Neuropathy associated with leflunomide: a case series

The prevalence and clinical features of leflunomide-associated peripheral neuropathy in patients with rheumatic disease in a New Zealand cohort

OBJECTIVE

To identify the prevalence and clinical features of leflunomide-associated peripheral neuropathy in patients with rheumatic disease over a 42-month observational period between January 1, 2016 and June 30, 2019.

METHODS

A retrospective observational study was conducted using regional prescription data identifying all patients treated with leflunomide for rheumatic diseases in the Southern District Health Board of New Zealand. Medical records were used to identify patients who developed peripheral neuropathy while receiving treatment with leflunomide. Demographic characteristics, co-therapies, and additional risk factors for peripheral neuropathy were also recorded.

RESULTS

A total of 482 patients were identified as receiving leflunomide for the treatment of rheumatic during the study period. In total, 23 patients developed leflunomide-induced peripheral neuropathy within the cohort giving a prevalence of 4.7%. Nerve conduction studies (NCS) performed in 18 (78.2%) of these patients confirmed a distal axonal, sensory, or sensorimotor peripheral neuropathy. The majority of patients (n = 22; 95.6%) either improved, stabilized, or resolved on cessation of the drug, with or without medication washout. Adverse symptoms were reported in association with peripheral neuropathy in 15 of the 23 patients (65.2%): these included pain, poor sleep, compromised skin integrity, poor balance, and a Charcot-like arthropathy. Additional treatment was required to manage symptoms of peripheral neuropathy including nine patients (39%) who received pain relief.

CONCLUSIONS

This study supports the previously reported association between leflunomide treatment and the development of a peripheral neuropathy. However, our findings suggest that this is more common than the previous estimates. In patients with psoriatic arthritis and previous tarsitis, there appeared to be an association with a Charcot's-like arthropathy, a complication not previously noted in the literature.

[Formula: see text] Cognitive dysfunction in pediatric systemic lupus erythematosus: current knowledge and future directions

Cognitive dysfunction (CD) is a neurologic complication of pediatric systemic lupus erythematosus (SLE) that remains poorly understood and understudied, despite the potential negative effects of CD on long-term socioeconomic status and quality of life. Data regarding the prevalence and risk factors for CD in pediatric SLE as well as the optimal screening, treatment, and long-term outcomes for CD are lacking. In this review, we present current knowledge on CD in pediatric SLE with a focus on the application to clinical practice. We discuss the challenges in diagnosis, clinical screening methods, potential impacts, and interventions for this complication. Finally, we discuss the remaining gaps in our knowledge of CD in pediatric SLE, and avenues for future research efforts.

High-resolution ultrasound of peripheral neuropathies in rheumatological patients: An overview of clinical applications and imaging findings

Peripheral neuropathies are surprisingly common and can be associated with a number of conditions, including rheumatological diseases. Whether the co-existence of peripheral neuropathies with rheumatological disorders is coincidental or related to a common pathogenic mechanism, these disabling conditions can affect the outcome of rheumatological patients and should be targeted with specific treatment. The clinical presentation of peripheral neuropathy can be multifaceted and difficult to recognize in polysymptomatic patients. However, physicians adopting state-of-art diagnostic strategies, including nerve imaging, may improve the detection rate and management of neuropathies. In particular, a diagnostic approach relying exclusively on clinical history and nerve conduction studies may not be sufficient to disclose the etiology of the nerve damage and its anatomical location and thus requires integration with morphological studies. High-Resolution Ultrasound (HRUS) is increasingly adopted to support the diagnosis and follow-up of both joint disorders in rheumatology and peripheral neuropathies of different etiologies. In this review, the different types of nerve disorders associated with the most common syndromes of rheumatological interest are discussed, focusing on the distinctive sonographic features.

Drug-Induced Peripheral Neuropathy: Diagnosis and Management

Peripheral neuropathy comes in all shapes and forms and is a disorder which is found in the peripheral nervous system. It can have an acute or chronic onset depending on the multitude of pathophysiologic mechanisms involving different parts of nerve fibers. A systematic approach is highly beneficial when it comes to cost-effective diagnosis. More than 30 causes of peripheral neuropathy exist ranging from systemic and auto-immune diseases, vitamin deficiencies, viral infections, diabetes, etc. One of the major causes of peripheral neuropathy is drug induced disease, which can be split into peripheral neuropathy caused by chemotherapy or by other medications. This review deals with the latest causes of drug induced peripheral neuropathy, the population involved, the findings on physical examination and various workups needed and how to manage each case.

Drug-Induced Peripheral Neuropathy: A Narrative Review

Background

Peripheral neuropathy is a painful condition deriving from many and varied etiologies. Certain medications have been implicated in the iatrogenic development of Drug Induced Peripheral Neuropathy (DIPN) and include chemotherapeutic agents, antimicrobials, cardiovascular drugs, psychotropic, anticonvulsants, among others. This review synthesizes current clinical concepts regarding the mechanism, common inciting medications, and treatment options for drug-induced peripheral neuropathy.

Methods

The authors undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question and inclusion/exclusion criteria. The most relevant and up to date research was included.

Results

Drug-induced peripheral neuropathy is a common and painful condition caused by many different and frequently prescribed medications. Most often, DIPN is seen in chemotherapeutic agents, antimicrobials, cardiovascular drugs, psychotropic, and anticonvulsant drugs. Certain drugs exhibit more consistent neuropathic side effects, such as the chemotherapeutic compounds, but others are more commonly prescribed by a larger proportion of providers, such as the statins. DIPN is more likely to occur in patients with concomitant risk factors such as preexisting neuropathy, diabetes, and associated genetically predisposing diseases. DIPN is often difficult to treat, however medications including duloxetine, and gabapentin are shown to reduce neuropathic pain. Advanced techniques of neuromodulation offer promise though further randomized and controlled studies are needed to confirm efficacy.

Conclusion

Awareness of the drugs covered in this review and their potential for adverse neuropathic effect is important for providers caring for patients who report new onset symptoms of pain, paresthesia, or weakness. Prevention of DIPN is especially important because treatment often proves challenging. While many pharmacologic therapies have demonstrated analgesic potential in the pain caused by DIPN, many patients remain refractive to treatment. More studies are needed to elucidate the effectiveness of interventional, neuromodulating therapies.

De novo identification of toxicants that cause irreparable damage to parasitic nematode intestinal cells

Efforts to identify new drugs for therapeutic and preventive treatments against parasitic nematodes have gained increasing interest with expanding pathogen omics databases and drug databases from which new anthelmintic compounds might be identified. Here, a novel approach focused on integrating a pan-Nematoda multi-omics data targeted to a specific nematode organ system (the intestinal tract) with evidence-based filtering and chemogenomic screening was undertaken. Based on de novo computational target prioritization of the 3,564 conserved intestine genes in A. suum, exocytosis was identified as a high priority pathway, and predicted inhibitors of exocytosis were tested using the large roundworm (Ascaris suum larval stages), a filarial worm (Brugia pahangi adult and L3), a whipworm (Trichuris muris adult), and the non-parasitic nematode Caenorhabditis elegans. 10 of 13 inhibitors were found to cause rapid immotility in A. suum L3 larvae, and five inhibitors were effective against the three phylogenetically diverse parasitic nematode species, indicating potential for a broad spectrum anthelmintics. Several distinct pathologic phenotypes were resolved related to molting, motility, or intestinal cell and tissue damage using conventional and novel histologic methods. Pathologic profiles characteristic for each inhibitor will guide future research to uncover mechanisms of the anthelmintic effects and improve on drug designs. This progress firmly validates the focus on intestinal cell biology as a useful resource to develop novel anthelmintic strategies.

[Peripheral nerve involvement in rheumatic diseases]

Peripheral neuropathies are probably an under-diagnosed complication of many rheumatic diseases. In some cases they take a mild clinical course, in others they cause severe impairment of patients' quality of life. A precise diagnosis and etiological classification are of major importance for successful treatment and prognosis of peripheral neuropathies. A detailed patient history and physical examination are the foundation of every diagnostic approach. Electrophysiological studies are obligatory when peripheral neuropathy is suspected, whereas nerve or nerve-muscle biopsies are indicated only in selected cases. Therapeutic approaches are often complicated by a lack of evidence. They correspond to frequently tested immunosuppressive treatment of the underlying disease, such as glucocorticoids, cyclophosphamide, mycophenolate mofetil and intravenous immunoglobulins and are based on the symptomatic pain treatment of other neuropathies. As first-line treatment gabapentin, pregabalin, duloxetine, venlafaxine and tricyclic antidepressants are frequently used.

The effect of leflunomide on cold and vibratory sensation in patients with rheumatoid arthritis

Objective

To evaluate the prevalence and risk factors of peripheral neuropathy in patients with rheumatoid arthritis (RA) treated with leflunomide (LEF) by quantitative sensory testing (QST).

Method

A total of 94 patients were enrolledin this study, out of which 47 patients received LEF. The other 47 patients received alternative disease-modifying antirheumatic drugs and served as the control group. The demographic characteristics, laboratory findings, concomitant diseases, and medication history were evaluated at the time of QST. The cooling (CDT) and vibratory detection threshold (VDT) as the representative components of QST were measured.

Results

Age, gender, RA duration, ESR, and CRP did not show any significant differences between the two groups. VDT did not demonstrate any significant difference in both groups. However, CDT in LEF group was significantly higher than that of the control group (8.6±2.7 in LEF vs. 5.6±3.8 in control). The proportion of RA patients in the LEF group showing abnormally high CDT was over 2 times greater than that of the control group, but these findings were not statistically significant. Age, RA duration (or LEF medication in LEF group), ESR, and CRP did not show significant correlation with CDT in both groups. VDT significantly correlated with age in both groups.

Conclusion

LEF treatment in patients with RA may lead to abnormal CDT in QST. CDT value was not affected by age, RA duration, disease activity, or LEF duration. It remains to be determined whether QST may be a valuable non-invasive instrument to evaluate the early sensory changes in patients with RA taking LEF.

Beyond the joints: neurological involvement in rheumatoid arthritis

Although arthritis is the most notable component, rheumatoid arthritis (RA) is a systemic inflammatory disorder where extra-articular manifestations are common; among them, central and peripheral nervous system involvement is frequent and associated with significant morbidity and, in some cases, reduced life span. It may produce a myriad of symptoms and signs ranging from subtle numbness in a hand, to quadriparesis and sudden death. Central and peripheral neurologic manifestations may arise from structural damage produced by RA in diarthroidal joints, by the systemic inflammatory process of the disease itself or by the drugs used to treat it. Neurologic syndromes may appear suddenly or developed slowly through months, and emerge early or after years of having RA. Neurologic manifestations may be easily overlooked or incorrectly assigned to peripheral arthritis unless the attending physician is aware of these complications. In this article, we review neurologic involvement in RA patients with emphasis on clinical approach for early detection.

Leflunomide in the treatment of rheumatoid arthritis

Rheumatoid arthritis is a chronic and highly morbid disease affecting approximately 1% of the world's population. With the advent of disease-modifying antirheumatic drugs, patients are increasingly able to maintain control of their arthritis and prevent joint destruction. However, not all patients respond adequately to any single disease-modifying antirheumatic drug, and many newer parenteral therapies are cost prohibitive. Leflunomide, an inhibitor of pyrimidine biosynthesis, is the first oral disease-modifying antirheumatic drug to have been approved for rheumatoid arthritis in the USA in the last 15 years, and is now widely used in over 70 countries around the world. Leflunomide is efficacious when used as monotherapy or in combination with methotrexate to treat patients with rheumatoid arthritis, and is generally well tolerated. As clinical use increases, new ways to use leflunomide in order to minimize toxicity and maximize efficacy are being explored.

Update on medication-induced peripheral neuropathy

Despite improvements in the identification of causes of peripheral neuropathy, idiopathic polyneuropathy remains common. Medication and toxic neuropathy account for a small but important percentage of potentially preventable or reversible causes of neuropathy. New drugs that can induce neuropathy have been approved over the past several years, including the anticancer agents bortezomib, ixabepilone, and oxaliplatin. We review the neurotoxic effects of tumor necrosis factor-alpha blockers infliximab and etanercept, the inflammatory arthritis agent leflunomide, and the antibiotic linezolid. The controversy of statin-induced neuropathy continues to unfold; the large Fremantle Diabetes Study has suggested that statins may have neuroprotective effects. Dichloroacetate is a promising agent for lactic acidosis-associated disorders, but toxic neuropathy is a treatment-limiting factor. We also describe a progressive inflammatory neuropathy in swine slaughterhouse workers that appears to be a toxin-induced immune response.

Sacroiliitis and polyneuropathy during isotretinoin treatment

Isotretinoin, a medication for acne, has been reported to cause a variety of side effects on the musculoskeletal system. We present a case of sacroiliitis (a relatively uncommon feature) and sensorimotor demyelinating polyneuropathy, which has been reported previously in only a few cases during isotretinoin therapy. Clinical symptoms were improved after the withdrawal of isotretinoin and the follow-up electrophysiological study performed 2 years after the initial diagnosis of polyneuropathy showed mild improvement. Dermatologists are advised to be alert to symptoms of polyneuropathy and sacroiliitis during treatment with isotretinoin.

Peripheral neuropathy associated with leflunomide: is there a risk patient profile?

PURPOSE

(i) To monitor the potential clinical neurotoxic symptoms in patients treated with leflunomide in daily practice and (ii) to describe the characteristics of patients presenting with this peripheral nervous system symptoms.

METHOD

All patients treated with leflunomide between May 2000 and April 2003 and followed in the rheumatology department of the University Hospital participated in the study. Data concerning treatment patterns with leflunomide, demographic and disease characteristics were obtained from clinical charts. Neuropathy was diagnosed with nerve conduction study (NCS). Cases of neuropathy were described and then compared to other patients using univariate analyses.

RESULTS

One hundred and thirteen patients were included in the study. M/F sex ratio was 0.45. Mean age at start of treatment was 55.6 years (range = 27-81). During the study period, eight incident cases of peripheral neuropathy and two cases of worsening of preexisting neuropathy were reported (incidence: 9.8%). Compared with other patients, neuropathy cases were older (69 vs. 54 years, p = 0.0006), more often diabetic (30% vs. 2.9%, p = 0.009) and more often treated with potentially neurotoxic drugs (20% vs. 1.9%, p = 0.039). At least one risk factor (potentially neurotoxic drug or diabetes) was found in 50% of patients with neuropathy versus 4% of patients without neuropathy (56% PPV, 96% NPV).

CONCLUSION

Cases of toxic neuropathy have been observed during treatment of rheumatoid arthritis with leflunomide. Their occurrence seems to be associated with known risk factors. Careful monitoring of the patient's neurological status during leflunomide treatment is therefore mandatory.

Leflunomide-induced peripheral neuropathy

Two cases of leflunomide-induced peripheral neuropathy are described; in a 60-year-old woman with sero-negative polyarthralgia-myalgia syndrome and a 65-year-old man with sero-negative rheumatoid arthritis, both treated with leflunomide at 20mg/day. Nerve conduction studies and electromyogram showed sensorimotor axonal neuropathy in both cases. An alternative cause for the axonal neuropathy was excluded by extensive investigations, including cerebrospinal fluid examination and nerve biopsy in the second patient. Both patients stabilized symptomatically and electrophysiologically upon cessation of leflunomide. It is possible that leflunomide-induced peripheral neuropathy has been under-reported and under-recognized.

Effect of the immunomodulator leflunomide on the induction of endometriosis in an experimental rat model

The effect of immunomodulator leflunomide on the development of an experimental endometriosis model was assessed by surgically transplanting autologous fragments of endometrial tissue onto the inner surface of the abdominal wall and arterial cascades of the small intestines. Leflunomide was found to affect the development of endometriosis negatively and seemed to interfere with the growth and maintenance of the uterine explant in this experimental rat model.

Toxic neuropathy

PURPOSE OF REVIEW

This paper examines recent research on toxic neuropathy and potential therapeutic developments. It also summarizes reports of new agents reported to cause peripheral neuropathy.

RECENT FINDINGS

Gene therapy with vasoactive endothelial growth factor, neurotrophic substances such as nerve growth factor and neurotrophin-3 are reported to reverse or protect against neurotoxicity in animal models. The neuroprotective effects of more established therapeutic agents like vitamin E, tacrolimus (FK 506) and erythropoietin hold promise for the immediate future. Cisplatin and high-dose pyridoxine are used more frequently to produce robust models of peripheral neuropathy in animals. Statins do appear to cause peripheral neuropathy. The incidence is low, however, and compared to its benefits in terms of cardiovascular protection, relatively innocuous. The profile of thalidomide neuropathy is becoming clearer as the indications for this drug increases. The incidence of thalidomide neuropathy is high, up to three quarters in some series, and although the information on dose dependency is variable, lower cumulative doses appear to be less toxic. Like thalidomide bortezomib, a novel proteosome inhibitor, is reportedly effective in the treatment of multiple myeloma and is associated with peripheral neuropathy. Oxaliplatin and epothilone are emerging anticancer drugs with neurotoxic potential. Similarly, leflunomide, a new disease modifying-agent approved for the treatment of rheumatoid arthritis, is reported to cause neuropathy.

SUMMARY

The study of toxic neuropathy is not only enhancing our knowledge of the mechanisms of neurotoxicity but also the neurobiology of peripheral neuropathy in general; and is likely to reveal avenues for therapeutics.