Lung mass surgery in dogs

Removal of lung tumours at open surgery is associated with high levels of discomfort and postoperative complications. Thoracoscopic resection of lung masses can reduce these problems.

Park et al¹ performed a retrospective cohort study to assess the risk factors for conversion from thoracoscopic resection to thoracoscopy-assisted or open surgery. Sixty-one dogs were included in the study. Sixty cases had histopathology available. 95% of masses were primary lung tumours and 81% were carcinomas.

Clean surgical margins were achieved in 88% of cases. 26% of cases required conversion from thoracoscopy to thoracoscopic-assisted or open surgery techniques. Size of tumour and presence of lymphadenopathy on preoperative CT scans were associated with an increased chance of needing conversion, but body condition score and tumour location were not associated with a need for conversion. All dogs survived to discharge, and median overall survival time was 311 days. Tracheobronchial lymphadenopathy on preoperative CT scans was a risk factor for shorter survival, but adjuvant chemotherapy and incomplete margins were not associated with survival.

The authors concluded that the prognosis following thoracoscopic lung lobectomy was favourable, but large tumour size and local lymphadenopathy was associated with an increased chance of necessity for conversion.

Novel thyroid-stimulating hormone assay

Hyperthyroidism is a common endocrine condition of cats which can be treated with radioactive iodine (I-131). However, the treatment can lead to hypothyroidism. Thyroid-stimulating hormone (TSH) concentrations are usually measured in cats using canine TSH chemiluminescent assays (CLIA), but these are unable to measure low TSH concentrations, and so are of limited use for aiding the diagnosis of hyperthyroidism.

Peterson et al² performed a study to evaluate the use of a novel TSH assay using bulk acoustic wave (BAW) technology that is able to detect lower levels of TSH.

One hundred and sixty-nine cats with untreated hyperthyroidism, 53 cats treated with I-131, 12 cats with chronic kidney disease and 78 healthy cats were included in the study.

Thyroxine (T4) was measured along with the new and old methods of measuring TSH. Sensitivity, specificity and positive predictive values were higher for the BAW method than the CLIA method for diagnosing hyperthyroidism.

T4 had low sensitivity for identifying hypothyroidism induced by I-131, but both the BAW and CLIA methods had 100% sensitivity for this. TSH-BAW had a higher positive predictive value for hypothyroidism than either of the other methods.

The authors concluded that TSH measured by the BAW method with or without concurrent T4 measurement is highly specific, and sensitive for diagnosis feline hyperthyroidism and iatrogenic hypothyroidism.

Tooth resorption in cats

Feline tooth resorption (TR) is a common and painful dental disease. The cause is unknown, but age, breed and other dental and oral diseases, as well as environmental factors, are thought to predispose to the condition.

Vapalahti et al³ performed a case control study using data from a feline online health survey of more than 8,000 cats in Finland. Only cats with oral or dental disease that had been examined by a vet under sedation or anaesthesia were included.

Nine hundred and forty-four cats were included in the study, 202 of which were diagnosed with TR, while the rest were considered controls. Age was a risk factor, as were gingivitis and periodontitis associated with calculus. Cornish rex, European and ragdoll breeds were at higher risk, and the exotic-Persian, Turkish Van and Devon rex breeds had lower risk.

Another finding was that female cats with constant access to food had less TR than female cats which had set feeding times. The authors concluded that a genetic contribution to TR likely exists.

Cardiac changes in dogs fed high-pulse diets

Non-traditional high-pulse diets have been associated with cardiac changes in apparently healthy dogs, such as increased left ventricular diameter, reduced systolic function and increased numbers of ventricular premature complexes (VPCs).

Coppinger et al⁴ performed a retrospective study to compare the electrocardiographic (ECG) and echocardiographic findings between Irish wolfhounds that were fed diets high or low in pulses.

Ninety-seven Irish wolfhounds that had echocardiography performed were included in the study. Diets were classified as high in pulses based on the presence and amount of pulses such as peas, lentils and chickpeas. 36% of dogs were being fed high-pulse diets and 64% low-pulse diets.

No difference was recorded between the groups in echocardiographic findings, but VPCs were more common in dogs fed high-pulse diets.

The authors concluded that the presence of VPCs in these dogs might indicate the development of early cardiac disease.

Aerophagia in dogs

Aerophagia, the ingestion of air, is a functional digestive disorder. Aerophagia in dogs is defined as a bolus that is at least one-third air, which results in gastric distension that constitutes one-third of the final gastric volume, occurring during eating and drinking. The incidence, clinical signs and associated disorders have not been previously reported.

Grobman et al⁵ performed a retrospective study which aimed to evaluate the incidence of aerophagia and the clinical signs it causes, as well as identify predisposing factors. One hundred and twenty dogs were included in the study.

The incidence of aerophagia was 40%, and dogs with a mix of gastrointestinal and respiratory clinical signs were more likely to suffer from aerophagia than those with purely respiratory signs. The incidence in brachycephalic dogs was 46% compared to 14% in non-brachycephalic dogs, and was more common in dogs with non-brachycephalic upper airway obstruction and signs of gagging.

The authors concluded that aerophagia is common and seen more often in dogs with mixed clinical signs, brachycephalic dogs and dogs with upper airway obstruction. A high risk of aspiration was noted in dogs with aerophagia.

Traumatic pneumomediastinum

Pneumomediastinum is an uncommon condition in dogs and cats which can be associated with blunt trauma.

Klainbart et al⁶ performed a retrospective study of 52 patients – 29 dogs and 23 cats – that had traumatic pneumomediastinum (TPM) to describe the characteristics of the condition.

Clinical signs in dogs were mainly tachycardia and tachypnoea, while in cats hypothermia and tachypnoea were more common. Both species tended to exhibit concurrent subcutaneous emphysema and pneumothorax as well as dyspnoea. Pneumothorax and lung contusions were often seen on radiographs.

The overall mortality rate was 18% but 93% of dogs survived and only 68% of cats.

The authors concluded that TPM is uncommon, but can occur without obvious signs of external injury. Most cases did not require direct treatment of the TPM. The prognosis was fair for dogs, but guarded for cats.

Syringomyelia and Chiari-like malformation in the Pomeranian

Chiari-like malformation (CM) and syringomyelia (SM) have a high prevalence in certain toy-breeds, in particular the cavalier King Charles spaniel. The condition is associated with clinical signs of pain and persistent scratching. Increasing age is considered to be a risk factor for SM.

Santifort et al⁷ performed a longitudinal study of CM and SM in the Pomeranian breed to investigate the change in clinical signs and imaging findings over time in this breed. Nineteen Pomeranians with or without clinical signs of CM/SM were included in the study. The first MRI was conducted at a median age of 26 months with a median interval to the second scan of 26 months.  58% of dogs had clinical signs of CM/SM at the time of the first scan, and 89% at the time of the second scan. Significant differences were found between the two MRI scans for the size of the syrinx.

The authors concluded that the SM status of Pomeranians changes as they age.

Use of some of the drugs in this article is under the veterinary medicine cascade.