Glucocorticoids, Cyclosporine, Azathioprine, Chlorambucil, and Mycophenolate in Dogs and Cats

Clinical features, treatment, and outcome of juvenile dogs with meningoencephalitis of unknown etiology

BACKGROUND

The information relating to the outcome specifically for juvenile dogs with meningoencephalitis of unknown etiology (MUE) is lacking.

OBJECTIVES

To describe the clinical presentation, diagnostic findings, treatment, and outcome in a cohort of dogs with MUE <52 weeks old.

ANIMALS

Thirty-four client-owned dogs.

METHODS

Multicenter retrospective case series. Records from 5 referral centers were searched. Data was extracted from the medical records and referring veterinarians were contacted for survival data if this was not available from the record.

RESULTS

The mean age was 31 weeks; the youngest dog was 11 weeks and 3 dogs were <16 weeks old. Altered mentation (71%), ataxia (44%), seizures (29%), and circling (26%) were the most common presenting complaints. Neuroanatomical localization was to the forebrain (38%), multifocal (35%), brainstem (18%), and cerebellum (12%). Corticosteroid monotherapy (n = 15) and corticosteroid plus cytosine arabinoside (n = 15) were used in equal proportions. Outcome data was available for 26 dogs, 8 (31%) were alive at the time of data collection with a follow-up range of 135 to 2944 days. Death or euthanasia was related to MUE in 17/18 dogs that died during the study period. Kaplan-Meier survival analysis demonstrated a median survival time for all-cause death of 84 days.

CONCLUSION

The prognosis for MUE in this subset of dogs was considered poor.

Pharmacology of drugs used in autoimmune dermatopathies in cats and dogs: A narrative review

Immunosuppressive drugs are the mainstay of treatment for many feline and canine autoimmune skin diseases, either as monotherapy or in combination with other drugs. Treatment with these drugs is often lifelong and may have long-term consequences on the affected animal's overall quality-of-life. Clinicians need to understand the pharmacology of immunosuppressants in planning and executing the treatment regimen for the best possible clinical outcome, as well as reducing the risk of adverse effects. This review paper will focus on the mechanism of action, pharmacokinetics and pharmacodynamics, clinical uses and adverse effects of immunosuppressive drugs used to treat autoimmune dermatoses in cats and dogs. These include glucocorticoids, ciclosporin A, azathioprine, chlorambucil, mycophenolate mofetil, oclacitinib and Bruton's tyrosine kinase inhibitors.

Filgrastim Use in the Treatment of Azathioprine-Induced Myelosuppression Toxicity After Prescription Error in the Feline

Only one report on the successful use of filgrastim (granulocyte colony-stimulating factor) in cats for severe neutropenia following azathioprine toxicity exists. Here, we report on a case in which a cat was prescribed methimazole but the medication was filled incorrectly with azathioprine tablets and the prescription label indicated a methimazole dosing regimen that was administered for three days before recognition of the error. On presentation, the cat's physical examinations were consistent with previous examinations before ingestion of azathioprine. A complete blood cell count revealed neutropenia and leukopenia. The cat later developed hyporexia, dehydration, and vomiting. Treatment included antinausea and appetite stimulant medications, filgrastim, and antibiotics. Filgrastim given as subcutaneous injections over the course of treatment increased neutrophil cell counts after suppression. The cat made a full recovery after responding to the treatment protocol. Based on the perceived response to filgrastim in this single feline case report, its use can be considered for the treatment of azathioprine-induced neutropenia in cats.

Retrospective evaluation of leflunomide as an adjunctive therapy in dogs with non-associative immune-mediated thrombocytopenia: 20 cases (2008-2021)

OBJECTIVE

To describe leflunomide as an adjunctive therapy in the treatment of non-associative immune-mediated thrombocytopenia.

MATERIALS AND METHODS

A retrospective study of dogs with a diagnosis of non-associative immune-mediated thrombocytopenia treated with leflunomide March 2008 to September 2021 was conducted. Data collected included signalment, clinical signs, physical examination findings and diagnostic testing performed. Medications administered, duration of hospital stay, time to platelet concentration >150×109/L and adverse events during leflunomide therapy were recorded. Relapses within a year of diagnosis were reported.

RESULTS

A total of 20 client-owned dogs met inclusion criteria. Nineteen of 20 dogs (95%) achieved a platelet concentration >150×109/L with leflunomide and prednisone combination therapy and four dogs (21.1%) relapsed during treatment or shortly after treatment. Adverse effects included diarrhoea (n=5), mild lymphopenia (n=9) and mild intermittent anaemia (n=1). A single dog developed hepatotoxicity presumed to be secondary to leflunomide therapy that resolved after drug discontinuation. One dog was treated for aspiration pneumonia during treatment. Two dogs were euthanased while receiving leflunomide.

CLINICAL SIGNIFICANCE

Length of hospitalisation, time to platelet recovery, treatment response and relapse rate were comparable with alternative treatment protocols. Most adverse effects did not require leflunomide dose adjustment; however, two dogs died while undergoing leflunomide treatment and there is compelling evidence that one of these dogs experienced fatal infection secondary to immune-suppression. Hepatotoxicity remains a known complication of leflunomide treatment and serial biochemistry testing is recommended.

Novel Management of Masticatory Myositis in Three Dogs with a Selective Janus Kinase (JAK-1) Inhibitor

Masticatory myositis (MM) is an inflammatory myopathy reported in dogs and is characterized by inflammation of the masticatory muscles (temporalis, masseter, and pterygoid muscles). Immunosuppressive therapy is the current recommended treatment for MM and may involve glucocorticoids, cyclosporine, azathioprine, mycophenolate mofetil, leflunomide, or a combination of these treatments that are slowly tapered to the lowest effective dose. However, side effects from multimodal medical therapy and complications associated with MM relapses have been reported. The purpose of this case series was to report oclacitinib as a treatment alternative to traditional medical management of MM. The intent of this alternative is to manage side effects from glucocorticoid use. Oclacitinib (1mg/kg per os q12h) was used solely for treatment of MM in three dogs. The dogs were followed up to >6 months after oclacitinib administration. An increase in oral range of motion, as determined by gape angle, was noted in all three dogs. However, a corresponding drop in antibody titers (2M fiber) did not occur. All dogs showed improvement in overall clinical management of MM, side effects from glucocorticoids, and clinical signs related to chronic prednisone use. Larger controlled trials with consistent measurements (interincisal distance, gape angle) and 2M fiber antibody titers are indicated to further assess validation of oclacitinib treatment of MM. The clinical outcome of all dogs was considered successful.

The use of oclacitinib compared to azathioprine in the management of canine pemphigus foliaceus: A retrospective analysis

BACKGROUND

Oclacitinib (Apoquel; Zoetis) has been reported to be beneficial for treating immune-mediated disorders.

HYPOTHESIS/OBJECTIVES

This retrospective study evaluates in which group of dogs [oclacitinib (OC) or azathioprine (AZ)] remission of pemphigus foliaceus (PF) was more effectively achieved with matched induction dosing of glucocorticoids; it further evaluates which group had a higher glucocorticoid-sparing effect.

ANIMALS

Review of 30 medical records of dogs diagnosed with PF presented to a private practice dermatological service.

MATERIALS AND METHODS

Retrospective analysis of dogs diagnosed with PF and treated with OC or AZ in combination with glucocorticoids.

RESULTS

There was no significant difference in the ability to induce remission between AZ and OC groups. In the AZ group, 13 of 15 dogs went into some type of remission (partial or complete), compared with 11 of 15 in the OC group. There was no significant difference between the two groups for the glucocorticoid-sparing effect. The AZ group had an average reduction of 77.9% from the induction glucocorticoid dose, and OC group had an average reduction of 64.4%. One of 15 patients in the AZ group and three of 15 patients in the OC group had a 100% reduction of the glucocorticoid dose.

CONCLUSIONS AND CLINICAL RELEVANCE

These results indicate that OC can be considered as a treatment option for canine PF.

Fuzapladib reduces postsurgical inflammation in the intestinal muscularis externa

Postoperative ileus (POI) is a surgical complication that induces emesis and anorexia. Fuzapladib (FUZ), an inhibitor of leukocyte-function-associated antigen type 1 (LFA-1) activation, a leukocyte adhesion molecule, exerts anti-inflammatory effects by inhibiting leukocyte migration into the inflammatory site. In this study, we examined the prophylactic impact of FUZ on POI in a mouse model. POI model mice were generated by intestinal manipulation, and the effect of FUZ on intestinal transit and the infiltration of inflammatory cells into the ileal muscularis externa was assessed. The increased number of macrophages was significantly suppressed by FUZ, whereas the infiltration of neutrophils into the ileal muscularis externa was not sufficiently inhibited in the POI model mice. Additionally, FUZ did not ameliorate delayed gastrointestinal transit in POI model mice. In conclusion, our results suggest that FUZ does not improve delayed gastrointestinal transit but partially inhibits inflammation in the ileal muscularis externa in POI model mice. FUZ may be a potential anti-inflammatory agent for the management of post-surgical inflammation.

Polyautoimmunity manifest as inflammatory myopathy, uveitis, and progressive cutaneous depigmentation in a mixed breed dog: a case report

BACKGROUND

Polyautoimmunity is the expression of more than one autoimmune disease in a single patient. This report documents polyautoimmunity in a mixed breed dog with concurrent uveitis, cutaneous depigmentation, and inflammatory myopathy.

CASE PRESENTATION

A 1-year-old male neutered mixed breed dog was presented for progressive generalized leukotrichia and leukoderma, bilateral panuveitis, and masticatory muscle atrophy. The latter progressed to myositis of lingual, pharyngeal, and masticatory muscles confirmed by biopsy. Temporalis muscle was completely replaced by adipose and fibrous tissue, and necrotic myofibers with extensive infiltration of mononuclear cells indicated active myositis of lingual muscle. Skin biopsies showed severe melanin clumping in epidermis, hair follicles, and hair shafts, and perifollicular pigmentary incontinence. Uveitis, depigmentation, and myositis affecting the masticatory, pharyngeal, and tongue muscles were diagnosed based on clinical, histological, and laboratory findings.

CONCLUSIONS

To the authors' knowledge, this is the first report of concurrent uveitis, progressive cutaneous depigmentation, and inflammatory myopathy in a dog.

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.

Advances in Dystrophinopathy Diagnosis and Therapy

Dystrophinopathies are x-linked muscular disorders which emerge from mutations in the Dystrophin gene, including Duchenne and Becker muscular dystrophy, and dilated cardiomyopathy. However, Duchenne muscular dystrophy interconnects with bone loss and osteoporosis, which are exacerbated by glucocorticoids therapy. Procedures for diagnosing dystrophinopathies include creatine kinase assay, haplotype analysis, Southern blot analysis, immunological analysis, multiplex PCR, multiplex ligation-dependent probe amplification, Sanger DNA sequencing, and next generation DNA sequencing. Pharmacological therapy for dystrophinopathies comprises glucocorticoids (prednisone, prednisolone, and deflazacort), vamorolone, and ataluren. However, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and β-blockers are the first-line to prevent dilated cardiomyopathy in dystrophinopathy patients. Duchenne muscular dystrophy gene therapy strategies involve gene transfer, exon skipping, exon reframing, and CRISPR gene editing. Eteplirsen, an antisense-oligonucleotide drug for skipping exon 51 from the Dystrophin gene, is available on the market, which may help up to 14% of Duchenne muscular dystrophy patients. There are various FDA-approved exon skipping drugs including ExonDys-51 for exon 51, VyonDys-53 and Viltolarsen for exon 53 and AmonDys-45 for exon 45 skipping. Other antisense oligonucleotide drugs in the pipeline include casimersen for exon 45, suvodirsen for exon 51, and golodirsen for exon 53 skipping. Advances in the diagnosis and therapy of dystrophinopathies offer new perspectives for their early discovery and care.

Toxoplasma gondii and Alternaria sp.: An Original Association in an Immunosuppressed Dog with Persistent Skin Lesions

Dogs and cats may suffer from a variety of diseases, mainly immune mediated, that require the administration of immunosuppressive drugs. Such therapies can cause adverse effects either by the toxicity of the drugs or as a consequence of immune suppression and associated opportunistic infections. Here we present an, yet unknown, association of Toxoplasma gondii and Alternaria fungus, within cutaneous lesions in a dog under long-term immunosuppressive therapy. The diagnosis of such infections is laborious and not obvious at first glance, since the clinical signs of cutaneous toxoplasmosis, neosporosis or alternariosis are not specific. A further laboratory confirmation is needed. Therefore, we currently recommend that dogs and cats should undergo serologic testing for toxoplasmosis or neosporosis prior to immunosuppressive therapy and a regular dermatological evaluation during the immunosuppressive therapy.

A shortened whole brain radiation therapy protocol for meningoencephalitis of unknown origin in dogs

Introduction

A variety of treatment options have been described for canine meningoencephalitis of unknown origin (MUO). Few studies focused on radiation therapy as a second line immunomodulating treatment, implicating its effective use. However, a standard radiation therapy protocol is lacking, and further research will help to evaluate the effect of different dose regimens.

Methods

Ten dogs diagnosed with MUO based on MRI and CSF findings were prospectively enrolled. The dogs were treated with a shortened whole brain radiation therapy protocol (5 × 4 Gy) in combination with prednisolone. Neurologic changes were quantified using an established scoring scheme. Follow-up MRI and CSF examination was scheduled three months after radiation therapy. Overall survival and time to progression were calculated. Histopathology of the brain was performed in case of death.

Results

Seven dogs were diagnosed de novo and three had a history of relapsing MUO. Neurological status improved in all 10 dogs during radiation therapy, with 4/10 returning to normal shortly after radiation therapy. Three dogs died within the first three months after radiation therapy. At follow-up MRI lesions completely resolved in two dogs, partially resolved in five dogs, and progressed in one dog. After follow-up MRI, dogs were further treated with prednisolone monotherapy (two dogs) and additional immunosuppressant drugs (five dogs). Overall, four dogs showed disease progression, with a mean time to progression of 691 days (95%CI: 396-987) and mean overall survival for all dogs was 723 days (95%CI: 436-1011) (both medians not reached). Histopathology confirmed MUO in three dogs but was suggestive for oligodendroglioma in one dog. Radiation induced side effects were not seen.

Conclusion

Shortened whole-brain radiation therapy could be an additional treatment option for MUO in conjunction to prednisolone, specifically for cases that require rapid relief of symptoms and with relapsing history.

Vaccination of Immunocompromised Cats

Immunocompromise is a common condition in cats, especially due to widespread infections with immunosuppressive viruses, such as feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV), but also due to chronic non-infectious diseases, such as tumours, diabetes mellitus, and chronic kidney disease, as well as treatment with immunosuppressive drugs, such as glucocorticoids, cyclosporins, or tumour chemotherapy. In this review, the European Advisory Board on Cat Diseases (ABCD), a scientifically independent board of experts in feline medicine from eleven European countries, discusses the current knowledge and rationale for vaccination of immunocompromised cats. So far, there are few data available on vaccination of immunocompromised cats, and sometimes studies produce controversial results. Thus, this guideline summarizes the available scientific studies and fills in the gaps with expert opinion, where scientific studies are missing. Ultimately, this review aims to help veterinarians with their decision-making in how best to vaccinate immunocompromised cats.