Pain in ALS Patients is Common but Not Studied Enough, Review Finds

People with amyotrophic lateral sclerosis (ALS) are frequently in pain, yet few studies focus on this aspect of the disease, according to an analysis by researchers at Italy’s University of Turin.

Their study, “Pain in amyotrophic lateral sclerosis,” recently appeared in the journal The Lancet Neurology. A comprehensive overview of published data, it deals with the epidemiology, assessment and treatment of pain in ALS, as well as the characteristics and mechanisms of pain. They found that patients are sometimes in pain even before they’re diagnosed with ALS, yet pain can also complicate the course of the disease.

But the problem is not only the lack of good pain research in ALS, they said. It’s also because some studies find that only 15 percent of ALS patients are in pain, while others say it’s more like 85 percent. One reason may be highly variable study methods; another is the variety of types and localizations of pain in ALS — ranging from cramps, itching and nerve-related pain to pain caused by pressure sores or reduced mobility.

One thing researchers do know that in earlier stages of the diseases, pain is often mild. But it tends to get more frequent and more severe in later stages. Studies also show that ALS patients are often depressed, and that pain is more common in patients who also have depression — with both factors significantly reducing their quality of life. Unfortunately, most studies on pain do not assess how symptoms of depression influence ALS, making it difficult to interpret the data.

The review also found no structured evidence of the most efficient pain treatments for ALS patients.

Clinics specializing in ALS often use treatments that are specific for the type of pain, including non-steroid anti-inflammatory drugs, opioids and paracetamol. They generally treat leg cramps with quinine sulphate — a compound approved only for malaria treatment. Non-pharmacological treatments such as stretching or range-of-motion exercise have been evaluated and show some effectiveness. Patients with reduced mobility also use assistive devices.

The researchers urged more studies that follow ALS patients over time in order to assess the impact of depression and chart the natural course and appearance of pain among this group.

“Until results from more robust treatment studies are available, treatment should be based on good clinical practice backed up by available guidelines on non-malignant chronic pain,” they concluded.