, breathing, hearing, and seeing. The brain lesions are often accompanied by loss of the myelin coating around nerves (demyelination), which reduces the ability of the nerves to activate muscles used for movement or relay sensory information back to the brain.

How common is Leigh syndrome?
Leigh syndrome affects at least 1 in 40,000 newborns. The condition is more common in certain populations. For example, the condition occurs in approximately 1 in 2,000 newborns in the Saguenay Lac-Saint-Jean region of Quebec, Canada.

Duchenne muscular dystrophy (DMD)

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What is Duchenne muscular dystrophy?
Duchenne muscular dystrophy (DMD) is a genetic disorder characterized by progressive muscle degeneration and weakness. It is one of nine types of muscular dystrophy.

DMD is caused by an absence of dystrophin, a protein that helps keep muscle cells intact. Symptom onset is in early childhood, usually between ages 3 and 5. The disease primarily affects boys, but in rare cases it can affect girls.

What are the symptoms of DMD?
Muscle weakness can begin as early as age 3, first affecting the muscles of the hips, pelvic area, thighs and shoulders, and later the skeletal (voluntary) muscles in the arms, legs and trunk. The calves often are enlarged. By the early teens, the heart and respiratory muscles also are affected.

The heart
Lack of dystrophin can weaken the muscle layer in the heart (myocardium), resulting in a condition called cardiomyopathy. Over time, sometimes as early as the teen years, the damage done by DMD to the heart can become life-threatening. The heart should be monitored closely, usually by a pediatric cardiologist.
Respiratory function
Beginning at about 10 years of age, the diaphragm and other muscles that operate the lungs may weaken, making the lungs less effective at moving air in and out. Although the child may not complain of shortness of breath, problems that indicate poor respiratory function include headaches, mental dullness, difficulty concentrating or staying awake, and nightmares. Weakened respiratory muscles make it difficult to cough, leading to increased risk of serious respiratory infection. A simple cold can quickly progress to pneumonia.