Amyotrophy is a condition characterized by motor neuropathy in the limbs and goes by diabetic lumbosacral plexus neuropathy (or Diabetic amyotrophy for short) and Bruns-Garland syndrome, as well. The condition involves nerve roots and peripheral nerves and usually occurs in the lower limbs. The effects of amyotrophy are different than the effects of an injury. Injuries are felt immediately or shortly after they occur. Amyotrophy develops gradually except in cases of monomelic amyotrophy, which has a rapid onset.
Symptoms
The first symptoms someone with amyotrophy will experience are a weakness in the legs and muscle pain that often presents as a sudden, sharp pain in the hip or thigh. The pain spreads to the opposite side of the body in the following weeks or months. Initial symptoms are followed by muscle wasting and slowed or absent reflexes. Weakness in the front thigh muscles is the most pronounced.
Diabetic Amyotrophy
Diabetic amyotrophy, also known as diabetic lumbosacral plexus neuropathy, usually occurs in adults over 50 with type 2 diabetes. Severe, burning thigh pain increases at night and sometimes spreads to the buttocks and back. Asymmetrical neuropathy tends to progress quickly while symmetrical neuropathy progresses gradually. Diabetic amyotrophy can occur even if a person has only mild diabetes.
Characteristics of Diabetic Amyotrophy
Pain is most severe in the thighs, back, or both. Diabetic amyotrophy renders the quadriceps muscle group weak almost continuously, while muscles in the buttocks and back of the thighs experience weakness about half the time. A working theory on the cause of amyotrophy states that inflamed blood vessels interrupt and slow blood supply to the nerves. This theory could explain why weakness comes and goes in some muscle groups but is continuous in others.
Monomelic Amyotrophy
Monomelic amyotrophy is a rare motor neuron disease that occurs randomly in most cases, though doctors occasionally observe it in multiple members of a family. This type of amyotrophy is much more common in men than women, and most people with the disease are between 18 and 22 years old. Limbs affected by the disease retain sensation, except for the top of the hand in rare cases.
Symptoms of Monomelic Amyotrophy
Early symptoms include a slow onset of weakness on one or both sides of the body and loss of mass and function in hand muscles. This weakness spreads and increases in severity for roughly three years before stabilizing. Deep tendon reflexes remain normal while upper motor neuron signs are gone. Some people with monomelic amyotrophy experience cold paresis — they feel increased weakness during exposure to cold temperatures.
Neuralgic Amyotrophy
Neuralgic amyotrophy affects the peripheral nerves in upper limbs, most often in men in their early twenties. While not a permanent or continuous disorder, the condition can be recurrent in a minority of cases. There is usually no known cause or trigger, though some cases occur within hours or weeks of upper respiratory tract infections, vaccinations, childbirth, and invasive medical procedures.
Amyotrophy with Multiple Sclerosis
Amyotrophy is common for people with multiple sclerosis. Poor posture in wheelchairs or improvised use of limbs to compensate for lost function can aggravate the condition. An example of compensation is using the elbows to turn or get out of bed due to decreased functionality in the body parts one usually uses for this purpose. Odd positioning and pressure can cause numbness, pain, or weakness that mimics symptoms of amyotrophy. Lesions on neural pathways also imitate and magnify effects of amyotrophy.
Diagnosing
Diagnosis of amyotrophy is complicated because there are several types with unique symptoms. When physicians suspect amyotrophy due to medical history and physical evaluation, they generally must rule out other disorders with additional tests. Ordering electromyography approximately three weeks after symptoms first appear can show changes along nerves. Doctors differentiate between types of amyotrophy by comparing results to the available demographic and incidence reports of amyotrophy cases.
Treatment
Many types of amyotrophy improve over time without intervention. Treatment focuses on shortening the period of pain and weakness while working toward the best possible outcome. Physical therapy can help manage diabetic amyotrophy, along with close monitoring of blood glucose levels. A healthy diet and plenty of rest give the body a chance to heal itself. Analgesic medications and steroids treat pain.
Prognosis
Diabetic amyotrophy has a very high chance of spontaneous recovery, wherein the affected individual gains back almost all function. Pain is the first symptom to improve. This can happen in a few weeks after the first appearance of symptoms, or it can take up to a year. Weakness dissipates between three and four months after symptom onset, but severe cases may require up to three years of recovery. Most people experience a nearly complete recuperation while a small minority require ambulatory aids or wheelchairs.