Pathogenesis of large vessel vasculitis: Implications for disease classification and future therapies

Serum leukemia inhibitory factor (LIF) levels in patients with Takayasu's and Giant cell arteritis: A cross-sectional study

INTRODUCTION AND OBJECTIVES

In this study, we aimed to evaluate LIF levels and its possible relationship with disease activity in patients with Takayasu's (TAK) and Giant cell arteritis (GCA) patients.

MATERIALS AND METHODS

23 Takayasu's arteritis, 9 Giant cell arteritis patients and 25 healthy volunteers were included in the study. Serum LIF levels were measured ELISA.

RESULTS

The mean age of Giant cell arteritis patients was statistically significantly higher than the other groups (p<0.001). The rate of women was found to be higher in Takayasu's arteritis (p=0.021). When healthy control, patients with GCA and Takayasu arteritis were compared, there was a difference in LIF values (p=0.018). In subgroup analyzes, LIF values were found to be higher in GCA patients compared to healthy controls (p<0.05). There was no statistically significant correlation between LIF and CRP (Rho=-0.038, p=0.778), ESR (Rho=0.114, p=0.399) and ITAS (Rho=-0.357, p=0.094). While CRP was statistically significantly higher in patients with disease activity (p=0.003), there was no statistically significant difference between patients in terms of ESR and LIF values. While there was a statistically significant relationship between CRP (OR=1.19 [1.03-1.37], p=0.018) and disease activity in univariate analyses, no statistically significant variable was found in multivariable analyses.

CONCLUSIONS

LIF values were significantly higher in patients with Giant cell arteritis compared to healthy controls.

A clinical case of Takayasu disease: emphasis on cardiac manifestations

Takayasu arteriitis (TA) is a rare systemic vasculitis, affecting large vessels, cardiac valves and myocardium. Cardiac involvement is a major cause of morbidity and mortality in such patients. This publication presents a clinical case of a patient with severe aortic regurgitation combined with restrictive cardiomyopathy. It is emphasized that surgical treatment is associated with potential difficulties in patients with TA due to its inflammatory nature, disease activity and multiorgan involvement.

The role of plateletcrit in Takayasu arteritis: A potential biomarker for disease activity and 6-month treatment response

OBJECTIVES

To determine the role of plateletcrit as a potential biomarker for disease activity and treatment response in Takayasu arteritis (TAK).

METHODS

Totally, 215 newly diagnosed TAK patients were consecutively enrolled. Demographic data, clinical manifestations, laboratory and imaging examinations, and treatment strategy were recorded at baseline and at each visit during the 6-month treatment period. Normal plateletcrit (0.1%-0.4%) and hyper-plateletcrit (>0.4%) observed at baseline were used as group criteria.

RESULTS

At baseline, the overall plateletcrit was 0.32 (0.24-0.38)%, with a normal and high level observed in 172 (80.00%) and 43 (20.00%) patients, respectively. Baseline plateletcrit was significantly higher in patients with active disease and associated with inflammatory biomarkers, including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and interleukin (IL)-6 (all p < .01). At 6 months, complete remission was achieved in 171 (79.53%) patients, and a significant decrease in plateletcrit was observed in these cases (p < .01). Patients with a normal baseline plateletcrit were more likely to achieve complete remission compared to those with a high baseline plateletcrit (HR = 4.65, 95% CI: 2.38-19.08, p < .01). In addition, ESR (p = .01) and IL-6 (p = .02) levels were still higher in patients with a high baseline plateletcrit at 6 months. Progression of vascular lesions was indicated in 18 (8.37%) patients at 6 months, and these patients also had significantly higher baseline plateletcrit (p = .03).

CONCLUSION

Plateletcrit levels were positively related to disease activity and inflammatory index in TAK. Importantly, patients with high baseline plateletcrit levels may show a worse treatment response at 6 months.

Ultrasonography and contrast-enhanced ultrasound for activity assessment in 115 patients with carotid involvement of Takayasu arteritis

OBJECTIVES

To evaluate the efficacy of ultrasound and contrast-enhanced ultrasound (CEUS) in disease activity assessment of Takayasu arteritis (TA) with carotid involvement.

METHODS

This is a cohort study of 115 patients of TA with carotid involvement. We investigated correlations between clinical data, sonographic features, and CEUS enhancement at the site most prominent lesion of each patient. Disease activity was assessed by the National Institute of Health Kerr criteria. Sonographic findings were compared with follow-up examinations. CEUS was repeated after a 3-7 months interval in 35 patients to evaluate change of CEUS enhancement after treatment.

RESULTS

Extensiveness of CEUS enhancement at most prominent carotid lesions had significant correlations with disease activity by the Kerr criteria (P < .001). The specificity of extensive enhancement for indicating active disease was 95%, while sensitivity was 67%. Patients with active disease showed greater arterial wall thickness and more prominent reduction of arterial wall thickness after treatment. Most of the patients (68%) with subsided active disease after treatment featured decrease of CEUS enhancement.

CONCLUSIONS

Extensiveness of enhancement by CEUS and arterial wall thickness by ultrasonography may be useful markers for initial and follow-up assessment of disease activity of TA with common carotid artery involvement.

Arterial wall fibrosis in Takayasu arteritis and its potential for therapeutic modulation

Arterial wall damage in Takayasu arteritis (TAK) can progress despite immunosuppressive therapy. Vascular fibrosis is more prominent in TAK than in giant cell arteritis (GCA). The inflamed arterial wall in TAK is infiltrated by M1 macrophages [which secrete interleukin-6 (IL-6)], which transition to M2 macrophages once the inflammation settles. M2 macrophages secrete transforming growth factor beta (TGF-β) and glycoprotein non-metastatic melanoma protein B (GPNMB), both of which can activate fibroblasts in the arterial wall adventitia. Mast cells in the arterial wall of TAK also activate resting adventitial fibroblasts. Th17 lymphocytes play a role in both TAK and GCA. Sub-populations of Th17 lymphocytes, Th17.1 lymphocytes [which secrete interferon gamma (IFN-γ) in addition to interleukin-17 (IL-17)] and programmed cell death 1 (PD1)-expressing Th17 (which secrete TGF-β), have been described in TAK but not in GCA. IL-6 and IL-17 also drive fibroblast activation in the arterial wall. The Th17 and Th1 lymphocytes in TAK demonstrate an activation of mammalian target organ of rapamycin 1 (mTORC1) driven by Notch-1 upregulation. A recent study reported that the enhanced liver fibrosis score (derived from serum hyaluronic acid, tissue inhibitor of metalloproteinase 1, and pro-collagen III amino-terminal pro-peptide) had a moderate-to-strong correlation with clinically assessed and angiographically assessed vascular damage. In vitro experiments suggest the potential to target arterial wall fibrosis in TAK with leflunomide, tofacitinib, baricitinib, or mTORC1 inhibitors. Since arterial wall inflammation is followed by fibrosis, a strategy of combining immunosuppressive agents with drugs that have an antifibrotic effect merits exploration in future clinical trials of TAK.

Assessment of Takayasu's arteritis activity by ultrasound localization microscopy

BACKGROUND

Ultrasound localization microscopy (ULM) based on ultrafast ultrasound imaging of circulating microbubbles (MB) can image microvascular blood flows in vivo up to the micron scale. Takayasu arteritis (TA) has an increased vascularisation of the thickened arterial wall when active. We aimed to perform vasa vasorum ULM of the carotid wall and demonstrate that ULM can provide imaging markers to assess the TA activity.

METHODS

Patients with TA were consecutively included with assessment of activity by the National Institute of Health criteria: 5 had active TA (median age 35.8 [24.5-46.0] years) and 11 had quiescent TA (37.2 [31.7-47.3] years). ULM was performed using a 6.4 MHz probe and a dedicated imaging sequence (plane waves with 8 angles, frame rate 500 Hz), coupled with the intravenous injection of MB. Individual MB were localised at a subwavelength scale then tracked, allowing the reconstruction of the vasa vasorum flow anatomy and velocity.

FINDINGS

ULM allowed to show microvessels and to measure their flow velocity within the arterial wall. The number of MB detected per second in the wall was 121 [80-146] in active cases vs. 10 [6-15] in quiescent cases (p = 0.0005), with a mean velocity of 40.5 [39.0-42.9] mm.s^-1 in active cases.

INTERPRETATION

ULM allows visualisation of microvessels within the thickened carotid wall in TA, with significantly greater MB density in active cases. ULM provides a precise visualisation in vivo of the vasa vasorum and gives access to the arterial wall vascularisation quantification.

FUNDING

French Society of Cardiology. ART (Technological Research Accelerator) biomedical ultrasound program of INSERM, France.

Large vessel vasculitis with rare presentation of acute rhabdomyolysis: A case report and review of literature

BACKGROUND

Musculoskeletal involvement in primary large vessel vasculitis (LVV), including giant cell arteritis and Takayasu's arteritis (TAK), tends to be subacute. With the progression of arterial disease, patients may develop polyarthralgia and myalgias, mainly involving muscle stiffness, limb/jaw claudication, cold/swelling extremities, etc. Acute development of rhabdomyolysis in addition to aortic aneurysm is uncommon in LVV. Herein, we report a rare case of LVV with the first presentation of acute rhabdomyolysis.

CASE SUMMARY

A 70-year-old Asian woman suffering from long-term low back pain was hospitalized due to limb claudication, dark urine and an elevated creatine kinase (CK) level. After treatment with fluid resuscitation and antibiotics, the patient remained febrile. Her workup showed persistent elevated levels of inflammatory markers, and imaging studies revealed an aortic aneurysm. A decreasing CK was evidently combined with elevated inflammatory markers and negativity for anti-neutrophilic cytoplasmic antibodies. LVV was suspected and confirmed by magnetic resonance angiography and positron emission tomography with 18F-fluorodeoxyglucose/computed tomography. With a favourable response to immunosuppressive treatment, her symptoms resolved, and clinical remission was achieved one month later. However, after failing to follow the tapering schedule, the patient was readministered 25 mg/d prednisolone due to disease relapse. Follow-up examinations showed decreased inflammatory markers and substantial improvement in artery lesions after 6 mo of treatment. At the twelve-month follow-up, she was clinically stable and maintained on corticosteroid therapy.

CONCLUSION

An exceptional presentation of LVV with acute rhabdomyolysis is described in this case, which exhibited a good response to immunosuppressive therapy, suggesting consideration for a differential diagnosis when evaluating febrile patients with myalgia and elevated CK. Timely use of high-dose steroids until a diagnosis is established may yield a favourable outcome.

The Th17 Pathway in Vascular Inflammation: Culprit or Consort?

The involvement of IL-17A in autoimmune and inflammatory diseases has prompted the development of therapeutic strategies to block the Th17 pathway. Promising results came from their use in psoriasis and in ankylosing spondylitis. IL-17A acts on various cell types and has both local and systemic effects. Considering the premature mortality observed during chronic inflammatory diseases, IL-17A action on vascular cells was studied. Both in vitro and in vivo results suggest that this cytokine favors inflammation, coagulation and thrombosis and promotes the occurrence of cardiovascular events. These observations led to study the role of IL-17A in diseases characterized by vascular inflammation, namely allograft rejection and vasculitis. Increased circulating levels of IL-17A and histological staining reveal that the Th17 pathway is involved in the pathogenesis of these diseases. Vasculitis treatment faces challenges while the use of steroids has many side effects. Regarding results obtained in giant cell arteritis with IL-6 inhibitors, a cytokine involved in Th17 differentiation, the use of anti-IL-17 is a promising strategy. However, lessons from rheumatoid arthritis and multiple sclerosis must be learnt before targeting IL-17 in vasculitis, which may be culprit, consort or both of them.

Plasmapheresis for systemic vasculitis

Systemic vasculitides include a variety of, and numerous diseases. In 2012, the International CHAPEL HILL Consensus Conference (CHCC2012) led to a major reorganization of the classification of vasculitis, and this is still in wide use today. Although the results of plasmapheresis for individual diseases have been sometimes shown, there are few systematic reviews that discuss the effects along with vasculitis classification. Therefore, we will discuss the efficacy and the latest evidence for each vasculitis according to the CHCC 2012 classification in this review. This review provides a comprehensive overview of the estimation of plasmapheresis in each of the vasculitides, with a particular focus on small vasculitides, which have recently discussed frequently. For some time now, plasma exchange therapy (PEX) has been frequently used and is expected to be effective in some diseases, most of which are included in small vessel vasculitides. In particular, data showing efficacy have been accumulated for immune complex vasculitis, and the recommendation seems to be high. For instance, anti‐GBM nephritis, concomitant use of PEX is essential and strongly recommended. On the other hand, for ANCA‐related vasculitis among small vessel vasculitis, RCTs have recently shown negative results. In particular, the PEXIVAS trial statistically showed that PEX has no potential to reduce the mortality and renal death in AAV, but the ASFA, ACR, and KDIGO guidelines following this trial all regard PEX as salvage therapy or selective treatment for severe cases. As plasmapheresis is often performed in combination with other therapies, it is difficult to evaluate to clarify its efficacy on its own, and this predisposition may be pronounced in vasculitis, a rare disease. Although statistically significant differences are not apparent, the diseases that show a trend toward efficacy may possibly include treatment‐sensitive subgroups. Further analysis is expected in the future.

Role of ferroptosis-related genes in Stanford type a aortic dissection and identification of key genes: new insights from bioinformatic analysis

Stanford type A aortic dissection (TAAD) is one of the most dangerous vascular diseases worldwide, and the mechanisms of its development remain unclear. Further molecular pathology studies may contribute to a comprehensive understanding of TAAD and provide new insights into diagnostic markers and potential therapeutic targets. Recent studies have identified that ferroptosis, a form of cell death, may play a previously unrecognized role in influencing the development of TAAD. In this study, we explored the pathological role of ferroptosis in TAAD by performing bioinformatics analyses. Gene set enrichment analysis (GSEA) showed that the ferroptosis-related gene (FRG) set was significantly different between normal and TAAD aortic samples at an overall level (p < 0.001). Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses explored the potential functions and pathways of FRG in TAAD. We further identified six key genes (CA9, HMOX1, IL6, CDKN1A, HIF1A, MYC) from differentially expressed FRGs in TAAD by constructing a protein-protein interaction (PPI) network, all key genes were upregulated in TAAD. Four of the key genes (CA9, IL6, CDKN1A, and HIF1A) were demonstrated to be correlated with cigarette smoke extract-induced ferroptosis in aortic vascular smooth muscle cells. These results suggest that ferroptosis is one of the essential pathological processes in the development of TAAD, and some FRGs affect TAAD development by mediating cellular ferroptosis, which provides deepening insights into the molecular mechanisms and potential therapeutic targets of TAAD.

Toward Reliable Uptake Metrics in Large Vessel Vasculitis Studies

The aim of this study is to investigate the influence of sex, age, fat mass, fasting blood glucose level (FBGL), and estimated glomerular filtration rate (eGFR) on blood pool activity in patients with large vessel vasculitis (LVV). Blood pool activity was measured in the superior caval vein using mean, maximum, and peak standardized uptake values corrected for body weight (SUVs) and lean body mass (SULs) in 41 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scans of LVV patients. Sex influence on the blood pool activity was assessed with t-tests, while linear correlation analyses were used for age, fat mass, FBGL, and eGFR. Significantly higher SUVs were found in women compared with men, whereas SULs were similar between sexes. In addition, higher fat mass was associated with increased SUVs (r = 0.56 to 0.65; all p < 0.001) in the blood pool, but no correlations were found between SULs and fat mass (r = −0.25 to −0.15; all p > 0.05). Lower eGFR was associated with a higher FDG blood pool activity for all uptake values. In FDG-PET/CT studies with LVV patients, we recommend using SUL over SUV, while caution is advised in interpreting SUV and SUL measures when patients have impaired kidney function.

Stroke secondary to giant-cell arteritis: A literature review

Stroke is a leading cause of death and disability worldwide. In addition to the classical etiologies of stroke as atherosclerosis and cardioembolism there are many unusual, rare causes, which require a high level of clinical suspicion and further investigations for correct and early diagnosis and adequate treatment. Giant-cell arteritis or temporal arteritis, the most frequent vasculitis in the elderly population is one of the uncommon causes of stroke. In the setting of giant-cell arteritis, stroke more likely affects the vertebrobasilar territory and is the main cause of mortality. Duplex ultrasound examination is a routine investigation for stroke patients and may be key to the diagnosis if the classical hypoechoic ‘halo sign’ is recognized at the level of vertebral arteries. In this situation the ultrasound evaluation of temporal arteries and temporal artery biopsy are mandatory. The Giant-cell arteritis-related stroke is a rare condition; therefore, there are no evidence-based guidelines or standard recommendations for the treatment. In the present review, the main characteristics of giant-cell arteritis-related stroke are discussed.

Clinical features of large vessel vasculitis (LVV): Elderly-onset versus young-onset

OBJECTIVES

We compared large vessel vasculitis (LVV) clinical features between age groups.

METHODS

We retrospectively examined clinical features and therapies in 41 LVV patients at our hospital from January 2010 to March 2020. We compared two patient groups, elderly (≥50 years) and young (<50 years).

RESULTS

Of all patients, 29 were elderly and 12 were young. In the younger group, upper extremity symptoms (p <.05), bruits (p <.01), and cardiovascular complications (p <.01) were more common. Of the elderly group, 7 (24%) met classification criteria for giant cell arteritis while none of the younger group met these criteria; however, 10 (83%) of the younger group and 3 (10%) of the elderly group met the ACR classification criteria for Takayasu arteritis (p <.01). In the elderly group, 16 patients (66%) met no criteria (p <.01). There were no significant differences in laboratory findings but imaging showed a significantly higher incidence of head and neck artery lesions in the younger group (p <.05). The younger group was more likely to receive additional tocilizumab (p <.01) and cardiovascular complications were more likely to occur in younger patients (p < .01).

CONCLUSION

LVV clinical features differed between elderly- and young-age-onset groups.

Aortitis: recent advances, current concepts and future possibilities

Broadly defined, aortitis refers to inflammation of the aorta and incorporates both infectious and non-infectious aetiologies. As advanced imaging modalities are increasingly incorporated into clinical practice, the phenotypic spectrum associated with aortitis has widened. The primary large vessel vasculitides, giant cell arteritis and Takayasu arteritis, are the most common causes of non-infectious aortitis. Aortitis without systemic disease or involvement of other vascular territories is classified as clinically isolated aortitis. Periaortitis, where inflammation spreads beyond the aortic wall, is an important disease subset with a distinct group of aetiologies. Infectious aortitis can involve bacterial, viral or fungal pathogens and, while uncommon, can be devastating. Importantly, optimal management strategies and patient outcomes differ between aortitis subgroups highlighting the need for a thorough diagnostic workup. Monitoring disease activity over time is also challenging as normal inflammatory markers do not exclude significant vascular inflammation, particularly after starting treatment. Additional areas of unmet clinical need include clear disease classifications and improved short-term and long-term management strategies. Some of these calls are now being answered, particularly with regard to large vessel vasculitis where our understanding has advanced significantly in recent years. Work extrapolated from temporal artery histology has paved the way for targeted biological agents and, although glucocorticoids remain central to the management of non-infectious aortitis, these may allow reduced glucocorticoid reliance. Future work should seek to clarify disease definitions, improve diagnostic pathways and ultimately allow a more stratified approach to patient management.

Familial risks between giant cell arteritis and Takayasu arteritis and other autoimmune diseases in the population of Sweden

Giant cell arteritis (GCA, also called temporal arteritis) is a rare and Takayasu arteritis (TA) is an even rarer autoimmune disease (AID), both of which present with inflammatory vasculitis of large and medium size arteries. The risk factors are largely undefined but disease susceptibility has been associated with human leukocyte antigen locus. Population-level familial risk is not known. In the present nation-wide study we describe familial risk for GCA and for GCA and TA with any other AID based on the Swedish hospital diagnoses up to years 2012. Family relationships were obtained from the Multigeneration Register. Familial standardized incidence ratios (SIRs) were calculated for offspring whose parents or siblings were diagnosed with GCA, TA or any other AID. The number of GCA patients in the offspring generation was 4695, compared to 209 TA patients; for both, familial patients accounted for 1% of all patients. The familial risk for GCA was 2.14, 2.40 for women and non-significant for men. GCA was associated with 10 other AIDs and TA was associated with 6 other AIDs; both shared associations with polymyalgia rheumatica and rheumatoid arthritis. The results showed that family history is a risk factor for GCA. Significant familial associations of both GCA and TA with such a number of other AIDs provide evidence for polyautoimmunity among these diseases.

Delicate Role of PD-L1/PD-1 Axis in Blood Vessel Inflammatory Diseases: Current Insight and Future Significance

Immune checkpoint molecules are the antigen-independent generator of secondary signals that aid in maintaining the homeostasis of the immune system. The programmed death ligand-1 (PD-L1)/PD-1 axis is one among the most extensively studied immune-inhibitory checkpoint molecules, which delivers a negative signal for T cell activation by binding to the PD-1 receptor. The general attributes of PD-L1's immune-suppressive qualities and novel mechanisms on the barrier functions of vascular endothelium to regulate blood vessel-related inflammatory diseases are concisely reviewed. Though targeting the PD-1/PD-L1 axis has received immense recognition-the Nobel Prize in clinical oncology was awarded in the year 2018 for this discovery-the use of therapeutic modulating strategies for the PD-L1/PD-1 pathway in chronic inflammatory blood vessel diseases is still limited to experimental models. However, studies using clinical specimens that support the role of PD-1 and PD-L1 in patients with underlying atherosclerosis are also detailed. Of note, delicate balances in the expression levels of PD-L1 that are needed to preserve T cell immunity and to curtail acute as well as chronic infections in underlying blood vessel diseases are discussed. A significant link exists between altered lipid and glucose metabolism in different cells and the expression of PD-1/PD-L1 molecules, and its possible implications on vascular inflammation are justified. This review summarizes the most recent insights concerning the role of the PD-L1/PD-1 axis in vascular inflammation and, in addition, provides an overview exploring the novel therapeutic approaches and challenges of manipulating these immune checkpoint proteins, PD-1 and PD-L1, for suppressing blood vessel inflammation.

Current State of Precision Medicine in Primary Systemic Vasculitides

Precision medicine (PM) is an emerging data-driven health care approach that integrates phenotypic, genomic, epigenetic, and environmental factors unique to an individual. The goal of PM is to facilitate diagnosis, predict effective therapy, and avoid adverse reactions specific for each patient. The forefront of PM is in oncology; nonetheless, it is developing in other fields of medicine, including rheumatology. Recent studies on elucidating the genetic architecture of polygenic and monogenic rheumatological diseases have made PM possible by enabling physicians to customize medical treatment through the incorporation of clinical features and genetic data. For complex inflammatory disorders, the prevailing paradigm is that disease susceptibility is due to additive effects of common reduced-penetrance gene variants and environmental factors. Efforts have been made to calculate cumulative genetic risk score (GRS) and to relate specific susceptibility alleles for use of target therapies. The discovery of rare patients with single-gene high-penetrance mutations informed our understanding of pathways driving systemic inflammation. Here, we review the advances in practicing PM in patients with primary systemic vasculitides (PSVs). We summarize recent genetic studies and discuss current knowledge on the contribution of epigenetic factors and extracellular vesicles (EVs) in disease progression and treatment response. Implementation of PM in PSVs is a developing field that will require analysis of a large cohort of patients to validate data from genomics, transcriptomics, metabolomics, proteomics, and epigenomics studies for accurate disease profiling. This multi-omics approach to study disease pathogeneses should ultimately provide a powerful tool for stratification of patients to receive tailored optimal therapies and for monitoring their disease activity.

Current Controversies in Large-Vessel Inflammatory Vasculitis and Thoracic Aortic Aneurysm Disease

Large-vessel vasculitis encompasses the spectrum of vasculitides, which pathologically cause chronic granulomatous inflammatory changes, primarily in the aorta and its major branches. These patients are at risk of developing life-threatening aortic lesions that, without recognition and prompt treatment, can cause detrimental effects. Many provocative issues surrounding large-vessel vasculitis and its surgical treatment still remain, spanning from recognition to management. In this review, we discuss the main large-vessel vasculitides, Takayasu's arteritis and giant cell arteritis. We include the key points and current controversies surrounding diagnostic imaging, timing of interventions, and patient outcomes.

The swollen optic nerve: an approach to diagnosis and management

The differential diagnosis of swollen optic nerves differs according to whether the swelling is unilateral or bilateral, or whether visual function is normal or affected. Patients with a unilaterally swollen optic nerve and normal visual function most likely have optic nerve head drusen. Patients with abnormal visual function most likely have demyelinating optic neuritis or non-arteritic anterior ischaemic optic neuropathy. Patients with bilaterally swollen optic nerve heads and normal visual function most likely have papilloedema, and require neuroimaging followed by lumbar puncture. However, if their visual function is affected, the most likely causes are bilateral demyelinating optic neuritis, neuromyelitis optica spectrum disorder and anti-myelin oligodendrocyte glycoprotein optic neuritis: these patients require investigating with contrast-enhanced MRI of the orbits.