Numbness and Tingling in Limbs May Be Signs of an Undiagnosed, Serious Illness

The disease can heighten the risk of falls, infections, and even amputations if left unchecked.

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That pins-and-needles feeling when your foot falls asleep? For millions of Americans, it’s more than a temporary nuisance—it could be a sign of an underdiagnosed nerve disorder.

Distal symmetric polyneuropathy (DSP), the most prevalent form of peripheral nerve neuropathy, can heighten the risk of falls, infections, and even amputations if left unchecked. Yet scientists say most cases go undetected, allowing the condition to quietly ravage the nervous system.

Many Causes Beyond Diabetes

Neuropathy refers to nerve damage in the body’s peripheral nervous system, the network of nerves beyond the brain and spinal cord. It is the most common complication of diabetes.

DSP, also known as diabetic neuropathy, is a type of neuropathy associated with diabetes, affecting around 15 percent of people over 40 and about 30 percent of those with diabetes. It is estimated to affect over 20 million Americans.

However, diabetes isn’t the sole risk factor for neuropathy. It could also be an early warning sign of other underlying, undiagnosed disorders, according to Dr. Norman Latov, a neurologist and director of the Peripheral Neuropathy Clinical and Research Center at Weill Cornell Medicine. These include thyroid or kidney disease, B vitamin deficiency, rheumatological or autoimmune conditions, toxic exposure, or infections like Lyme disease, hepatitis C, or syphilis. In some cases, it may even indicate cancer if a tumor is growing close to a nerve and putting pressure on it.

“Any delay in diagnosis and treatment would allow these conditions to progress and cause permanent damage, not just to the nerves,” Dr. Latov added.

Symptoms of diabetic neuropathy vary based on the affected nerves, ranging from pain and numbness in the extremities to issues with digestion, urination, blood vessels, and the heart. While some experience mild symptoms, for others, this condition can cause debilitating pain.

75 Percent of Neuropathy Cases in Black, Medicaid Recipients Undiagnosed

New research published in Neurology finds that the vast majority of participants not only had neuropathy but were also unaware they had it.

The study analyzed data from 169 patients at an outpatient clinic in Flint, Michigan, predominantly serving Medicaid recipients. Nearly 70 percent of the participant group were non-Hispanic black. Half had diabetes, 67 percent were diagnosed with metabolic syndrome, and about half had a household income below $20,000 per year.

The findings revealed that 73 percent of participants had DSP, with 75 percent of those cases previously undiagnosed. Also, 57 percent of participants with DSP reported neuropathic pain.

Dr. Latov called this important research, drawing attention to the need for better neuropathy recognition and treatment, “particularly the association with metabolic syndrome, a treatable condition.”

The researchers noted a limitation: The study provided a “snapshot in time” and did not follow participants without DSP to see if they developed it later. It also did not investigate why some participants struggled to manage neuropathy risk factors.

Neuropathy Within Weeks of COVID-19 Vaccination Documented

As early as 2022, evidence suggested that COVID-19 vaccination could be a new risk factor for neuropathy.

In one study, researchers evaluated 23 self-referred patients from January to September 2021 who developed new-onset combination neuropathy symptoms (sensory, motor, or autonomic) within a month of receiving a COVID-19 vaccine dose. Patients with non-neurological complaints, worsening of preexisting neurological issues, or underlying risk factors for neuropathy were excluded, according to the preprint.

The vaccines received included one from AstraZeneca, one from Janssen (J&J), nine from Moderna, and 12 from Pfizer.

All participants developed neurological symptoms within 21 days post-vaccination, with an average onset of four days after inoculation.