Lou Gehrig's Disease (ALS)

Diagnosis

ALS can be difficult to diagnose in its early stages, since the symptoms and signs are similar to other neurological (nerve) diseases and disorders, including infectious diseases such as HIV, human T-cell leukemia virus (HTLV) and Lyme disease, or neurological disorders such as multiple sclerosis, multifocal motor neuropathy and spinal muscular atrophy.

The patient will first have a complete physical examination, along with a detailed history of symptoms and any family history of muscle disease. During the physical exam, the physician will check for signs of muscle weakness. In addition, the patient may undergo various tests, including tests to rule out other conditions. Diagnostic tests may include:

Blood Test

Blood can be tested for the enzyme creatine kinase, or CK, which leaks out of damaged muscle. High levels of CK suggest the muscles are likely causing weakness. Blood tests can also be used for genetic testing to detect Familial ALS, which occurs when ALS is present in two or more blood-related family members.

Electromyogram (EMG or Electromyography)

This test measures the tiny electrical signals in muscles. A thin-needle electrode is inserted into the muscle to be tested. An instrument records the electrical activity in the muscle at rest and as the patient tries to move or contract the muscle. An EMG may indicate that the motor nerves are not functioning, yet the sensory nerves are normal, a sign of ALS.

Nerve Conduction Study (NCS or Electroneurograph)

Similar to electromyography, this test measures electrical nerve impulses in muscles. Two electrodes are taped to the skin in the affected area of the patient's body. A small shock is passed through to measure the electrical impulses from one electrode to the other. This test is used to determine if the muscle weakness is due to a muscle disease (myopathy) rather than ALS.

Respiratory Testing

To determine if muscles that control breathing are affected, a respiratory test may be done.

Muscle Biopsy

To determine if the patient has a myopathy (muscle disorder) such as muscular dystrophy, rather than ALS, the patient may have a muscle biopsy. A small amount of tissue is taken from a muscle and tested.

Magnetic Resonance Imaging (MRI)

An MRI of the brain, spine or both may be done to rule out other conditions. This test uses powerful magnets and radio waves to produce a detailed, three-dimensional view of the nervous system.