Causes and Diagnoses

Causes and Diagnoses of Amyotrophic Lateral Sclerosis (ALS)

The cause of amyotrophic lateral sclerosis (ALS) is unknown. As the disease progresses, symptoms such as muscle weakness and atrophy become apparent. To diagnose ALS, your physician will consider your medical history and symptoms and perform certain tests to rule out other conditions.

Causes of ALS

The cause of ALS is unknown, though there may be a hereditary factor in 5 to 10 percent of ALS cases (known as familial ALS).

Diagnoses of ALS

There is not one specific test to diagnose ALS. Your physician will take into account your medical history and symptoms, and may use one or more of the following tests to arrive at a diagnosis:

  • Blood test
  • Urine test
  • Thyroid functioning test
  • Spinal tap (lumbar puncture)
  • Muscle biopsy
  • Nerve biopsy
  • X-ray
  • Electromyography (EMG) or nerve conduction study (NCS) to identify muscle and motor neuron disorders
  • Magnetic resonance imaging (MRI)

Diagnostic Tests

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