Treatment of meningoencephalitis of unknown origin in a dog

Abstract

MENINGOENCEPHALITIS of unknown origin (MUO) is one of the most common causes of inflammatory central nervous system disease in dogs (Sarfarty and others 1986, Thomas and Eger 1989, Tipold and others 1993, Tipold 1995, Schatzberg 2005. Despite immunosuppressive treatment, relapses remain a feature of MUO (Muñana and Luttgen 1998, Sorjonen 1990, Cuddon and others 2002. This short communication describes the use of prednisolone, cytosine arabinoside and ciclosporin to manage a relapse of MUO in a dog.A four-year-old entire male French bulldog was presented for acute onset of falling to the left and head tilt to the left. The dog was vaccinated and had not suffered from previous medical or surgical conditions. The general examination was unremarkable. Neurological examination revealed depressed mental status, left-sided head tilt, tetraparesis (worse on the left) and ataxia. Postural reactions were decreased in the left thoracic and left pelvic limbs. Cranial nerve examination revealed an absent left palpebral reflex and left menace response. The neurological examination was consistent with left-sided central vestibular syndrome associated with left facial paralysis. These signs were consistent with a left-sided caudal brainstem lesion (that is, metencephalon and myelencephalon). The likely differential diagnoses included infectious meningoencephalitis (bacterial secondary to otitis interna, viral or protozoal), MUO (granulomatous meningoencephalomyelitis, necrotising meningoencephalitis and necrotising leucoencephalitis), cerebrovascular accident (ischaemic or haemorrhagic) and primary or secondary brain neoplasia.Haematology and biochemistry, serology for neosporosis (IgG) and toxoplasmosis (IgG and IgM), chest radiographs and abdominal ultrasound were all within normal limits. A MRI study of the brain was performed using a 0·4 Tesla permanent magnet (Aperto; Hitachi) and a human knee coil. The following pulse sequences were used: T 1 -weighted (T1W) pre-and postcontrast (0·1 mmol/kg gadobenate dimeglumine [MultiHance; Bracco]), T 2 -weighted (T2W), fluid attenuated inversion recovery (FLAIR) and T 2 * gradient-echo. The MRI study revealed a large, ill-defined lesion of high signal on T2W and FLAIR sequences, extending from the left caudal colliculus to the left lateral recess. The lesion involved the left mesencephalon, metencephalon, myelencephalon and the lateral and interposital cerebellar nuclei (Fig 1a, b, c). Mild and heterogeneous contrast uptake was noticeable on the T1W postcontrast sequence. Several smaller high signal areas, scattered throughout the corona radiata, were seen on T2W and FLAIR sequences. Lumbar cerebrospinal fluid (CSF) was Veterinary Record (2009) 164, 627-629 collected, which was clear, watery and colourless. Laboratory analysis revealed a normal protein concentration (0·25 g/l), a cell count revealed two red blood cells/µl and four nucleated cells/µl (reference range <4 nucleated cells/µl), and CSF cytology revealed the presence of monocytes and lymphocytes. PCR performed on blood an...

Perspectives on Meningoencephalomyelitis of Unknown Origin

“…Reported second-line immunosuppressive drug therapies for MUO include leflunomide, 145 procarbazine, 146 cytosine arabinoside, 17,[147][148][149][150][151][152] lomustine, 144,153 mycophenolate mofetil, 154 azathioprine 155 ; COP 149 (cyclophosphamide, vincristine, prednisone), and cyclosporine ( Table 3). 118,[155][156][157][158][159] Radiation therapy has also proved to be effective for focal GME lesions.…”

“…17,[144][145][146][147][148][149][150][151][152][153][154][155][156][157][158][159] MR imaging may offer a broader assessment by which to guide therapy in dogs with MUO. MR imaging abnormalities of foramen magnum herniation, loss of cerebral sulci, or mass effect attributable to MUO have been associated with reduced survival time.…”

The pharmacokinetics of cytarabine in dogs when administered via subcutaneous and continuous intravenous infusion routes

“…Cytarabine inhibits DNA polymerase in mitotically active cells and produces topoisomerase dysfunction and prevents DNA repair. Combination therapy with prednisone and cytarabine has been reported to improve the temporary and long‐term remission and prognosis for dogs diagnosed with MUE (Nuhsbaum et al ., ; Schatzberg, ; Zarfoss et al ., ; Menaut et al ., ; Behr et al ., ). The dose of cytarabine commonly used in the treatment of MUE (total dose of 200 mg/m 2 ) is lower than that used in the treatment of neoplasia (total dose of 400–600 mg/m 2 ).…”

Evaluating the use of cytosine arabinoside for treatment for recurrent canine steroid‐responsive meningitis‐arteritis

“…In other canine non‐infectious inflammatory diseases of the CNS such as meningoencephalitis of unknown origin (MUO) several studies have been published evaluating combinations of prednisolone with additional immunosuppressive drugs. Various combinations including cyclosporine, azathioprine, mycophenolate mofetil, cytosine arabinoside (CA), procarbazine, cyclophosphamide with vincristine, lomustine, leflunamide and radiation therapy have been described 17–22 . No gold standard has been recommended.…”