Journal of Feline Medicine and Surgery

The use of blood lactate concentrations as a prognostic indicator and therapeutic gauge in feline medicine has been hindered by the inability to obtain values in a timely manner with minimal quantities of blood. Recently, hand-held point-of-care (POC) lactate meters have become commercially available. The objective of this prospective study was to determine if lactate values produced by three commercially available and one medical grade POC meter were in agreement with a laboratory blood analyzer. Blood samples from 47 cats were collected on presentation to an emergency service and processed on four POC meters and a Stat Profile Critical Care Xpress blood analyzer. The results were analyzed using the Bland–Altman method. The blood lactate values produced by the hospital grade POC meter and one of the commercially POC meters were in good agreement with the Critical Care Xpress blood analyzer. Other commercially available POC meters produced acceptable agreement.

Polycystic kidney disease (PKD) is an inherited autosomal kidney disease which is most commonly identified in Persian and Persian related cats. Positive cats have multiple cysts of various sizes that occur in the renal cortex and medulla and occasionally in other abdominal organs. PKD often leads to renal failure which occurs from mid to late in life. Renal cysts can be diagnosed ultrasonographically after 7 weeks of age by an experienced ultrasonographer and a high resolution machine. However, ultrasonography is now being replaced by genetic screening. A total of 340 cats of variable breeds aged from 5 months to 18 years were ultrasonographically examined in the past 7 years at the University Veterinary Small Animal Clinic. Of these, 13.8% were PKD positive with very high prevalence in Persian cats (36%). There was no sex predilection identified. The C>A transversion at position 3284 on exon 29 of PKD1 gene, resulting in a stop mutation has been identified in the heterozygous state in eight affected cats examined (Persian breed). All heterozygous cats were also ultrasonographically positive.

The aim of this study was to determine the prevalence and risk factors for Mycoplasma haemofelis (Mhf) and ‘Candidatus Mycoplasma haemominutum’ (Mhm) infections in domestic cats tested for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Based on serological testing, cats were grouped as i) FIV-positive (n=25); ii) FeLV-positive (n=39); iii) FIV/FeLV-positive (n=8); and iv) FIV/FeLV-negative (n=77). Complete blood counts were followed by DNA extraction, species-specific polymerase chain reaction (16S rRNA gene) for Mhf and Mhm and Southern blotting for all animals. Mhf DNA was found in 4.0, 2.6, 12.5 and 7.8% of the cats from groups i, ii, iii and iv, respectively, while 32, 5.1, 50 and 5.2% of these animals had an Mhm infection. Cats with FIV (OR=4.25, P=0.009) and both FIV and FeLV (OR=7.56, P=0.014) were at greater risk of being hemoplasma infected than retroviral-negative cats, mainly due to Mhm infection (OR=8.59, P=0.001 and OR=18.25, P=0.001, respectively). Among pure-breed cats, FIV-positive status was associated with hemoplasma infection (OR 45.0, P=0.001).

Dysautonomia of domestic animals is pathologically characterized by chromatolytic degeneration of the neurons in the autonomic nervous ganglia that results in clinical signs related to dysfunction or failure of the sympathetic and parasympathetic nervous systems. The exact cause is unknown. It has a poor prognosis among all species reported and no definitive treatment is available currently. To date, most reported feline cases have occurred in the United Kingdom and Scandinavia. The cases reported here highlight the clinical signs, physical examination findings, and results of autonomic nervous system function testing in nine cats with dysautonomia in the US. Feline dysautonomia is uncommon in the US, but may have a regional prevalence, as is seen in dogs with most cases reported in Missouri and Kansas.

Feline heartworm disease is caused by the filarial nematode Dirofilaria immitis, and is transmitted by mosquitoes in heartworm-endemic areas worldwide. While dogs are the definitive hosts for this parasite, cats can also be infected, and the overall prevalence in cats is between 5% and 10% of that in dogs in any given area. The spectrum of feline presentations varies from asymptomatic infections to chronic respiratory signs, sometimes accompanied by chronic vomiting to acute death with no premonitory signs. Ante-mortem diagnosis can be challenging and relies on a combination of tests, including antigen and antibody serology, thoracic radiography and echocardiography. As treatment with heartworm adulticidal drugs can be life-threatening and heartworm infection in cats is often self-limiting, infected cats are frequently managed with supportive treatment (corticosteroids, bronchodilators, and anti-emetics). Surgical removal of filariae using extraction devices may be considered in some acute cases where immediate curative treatment is necessary, but filarial breakage during the procedure may result in an acute fatal shock-like reaction. Necropsy findings are mainly pulmonary and include muscular hypertrophy of the pulmonary arteries and arterioles on histopathology. A number of safe and effective macrocytic lactone drugs are available for prophylaxis in cats. These drugs can kill a range of larval and adult life-cycle stage heartworms, which may be advantageous in cases of owner compliance failure or when heartworm infection status is undetermined at the time prophylaxis is commenced. An index of suspicion for feline heartworm disease is warranted in unprotected cats with respiratory signs, and perhaps chronic vomiting, in areas where canine heartworm disease is endemic. Many cats, once diagnosed and with appropriate supportive care and monitoring, will resolve their infection and be free of clinical signs.

The objective of this study was to examine clinical signs, laboratory parameters, and course of disease in Abyssinian and Somali cats with pyruvate kinase (PK) deficiency. The clinical course of 25 PK-deficient cats was followed over a time period of 0.8–11.3 years (median 4.3). Eleven cats (age 0.8–7.8 years, median 4.4) did not show signs according to the owners. In 14 cats (age 0.1–5 years, median 1.7) the owners noted lethargy (10), diarrhoea (seven), pale mucous membranes (six), inappetence (six), poor coat quality (six), weight loss (four), icterus (four), and pica (two). Sixteen cats had been used for breeding at least once before diagnosis. Laboratory abnormalities included anaemia (70%), increased aggregated reticulocyte counts (94%), hyperglobulinaemia (80%), hyperbilirubinaemia (53%), and increased liver enzymes (47%). Six of 25 affected cats died (four) or were euthanased (two) at ages ranging from 1.3 to 11.3 years (median 4.1) presumably because of PK-deficiency. These findings emphasise that PK deficiency shows variation in age of onset and severity of signs. As PK-deficient cats can be asymptomatic testing for PK deficiency before breeding is strongly recommended.

To evaluate the clinically normal feline cornea for the presence of virulent feline herpesvirus-1 (FHV-1), corneas from 31 cats (25 with normal eyes and six with active disease or corneal scarring) euthanased at a shelter were collected. Corneas from two specific pathogen-free cats were included as negative controls. Virus isolation (VI), fluorescent antibody (FA) staining and real-time polymerase chain reaction (rt-PCR) were performed on all samples. The presence or absence of dexamethasone in the media was evaluated for its effect on VI. VI was positive for FHV-1 in six corneas from five cats, all with clinically normal eyes. One cornea was positive for feline calicivirus (FCV) in addition to FHV-1, but only in media that included dexamethasone. Eight corneas were positive on rt-PCR for FHV-1, all from cats with clinically normal eyes. All positive VI samples were confirmed with FA staining. VI and rt-PCR were negative for FHV-1 and FCV in cats with active disease or corneal scarring. Data from this study indicate that virulent FHV-1 and FCV can be present in feline corneas that are clinically normal. Dexamethasone may enhance viral spread through a cell receptor mechanism.

To determine if routine pre-treatment clinical data can be used to predict the development of overt renal insufficiency following treatment of feline hyperthyroidism, we studied retrospectively all non-azotemic cats undergoing treatment for hyperthyroidism at our hospital. Medical records were reviewed for signalment, clinical signs, and serum biochemical, hematologic and urinalysis parameters before and after treatment for hyperthyroidism. Two groups – cats that developed post-treatment renal insufficiency, and those that did not – were compared. No significant differences could be detected between the groups with respect to the parameters measured. Our study suggests that the results of routine pre-treatment clinical data cannot be used to reliably predict renal function after treatment for hyperthyroidism, validating the necessity of a methimazole trial prior to definitive therapy. The widely held belief that cats with pre-treatment urine specific gravity>1.035 are at less risk for development of renal azotemia after treatment of hyperthyroidism seems unwarranted.

Faecal samples were taken from cats living in multi-cat households with endemic feline coronavirus (FCoV) infection. Total RNA was extracted from faecal suspensions and FCoV RNA was quantified using a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The real-time RT-PCR threshold cycle (C_T) values were consistently high suggesting that the samples contained very little viral RNA. However, experiments in which RNA extracted from FCoV-infected cell culture supernatants was combined with RNA extracted from faecal suspensions revealed the presence of faecal factors that significantly inhibited the reverse transcription reaction. Consequently, three methods of RNA extraction were investigated and RNA dilution was undertaken to investigate whether the effects of the faecal inhibitors could be reduced. Our results show that using the QIAgen RNA mini kit for RNA extraction and dilution of the RNA samples helps to reduce the inhibitory effects. However, because the extent of the inhibitory effects varied between faecal samples, accurate quantification proved difficult. We, therefore, conclude that although real-time RT-PCR provides an excellent method for detecting the presence of viral shedding, quantification of FCoV RNA in faecal material has to take into account the possible effects of RT-PCR inhibitors. It is, therefore, essential that all new assays, and the methods of sample preparation, are carefully evaluated before being used in a clinical setting.

A 3-year female-neutered domestic shorthair cat presenting with exophthalmos and an ipsilateral subzygomatic soft tissue mass lesion is described. Magnetic resonance imaging of the mass was performed followed by complete surgical excision. The mass was determined to be a retrobulbar teratoma and complete resection was curative. Teratomas are rare germ-cell tumours that uncommonly form in extragonadal sites. A retrobulbar location has not been previously reported in the cat and should be considered a rare cause of exophthalmos in this species.

This report describes a case of feline infectious peritonitis (FIP) in a castrated cat which first presented with the unusual sign of priapism. Laboratory examinations showed increased serum protein content and decreased albumin/globulin ratio. Serum electrophoresis revealed increased α₂- and γ-globulin content. One month after the first examination, the cat died. At necropsy, histopathological evaluation of organs showed inflammatory granulomatous lesions compatible with non-effusive FIP and coronavirus-specific polymerase chain reaction confirmed the diagnosis. FIP antigen was demonstrated immunohistochemically in penile tissue.

A 13-year-old female domestic shorthair cat was examined because of weight loss over 4 months. The history included being neutered when a kitten and no signs of estrus recognized by the owner since this surgery. A mid-abdominal mass was palpated. Ultrasonographic abdominal evaluation revealed a tubular fluid-filled mass. The cat underwent surgery to remove the mass, which was one horn of the uterus. The patient made a full recovery.

A cat was referred for investigation of a soft tissue mass caudal to the left mandible. Initial investigations suggested a malignant salivary gland tumour, and the mass was removed by extracapsular resection of the mandibular gland. Histopathology showed an oncocytoma within the salivary gland. An oncocytoma is a neoplastic transformation of oncocytes. Oncocytes are cells with a small nucleus and intense eosinophilic granular cytoplasm due to numerous mitochondria, which proliferate during ageing in exocrine and endocrine glandular tissues. Physiological proliferation occurs next to oncocytosis, oncocytoma, and oncocytic carcinoma. This is the first report of an oncocytoma in a feline mandibular salivary gland, and the first report of long-term survival after surgical removal.

This report describes a rare clinical case of a 4.5-month-old, female domestic shorthair, cat with isolated abdominal fat tissue inflammation and necrosis, resembling human omental panniculitis. Its possible relationship with pancreatitis or bile induced chemical peritonitis is also discussed. The overall clinical course was considered benign. Initial clinical signs were vomiting and anorexia, presumably due to inflammation, followed by mass development. It was speculated that, eventually, the kitten was vomiting because of mechanical pressure from the mass, and that this pressure subsided as the kitten grew. The mass was surgically resected and no relapse was evident during the next 4 years.

Three cats were examined because of acute dyspnoea and sudden abdominal enlargement. In all cats, radiographs revealed gastric dilatation–volvulus (GDV) and diaphragmatic hernia. Cardiovascular shock and dyspnoea were treated by intravenous fluid-therapy, oxygen administration and relief of diaphragmatic pressure by means of stomach decompression and in one case placing the patient in an inclined position. Gastric decompression was performed by needle gastrocentesis, placement of a rhino-gastric tube, or a combination of these. Diaphragmatic herniorrhaphy was performed in either case; one cat also underwent gastropexy. The immediate postoperative period resolved uneventfully and the cats were doing well at follow-up. Feline GDV is a rare event in which diaphragmatic hernia may be a predisposing factor.

A 14-year-old spayed female domestic shorthair cat presented with an interscapular mass. A computed tomography scan, biopsy, and histological examination revealed a fibrosarcoma adjacent to a pet identification microchip. Because the cat was previously vaccinated at this site, it is not possible to establish definitive causation of the fibrosarcoma, but this is the first report of a tumor in the vicinity of a microchip in a cat. Microchip-associated tumors have been reported in rodents and dogs. Veterinarians should be aware that because inflammation may predispose felines to tumor formation, separation and observation of vaccination and implantation sites are indicated. Adherence to American Association of Feline Practitioners (AAFP) vaccination guidelines and monitoring of microchip implantation sites are recommended.

Cerebellar vascular hamartoma was diagnosed in a 16-month-old cat following magnetic resonance imaging and incisional biopsy. The clinical features were consistent with the cerebellar site of the lesion accompanied by signs attributable to cerebellar herniation through the foramen magnum and increased intra-cranial pressure. A lesion of this type represents a previously unreported differential diagnosis for central nervous system lesions in young cats.