Combination of Prednisolone and Azathioprine for Steroid-Responsive Meningitis-Arteritis Treatment in Dogs

Prospective randomized trial comparing relapse rates in dogs with steroid-responsive meningitis-arteritis treated with a 6-week or 6-month prednisolone protocol

BACKGROUND

Traditionally, 6-month courses of prednisolone are used to treat steroid-responsive meningitis-arteritis (SRMA), but this medication is associated with adverse effects that can lead to poor quality of life.

HYPOTHESIS/OBJECTIVES

Resolution of clinical signs and rate of relapse of SRMA would not be significantly different between a 6-month prednisolone protocol and a 6-week protocol.

ANIMALS

Forty-four hospital cases from multiple referral centers in the United Kingdom (2015-2019). Twenty of 44 were treated with the 6-month protocol and 24/44 with the 6-week protocol.

METHODS

Prospective, randomized trial with 12-month follow-up. The same prednisolone protocol reinitiated in the event of relapse. Analysis of relapses with binary logistic and Poisson regression modeling.

RESULTS

All cases responded to their treatment protocol. Relapses occurred in 6/20 (30%) of the 6-month protocol and 9/24 (38%) of the 6-week protocol. There was no statistical difference in the incidence risk of at least 1 relapse between the 2 groups (odds ratio = 1.40; 95% confidence interval [CI], 0.40-4.96, P = 0.60). Among the 15 dogs that relapsed, 10/15 (67%) relapsed once, 3/15 (20%) relapsed twice, and 2/15 (13%) relapsed 3 times. No statistical difference was detected in the incidence rate ratio (IRR) of total relapse events between the 2 groups (IRR = 1.46; 95% CI, 0.61-3.48; P = 0.40).

CONCLUSIONS AND CLINICAL IMPORTANCE

"Short" 6-week prednisolone protocols could be used to treat SRMA, thereby presumably reducing the duration and severity of prednisolone's adverse effects.

Steroid-responsive meningitis-arteritis: What have we learned since 2010? A narrative review

Steroid-responsive meningitis-arteritis (SRMA) occurs as an immune-mediated, inflammatory, and non-infectious disorder of juvenile and young-adult dogs. In principle, SRMA is divided into two clinical courses: during the typical acute form, dogs are presented with fever, cervical hyperaesthesia, and reluctance to move. The more protracted form most probably emerges after insufficient immunosuppressive treatment or relapses, with additional neurologic deficits localized in the cervical and thoracolumbar spinal cord or multifocally. The trigger leading to SRMA still remains an unsolved riddle for immunologists and clinical neurologists. In the past, many attempts have been made to clarify the etiology of this disease without success. The purpose of writing this narrative review about SRMA is to summarize new insights on the pathogenesis of SRMA with a focus on immunologic dysregulation. Furthermore, unusual manifestations of the disease, new diagnostic approaches using possible laboratory biomarkers or diagnostic imaging tools, and potential innovative treatment strategies are discussed.

Elevated Interleukin-31 Levels in Serum, but Not CSF of Dogs with Steroid-Responsive Meningitis-Arteritis Suggest an Involvement in Its Pathogenesis

Steroid-responsive meningitis-arteritis (SRMA) is a predominantly Th-2 immune-mediated disease, but the exact pathomechanism remains unclear. Interleukin-31 (IL-31) is predominantly produced by T cells with a Th-2 phenotype during proinflammatory conditions. We hypothesize that IL-31 might be involved in the pathogenesis of SRMA. IL-31 was measured in archived samples (49 serum and 52 CSF samples) of dogs with SRMA, meningoencephalitis of unknown origin (MUO), infectious meningoencephalitis, and atopic dermatitis, and of healthy control dogs using a competitive canine IL-31 ELISA. The mean serum IL-31 level in dogs with SRMA (n = 18) was mildly higher compared to dogs with atopic dermatitis (n = 3, p = 0.8135) and MUO (n = 15, p = 0.7618) and markedly higher than in healthy controls (n = 10, p = 0.1327) and dogs with infectious meningoencephalitis (n = 3, no statistics). Dogs with SRMA in the acute stage of the disease and without any pre-treatment had the highest IL-31 levels. The mean CSF IL-31 value for dogs with SRMA (n = 23) was quite similar to that for healthy controls (n = 8, p = 0.4454) and did not differ markedly from dogs with MUO (n = 19, p = 0.8724) and infectious meningoencephalitis. Based on this study, an involvement of IL-31 in the pathogenesis of the systemic Th-2 immune-mediated immune response in SRMA can be assumed as a further component leading to an aberrant immune reaction.

Effects of Lactiplantibacillus plantarum 19-2 on immunomodulatory function and gut microbiota in mice

This study aims to evaluate the effects of Lactiplantibacillus plantarum 19-2 (L. plantarum 19-2) on mice treated with the alkylating agent cyclophosphamide (CTX). Our findings show that L. plantarum 19-2 restored the spleen and thymus index and the number of white blood cells and lymphocytes% in CTX treated mice. Serum immunoglobulin levels in CTX-treated mice were increased by L. plantarum 19-2. In addition, as compared to the model group, L. plantarum 19-2 upregulated the content of SIgA, while L. plantarum 19-2 regulates the mRNA and protein expression levels of GATA-3, T-bet, IFN-γ, and IL-4 in small intestinal tissues, which adjusted mucosal barriers, structural status, and the balance of Helper T-cell 1 and Helper T-cell 2. Lactiplantibacillus plantarum 19-2 regulated the distribution of intestinal flora in mice, promoting the growth of Bacteroides and Proteobacteria. In addition, L. plantarum 19-2 inhibited the growth of several harmful bacteria, including Actinobacteria and Firmicutes.

Immunomodulatory and immunosuppressive drug protocols in the treatment of canine primary immune thrombocytopenia, a scoping review

Primary immune thrombocytopenia (ITP) is a cause of severe thrombocytopenia in dogs. Immunosuppressive corticosteroid drugs are frequently used in the management of ITP, but treatment failure may occur. Immunomodulatory and non-corticosteroid immunosuppressive drugs might improve outcomes from therapy either alone or in combination with corticosteroids. The objectives of this scoping review were (1) to evaluate the current evidence relating to immunomodulatory and immunosuppressive drug protocols in the treatment of canine ITP, and (2) to answer the clinical question, whether or not therapy with immunomodulatory or non-corticosteroid immunosuppressive drugs alone or in combination with corticosteroids could improve outcome, compared to therapy with corticosteroids alone. A literature search was performed in the electronic databases of Agricola, CAB Abstracts, Embase, Medline and Web of Science for publications in November 2019 and again February 1, 2021. Selection criteria were relatively strict and included peer-reviewed research papers reporting outcome measures from immunomodulatory and immunosuppressive drug protocols in the treatment of canine ITP with a pre-therapeutic mean or median platelet count < 50,000/µL as a strict criterion for inclusion. Studies were evaluated if they had an appropriate diagnostic work up to exclude underlying conditions. Outcome measures and adverse events were compared between drug protocols both within studies and between studies. The search identified 456 studies, with six studies being eligible for inclusion. The studies were mostly case series while two were randomized controlled trials. Level of evidence varied with an overall uncertain subject enrollment, small groups, inadequate description and variable use of drug protocols or outcome measures. For outcomes such as platelet recovery time and duration of hospitalization, an improvement was observed using adjunctive therapy (human intravenous immunoglobulin) compared to therapy with corticosteroids alone. For outcomes of complete platelet recovery time, survival (6-month), mortality and relapse, no improvement was observed using adjunctive drugs compared to corticosteroids alone. Specifically, therapy with mycophenolate mofetil alone and adjunctive azathioprine were associated with more severe adverse events compared to other drug protocols. Evidence relating to immunomodulatory and immunosuppressive drug protocols in the treatment of canine ITP was of variable quality. Future larger case-controlled trials are required for determination of optimal treatment protocols in canine ITP.

Successful surgical and medical treatment of a severe, acute epidural bleed in a young dog due to steroid responsive meningitis-arteritis

Background

Steroid responsive meningitis-arteritis (SRMA) is an immune-mediated disease of the leptomeninges and its associated blood vessels, typically responsive to corticosteroids. Clinically relevant haemorrhage is a rare finding in such patients and for this reason surgical decompression of the spinal cord is normally not considered. The diagnosis of SRMA is supported by serum C-reactive protein (CRP) increase, cerebrospinal fluid (CSF) examination, including cytology (polymorphonuclear pleocytosis in the acute form), nucleated cell-, red blood cell- and protein count, as well as by evaluating CSF and serum IgA concentrations. D-dimer concentrations in serum and CSF should be elevated as well and therefore can be also evaluated as a further diagnostic tool.

Case presentation

A 1.5-year-old mixed breed dog was presented with pyrexia, cervical pain and acute tetraparesis. Magnetic resonance imaging revealed an extradural mass lesion at the level of the sixth cervical vertebra, consistent with a subacute epidural haemorrhage, causing severe compression of the spinal cord. Based on the dog’s signalment, clinical history and results of the blood and CSF analyses (incl. D-dimer determination), SRMA with secondary epidural haemorrhage was suspected. Decompressive surgery was performed through a right sided partial dorsal laminectomy. Post-surgical immunosuppressive treatment was started with cytarabine and then continued with prednisolone after completion of wound healing.

Conclusions

This is the first report in which medical and surgical treatment were combined in a patient with SRMA and it highlights the possibility of performing a successful surgical intervention despite the need for immunosuppressive therapy. Moreover, while SRMA diagnosis is normally based on CSF analysis and CSF and serum IgA concentrations, D-dimer concentrations in serum and CSF were also useful in this patient.