Neurological lameness in the cat: common causes and clinical approach

PRACTICAL RELEVANCE: Neurological causes of lameness are infrequently seen in cats but they are an important consideration when an obvious orthopaedic cause cannot be identified. Monoparetic cats are also frequently presented for veterinary investigation with the main complaint being lameness. CLINICAL CHALLENGES: Neurological causes of lameness may be difficult to determine without access to advanced imaging modalities, electrodiagnostics or cerebrospinal fluid analysis. AUDIENCE: This review, aimed at all veterinarians who treat cats, sets out to describe the specific approach to cats with lameness that cannot be attributed to an orthopaedic cause. It describes the diagnosis and management of the most common neurological conditions responsible for lameness or monoparesis in cats.     

The clinical examination for neuromuscular disease.

Neuromuscular disease can present even the most astute clinician with a challenging diagnostic dilemma. This article focuses on the neuroanatomy and the historical, physical, and neurologic examination findings observed in many of the neuromuscular disorders affecting dogs and cats. In addition, some common laboratory tests and imaging modalities used in the diagnosis of neuromuscular disease, including routine radiography, computed tomography, and magnetic resonance imaging, are discussed. A brief discussion of sensory nerve disorders is also presented.     

Ultrasonographic examination of the musculoskeletal system in cattle

Ultrasound machines with 7.5 to 5.0MHz linear transducers are well suited for rapid and straightforward differentiation of soft tissue swelling in the musculoskeletal system of cattle; in proximal limb regions 3.5MHz convex scanners allow better imaging. The main indications for ultrasonography of the musculoskeletal system in cattle are suspected arthritis, tenosynovitis, bursitis, abscesses, haematomas, diagnosis of muscle and tendon lesions, and generally the evaluation of soft tissue swellings everywhere that cannot be diagnosed based on clinical examination. The examiner starts by obtaining a general overview of the affected region for orientation purposes. This is achieved by locating and identifying anatomical landmarks, thereafter one can search for pathological changes by examination of the region of interest in longitudinal and transverse planes from all sides. The ultrasonographic investigation should follow a standardised systematic protocol. Normal synovial cavities in cattle are difficult or impossible to visualize via ultrasonography because of the very small physiological amount of synovial fluid. Thus, effusion that is easily visualized usually indicates a pathological process like arthritis, tenosynovitis or bursitis. Ultrasonography provides accurate information about the location and size of lesions or fluid-filled cavities, the nature of the content and an exact measurement of the distance from pathologically altered structures to the skin surface. Targeted centesis of synovial or other cavities can be carried out after a preliminary ultrasonographic inspection. Characterization of the lesions and a thorough preoperative inspection of affected regions are of enormous benefit for planning surgery and treatment.     

The value of a single haematological examination in the diagnosis of disease in the cat

A single haematological examination, which included plasma fibrinogen and total protein measurement, was performed on 191 cats when first presented with an owner-suspected abnormality. Apart from anaemia and leucopenia in nine cases of Haemobartonella felis infection and five of panleucopenia, the results with a variety of other disorders were variable. Anaemia was present in a further thirty cats, of which only two showed evidence of remission. Plasma protein values were frequently elevated, an indication that dehydration is common in sick cats. In addition to changes in total and differential leucocyte counts, seventy-three of the blood smears examined showed toxic changes, indicative of interference with neutrophil maturation. Most haemograms had one or more abnormal values. In conjunction with other observations and diagnostic aids, a single haematological examination at the time of a cat's presentation can provide valuable information on a disease process.     

Myeloproliferative disease in the dog and cat: clinical presentations, diagnosis and treatment

The myeloproliferative diseases may present with a variety of clinical signs including regenerative or non-regenerative anaemias, bleeding diatheses, septicaemia or fever of unknown origin. These signs will raise suspicions of myeloproliferative disease but such disease may also be an incidental finding on routine haematological examination. In either case a bone marrow biopsy will be required for confirmation. Investigation for other causes of anaemia, haemostatic dysfunction or other causes of white cell abnormalities is important in animals where the peripheral blood and bone marrow findings are equivocal or atypical of myeloproliferative disease. Treatment of acute myeloproliferative diseases is presently impractical in veterinary medicine. Therapy of the chronic myeloproliferative diseases depends upon the suppression of the proliferation of the affected clones together with attention to the secondary effects of the disease and to the adverse effects of therapy.     

Blindness and behavioural changes in the cat: common neurological causes

PRACTICAL RELEVANCE: Blindness and behavioural changes occur relatively commonly in cats, either separately or in combination, causing devastating consequences for the cat and owner. Blindness can be caused by primary ophthalmic, metabolic or intracranial disease. Similarly behavioural changes may be the primary result of intracranial or systemic disease, but also occur secondarily to visual deficits or changes in interaction with the external environment (ie, non-medical problems). The anatomical pathways involved in vision are very close to those involved in behavioural regulation. It is, therefore, likely that a brain lesion (especially a forebrain lesion) that causes blindness will also cause behavioural abnormalities. CLINICAL CHALLENGES: In cases of partial or unilateral blindness, obvious visual deficits may not be apparent to the owner or clinician. Rather, the visual impairment may manifest more subtly as changes in behaviour, reluctance to jump or unwillingness to go outside. Similarly, behavioural problems may be episodic and, hence, a cat presenting with behavioural disturbances may appear clinically normal on evaluation. Behavioural changes are unlikely to be noticed unless marked and associated with bilateral blindness or advanced systemic illness. AUDIENCE: This article discusses these two major disorders separately, with the aim of highlighting for the clinician some of the important aspects of the general clinical and neurological examination that can be performed to identify these challenging cases.     

Hips, elbows and stifles: common joint diseases in the cat

PRACTICAL RELEVANCE: Cats commonly present with joint disease and trauma. A methodical approach to diagnostics and treatment can aid the clinician in the management of these cases. CLINICAL CHALLENGES: Cats with joint disease may present with a vague history owing to their independent nature, and gait assessment is often challenging when compared with the dog. Knowledge of feline-specific anatomy is important to avoid over- or misinterpretation of physical examination or imaging findings. AUDIENCE: This review of feline joint disease focuses on the more common, non-traumatic conditions of the hip, stifle and elbow. It aims to provide first opinion clinicians with a guide to decision making that will assist them in achieving a diagnosis and formulating a management strategy. EVIDENCE BASE: There is an extensive body of original articles and textbooks in the published literature relating to aspects of feline joint disease. This article combines information from key companion animal and feline-specific references together with the author's clinical experience to provide a practical overview of joint disease, and highlight important differences between cats and dogs in terms of presentation and treatment.     

The role of clinical examination in the accurate diagnosis of bovine neurologic disease

Accurate, specific diagnosis of bovine neurologic disease is both possible and necessary in practice settings. The requirements for accurate diagnosis are a knowledge of the pathogenesis and epizootiology of the bovine neurologic diseases as described in this issue and a systematic approach to clinical examinations including accurate history taking, careful physical examination, neurologic examination, and inspection of the environment. Support for an accurate diagnosis can be obtained by use of the clinical pathology laboratory and, in herd problems, necropsy. The value of a precise diagnosis in bovine neurologic disease lies in the avoidance of costly, inappropriate therapy, the restriction of transmission of zoonotic disease, avoidance of ineffective treatment, more efficient salvage of affected individuals, and cost-efficient implementation of appropriate preventive measures as well as a sense of professional satisfaction in overcoming a challenging and difficult diagnostic problem.     

Neuromuscular disorders in the cat: clinical approach to weakness

PRACTICAL RELEVANCE: Weakness is a relatively common clinical presentation in feline medicine and can be caused by primary neuromuscular disease or by diseases of other body systems affecting the neuromuscular system secondarily. Successful work-up relies on a thorough clinical and neurological examination, and logical problem solving, based on an understanding of the underlying neuroanatomical and pathophysiological mechanisms. CLINICAL CHALLENGES: Feline neuromuscular diseases can be a diagnostic challenge. On initial inspection, the presenting signs can mimic disorders of other body systems, particularly cardiovascular, pulmonary and orthopaedic disease, or may be confused with systemic illnesses. Additionally, because many different pathologies of the feline neuromuscular system converge to a similar clinical phenotype, further diagnostic steps such as electrodiagnostics, cerebrospinal fluid analysis, and muscle and nerve biopsies must be considered even after neuromuscular dysfunction has been identified. AUDIENCE: This review provides a framework for the clinical approach to the weak cat and gives a practical summary of neuromuscular diseases for the general practitioner and specialist alike. EVIDENCE BASE: Many diseases affecting the feline neuromuscular system have been well described in the veterinary literature, mostly based on retrospective case reports and series. The evidence base for the treatment of feline neuromuscular diseases remains very limited.     

Renal biopsy in the normal cat: examination of the effects of repeated needle biopsy

Three healthy cats were subjected to percutaneous renal biopsy of the left kidney on three occasions at monthly intervals. Three other cats were subjected to three consecutive biopsy attempts on one occasion using the left kidney. Thereafter the six cats were monitored clinically and by means of laboratory analyses of blood and urine until euthanasia four weeks after the last biopsy. Cautious insertion of the biopsy needle in an attempt to avoid over penetration of the kidney resulted in failure to obtain renal tissue on six occasions but in all 12 specimens which did contain renal tissue, glomeruli were present. Major blood vessels were present in two biopsy specimens. At necropsy, radiographic and histological studies demonstrated renal parenchymal and vascular changes in the biopsied kidneys which were similar to but less severe than those produced by a single biopsy attempt. This confirmed that avoidance of damage to major renal vessels is important and suggested that, with care, repeated biopsies need be no more harmful to the kidney than a single biopsy.     

Membranous nephropathy in the cat: a clinical and pathological study

A series of 13 cases of feline membranous nephropathy is presented. Two groups were distinguished clinically; eight cats had the nephrotic syndrome and five others were in renal failure but not nephrotic. The definitive diagnosis was based on histological, immunofluorescence and ultrastructural examinations of renal tissue obtained at renal biopsy or necropsy. Glomerular lesions were classified according to the degree of glomerular change into three distinct groups; mild, moderately severe and advanced. A relationship was established between the mild and moderately severe groups and cats with the nephrotic syndrome, and the advanced group and cats in renal failure. Diuretic therapy was satisfactory in initial control of oedema in the nephrotic cases. Monitoring of previously nephrotic cats for up to three years indicated that the disease is progressive, although in some cases it is sufficiently slow for a cat to live a relatively normal life without continuing treatment. The prognosis for cats presented in renal failure is hopeless.     

Medulloblastoma in a cat: clinical and MRI findings

A two-year-old, castrated crossbred cat presented with loss of balance and anorexia. A mass of the caudal aspect of the cerebellum was revealed by magnetic resonance imaging (MRI). The mass was hypointense on T1-weighted images, iso- and hyperintense on T2-weighted images and was enhanced by intravenous gadolinium contrast medium. The MRI characteristics of this case were similar to those of medulloblastoma of the cerebellar vermis in humans. The authors were able to remove almost all of the tumour. The cat was discharged from hospital on day 22 after surgery, but died on day 45. The excised tissue was histologically diagnosed as medulloblastoma.     

Medulloblastoma in a cat: clinical and MRI findings

A two-year-old, castrated crossbred cat presented with loss of balance and anorexia. A mass of the caudal aspect of the cerebellum was revealed by magnetic resonance imaging (MRI). The mass was hypointense on T1 -weighted images, iso- and hyperintense on T2-weighted images and was enhanced by intravenous gadolinium contrast medium. The MRI characteristics of this case were similar to those of medulloblastoma of the cerebellar vermis in humans. The authors were able to remove almost all of the tumour. The cat was discharged from hospital on day 22 after surgery, but died on day 45. The excised tissue was histologically diagnosed as medulloblastoma.     

Cleaning and disinfection: tips for the practice

Cleaning (removal of visible dirt) and disinfection (reduction of the number of micro-organisms to an acceptable level) are necessary to limit 'carry over' of infections agents between patients and people as much as possible. Loose dirt should be removed prior to the use of a detergent. Apart from cases of contamination of an otherwise clean surface or in case of a highly infectious agent, thorough cleaning should always precede disinfection. Several active ingredients are approved for disinfection of animal accommodation. From the point of view of safety and effectiveness, individual chemicals should never be mixed or added to detergents. Queries about the use of chemical agents can be addressed to the College voor de Toelating van Bestrijdingsmiddelen or the manufacturer of the product.