From the clinic: when foot pain was more than chemotherapy neuropathy

This patient had been left with tingling in her feet after chemotherapy. When she developed a more intense pain in her left forefoot, she was told it was part of that neuropathy. But this pain felt different: it was concentrated around the toes, with burning and shooting sensations travelling to their tips.

A history of neuropathy explained some of her symptoms, but it did not mean every new foot symptom had the same cause. I examined the painful area and performed an ultrasound scan to investigate further.

What did the examination and scan show?

A clinical test called Mulder’s test reproduced signs consistent with an irritated nerve in the forefoot. The ultrasound scan showed thickening in two spaces between the toes of her left foot: one measured 3.3 mm and the other 3.8 mm. These findings, together with her symptoms and examination, supported a diagnosis of two Morton’s neuromas. There were no corresponding signs of a neuroma on the scan of her right foot.

A Morton’s neuroma involves thickening and irritation of a nerve between the long bones of the forefoot. It can cause burning, shooting pain and tingling into the toes. Those sensations can sound similar to peripheral neuropathy, which is why the location of the pain and a careful examination mattered in this case.

Her chemotherapy-related neuropathy had not been dismissed. It was still the likely explanation for some of the background tingling in her feet. The new, localised pain in the left forefoot had an additional, treatable cause.

Treating the source of the new pain

After discussing the treatment and obtaining her consent, I performed an ultrasound-guided corticosteroid injection into each of the two affected spaces in her left foot. Ultrasound allowed me to see the areas we had identified and guide the injections accordingly.

We discussed possible side effects, including a temporary increase in pain after the injection, changes to the skin at the injection site and the small risk of infection. I advised her that improvement might be gradual over the following weeks.

She could continue comfortable activities such as strength training or circuit classes, while avoiding running, jumping and contact sports for the first week. We arranged a review at four weeks to assess her response. If pain remained troublesome, we could consider insoles designed to reduce pressure across the forefoot.

At the time of writing, we had not yet assessed the result of the injections. The important finding from this appointment was the diagnosis: her existing neuropathy was real, but it was not the whole explanation for her pain.

About the author

Mr Liam Stapleton MSc, PGCert, PGDip, FFPM RCPS(Glas), FRCPodM is an Advanced Practice Podiatrist Prescriber and Specialist in Podiatric Sports Medicine. His postgraduate qualifications include Independent Prescribing, Musculoskeletal Ultrasound, Advanced Clinical Practice, the Theory of Podiatric Surgery and Podiatric Sports Medicine.

If you have persistent or changing foot pain, you can book an assessment with Kent Sports Podiatry at one of our clinics across Kent.

Call: 01622 961005Book online: www.kentsportspod.com/online-booking