SMA Patients at Risk of Metabolic Disorder Known as Ketoacidosis, Case Study Shows

Patients with spinal muscular atrophy (SMA) are at risk of developing the metabolic disorder ketoacidosis, a less recognized complication that is easy to treat, according to a case study.

Researchers behind the work, “Stress-Induced Ketoacidosis in Spinal Muscular Atrophy: An Under-Recognized Complication,” noted that testing for the condition, which is easily done with a blood sample, could save a patient from unnecessary over-investigation of their condition and inappropriate treatment. The work was published in the Journal of Neuromuscular Diseases. 

Metabolism is the process by which cells produce energy.

Ketoacidosis is a metabolic condition that is usually seen in people who starve, have diabetes, or drink excessive amounts of alcohol.

The body produces ketone bodies to ensure that the brain gets enough energy when blood sugar levels are low. Under such circumstances, the body breaks down muscle tissue to generate energy, producing acidic compounds in the process.

Earlier research has shown that people with SMA and other neuromuscular diseases are at increased risk of ketoacidosis. This is likely brought about by a combination of reduced muscle mass, abnormal sugar and fat metabolism, and perhaps changes in hormone and nerve signaling.

Researchers at Dunedin Public Hospital in New Zealand said a 50-year-old man with SMA was brought to an emergency room  because he was nauseous, vomiting, and experiencing stomach discomfort.

He had SMA type 2, with substantial loss of muscle, so he needed assistance with daily activities. Although unable to walk, he could feed himself. He also had marked respiratory muscle weakness.

Two days earlier, he was treated for a suspected urinary tract infection after having difficulty urinating. A blood test showed he had severe ketoacidosis and slightly lower blood glucose than normal.

The man received intravenous dextrose sugar and ceftriaxone antibiotic for the urinary tract infection. The next morning, his blood pH and sugar levels were back to normal.

The physicians learned he had suffered a similar episode five years earlier. Routine blood testing after sinus surgery had revealed severe ketoacidosis, which responded well to treatment.

“Episodes of ketoacidosis in SMA patients occur when several factors converge to create a perfect storm of metabolic instability,” the researchers wrote, indicating that the condition can develop during periods of bodily stress.

Realizing that SMA patients are at risk for the metabolic disturbance might save them from unnecessary suffering, the researchers said.