Arthrogryposis (Multiplex Congenita)

Definition

Definition of Arthrogryposis (Multiplex Congenita)
Arthrogryposis Multiplex Congenita (AMC) is a disease of newborns resulting in decreased flexibility of the joints. Symptoms differ drastically from person to person, including stiff joints and muscle weakness. The areas that are most likely to have lack of movement are the shoulders, elbows, wrists, hands, hips, knees, and feet. The lack of movement, unlike many other diseases, does not get worse as time goes by. However, it is necessary to seek treatment to prevent further impediments of the joints.

Symptoms

Symptoms of Arthrogryposis (Multiplex Congenita)
Deformities are prominent at birth. AMC is not progressive; however, the condition that causes it (eg, muscular dystrophy) may be. Affected joints are contracted in flexion or extension. In classic AMC, shoulders are sloped, adducted, and internally rotated; the elbows are extended; and the wrists and digits are flexed. Hips may be dislocated and are usually slightly flexed. Knees are extended; feet are often in the equinovarus position. Leg muscles are usually hypoplastic, and limbs tend to be tubular and featureless. Soft-tissue webbing sometimes occurs over ventral aspects of the flexed joints. The spine may be scoliotic. Except for slenderness of the long bones, the skeleton appears normal on x-rays. Physical disabilities may be severe. As noted, some children may have primary CNS dysfunction, but intelligence is usually unimpaired.

Causes

Causes of Arthrogryposis (Multiplex Congenita)
There are many causes of the disease, some of which are inherited. Before birth, four possibilities exist that limit joint movements:

1. abnormal development of muscles;
2. inadequate room in the uterus for the baby;
3. a malformed central nervous system and spinal cord; and
4. tendons, joints, bones, and joint linings which did not mature correctly. The decrease in range of motion is also caused by extra tissue that has formed around the joint, prohibiting movement.

Out of 3000 births, only one is apt to develop AMC, and only 30% of those are genetically related.

Diagnosis

Diagnosis of Arthrogryposis (Multiplex Congenita)
There are many neuromuscular causes of AMC. Abnormalities can be found in the nerve cells in the spinal cord, the nerves themselves, the junction between the nerve and muscle, and the muscles. Electrodiagnostic testing is helpful to the electrodiagnostic medicine physician in making a diagnosis because it provides information about the function of the nerves and muscles. Information obtained from an electrodiagnostic consultation helps direct the need for any additional testing that may be done in order to make a definitive diagnosis of AMC.

Treatment

Treatment of Arthrogryposis (Multiplex Congenita)
This is likely to involve several different specialists and therapists. Ideally, management should be co-ordinated by a key specialist (often a paediatrician) who is part of a team looking after affected patients. Broadly speaking, management can be divided into medical, surgical, social and psychological care.

1. Medical Care: Physical therapy to improve the range of motion and stretch surrounding tissues is very useful, especially in amyoplasia and distal arthrogryposis, although in diastrophic dysplasia it may lead to ankylosis instead. It should be started early. Splinting between times can correct deformity, especially in the hands and wrists. Serial casting after physical therapy has achieved maximum usefulness with weekly changes of cast and gentle manipulation.
2. Surgical Care: Surgery is often needed to correct soft-tissue contractures and joint deformities. It can also reduce and stabilise dislocated hips, correct foot deformities and stabilise spinal deformities. Anaesthesia can be a problem, as some patients with some forms of arthrogryposis are at risk of malignant hyperpyrexia.
3. Social and Psychological Care: This encompasses some fundamental care needs which will be associated with the condition. The extent of the need for care will vary depending on the individual, their circumstances and the impact of the condition on the particular individual. Information is important and support groups provide useful information and advice.9 The new system of social care and support is called Self Directed Support and this should allow for the varied and complex care needs of this particular condition.

Prognosis

Prognosis of Arthrogryposis (Multiplex Congenita)
Prognosis depends on the underlying cause, but most have a normal life span.

1. If, however, there is a central nervous system problem in addition, about 50% of patients die in the first year.
2. Scoliosis is common and can appear at any age but needs correction before it becomes severe.
3. The long-term prognosis in terms of dependency is poor in many cases but for amyoplasia it is quite reasonable.
4. Of those with amyoplasia, 2/3 are ambulant by age 5. Most achieve independent life and can attend mainstream school. However, most require serial casting or surgery.

Prevention

Prevention of Arthrogryposis (Multiplex Congenita)
Genetic advice may be essential to prevent arthrogryposis. Extrinsically derived contractures have a low recurrence risk, but the recurrence risk for intrinsically derived contractures depends on aetiology and ranges from 3% to 50%.