Neuroimaging has a key role in identifying small-vessel vasculitis from common diseases it mimics, such as multiple sclerosis. Oftentimes, a multitude of these conditions present similarly, and thus diagnosis is difficult. To date, there is no standardized method to differentiate between these diseases. This review identifies and presents existing scoring tools that could serve as a starting point for integrating artificial intelligence/machine learning (AI/ML) into the clinical decision-making process for these rare diseases. A scoping literature review of EMBASE and MEDLINE included 114 articles to evaluate what criteria exist to diagnose small-vessel vasculitis and common mimics. This paper presents the existing criteria of small-vessel vasculitis conditions and mimics them to guide the future integration of AI/ML algorithms to aid in diagnosing these conditions, which present similarly and non-specifically.

UNASSIGNED: Data on non-infectious cryoglobulinemic vasculitis (NICV) is scarce, especially concerning the management of relapses, which are troublesome. We aimed to investigate risk factors for relapse in NICV.
UNASSIGNED: A systematic literature search of CINAHL, Embase, MEDLINE, Scopus, and the Web of Science databases was implemented until April 2023. Eligible studies included randomized control trials, observational studies, and case series with ≥4 patients. Two reviewers independently extracted data and assessed the quality of the eligible studies.
UNASSIGNED: A total of 3,724 articles were retrieved from a database search, with 27 studies meeting the inclusion criteria for review. Most studies (n = 23) detailed relapses, with the time to relapse varying between 1 and 80 months. The relapse rate was reported at 28% in Type I NICV and ranged from 22% to 60% in mixed NICV. Risk factors for relapse in NICV were identified based on the cryoglobulin subtype and correlated with clinical and immunological responses to varying treatment regimens. Type I NICV with an associated lymphoproliferative disorder exhibited a response-relapse pattern. Cutaneous and articular involvement and incomplete clinical and immunological responses to treatment, particularly corticosteroid monotherapy and occasionally rituximab, influence the risk of relapse in Type II and Type III NICV.
UNASSIGNED: Our findings underscore the significance of attaining both clinical and immunological responses and identifying risk factors for relapse in NICV. Appropriate risk stratification for NICV patients is essential for the successful implementation of effective treatment strategies.
UNASSIGNED: https://www.crd.york.ac.uk/prospero/, identifier CRD42023408140.

Leukocytoclastic vasculitis (hypersensitivity vasculitis) is defined as small blood vessel inflammation with skin or other systemic manifestations due to infections, drugs, or neoplastic disease. This clinical case report highlights an association between ceftriaxone and leukocytoclastic vasculitis in a 49-year-old female patient with a history of penicillin allergy, on mirtazapine for anxiety disorder. Articles concerning antibiotic-induced leukocytoclastic vasculitis are also reviewed. The patient reported a symptom of upper respiratory tract infection and fever 5 days previously for which she received ceftriaxone for 2 days before presenting to the emergency department with a pruritic skin rash in the upper and lower extremities and swollen lips for 1 day. The rash was erythematous, maculopapular, itchy, and non-tender, with no mucus membrane involvement. Laboratory investigations revealed leukocytosis (white blood cells, 22.3 × 109/L) that was mainly eosinophilic (18.4%). The patient was administered prednisolone and antihistamine after stopping ceftriaxone empirically. A skin biopsy confirmed the diagnosis of leukocytoclastic vasculitis. Significant clinical improvement was observed after treatment initiation. Upon follow-up, the skin rash was resolved entirely with no scars; however, there was skin-peeling over the lower extremities. Recognition of antibiotic-induced leukocytoclastic vasculitis is crucial as many classes of antibiotics can contribute to this condition. Continuation of the offending drug may lead to life-threatening complications.

Background: IgA vasculitis/Henoch-Schoenlein purpura (IgAV/HSP) is a systemic small vessel vasculitis of unknown pathogenesis predominantly affecting children. While skin, GI tract, joints, and kidneys are frequently affected and considered, central nervous system (CNS) involvement of this disease is underestimated. Methods: We provide a case report and systematically review the literature on IgAV, collecting data on the spectrum of neurological manifestations. Results: We report on a 7-year-old girl with IgAV who presented with diplopia and afebrile focal seizures, which preceded the onset of purpura. Cranial magnetic resonance imaging was consistent with posterior reversible encephalopathy syndrome (PRES), showing typical focal bilateral parietal swelling and cortical and subcortical high signal intensities on T2-fluid attenuated inversion recovery (FLAIR) images predominantly without diffusion restriction. Cerebrospinal fluid analysis and blood tests excluded systemic inflammation or vasculitis. Interestingly, hypertension was not a hallmark of the developing disease in the initial phase of PRES manifestation. Renal disease and other secondary causes for PRES were also excluded. Supportive- and steroid treatment resulted in restitution ad integrum. Reviewing the literature, we identified 28 other cases of IgAV with CNS involvement. Severe CNS involvement includes seizures, cerebral edema, or hemorrhage, as well as PRES. Thirteen patients fulfilled all diagnostic criteria of PRES. The mean age was 11.2 years (median 8.0, range 5-42 years), with no reported bias toward gender or ethnic background. Treatment regimens varied from watchful waiting to oral and intravenously steroids up to plasmapheresis. Three cases showed permanent CNS impairment. Conclusion: Collectively, our data demonstrate that (I) severe CNS involvement such as PRES is an underappreciated feature of IgAV, (II) CNS symptoms may precede other features of IgAV, (III) PRES can occur in IgAV, and differentiation from CNS vasculitis is challenging, (IV) pathogenesis of PRES in the context of IgAV remains elusive, which hampers treatment decisions. We, therefore, conclude that clinical awareness and the collection of structured data are necessary to elucidate the pathophysiological connection of IgAV and PRES.