25 Aug 2026
Alex Gough MA, VetMB, PhD, CertSAM, CertVC, MRCVS covers diagnosis, treatment and management of breathing issues in cats and dogs.
Alex Gough
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Dogs and cats commonly present to the clinic with respiratory signs, sometimes as an emergency, but diagnosis and management can be challenging. This article discusses some of the latest research into the diagnosis and management of respiratory disorders.
Bronchomalacia is an important and hard to manage respiratory disease. However, little data exists on prognosis and risk factors for progression of the disease.
Chang et al1 performed a prospective observational cohort study to assess the clinical course and risk factors for the condition. Seventy dogs with bronchomalacia confirmed with bronchoscopy were included in the study. The median survival time after diagnosis was 998 days for all-cause mortality and 1,323 days for cardiorespiratory mortality. Roughly two-thirds of deaths were thought to be due to cardiorespiratory causes.
One-third of the cases had pulmonary hypertension and pneumonia or pneumonitis. Being older, having inflammatory airway disease treated with corticosteroids and pulmonary hypertension were associated with the development of pneumonia/pneumonitis.
Pulmonary hypertension, older age and severe bronchomalacia were associated with increased all-cause mortality. High-grade tracheal collapse, pulmonary hypertension and inflammatory airway disease treated with corticosteroids were associated with increased cardiorespiratory mortality.
The authors concluded that bronchomalacia in dogs is associated with marked mortality. Knowledge of risk factors may help inform management choices.
Tuberculosis is a moderately common presentation in cats in certain geographic areas, but is much less commonly reported in dogs.
O’Halloran et al2 performed a retrospective-prospective observational study of dogs infected with Mycobacterium tuberculosis-complex organisms. Just less than 600 cases were included in the study. Diagnosis was made with a variety of techniques including culture, PCR and interferon-gamma release assay. In those cases where species identification was performed, all cases were caused by either M tuberculosis, M bovis or M microti, this last not having been reported in UK-based dogs before.
Clinical signs were often non-specific and long term, although rapidly progressive in the terminal phase. A total of 44% of cases were primarily pulmonary in location, with 15% being abdominal. Thirteen dogs were treated with combination antibiotics, with a good response being seen in 12 of these.
Influenza can affect various species, and highly pathogenic avian influenza A/H5N1 has been identified as a serious disease in cats. Jańczak et al3 performed a retrospective study of the clinical findings in cats diagnosed with this condition during an outbreak in Poland in June 2023. Twenty-two cats with a laboratory-confirmed diagnosis of A/H5N1 were included in the study. It was noted that six of the cats were strictly indoor cats that had been fed a diet that included raw poultry meat. The disease had an acute onset, with signs including fever, lethargy and anorexia, which quickly progressed to severe dyspnoea and neurological signs such as ataxia, seizures and paraplegia. All affected cats died, usually within three days of the first clinical signs.
Clinicopathologic findings included thrombocytopenia, lymphopenia and eosinopenia, as well as a stress or inflammatory leukogram. Urea and creatinine largely remained normal. Radiography showed the presence of pneumonia. The authors noted that feline A/H5N1 infection is a rapidly fatal disease in cats, and it is important it is monitored to safeguard human health.
Pyothorax is a life-threatening exudate in the pleural cavity, often bacterial, which can occur because of circulating bacteria or direct penetration of the pleural cavity; for example, via the gastrointestinal tract, respiratory tract or chest wall. Diagnosis is by a combination of clinical signs, imaging characteristics and clinical pathology.
Rei et al4 performed a retrospective study to describe the computed tomography (CT) characteristics of cats presenting with pyothorax. Forty-one cats with pre-contrast and post-contrast imaging series were blindly reviewed by two specialists and a third-year imaging resident. All cats were determined to have a pleural effusion; 85% had intrathoracic lymphadenopathy; 85% had pleural thickening; 49% had pneumonia; and 12% had foreign bodies suspected. Twenty cats were managed medically, 20 surgically, and one had unsuccessful medical treatment and then had surgery. Thirty-six cats survived to discharge, with a median duration of hospitalisation of seven days.
The authors noted that cats with pyothorax have a number of changes on CT and a favourable short-term prognosis.
Nasal carcinomas in dogs are hard to treat surgically because of their invasive nature and the difficulty of surgical access. Bottero et al5 carried out a retrospective study to investigate the ability of endoscopic diode laser and forceps debulking (EDLFD) to help palliate this form of neoplasia. Thirty-five dogs with histopathologically confirmed nasal carcinoma were included in the study. A total of 51% of dogs had had clinical signs for three months or more, and 80% had failed to respond to previous medical treatment. The most common clinical sign was unilateral nasal discharge.
No major complications associated with EDLFD treatment were reported, and the median postoperative survival time was 336 days, with more than 50% exhibiting a clinical benefit three months after treatment.
The authors concluded that EDLFD could be a useful approach for palliation of nasal carcinoma in dogs and could lead to an improvement in quality of life.
Pneumomediastinum is an uncommon condition in dogs and cats that 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.
Dogs and cats undergoing bronchoscopy and/or bronchoalveolar lavage often have an already compromised respiratory system, a situation that is worsened by the introduction of the endoscope and lavage fluid.
Dartencet et al7 performed a pilot study that aimed to explore the safety and feasibility of high-flow oxygen therapy (HFOT) compared to conventional oxygen therapy (COT) during bronchoscopy in dogs and cats. Six patients were randomised to HFOT or COT, which were commenced at the start of the bronchoscopy. Peripheral oxygen saturation (SpO2) was assessed regularly with pulse oximetry.
No complications were found when administering HFOT. No significant difference was found in the number of episodes of desaturation between the two groups, but no HFOT patients experienced severe desaturation (SpO2 less than 90%) while two COT patients did experience severe oxygen desaturation. The mean SpO2 was significantly higher in the HFOT group than the COT group at a number of time points. The authors concluded that HFOT is feasible and safe during bronchoscopy, and it may improve oxygenation during the procedure.
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 al8 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. In total, 95% of masses were primary lung tumours and 81% were carcinomas.
Clean surgical margins were achieved in 88% of cases. A total of 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 increase 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.
Alex Gough qualified from the University of Cambridge in 1996, and worked in mixed and small animal practice until 2002, when he co-founded a referral centre in south-west England. He gained an RCVS Certificate in Small Animal Medicine in 2001, an RCVS Certificate in Veterinary Cardiology in 2005, a Postgraduate Certificate in Neuroimaging for Research from The University of Edinburgh in 2009 and a PhD in Applied Health Research from the University of Birmingham. Alex is co-author of Breed Predispositions to Disease in Dogs and Cats, and the author of Differential Diagnosis in Small Animal Medicine. He also writes Vet Times‘ regular Research Review column.