Abstract

We report a case of a patient with a background of suspected lung malignancy, Behçet’s disease, and prior radiotherapy, who presented with acute left lower limb weakness, sensory loss, and bowel and bladder dysfunction. Imaging revealed thoracic spinal cord signal changes and periventricular brain lesions suggestive of an inflammatory demyelinating process. Extensive workup for malignancy, infection, and autoimmune conditions was inconclusive. The patient failed to improve with high-dose corticosteroids but showed a significant response to plasma exchange. This case highlights the diagnostic challenges of idiopathic myelopathy and supports early consideration of plasmapheresis in seronegative presentations.

Keywords

Neuroimmunology, Plasma Exchange Therapy, Transverse Myelitis

Introduction

Transverse myelitis (TM) is a rare but potentially disabling inflammatory disorder of the spinal cord.¹ It can be idiopathic or secondary to autoimmune, infectious, paraneoplastic, or post-radiation aetiologies.² Diagnosis requires careful exclusion of other causes and is supported by neuroimaging and cerebrospinal fluid (CSF) analysis.² This case highlights an unusual presentation of suspected idiopathic inflammatory myelopathy in a patient with complex comorbidities.

Case presentation

 This is a case of a male in his late 50s with a background of suspected right lung malignancy (previously treated with radiotherapy), Behçet’s disease, chronic kidney disease, monoclonal gammopathy of undetermined significance, left adrenal adenoma, pulmonary hypertension, and chronic obstructive pulmonary disease. At presentation, the lung lesion had not been biopsied, so malignancy remained unconfirmed. Six months later, a histological diagnosis had still not been established.

He presented with an acute onset of left buttock and leg pain, worsening over 5 days, progressing to paraesthesia

and weakness in the left lower limb. He developed bladder dysfunction requiring catheterisation and bowel incontinence.

On examination, he was fully oriented and cranial nerves and upper limb functions intact. Neurological findings revealed increased tone, reduced power (2-/5), and brisk reflexes in the left lower limb. Right lower limb motor function was normal. There was reduced sensation to light touch and pinprick at the T4 dermatome bilaterally. Vibration sensation was reduced to the ankles bilaterally, with preserved joint position sense.

Investigations

Magnetic resonance imaging (MRI) spinal imaging showed no metastatic compression, with a minor disc bulge at L5/S1 and a T3–T6 signal abnormality suggestive of inflammation or demyelination. Contrast MRI brain and spine imaging later revealed multiple white matter lesions, with slight regression of spinal changes, supporting a non-metastatic inflammatory process. CSF showed normal glucose, mildly elevated protein, no malignant cells, and negative cultures and polymerase chain reaction (PCR). Results later available confirmed identical IgG oligoclonal bands in serum and CSF, indicating systemic inflammation. Cytology from CSF remained negative.

Blood tests showed elevated C-reactive protein of 158mg/L and transient neutropenia, with no infection identified. Autoimmune screening, including antinuclear antibodies, antineutrophil cytoplasmic antibodies, extractable nuclear antigens, double-stranded DNA, anticardiolipin antibodies, and lupus anticoagulant, were negative. Serum copper and angiotensin-converting enzyme levels were normal. Paraneoplastic antibodies and serologies for HIV, syphilis, hepatitis B and C, Lyme disease, and aquaporin 4 were negative. Serum free light chains were elevated, with reduced IgG and IgM. Nerve studies showed peripheral neuropathy without denervation or radiculopathy. CT imaging confirmed progression of the lung lesion, but no metastasis or other cause for symptoms. Specialist reviews from dermatology and ophthalmology found no active Behçet’s disease.

Differential diagnosis

The initial working diagnosis was metastatic spinal cord compression, which was excluded following an MRI of the spine. Other considerations included paraneoplastic myelopathy, neuro-Behçet’s syndrome, post-radiation myelitis, infectious myelitis, and idiopathic TM. No pathogens were identified to suggest an infective cause, and given the regression of spinal cord lesions and improvement following immunomodulatory treatment, paraneoplastic and infectious causes were deemed unlikely. The absence of dermatological and ophthalmological features, in combination with a lack of response to steroids, made active neuro-Behçet’s syndrome improbable. Radiation-induced myelopathy was considered but felt less likely given the timing, anatomical distribution, and regression on follow-up imaging.

Treatment

The patient was initially managed with high-dose intravenous corticosteroids, with minimal clinical response. Following neurological consultation, based on suspicion of an autoimmune or idiopathic inflammatory aetiology, he underwent a five-day course of plasma exchange (PLEX) in collaboration with the renal team, who agreed to insert a temporary central line and deliver membrane-based plasmapheresis in the dialysis ward using haemodialysis.

PLEX is a treatment that involves the exchange of blood plasma to eliminate pathogenic substances such as autoantibodies, immune complexes, or toxins.³ Antibiotics were also administered due to neutropenic fevers, though no source of infection or pathogens was identified.

Outcome

Following completion of PLEX, the patient showed significant neurological improvement, including partial recovery of motor function in the left lower limb. He regained the ability to sit unsupported and exhibited improved sensation below the T4 level. Residual deficits included left-sided weakness (power 3-/5), thigh muscle wasting, and ongoing bowel incontinence. He remained catheterised.

At the time this case report was written, the patient was undergoing inpatient neurorehabilitation with ongoing improvement in strength and mobility.

Discussion

There are many studies on autoimmune disorders of the nervous system.⁴ Even though studies attempt to understand the autoimmune system, there are multiple mechanisms that can affect breakdown of immune tolerance, which affects peripheral tolerance more than central tolerance.⁵

This case illustrates the complexity of diagnosing TM in the context of suspected malignancy and autoimmune disease. Although many potential causes were investigated, the patient’s clinical course, imaging findings, and positive response to PLEX pointed toward an idiopathic or seronegative autoimmune myelopathy.

While radiotherapy-induced myelopathy can present with delayed onset, the thoracic cord involvement and periventricular brain lesions suggested an inflammatory demyelinating process. This case highlights the importance of early multidisciplinary involvement and consideration of immunomodulatory therapy in patients with progressive myelopathy and inconclusive diagnostic workup.

Similar cases have been published in the literature where the cause is unidentifiable for TM.^6,7 This illustrates the need to invest in further research for potential antibodies causing immune tolerance, not only to predict outcome but also risk of recurrence.

Conclusion

 TM may present as a rapidly progressive neurological deficit. Such presentations warrant urgent neuroimaging and a comprehensive immunological workup to identify potential underlying causes and initiate timely treatment. A negative paraneoplastic or infectious screen does not exclude an immune-mediated pathology. In selected cases, empirical plasmapheresis may be considered, particularly when clinical suspicion remains high despite inconclusive diagnostic findings.

In oncological patients, idiopathic TM can occur and may be difficult to distinguish from paraneoplastic or radiation-induced aetiologies. Differentiation requires careful clinical assessment and consideration of the patient’s cancer history and treatment exposure.

Clinical improvement following PLEX may suggest an antibody-mediated pathogenesis, even in the absence of a confirmed autoantibody. This therapeutic response supports the use of immunomodulatory strategies in cases where diagnostic clarity is limited.

Ethical statement

 Patient has provided written informed consent.

Journal of Geriatric Care and Research

References

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