Systemic vasculitis involving the kidney: the nephropathologist's point of view.

Kidneys are often targets of systemic vasculitis (SVs), being affected in many different forms and representing a possible sentinel of an underlying multi-organ condition. Renal biopsy still remains the gold standard for the identification, characterization and classification of these diseases, solving complex differential diagnosis thanks to the combined application of light microscopy (LM), immunofluorescence (IF) and electron microscopy (EM). Due to the progressively increasing complexity of renal vasculitis classification systems (e.g. pauci-immune vs immune complex related forms), a clinico-pathological approach is mandatory and adequate technical and interpretative expertise in nephropathology is required to ensure the best standard of care for our patients. In this complex background, the present review aims at summarising the current knowledge and challenges in the world of renal vasculitis, unveiling the potential role of the introduction of digital pathology in this setting, from the creation of hub-spoke networks to the future application of artificial intelligence (AI) tools to aid in the diagnostic and scoring/classification process.

Position statement of the Brazilian society of Rheumatology on mesna use as a preventive therapy for bladder disease in patients with systemic autoimmune diseases and systemic vasculitis under cyclophosphamide treatment.

OBJECTIVE: To review current literature to support the use of mesna as a preventive therapy for hemorrhagic cystitis and bladder cancer in patients with systemic autoimmune diseases and systemic vasculitis treated with cyclophosphamide. MATERIALS AND METHODS: The search for articles was conducted systematically through MEDLINE, LILACS, Cochrane Library, and Embase databases. Only articles in English were selected. For available records, titles and abstracts were selected independently by two investigators. RESULTS: Eighteen studies were selected for analysis. The known adverse effects of cyclophosphamide were hematological toxicity, infections, gonadal toxicity, teratogenicity, increased risk for malignancy and hemorrhagic cystitis. Long-term toxicity was highly dependent on cyclophosphamide cumulative dose. The risk of bladder cancer is especially higher in long-term exposure and with cumulative doses above 36 g. The risk remains high for years after drug discontinuation. Hemorrhagic cystitis is highly correlated with cumulative dose and its incidence ranges between 12 and 41%, but it seems to be lower with new regimens with reduced cyclophosphamide dose. No randomized controlled trials were found to analyze the use of mesna in systemic autoimmune rheumatic diseases and systemic vasculitis. Retrospective studies yielded conflicting results. Uncontrolled prospective studies with positive results were considered at high risk of bias. No evidence was found to support the use of mesna during the treatment with cyclophosphamide for autoimmune diseases or systemic vasculitis to prevent hemorrhagic cystitis and bladder cancer. In the scenarios of high cumulative cyclophosphamide dose (i.e., > 30 g), patients with restricted fluid intake, neurogenic bladder, therapy with oral anticoagulants, and chronic kidney disease, mesna could be considered. CONCLUSION: The current evidence was found to be insufficient to support the routine use of mesna for the prophylaxis of hemorrhagic cystitis and bladder cancer in patients being treated for systemic autoimmune diseases and systemic vasculitis with cyclophosphamide. The use may be considered for selected cases.

Clinical and anamnestic features of patients with systemic vasculitis: a single-center retrospective study.

Systemic vasculitides are the most complex and problematic autoimmune rheumatic diseases characterized by affections of large, medium, or small vessels. Although the immunopathogenesis of vasculitides is thoroughly studied, the epidemiology and etiology are poorly explored. The main triggers of vasculitides are environmental, genetic, and various infectious factors. Diagnosis of vasculitides is complicated due to the non-specific nature of their symptoms. Vasculitides affect various organ systems with abrupt or slow (weeks-months) development of symptoms. This study aims to analyze the demographic and clinical-anamnestic characteristics of patients with systemic vasculitides in a single centre before and during the COVID-19 pandemic in Kazakhstan. A single-centre retrospective study of medical records of 80 patients above 18 years was conducted in the Almaty City Rheumatology Center. Medical records of 24 males (30%) and 56 females (70%) with systemic vasculitides, diagnosed from January 2019 to December 2021, were analyzed. Age, gender, damaged organ systems, disability, concomitant diseases, disease experience, laboratory data, and other variables were recorded. The records of hospitalized patients with systemic vasculitides were analyzed. Of 80 patients registered in 2019-2021, the most common were those with IgA vasculitis (n = 32, 40%), Takayasu arteritis (n = 17, 21.25%), and granulomatosis with polyangiitis (n = 12, 15%). Behçet disease was diagnosed less frequently (n = 9, 11.25%). Patients with systemic vasculitides had pre-obesity (n = 19), class 1 obesity (n = 13), and class 2 obesity (n = 2). Musculoskeletal affections were present in 52 patients (65%). Gastrointestinal, cutaneous, and cardiovascular affections were recorded in 45 (56.3%), 37 (46.3%), and 39 (48.8%) cases, respectively. Only 8 patients (10%) had affections of the nervous system. Most patients had elevated C-reactive protein (n = 29, 36.3%) and leukocytosis (n = 33, 41.3%). One-third of patients with vasculitides had a history of abortions. Musculoskeletal, cutaneous, gastrointestinal, and cardiovascular affections are common in patients with systemic vasculitides. Obesity is a frequent comorbidity in vasculitides. Comorbidities and abortions complicate the disease course and its management.

Maternal and fetal outcomes of pregnancy in women with primary systemic vasculitis: A single-center cohort study of 20 patients and 30 pregnancies.

OBJECTIVES: To analyze pregnancy outcomes of patients with primary systemic vasculitis followed in a third-level referral center. METHODS: Retrospective cohort study of all pregnant women with systemic vasculitis followed between 2009 and 2022 at the High-Risk Pregnancy Clinic of the Department of Systemic Autoimmune Diseases of the Hospital Clínic, Barcelona. RESULTS: Twenty women with primary vasculitis were identified, with a total of 30 pregnancies. Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (n = 7) and Behçet disease (n = 4) were the most frequent types of vasculitis. All women had the diagnosis of vasculitis before pregnancy, with a median time between disease diagnosis and pregnancy of 5.8 years (range: 2 months-29 years). Most were in remission at conception (76.7 %). During pregnancy, a vasculitis flare occurred in 4 (13.3 %) patients (one each with Takayasu arteritis, eosinophilic granulomatosis with polyangiitis [EGPA], IgA vasculitis [IgAV], and Behçet disease [BD]). Four (16.7 %) of the successful pregnancies had post-partum relapses (one each with EGPA, granulomatosis with polyangiitis, IgAV, and BD). Eighty percent of pregnancies resulted in live babies. In four cases (13.3 %), medical termination of pregnancy was decided, considering the mother or baby health risk. There were two spontaneous miscarriages, and no stillbirths or neonatal deaths. Preeclampsia was the most frequent maternal complication (25 %). Newborns were preterm in 24 % and low birthweight in 20 % of cases. No maternal deaths occurred. CONCLUSIONS: This cohort study shows that vasculitis relapses during pregnancy and post-partum, together with other pregnancy complications, occur in a considerable number of patients with systemic vasculitides, although a final good pregnancy outcome can be expected in most cases. These findings emphasize the convenience of managing these special situations in expert reference centers.

[Severe systemic vasculitis induced by ibrutinib]. / Vascularite systémique sévère induite par l'ibrutinib.

INTRODUCTION: The specific cutaneous toxicity of Bruton's tyrosine kinase inhibitors is poorly described. We report a case of severe systemic vasculitis induced by ibrutinib. OBSERVATION: A 73-year-old woman with chronic lymphocytic leukemia was treated with ibrutinib. Eighteen months after treatment onset, ulceronecrotic lesions on toes and tongue occurred. Skin biopsy found vasculitis of small and medium vessels. Biologic tests were negative. This vasculitis was refractory to systemic corticosteroid therapy and azathioprine. Ibrutinib was stopped on the hypothesis of drug-induced vasculitis. Skin lesions improved after discontinuation of ibrutinib. CONCLUSION: The mechanism of action of ibrutinib does not explain the occurrence of vasculitis and an immunoallergic mechanism is suspected.

Systemic vasculitis and headache.

PURPOSE OF REVIEW: Vasculitis refers to heterogeneous clinicopathologic disorders that share the histopathology of inflammation of blood vessels. Unrecognized and therefore untreated, vasculitis of the nervous system or so called neurovasculitides, lead to pervasive injury and disability making these disorder of paramount importance to clinicians. RECENT FINDINGS: Headache is an important clue to vasculitic involvement of central nervous system (CNS) vessels. CNS vasculitis may be primary, in which only intracranial vessels are involved in the inflammatory process, or secondary to another known disorder with overlapping systemic involvement. A suspicion of vasculitis based on the history, clinical examination, or laboratory studies warrants prompt evaluation and treatment to forestall progression and avert cerebral ischemia or infarction. There has been remarkable progress in the pathogenesis, diagnosis, and treatment of primary adult and pediatric CNS vasculitides predicated on achievements in primary systemic forms. SUMMARY: Vasculitis can be diagnosed with certainty after intensive evaluation that includes tissue confirmation whenever possible. Clinicians must choose from among the available immune modulating, suppressive, and targeted immunotherapies to induce and maintain remission status and prevent relapse, tempered by the recognition of anticipated medication side effects.

Central Nervous System Vasculitis: Primary Angiitis of the Central Nervous System and Central Nervous System Manifestations of Systemic Vasculitis.

Central nervous system vasculitis (CNSV) is a group of disorders leading to inflammatory vasculopathy within the brain, spinal cord, and leptomeninges. CNSV is divided into primary angiitis of the central nervous system (PACNS) and secondary CNSV based on the underlying etiology. PACNS is a rare inflammatory disorder with poorly understood pathophysiology and heterogeneous and highly variable clinical features. The diagnosis depends on a combination of clinical and laboratory variables, multimodal imaging, and histopathological examination as well as exclusion of mimics. Several systemic vasculitides, infectious etiologies and connective tissue disorders have been shown to cause secondary CNSV and require prompt recognition.

Dermatological Lesions of Cholesterol Embolisation Syndrome and Kaposi Sarcoma Mimic Primary Systemic Vasculitis: Case report study.

Primary systemic vasculitis can present with a wide spectrum of manifestations ranging from systemic non-specific features such as fever, malaise, arthralgia and myalgia to specific organ damage. We describe two cases of cholesterol embolisation syndrome and Kaposi sarcoma mimicking primary systemic vasculitis, both of which were characterised by features such as livedo reticularis, blue toe syndrome, a brown purpuric skin rash and positive perinuclear anti-neutrophil cytoplasmic antibodies associated with Kaposi sarcoma. Establishing the right diagnosis was challenging and thus this report aimed to highlight the possible ways to distinguish them from primary systemic vasculitis.

The epidemiology of pathologically confirmed clinically isolated aortitis: a North American population-based study.

OBJECTIVES: Clinically isolated aortitis (CIA) refers to inflammation of the aorta without signs of systemic vasculitis or infection. Population-based data on the epidemiology of CIA in North America is lacking. We aimed to investigate the epidemiology of pathologically confirmed CIA. METHODS: Residents of Olmsted County, Minnesota were screened for thoracic aortic aneurysm procedures with current procedural terminology codes between January 1, 2000, and December 31, 2021, using the resources of the Rochester Epidemiology Project. The medical records of all patients were manually reviewed. CIA was defined as histopathologically confirmed active aortitis diagnosed by evaluation of aortic tissue obtained during thoracic aortic aneurysm surgery in the absence of any infection, rheumatic disease, or systemic vasculitis. Incidence rates were age and sex adjusted to the 2020 United States total population. RESULTS: Eight incident cases of CIA were diagnosed during the study period; 6 (75%) of them were female. Median (IQR) age at diagnosis of CIA was 78.3 (70.2-78.9) years; all were diagnosed following ascending aortic aneurysm repair. The overall age and sex adjusted annual incidence rate of CIA was 8.9 (95% CI, 2.7-15.1) per 1,000,000 individuals over age 50 years. The median (IQR) duration of follow-up was 8.7 (1.2-12.0) years. The overall mortality compared to the age and sex matched general population did not differ (standardised mortality ratio: 1.58; 95% CI, 0.51-3.68). CONCLUSIONS: This is the first population-based epidemiologic study of pathologically confirmed CIA in North America. CIA predominantly affects women in their eighth decade and is quite rare.

Microcirculation dynamics in systemic vasculitis: evidence of impaired microvascular response regardless of cardiovascular risk factors.

OBJECTIVES: Systemic vasculitides (SVs) are a highly inflammatory group of diseases characterized by significant cardiovascular (CV) mortality. Microvascular damage closely linked with accelerated atherosclerosis and thrombosis represents a core pathophysiological mechanism contributing to the excess CV risk of patients with SVs. Skin represents an easily accessible tissue facilitating non-invasive microvascular study. In this study we aimed to investigate microcirculation dynamics and associate them with disease-related factors in patients with SVs. METHODS: We assessed skin microcirculation using laser speckle contrast imaging (LSCI) and vascular reactivity by the post-occlusive reactive hyperaemia (PORH) protocol in a meticulously selected group of patients with SVs without CV disease and compared them to controls, matched for age, sex, BMI and smoking status. RESULTS: Sixty individuals were included in the study, 30 patients and 30 controls. Patients with SVs presented a lower peak magnitude during reperfusion phase (median [interquartile range] 207 [60.1] vs 143.7 [41.0] laser speckle perfusion units, P < 0.001) and lower percentage cutaneous vascular conductance increase (mean (s.d.) 190.0 [49.6]% vs 149.6 [48.9]%, P = 0.002) as compared with controls. Importantly, microvascular damage was correlated with disease duration (P < 0.001, r = -0.563 and P < 0.001, r = 0.442, respectively). CONCLUSION: For the first time we have shown that patients with SVs exhibit impaired microvascular function and blunted reactivity after occlusion, as this was demonstrated by the LSCI technique. Therefore, skin microcirculation may be a useful, non-invasive method in patients with SVs for the early detection of microvascular dysfunction, which is closely related to the high CV risk that these patients bear.

Case Report of Sotalol Induced IgA Vasculitis.

BACKGROUND: IgA vasculitis is the most common form of systemic vasculitis in children but can occur in adults. Inciting antigens include infections, drugs, foods, insect bites, and immunizations. Antibiotics and tumor necrosis factor (TNF) alpha inhibitors are the most common class of drugs that cause IgA vasculitis. Although sotalol and rivaroxaban have been documented to cause leukocytoclastic vasculitis, we have never come across any literature attributing IgA vasculitis to either drug. Additionally, Rocky Mountain spotted fever has not been associated with IgA vasculitis despite being described in cutaneous and systemic vasculitis cases. Here, we present a case of IgA vasculitis triggered by sotalol with challenging differentials, including a recent infection with Rocky Mountain spotted fever, malignancy, and rivaroxaban as possible triggers. CASE PRESENTATION: 68 yr old male with a history of lung cancer treated with resection and chemotherapy 5 years ago is currently in remission, and recently was started on sotalol and rivaroxaban for new-onset paroxysmal atrial fibrillation. He presented with diffuse petechial/purpural rash on the lower limbs, multiple joint pain, severe abdominal pain and rectal bleeds, hemoptysis, and renal dysfunction. IgG titers for RMSF were high. Punch biopsy of skin and renal biopsy were consistent with IgA vasculitis. Sotalol and rivaroxaban were stopped. The patient was treated with oral prednisone, and his condition relatively improved. CONCLUSION: Ig A vasculitis is mostly a self-limiting disease, but adults tend to have a severe course. It is important to diagnose early and identify a trigger. Removing the offending agent or treating the underlying infection is an important aspect of management.

Coexistence of relapsing polychondritis and eosinophilic granulomatous with polyangiitis: A rare entity.

Abstract: Relapsing polychondritis (RP) is a a rare multisystemic disease and it affects cartilaginous tissue and proteoglycan rich organs. The spectrum of clinical features are intermittent inflammation involving especially the auricular and nasal regions. In some patients with RP, systemic vasculitis, autoimmune diseases or malignancy may accompany. Although rare, any of the ANCA-associated vasculitis have been reported in patients with RP. Eosinophilic granulomatous with polyangiitis (EGPA) is a multisystem small vessel vasculitis associated with asthma and eosinophilia. Here we present a case of coexistence of RP and EGPA.

[Diagnostic difficulties of IgG4-related disease - a case report]. / Trudnosci diagnostyczne choroby zwiazanej z IgG4 ­ opis przypadku.

IgG4-related disease belongs to the group of immune-mediated diseases. It is a relatively new condition, classified in 2003. It is characterized by involvement of multiple organs, over time causing organ failure. The observed radiological changes are slow growing. As a rule, the course of the disease is subclinical, which means that the diagnosis is often made incidentally, retrospectively and many years after the onset of symptoms. In the initial stage of diagnosis, it is often confused with Sjögren's syndrome, systemic vasculitis, or neoplastic disorders. A CASE REPORT: We report the case of a female patient who was diagnosed with glomerulonephritis at the age of 34. The patient was qualified for renal replacement therapy with chronic hemodialyses in 2020 due to end-stage renal disease. In the same year, the patient was hospitalized for pneumonia of unknown etiology. After discharge from the hospital, the patient developed fever up to 39oC, chills, and pleural fluid. A suspicion of systemic disease was raised. Computed tomography of the chest showed enlargement of the anterior and middle mediastinum with increased densitization of adipose tissue and enlargement of mediastinal lymph nodes. Antibiotic therapy was introduced, followed by systemic corticosteroids, resulting in clinical improvement and remission of infiltrative lesions in radiological studies. The differential diagnosis excluded neoplastic lesions of the left lung, systemic connective tissue diseases, e.g. systemic lupus erythematosus and systemic vasculitis. Taking into account the whole clinical picture the suspicion of IgG4-related disease was raised. After the treatment, serum IgG4 level was found to be normal at 36.6 mg/ dl, anti-nuclear antibodies (ANA) were negative, rheumatoid factor was not elevated, complement component 4 (C4) was normal, complement component 3 (C3) decreased to 71 mg/dl (n: 90-180 mg/dl). Treatment with prednisone 10 mg/day was maintained. Histopathologic reanalysis of the renal biopsy (from a biopsy performed in 2012) was performed, which showed lymphocytic infiltration in the renal interstitium with segmental vascular loop sclerosis in the glomeruli and the presence of abundant granular IgG4 deposits in the glomerular mesangium by immunofluorescence. CONCLUSIONS: IgG4-related disease poses great diagnostic difficulty due to its non-specific and long-term course. Patients usually seek help with various specialists many years before the full picture of the disease is presented. It is poorly understood as it is a recently described condition (two decades ago). The classification criteria of IgG4 disease developed in 2019, the growing number of publications and recommendations being developed give hope for better understanding and more efficient diagnosis of the disease.

Case Report: Interventional therapy for portal venous stenosis caused by systemic vasculitis.

Systemic vasculitis are multisystem blood vessel disorders. However, Portal venous involvement is extremely rare, which represents a diagnostic and therapeutic challenge due to the heterogeneous nature, a lack of diagnostic criteria and limited effective therapy of vasculitis. We have reported a 48-year-old woman who was previously diagnosed with systemic vasculitis and was treated with prednisone, presented with gastrointestinal (GI) bleeding on admission. Further abdominal contrast-enhanced computed tomography (CT) with three-dimensional reconstruction suggested atrophic left hepatic lobe, enlarged spleen, and severe stenosis of main portal vein. Liver biopsy showed no evidence of fibrosis/cirrhosis. To prevent rebleeding, portal venous angioplasty by balloon dilation with collateral varices embolization was performed, and the GI hemorrhage was resolved completely. However, refractory ascites presented 8 months postoperatively. Abdominal CT angiography confirmed the recurrence of portal venous stenosis. Portal venous angioplasty by stent implantation was then performed to treat the portal hypertension (PHT)-related complications. After the intervention, the patient received anticoagulation therapy and continued immunosuppressive therapy. During the 5-year follow-up, the patient did not experience any onset of GI bleeding or ascites. Therefore, portal venous angioplasty with stent placement could be an effective treatment to prevent PHT-related complications when immunosuppression therapy failed.

Paradigm shift in monogenic autoinflammatory diseases and systemic vasculitis: The VEXAS syndrome. / Cambio de paradigma en las enfermedades autoinflamatorias monogénicas y las vasculitis sistémicas: el síndrome VEXAS.

VEXAS syndrome was described by the end of 2020 as an autoinflammatory disease caused by post-zygotic variants in the UBA1 gene. VEXAS syndrome occurs in adult males with recurrent fever, arthralgia/arthritis, ear/nose chondritis, neutrophilic dermatosis, lung inflammation, venous thrombosis, and different types of vasculitis. Common laboratory changes include raised acute phase reactants and macrocytic anemia. The coexistence of myelodysplasia is frequent, and bone marrow vacuolization of myeloid and erythroid precursors is characteristic. Glucocorticoids are effective at medium-high doses, but the remaining immunosuppressive drugs, either conventional or biological, have showed limited or absent efficacy. Azacitidine has been associated with a good response, especially in patients with accompanying myelodysplastic syndrome. Allogeneic hematopoietic stem cell transplantation appears to be the only curative therapy by now. VEXAS syndrome has become a paradigm shift in the diagnosis and treatment of autoinflammatory diseases and systemic vasculitis.

Granulomatosis with polyangiitis: A case report of early systemic fulminant presentation

Granulomatosis with polyangiitis is a systemic vasculitis that affects medium and small vessels, with high expression of anti-neutrophil cytoplasmic autoantibody. A case is pre sented on a patient with an initial compromise of the lower airway, who did not respond to management, required intensive care unit management, and died due to severe diffuse alveolar hemorrhage. His definitive diagnosis was established with a clinical autopsy. Gran-ulomatosis with polyangiitis is a disease with different ways of presentation, and can have fatal outcomes if it is not diagnosed early.

La granulomatosis con poliangeítis es un tipo de vasculitis que afecta a vasos de mediano y pequeño calibre de manera sistémica, con una alta expresión de anticuerpos contra el citoplasma del neutrófilo. Se presenta el caso de un paciente con un compromiso inicial de la vía área inferior, que no respondió al tratamiento y requirió manejo en unidad de cuidados intensivos. Finalmente, falleció por una hemorragia alveolar difusa severa. Su diagnóstico definitivo se estableció con una autopsia clínica. La granulomatosis con poliangeítis tiene diferentes formas de presentación y puede tener desenlaces fatales si no se diagnostica a tiempo.

Systemic proliferative arteriopathy and hypophysitis in a cow with chronic ovine herpesvirus 2-induced malignant catarrhal fever.

Malignant catarrhal fever (MCF) is a severe, systemic, lymphoproliferative disease affecting domestic ruminants, caused by a group of MCF viruses in the genus Macavirus. Infection of cattle and bison with ovine herpesvirus 2 (OvHV2) is economically significant in North America. Sheep are the reservoir host of the virus, and only rarely manifest disease. Cattle and bison, however, frequently have lymphoproliferation, mucosal ulceration, and systemic vasculitis. OvHV2-induced MCF in cattle and bison is often fatal, with clinical recovery reported only rarely. Chronic cases are uncommon, but vascular changes of variable severity and ocular lesions have been described. Here we present a case of chronic MCF in a cow with proliferative arteriopathy, systemic vasculitis, and OvHV2-associated hypophysitis. We demonstrated OvHV2 nucleic acid in affected tissues with in situ hybridization.

Immunoglobulin G4-Related Disease Presenting as Temporal Bone Lesion with Facial Nerve Palsy.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic condition which could present as local infiltration of skull base structures. We report a case of IgG4-RD with infiltration of the temporal bone and surrounding structures in a patient with systemic vasculitis on systemic steroids. A 31-year-old woman presented with right-sided facial weakness, headache, and right ear hearing loss. On examination, redness and retraction of the right tympanic membrane and facial paresis (House-Brackman IV) were noted. Computed tomography imaging showed mastoiditis, temporal lobe stroke, and brain abscess. Magnetic resonance imaging (MRI) showed infiltration in the infratemporal fossa, nasopharynx, spreading along the Eustachian tube and perineurally along the branches of CN V and CN VII intracranially, forming a dural based mass in the middle cranial fossa. Intracranial mass compressed the temporal lobe of the brain, causing perifocal brain edema. Endoscopic biopsy of the nasopharynx was chosen as the least invasive method. It showed marked fibrosis of the tissue, dense lymphoplasmacytic infiltrates, and an increased number of IGG4-positive plasma cells. Serum IgG4 levels were below the diagnostic criteria of IgG4-RD, but histological characteristics of IgG4-RD were met. The patient was treated with high-dose oral prednisolone. Resolution of symptoms, including facial nerve paresis, was observed and infiltration in the nasopharynx, infratemporal fossa decreased on subsequent MRI tests. No recurrence was noted on the follow-up of 16 months. The case presented itself as a diagnostic challenge for a multidisciplinary team to differentiate pathology caused by either IgG4-RD, systemic vasculitis, or atypic mastoiditis. MRI and histological reports were essential to establish a correct diagnosis.

Systemic Vasculitis Following SARS-CoV-2 mRNA Vaccination Demonstrated on FDG PET/CT.

ABSTRACT: Causality regarding adverse events following SARS-CoV-2 mRNA vaccine is undetermined for vasculitis. Herein, we report the case of an 80-year-old man who presented with a persistent high fever of 7 days' duration that began shortly after receiving a COVID-19 vaccination. There was also a complaint of persistent lower limb pain and walking difficulty on emergency transportation. FDG PET/CT demonstrated extensive linear hypermetabolic foci along the vessels of both legs, including the hips, and the arms, supraclavicular area, chest wall, and temporal regions, suggesting systemic vasculitis. Subsequent temporal artery biopsy revealed arteritis, which is not typical of giant cell arteritis.