Bilateral, hypertrophic neuritis of the brachial plexus in a cat: magnetic resonance imaging and pathological findings

A 9-year-old Burmese cat was presented for investigation of a subacute onset of bilateral forelimb paresis. Magnetic resonance imaging of the cervico-thoracic vertebral column and brachial plexus revealed a bilaterally symmetrical, severe and diffuse swelling of the spinal nerves forming the caudal part of the brachial plexus. Histopathology of the abnormal nerve roots, spinal nerves and brachial plexi showed inflammatory and marked proliferative changes with similar features to that of hypertrophic neuritis of man. Hypertrophic neuritis in man is a rare, tumor-like, chronic inflammatory peripheral nerve disorder of unknown origin most frequently involving the brachial plexus.     

The use of muscle relocation techniques in the treatment of peripheral nerve injuries in dogs and cats

The authors describe certain muscle relocation techniques for the treatment of peripheral nerve injuries (radial and peroneal) in small animals. Six clinical cases are related illustrating the usefulness of the techniques. It is stressed that only a functional muscle can be relocated and that the majority of peripheral nerve lesions in the dog and cat are too extensive, involving a number of nerves, to allow the application of such techniques. However, the procedures can be of great value in certain selected cases, avoiding limb amputation or euthanasia of the patient.     

Idiopathic polyradiculoneuropathy in a Bengal cat: electrophysiological findings and 1 year follow-up

This report describes a rapidly progressive loss of motor function in a 16-month-old male neutered Bengal cat, beginning in the pelvic limbs and progressing to involve all limbs and rendering the cat non-ambulatory. The neurological examination revealed flaccid tetraparesis with decreased spinal reflexes but preserved conscious proprioception and skin sensation. Extensive electrophysiological tests were conducted including electromyography, motor and sensory peripheral nerves potential recordings and 'late' potentials, defining the electrodiagnostic characteristics of this disease. Based on the electrophysiological findings, a generalised proximal and predominantly axonal neuropathy affecting the ventral (motor) nerve roots was suspected. As no aetiology was identified, this disease was classified as idiopathic polyradiculoneuropathy. Over a year, the cat presented three separate episodes of tetraparesis, each with a spontaneous complete recovery, consistent with the reportedly good prognosis for this disease.     

Elevated expression of CAPON and neuronal nitric oxide synthase in the sciatic nerve of rats following constriction injury

Neuronal nitric oxide synthase (nNOS) has been implicated in peripheral nerve lesions and regeneration. The CAPON adaptor protein interacts with the PDZ domain of nNOS, helping to regulate nNOS activity at post-synaptic sites in neurones, but it is not known whether its expression is altered in sciatic nerves after chronic nerve constriction injury. In the present study, the spatiotemporal expression of CAPON was determined in chronically constricted rat sciatic nerves. Similar to the level of protein expression, CAPON mRNA was significantly up-regulated for almost 5 weeks following sciatic nerve injury. Immunohistochemistry demonstrated that increased CAPON was found mainly in S-100-positive Schwann cells. In addition, co-immunoprecipitation demonstrated an interaction between CAPON and nNOS in Schwann cells and the interaction was enhanced in injured sciatic nerves. CAPON may be involved in peripheral nerve regeneration through regulation of nNOS activity.     

Neurofibroma of the ulnar nerve in the carpal canal in a dog: treatment by marginal neurectomy

Peripheral nerve sheath tumours arising in the plexus or peripheral nerves can be treated by limb amputation. There are few reports of these tumours affecting peripheral nerves in the distal regions of the limbs. Here we describe a case of neurofibroma affecting the palmar branch of the ulnar nerve in an Irish setter. Surgical treatment in the region of the carpus by ulnar neurectomy resulted in resolution of chronic thoracic limb lameness. At 11 months following the surgery, clinical examination and MRI did not detect any evidence of recurrence. Neurectomy may be a feasible option for management of selected cases of distally located peripheral nerve sheath tumours.     

Acute bilateral trigeminal neuropathy associated with nervous system lymphosarcoma in a dog

A nine-year-old dog presented with clinical signs consistent with bilateral trigeminal neuropathy. Multicentric lymphoma was diagnosed, and neoplastic lymphocytes were identified in the cerebrospinal fluid. Electromyography revealed spontaneous activity in temporal and masseter muscles. Histopathological examination demonstrated neoplastic cell invasion of temporal and masseter myofibers and of multiple peripheral nerves, including the trigeminal nerve. Central nervous system pathology consisted primarily of spinal root and leptomeningeal lymphoid cell infiltration with relative sparing of spinal cord and brain parenchyma.     

Generalized lymphadenopathy resembling lymphoma in cats: six cases (1972-1976)

Six cases of prominent generalized peripheral lymphadenopathy in the cat were reviewed. The lymph node biopsy specimens of these cats had many histologic features of lymphoma. One cat was euthanatized after the initial diagnosis of lymphoma. In the other 5 cats, the lymphadenopathy regressed without therapy within 1 to 17 weeks.     

Central diabetes insipidus in a cat with central nervous system B cell lymphoma

A 6-year-old male neutered cat presented with blindness, lethargy, polydipsia, hyposthenuria and severe hypernatraemia. Central diabetes insipidus was demonstrated by means of a low measured anti-diuretic hormone (ADH) concentration in the face of hypernatraemia, and clinical response to supplementation with desmopressin. Magnetic resonance imaging of the brain showed a discrete mass in the region of the hypothalamus. The cat was euthanased and post-mortem histological examination demonstrated B cell lymphoma involving the brain, optic nerves, urinary bladder wall and diaphragm. To the authors' knowledge, this case report is the first to describe central diabetes insipidus caused by central nervous system lymphoma in the cat.     

Squamous cell carcinoma causing blindness and ophthalmoplegia in a cat

Ophthalmoplegia and blindness caused by squamous cell carcinoma were reported in a cat. Unilateral functional deficits of cranial nerves II, III, IV, and VI and of the sympathetic nerve supply caused blindness, complete ophthalmoplegia, and Horner syndrome. Radiography and computed tomography revealed a proliferating bony lesion associated with the right tympanic bulla, right temporal bone, right side of the mandible, and left frontal bone. A focal area of bony destruction involved the right sphenoid bone. The cat was euthanatized and necropsied. Squamous cell carcinoma was identified invading the bones and rostral part of the right side of the skull. The tumor had extended through the sphenoid bones into the region of the cavernous sinus and had surrounded the cranial nerves passing through this region. It also had invested connective tissue surrounding the optic nerves and had invaded the right globe through the lamina cribrosa. This represents an unusual distribution for ocular cranial squamous cell carcinoma in a cat.     

Electrophysiologic characteristics of tibial and sciatic nerves in the hen

The peripheral nerve of the hen has become an increasingly important animal model in studies of peripheral neuropathy, especially that induced by organophosphorus agent exposure. However, few electrophysiologic studies have been performed, and few data on normal peripheral nerve function exist. The purpose in the present study was to measure the characteristics of the compound action potential of peripheral nerves of the healthy hen. The results showed that conduction velocities of the tibial and the sciatic nerves were 41 m/s and 60 m/s, respectively. The relative refractory period was slightly shorter in the sciatic nerve. The tibial nerve exhibited a lower threshold for stimulation and a significantly shorter chronaxie (19 microseconds) than did the sciatic nerve (25 microseconds). Variability between animals was relatively small. These data should provide useful reference points on studies in which peripheral neuropathy is induced or suspected.     

Presumptive primary cardiac lymphoma in a cat causing pericardial effusion

We report a case of primary cardiac lymphoma in a cat, causing pericardial effusion. A 13-year-old castrated male Himalayan cat was evaluated for chronic weight loss and radiographic finding of cardiomegaly. Pericardial effusion and a heart mass were detected via echocardiography. Pericardiocentesis and ultrasound-guided fine needle aspirate of the heart mass were performed under sedation. Antemortem diagnosis of cardiac lymphoma was made based on cytology of pericardial fluid. Based on physical examination, laboratory tests and abdominal radiographs, primary cardiac lymphoma was established as the presumptive clinical diagnosis. Treatment with chemotherapeutic agents was initiated.     

Mycobacterial neuritis in a cat

A 2-year-old spayed female domestic shorthair cat was referred for evaluation of rapidly progressive lameness of the right hind limb, which was paralyzed. Histologic examination of biopsy specimens revealed pyogranulomatous inflammation affecting the sciatic, common peroneal, and tibial nerves, and slender, beaded, acid-fast bacilli within macrophages, nerve fibers, and degenerate axons. A diagnosis of mycobacterial neuritis was made and the cat was treated with clofazimine and enrofloxacin for extended periods. Treatment was partially effective; the goal of returning normal function to the limb was not achieved, but disease progression was halted and the cat remained a viable pet.     

CHEMOTHERAPY FOLLOWED BY ABDOMINAL CAVITY IRRADIATION FOR FELINE LYMPHOBLASTIC LYMPHOMA

Combination chemotherapy is standard care for feline lymphoma, although clinically relevant improvements in remission duration are unlikely to result from manipulations of chemotherapy agents alone. Lymphopoietic tissues generally are sensitive to radiation, and support for chemoradiotherapy as a treatment for lymphoma is found in both humans and dogs. The goal of this prospective pilot study was to determine the normal tissue tolerance to 15 Gy total abdomen fractionated radiation therapy following induction chemotherapy in cats with lymphoblastic lymphoma. Eight cats with lymphoblastic gastrointestinal or multicentric lymphoma confined to the abdominal cavity were treated with a 6‐week combination chemotherapy protocol followed 2 weeks later by whole‐abdomen radiation therapy consisting of 10 daily fractions of 1.5 Gy. Treatment was well tolerated; renal insufficiency documented in one cat at the start of radiation therapy progressed to stable chronic renal failure. One cat not in complete remission at the time of radiation therapy relapsed 2 weeks later, one cat with multicentric lymphoma relapsed with hepatic large granular lymphoma, and one cat was euthanatized 3 weeks following completion of radiation therapy for other reasons; no evidence of lymphoma or radiation toxicoses was identified on post mortem evaluation. The remaining five cats remain in remission at least 266 days after starting therapy; median remission duration has not been reached (range, >266 to >1332 days). Results of this study suggest that 15 Gy total abdomen fractionated radiation therapy after induction chemotherapy is tolerated satisfactorily. This protocol is suitable for further testing to quantify efficacy.     

Diagnosis and management of B cell chronic lymphocytic leukaemia in a cat

A four-year-old, female neutered domestic shorthair cat had a history of chronic intermittent vomiting and lymphocytosis. B cell chronic lymphocytic leukaemia was diagnosed by flow cytometry, which revealed abnormally large numbers of mature B lymphocytes in the peripheral blood. The cat was treated conservatively with antiemetic drugs and remained stable without chemotherapy for over a year.     

Myelinated axons in peripheral nerves of adult beagle dogs: morphometric and electrophysiological measurements

The myelinated fibre composition and conduction velocities were measured for the ulnar, saphenous and caudal cutaneous sural nerves of 10 healthy beagle dogs. A systematic random sampling technique was used to estimate the fibre diameter frequency distributions and densities. Conduction velocities were measured from evoked compound nerve action potentials. All nerves showed bimodal diameter frequency distributions with modes being approximately the same for each nerve (2 to 4 microns and 8 to 10 microns or 10 to 12 microns). The variation in the average densities and in the shapes of histograms of the different nerves was slight; however, there was a wide variation for the same nerve in different individuals. The conduction velocities for the fastest conducting axons in the nerves ranged from 63 to 79 m s-1. These normal quantitative processes affecting peripheral nerves in the dog.     

Pathology of spontaneous tumour lesions in pullets and adult chickens in commercial farms - Short communication

Twenty pullets and adult chickens, aged 100 to 403 days, from several commercial chicken farms were examined by gross and histopathology. Grossly, all chickens had white-greyish masses in the visceral organs with or without enlargement of the peripheral nerves. Histopathological examination revealed Marek's disease (MD) lymphoma, lymphoid leukosis (LL) and myeloid leukosis (ML) in 14/20, 5/20 and 1/20 of the chickens, respectively. Lesions of the sciatic nerves in chickens diagnosed as having MD lymphoma were various. No neoplastic and/or inflammatory cells were noted in the peripheral nerves of chickens diagnosed as having LL and ML. These results indicated that MD lymphoma could also develop in older chickens; thus, microscopic examination is needed to identify MD in older chickens showing lymphocyte-derived tumours.     

鸡马立克氏病外周神经的病理组织学研究

用光镜、电镜及特殊染色法对兰州某鸡场２０例自然发生的马立克氏病鸡进行了外周神经的病理组织学研究。结果表明,外周神经主要表现增生性和渗出性病变,前者以瘤细胞增生为主,伴以脱髓鞘和雪旺氏细胞增生;后者以浆液渗出为特征,并发生神经纤维轴索肿胀和髓鞘变化,瘤细胞浸润很少。本文首次报告了马立克氏病的内脏－皮肤－神经混合型病变,还探讨了瘤细胞增生与脱髓鞘、神经水肿之间的关系。     

Malignant peripheral nerve sheath tumour of the urinary bladder in a cat

A 14-year-old domestic shorthair cat presented with a 5-month history of urinary incontinence and inappro-priate elimination. Ultrasonography revealed a well-marginated, vascular mass of mixed echogenicity ex-tending from the dorsal wall of the urinary bladder into the lumen. Partial cystectomy was performed for re-moval of the urinary bladder mass; histopathological evaluation revealed a spindle cell neoplasm with a prominent palisading pattern. Histomorphologic features and immunohistochemical demonstration of vimentin, glial fibrillary acidic protein and S-100 protein, combined with negativity for smooth muscle actin and desmin were consistent with malignant peripheral nerve sheath tumour. This case report describes a novel location of malignant peripheral nerve sheath tumour; to the authors' knowledge, the bladder has not been described as a site of origin in the cat or any other domestic species.