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Diagnosed With FND. It Was Buerger's Disease. She Lost Her Leg

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Danielle Thomas, a 40-year-old mother of two from Nottinghamshire, repeatedly sought medical help for numbness, pins and needles, and worsening difficulties walking. She described her legs as feeling as though they were dying whenever she walked more than 300 metres. Her symptoms were initially attributed to anxiety, and after neurological investigations failed to identify an explanation, she was diagnosed with Functional Neurological Disorder (FND).

Months later, doctors discovered that Danielle had severe arterial blockages caused by Buerger's disease, a condition affecting blood vessels and circulation. By then, her big toe had developed gangrene. On 7 September 2026, she underwent a below-knee amputation of her right leg.

Her experience was reported by the Manchester Evening News on 12 October 2026. It raises serious questions about diagnostic anchoring, the investigation of symptoms outside the nervous system, and the consequences of attributing unexplained physical symptoms to FND before other relevant causes have been adequately considered.


From Anxiety to an FND Diagnosis

Danielle first approached her GP in April 2025 after developing numbness and pins and needles in her hands and feet. She was referred to a neurologist at Sheffield Teaching Hospital, where she underwent investigations in July, including blood tests and an MRI scan. When these investigations failed to identify an explanation, Danielle says the neurologist suggested her symptoms might be related to her mental health.

She had previously experienced domestic abuse, which she acknowledged had significantly affected her. This history reportedly became part of the clinical discussion, although the available reporting does not establish precisely how it influenced the neurologist's assessment.

By November 2025, Danielle's condition had deteriorated. She returned to the neurologist and explained that walking more than 300 metres caused her legs to feel as though they were dying. Further investigations, including a CT scan of her spine, reportedly failed to identify the cause. She was subsequently diagnosed with FND.

This detail is particularly important because pain, weakness or discomfort in the legs brought on by walking can indicate impaired arterial circulation. Such symptoms may occur with intermittent claudication, a recognised manifestation of peripheral arterial disease. They do not establish a vascular diagnosis on their own, but they warrant consideration of vascular causes, particularly when symptoms are progressive.

Danielle described what she believed had been overlooked:

"They tested all of my nervous system, my brain, my cervical, but left out my vascular which was the problem."

She also reported telling the neurologist that it felt as though she had grit in her veins. In her view, clinicians appeared more interested in fitting her symptoms into an FND diagnosis than investigating other possible explanations.

We do not have access to her complete medical records, so the exact reasoning behind the diagnosis cannot be independently assessed. Nevertheless, the reported sequence raises an important question: why was a vascular explanation not identified earlier in a patient describing progressive walking-related symptoms?


The Discovery of Gangrene

Later in November 2025, Danielle returned to her GP because she believed she might have an ingrown toenail. She says she had to push for a referral to a podiatry specialist. When she finally attended the appointment in February 2026, the specialist discovered that the problem was considerably more serious. Her big toe had developed gangrene because of inadequate blood supply.

The podiatrist immediately recognised a circulation problem and referred Danielle to a vascular specialist at Doncaster Royal Infirmary. A CT scan of her legs revealed multiple arterial blockages affecting both limbs. Within days, she was diagnosed with Buerger's disease, also known as thromboangiitis obliterans.

Buerger's disease is an inflammatory vascular condition associated strongly with tobacco exposure. It primarily affects small and medium-sized blood vessels in the arms and legs, potentially causing restricted circulation, pain, tissue damage, ulcers and gangrene. Severe cases can result in amputation. Danielle reported a history of intermittent smoking, and her doctors associated her condition with that exposure.

The significance of the diagnosis was not simply that another medical condition had been discovered. It was that a serious vascular disorder had been identified in the same limbs where Danielle had repeatedly reported worsening symptoms. Those symptoms had previously been assessed within a neurological framework and ultimately labelled FND.

A Preventable Amputation?

Following the diagnosis, Danielle's toe continued to develop infections. Doctors warned that the infection could potentially lead to sepsis, and amputation became a serious consideration. In May 2026, she decided to proceed with a below-knee amputation, which was performed on 7 September.

Danielle believes her leg might have been saved if the vascular disease had been identified earlier. She explained that an earlier diagnosis could have prompted her to stop smoking sooner, potentially limiting the progression of the arterial blockages.

That possibility is medically relevant because smoking cessation is central to managing Buerger's disease. However, the available reporting does not establish whether earlier diagnosis and treatment would definitely have prevented amputation. By the time her vascular condition was recognised, gangrene had already developed.

What cannot be disputed in the reported timeline is the seriousness of the outcome: Danielle spent months seeking answers, received an FND diagnosis, subsequently developed gangrene, and ultimately lost her right leg below the knee.

She has described the emotional impact of the amputation as devastating. Previously independent, she now faces substantial changes to her mobility and everyday life. She is raising funds to adapt her car with specialist driving controls so that she can regain some independence.


The Diagnostic Questions That Remain

Several aspects of this case deserve closer examination. First, the Manchester Evening News report does not identify which positive clinical signs, if any, were documented to support Danielle's original FND diagnosis. It describes neurological investigations that did not reveal an explanation, followed by the diagnosis, but does not provide the examination findings or clinical reasoning needed to establish how that conclusion was reached.

This matters because an absence of abnormalities on neurological investigations does not establish that symptoms are functional. Nor does it exclude disease affecting another physiological system. Brain and spinal imaging cannot substitute for an assessment of arterial circulation when vascular disease is a plausible explanation for the symptoms being reported.

Second, Danielle's history of psychological trauma reportedly entered the diagnostic discussion. Trauma can be relevant to a patient's medical history, but it does not explain away physical symptoms or remove the need to investigate progressive disease. The subsequent discovery of severe vascular pathology demonstrates why psychological explanations must not replace appropriate investigation of potentially serious physical conditions.

Third, her condition appears to have progressed substantially between the initial neurological assessments and the eventual vascular diagnosis. The development of gangrene was an objective indication of serious tissue damage. The fact that a podiatry assessment ultimately prompted vascular investigation raises questions about whether earlier examination of circulation, peripheral pulses and walking-related symptoms might have identified the problem sooner.

There is also an important distinction between an FND diagnosis being incorrect and FND potentially coexisting with another condition. The newspaper report does not establish whether clinicians formally withdrew Danielle's FND diagnosis following the discovery of Buerger's disease. However, it does establish that a serious physical disease capable of explaining important aspects of her presentation was identified after the FND diagnosis. Whether any independent evidence for FND remained is not documented.

The central concern is therefore not merely that another disease was eventually discovered. It is whether the original diagnostic process adequately investigated the symptoms Danielle was reporting, and whether the FND label contributed to a delay in recognising a progressive vascular condition.

Without the complete clinical records, it would be inappropriate to declare precisely which individual decisions were negligent or whether the amputation could have been avoided. But those uncertainties do not make the reported sequence any less concerning.

Danielle repeatedly described worsening symptoms affecting her legs, including severe difficulty walking. The eventual diagnosis was a disease that restricts blood flow to the extremities. By the time that disease was identified, irreversible tissue damage had occurred.

Her experience illustrates why diagnostic uncertainty must remain open to reassessment, particularly when symptoms progress, new findings emerge or the existing diagnosis fails to account adequately for the clinical picture.

A diagnosis should help clinicians understand what is happening to a patient. It should never become a reason to stop looking when the patient's condition continues to deteriorate.


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