Case Report Demonstrates Presence of Polyneuropathy In LOPD

People with late-onset Pompe disease (LOPD) can develop damage to the nerves that run throughout their body, a recent case report about four patients shows.

Such nerve damage in LOPD patients can worsen disability and needs special attention and care, such as physiotherapy.

The report with those findings, “Late-onset Pompe disease associated with polyneuropathy,” was published in Neuromuscular Disorders.

LOPD is defined as Pompe disease that occurs after the first year of life. Generally, the muscles are the main part of the body affected in LOPD, but data from mouse models of the disease have suggested that nerves can be affected, too. Moreover, there have been reports of cases of patients with small fiber nerve damage. “To the best of our knowledge an involvement of large nerve fibers was never depicted,” the researchers behind the new report wrote.

They went through medical records for people with LOPD who were treated at Hôpital Erasme, Université Libre de Bruxelles in Belgium. Specifically, the researchers looked for individuals who met the criteria for polyneuropathy, a condition characterized by damage to the nerves in the peripheral nervous system (nerves in the body outside of the brain and spinal cord).

Out of six people with LOPD whose records were assessed, the researchers determined that four (67%) met the criteria for polyneuropathy. Specifically, they all had abnormally low nerve conduction, which is essentially a measurement of how well nerves can deliver electrical signals, in the lower limbs.

This was associated with symptoms like muscle weakness and difficulty balancing, which developed in the third or fourth decade of life for all four individuals included.

It is conceivable that the Pompe disease itself did not actually cause the detected polyneuropathy in these individuals; it’s plausible that these individuals could have some other polyneuropathy-causing condition in addition to having LOPD. So, the researchers systematically went through diagnostic criteria for dozens of other factors that could have caused the polyneuropathy. These ranged from lupus to diabetes to hepatitis infections, to the use of certain kinds of drugs and alcohol.

None of the assessed conditions were found. While the researchers acknowledged that, based on this data alone, it’s impossible to say with absolute certainty that polyneuropathy manifested as a direct result of LOPD, they concluded that, “our observation supports that polyneuropathy could be an additional comorbid condition in LOPD patients.”

The researchers noted that polyneuropathy may be particularly easy to overlook in people with LOPD because symptoms like muscle balance also can result from muscle problems.

They recommended that “Screening of polyneuropathy should be performed in LOPD patients in order to avoid missing this potentially disabling condition that carries a specific management pathway,” which can include avoiding certain medications and employing other types of medicines and therapy targeted at the nerves themselves, not the muscles.

“[…] this potentially disabling condition that carries a specific management pathway including avoidance of neurotoxic drugs, proprioceptive physiotherapy or neuropathic pain targeted painkillers drugs,” they wrote.

“We need to underline that our study concerns a small cohort of patients and that prevalence data may not be extrapolated from our observation. Moreover our observation certainly needs to be confirmed on large samples,” the researchers added.