The medical records of two dogs that were diagnosed with masticatory muscle myositis (MMM) were reviewed. The reported clinical signs included intense pain when opening the mouth and restricted jaw movement. MRI detected widespread, symmetrical, and inhomogeneously hyperintense areas in the masticatory muscle. Electromyography (EMG) demonstrated severe and spontaneous pathologic activity in the temporal and masseter muscles. With early therapeutic treatment, remission of symptoms occurred within 2 mo, and no relapses were observed for the subsequent 2 yr. The gold standard for the diagnosis of MMM is the 2M antibody test, but the purpose of this study was to evaluate the use of MRI as an accurate and efficient diagnostic tool for the initiation of early therapy for the treatment of muscle myositis.

A 6-year-old neutered female cat was examined for chronic and progressive pelvic limb ataxia that progressed to non-ambulatory paraparesis over 1 month. Haematological and serum analyses were mainly within normal ranges. Thoracic and abdominal radiographs did not reveal any morphological abnormalities. Magnetic resonance imaging investigation of the thoraco-lumbar spine demonstrated a well-defined, extradural mass that extended into the epidural space from the L2 to L3 vertebral bodies and expanded in the L2 to L3 left intervertebral foramen. During surgery, a long, narrow, white parasite which was weakly adherent to the phlogistic epidural fat tissue was gently removed from the spinal canal. Histological examination of the pathological tissue supported a diagnosis of epidural steatitis surrounding a female adult Dirofilaria immitis. This is a novel case of natural D immitis infection with spinal localisation in a cat, well documented with magnetic resonance investigation, and cytological and histological examinations, introducing a novel differential diagnosis for extradural spinal masses in cats.

A 7-year-old male Shih Tzu was examined because of acute onset of abnormal gait in pelvic limbs. Physical examination revealed pain at the level of the lumbar spine, paraparesis, ataxia, and decreased postural reactions in pelvic limbs. Muscle tone was normal. Normal patellar and cranial tibial reflexes were normal but flexor reflex was mildly reduced in the left pelvic limb. The neuroanatomic diagnosis was a focal or diffuse lesion between T 3 -L 3 . Hematologic and serum biochemical analysis revealed severe anemia (RBC 3.9, HB, HCT 27.5,, and on the following day paraparesis and ataxia increased.Bone marrow biopsy performed under general anesthesia at the level of humerus head revealed a leishmaniasis infection, with a high presence of amastigotes. Bone marrow plasmacytosis was present and numerous histiocytes containing Leishmania spp. were evident. Leishmania spp. were detected extracellulary microscopically. IFA titre for Leishmania was 4320. PCR for Ehrlichia and Borrelia spp. were negative.An MRI study was performed with an open permanent magnet operating in 0.2 T (ESAOTE). The study included T1-weighted spin echo (SE) sequences [800/26/ 3; repetition time (TR) echo time (TE)], T2-weighted SE sequences (3000/100/1; TR/TE), gadoliniumdimeglumide (0.5 mmol/mL, GE Healthcare Omniscan, Paderno Dugnano, Milan, Italy) enhanced T1-weighted SE sequences (gadolinium chelate dose was 0.1 mmol/kg, IV), in the 3 orthogonal planes, and Gradient echo STIR sequences (1490/25/1; TR/TE/IR).The MRI revealed the presence of an extradural mass ventral to the spinal cord and lateralized to the left localized on the L 4 -L 5 intervertebral disk to the midbody of L 5 , displacing the spinal cord. The lesion was hyperintense on T1-weighted, T2-weighted, and STIR images, and had heterogeneous postconstrast enhancement (Fig 1).As neurological signs were rapidly progressing, surgery was performed to decompress the spinal cord by means of a left L 4 -L 5 hemilaminectomy, an ill-defined extradural mass, located ventrolaterally, was identified. The mass was yellow and hardly distinguishable from the epidural fat, neither encapsulated nor adhesive and with friable appearance. The diseased tissue was then removed and fixed in 10% buffered formalin.After surgery, cephalosporine (20 mg/kg PO q12h for 10 days) and prednisolone (0.5 mg/kg PO q12h for 5 days) were administered.The surgically removed tissue consisted of epidural fat tissue heavily infiltrated by macrophages, lymphocytes, plasma cells, and neutrophils. Proliferation of capillaries and scattered hemorrhages were also seen. The cytoplasm of many foamy macrophages contained multiple Leishmania amastigotes (Fig 2). The parasites were also identified free within the interstitium. The organisms were strongly labeled by immunohistochemical staining by the streptavidin-biotin immunohistochemical method with canine hyperimmune serum as the primary antibody.

The electroencephalogram (EEG) is an electrodiagnostic technique widely used in both scientific research and clinical medicine. It makes it possible to study the neurophysiology of brain activity by recording real-time changes in electrical potential produced by cortical activation. The importance of EEG in diagnosing canine epilepsy demonstrates its usefulness when the owner's description of crises is not clear or when the episodes cannot be differentiated from behavioral or cardiac disorders. However, EEG recordings also often record electrical activity from sources other than the brain, which may interfere with the clinical event-related signal. This activity is known as artifactual electrical activity, and the signal changes recorded in these cases corrupt the trace when they are superimposed on brain activity or even, in some cases, mimic pathologic abnormalities. The first step in analyzing and interpreting EEG traces is to recognize artifacts and other specific transient events. This retrospective study set out to ascertain whether artifacts comparable to those described in humans are observed in protocols used to perform short-term interictal EEG for canine epilepsy and how these can be classified.

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