Laryngeal disease in cats: A retrospective study of 35 cases

Retrospective study of 540 cats with respiratory diseases in Japan (2003-2020)

BACKGROUND

Few epidemiological studies on respiratory medicine and the relationship between clinical signs and various respiratory diseases in cats have been reported.

OBJECTIVES

This retrospective study aimed to investigate the prevalence and breed predisposition to feline respiratory diseases in Japan and determine the association between clinical signs, duration and type of respiratory diseases.

METHODS

The medical records of cats with feline respiratory diseases were examined to obtain information on age, sex, breed, final diagnosis, clinical signs and duration. The odds ratios (ORs) and 95% confidence intervals were calculated to evaluate breed predispositions. Mann-Whitney U, Kruskal-Wallis and Dunn's tests were used to assess the duration of clinical signs.

RESULTS

This study included 540 cats with 615 respiratory diagnoses. The American Shorthair breed was predisposed to bronchopneumonia (BP; OR: 5.0) and pulmonary tumour (PT; OR: 3.6), while the Russian Blue breed exhibited a predisposition to inflammatory lower airway diseases (OR: 3.4), BP (OR: 6.1) and interstitial lung diseases (OR: 11.1). Similarly, the Scottish Fold breed displayed predisposition to PTs (OR: 5.8). The duration of clinical signs among nasal diseases, nasopharyngeal diseases and lower tracheal/bronchial and pulmonary diseases differed significantly (p = 0.001, p = 0.012, p < 0.0001, respectively).

CONCLUSIONS

The results suggest that some popular breeds in Japan are predisposed to feline respiratory diseases, especially the American Shorthair, Russian Blue and Scottish Fold breeds. The characteristics of occurrence, clinical signs and duration of each disease will aid in diagnosing, treating, preventing and elucidating the pathophysiology of feline respiratory disease.

Surgical management of a laryngeal rhabdomyosarcoma in a cat

Case summary

An 11-year-old male castrated British Shorthair was referred for investigations into an upper respiratory tract mass. A partial laryngectomy was performed to excise the mass. Marginal resection of the mass involved excision of parts of the thyroid cartilage and left arytenoid cartilage. A tracheostomy tube was maintained for 48 h postoperatively. The cat recovered without complication and was discharged at 72 h postoperatively. Histopathology of the mass was deemed most consistent with a rhabdomyosarcoma (RMS).

Relevance and novel information

Telephone follow-up 12 months postoperatively confirmed resolution of the clinical signs. To our knowledge, this is the first report of a laryngeal RMS in a cat. RMS should be considered a differential diagnosis for a laryngeal mass in a cat. This case demonstrates that resection via a partial laryngectomy may be a viable therapeutic option.

Evaluation of two unilateral laryngoplasty techniques and their effect on arytenoid cartilage abduction in cats

OBJECTIVES

The aim of this study was to evaluate two unilateral laryngoplasty (arytenoid lateralisation) techniques for use in the surgical management of laryngeal paralysis in cats.

METHODS

Left cricoarytenoid abduction (lateralisation) was performed in 20 ex vivo cat larynges; 10 following complete cricoarytenoid disarticulation (group LAA-dis) and 10 following no cricoarytenoid disarticulation (group LAA-nodis). For both groups, left arytenoid abduction (LAA) was measured in the resting and postoperative larynges using image analysis software. Measurements were evaluated using the Mann-Whitney U-test. For both groups, dorsal images of the postoperative larynges were assessed visually for evidence of epiglottic coverage of the entrance to the larynx.

RESULTS

The mean percentage increase in LAA was 311.5% and 199.4% (P <0.006) for group LAA-dis (complete cricoarytenoid disarticulation) and group LAA-nodis (no cricoarytenoid disarticulation), respectively. In both groups, there was no evidence of a lack of epiglottic coverage of the entrance of the larynx for any of the postoperative larynges.

CONCLUSIONS AND RELEVANCE

Placement of a single, tensioned suture between the muscular process of the left arytenoid cartilage and the caudolateral aspect of the ipsilateral cricoid cartilage (unilateral cricoarytenoid lateralisation) resulted in abduction of the left arytenoid cartilage and a corresponding increase in the area of the rima glottidis on the operated side. The clinical significance of the difference in outcome between left cricoarytenoid abduction following complete cricoarytenoid disarticulation and abduction following no cricoarytenoid disarticulation remains unclear, and both might be considered appropriate for the surgical management of laryngeal paralysis in the cat.

Clinical presentation, treatment and outcome in 23 cats with laryngeal or tracheal lymphoma

OBJECTIVES

Feline primary laryngeal or tracheal lymphoma (PLTL) is an uncommon extranodal presentation. Information on long-term survival is scarce, although some small case series describe this being achieved with multiagent protocols; an accurate outcome for cats with PLTL is yet to be determined. The aim of this study was to gather information on the clinical presentation, response to treatment and outcome in a large case series of feline PLTL.

METHODS

This retrospective multicentre study included cats with a cytological or histopathological confirmation of PLTL. Histopathology samples, when available, were reassessed for grade and immunophenotype. Clinical (age, signalment, retroviral status, presence of anaemia, clinical signs, location and therapy type) and outcome (response, progression-free survival [PFS] and overall survival [OS]) variables were recorded. Survival analyses to assess the impact of variables on PFS and OS were performed.

RESULTS

Twenty-three cases were included; cats had a median age of 11 years (range 2-16) and the male:female ratio was 3.6:1. Common clinical signs at presentation included increased respiratory effort (74%) and abnormal upper respiratory tract sounds (48%). Immunophenotyping was performed in 48% of cases and all were B cell. Debulking surgery was performed in 26% of cases. All cats received chemotherapy, COP (cyclophosphamide, vincristine and prednisolone; 39%), CHOP (cyclophosphamide, vincristine, doxorubicin and prednisolone; 44%) and other protocols (17%); 35% had a partial response and 65% a complete response. Median PFS and OS were 909 days (range 23-1484) and 909 days (range 23-2423), respectively. Complete response was associated with longer PFS (P <0.001) and OS (P = 0.012). Pretreatment with steroids was associated with longer OS (P = 0.003). No other variable was found to be significant.

CONCLUSIONS AND RELEVANCE

PLTL in cats is mostly of a B-cell phenotype, could be of a low-to-medium grade, and may respond to surgical and medical treatment with a longer survival time than has previously been reported.

Partial laryngectomy for the management of laryngeal masses in six cats

OBJECTIVES

Partial laryngectomy is an organ-sparing surgical procedure for the removal of laryngeal masses which has not been described in cats. The aim of this study was to report on the surgical procedure and the short- and long-term clinical outcomes of cats that underwent partial laryngectomy.

METHODS

Medical records were retrospectively collected over a 4-year period in two institutions. The following data were retrieved: signalment, history, clinical signs, diagnostic test results, surgical procedure, postoperative management, complications and outcome.

RESULTS

Six cats underwent partial laryngectomy. The most common clinical signs in cats with laryngeal masses were stridor (n = 4) and dyspnoea (n = 4). In all cats, a full-thickness portion of one or several laryngeal cartilages was resected, including thyroid cartilage alone (n = 2), thyroid cartilage and arytenoid (n = 2), and arytenoid cartilage and epiglottis (n = 2). The resected laryngeal masses were reported to be lymphoma (n = 3), carcinoma (n = 1), laryngeal cyst (n = 1) and inflammatory laryngeal disease (n = 1). All cats survived the surgical intervention of partial laryngectomy. Four cats showed varying degrees of respiratory distress in the short-term postoperative period. A temporary tracheostomy tube was placed in two cats. No other postoperative complications were noted in the short- or long-term. Four cats were still alive at the time of writing. These cats survived at least 252 days.

CONCLUSIONS AND RELEVANCE

In a small number of cases, our results show that successful long-term outcomes after partial laryngectomy are achievable, with longer survival times than previously reported. Therefore, partial laryngectomy should be considered as a viable treatment option in cats with laryngeal masses.

Unilateral Laryngeal Paralysis Secondary to Otitis Media/Interna in Two Cats

Two adult cats were presented for coughing, gagging, dysphonia, exaggerated swallowing attempts, unilateral vestibular dysfunction, and/or Horner syndrome. In both cats, unilateral laryngeal paralysis was identified on the side ipsilateral to other neurological deficits. Cross-sectional imaging was consistent with otitis media/interna. In both cats, there also was extensive cellulitis surrounding the tympanic bulla and dissecting through tissue planes to involve the opening of the tympano-occipital fissure on the side ipsilateral to the laryngeal paralysis. Laryngeal paralysis was presumed secondary to involvement of the vagus nerve as it emerged from the tympano-occipital fissure. Antibiotic therapy resulted in resolution of clinical signs in both cats and restored laryngeal function as evidenced by visual examination of the larynx in one cat.

Diagnosis and management of a laryngeal cyst in a domestic shorthair cat

Case summary

A 7-year-old male neutered domestic shorthair cat was presented with a 3-month history of dyspnea when exercising and increased respiratory noise when purring. Initial radiographs identified a suspected laryngeal mass. Point-of-care ultrasound found a fluid-filled structure on the larynx, which was drained percutaneously. The cat initially recovered well but, due to recurrence of clinical signs, a CT scan was performed, which confirmed the presence of a laryngeal cyst that was subsequently surgically resected. Histopathological analysis was consistent with a suspected thyroglossal cyst.

Relevance and novel information

This is only the second report of a laryngeal cyst in the cat. While malignant laryngeal disease may be more prevalent in the cat, benign differentials should be considered as treatment could be curative, as was observed in this case.

Undifferentiated laryngeal carcinoma with hyaline bodies in a cat

BACKGROUND

Primary laryngeal neoplasms are rare in cats, with lymphoma and squamous cell carcinoma being the most commonly diagnosed tumour types. These tumours are usually highly aggressive, difficult to treat, and have a poor prognosis. Here an undifferentiated laryngeal carcinoma with hyaline bodies in a cat is reported.

CASE PRESENTATION

A 13-year-old cat was presented for progressive respiratory signs. Diagnostic procedures revealed a partially obstructive laryngeal mass. Cytology was compatible with a poorly differentiated malignant tumour, with neoplastic cells frequently containing large intracytoplasmic hyaline bodies. After 1 month the patient was euthanised due to a worsening clinical condition and submitted for post-mortem examination, which confirmed the presence of two laryngeal masses. Histopathology confirmed the presence of an undifferentiated neoplasm with marked features of malignancy. Strong immunolabelling for pancytokeratin led to a diagnosis of undifferentiated carcinoma, however, histochemical and immunohistochemical investigations could not elucidate the origin of the large intracytoplasmic hyaline bodies observed in tumour cells, which appeared as non-membrane bound deposits of electron-dense material on transmission electron microscopy.

CONCLUSION

This is the first report of primary undifferentiated laryngeal carcinoma in a cat. Our case confirms the clinical features and the short survival that have been reported in other studies describing feline laryngeal tumours. Moreover, for the first time in feline literature, we describe the presence of intracytoplasmic hyaline bodies in neoplastic cells that were compatible with the so-called hyaline granules reported in different human cancers and also in the dog.

Total laryngectomy in a cat with a laryngeal peripheral nerve sheath tumor

OBJECTIVE

To report the surgical technique and outcome of total laryngectomy in a single clinical case.

STUDY DESIGN

Case report.

ANIMAL

A 5-year-old female spayed domestic shorthair cat.

METHODS

A cat presented for acute, severe respiratory distress caused by an invasive laryngeal mass. Incisional biopsy was indicative of sarcoma. Computed tomography of head, neck, and thorax was performed revealing no evidence of metastasis. A total laryngectomy and permanent tracheostomy were performed, and the cat could breathe without difficulties immediately postoperatively. Histopathology confirmed a laryngeal low-grade peripheral nerve sheath tumor (PNST).

RESULTS

Surgical margins were free of tumor cells. Surgical revision of the tracheostomy stoma due to obstructive granulation tissue was necessary 24 days after the initial surgery. Nine days after revision surgery, the cat was discharged from the hospital. No evidence of local recurrence or metastasis was detected on repeat computed tomography of the head, neck, and thorax at 6 months, nor on chest radiographs at 12 months postoperatively. At the time of writing (13 months postoperatively), the cat is still alive with a good quality of life.

CONCLUSION

Total laryngectomy with permanent tracheostomy allowed the complete removal of an obstructive laryngeal PNST and provided a good quality of life in a cat.

CLINICAL SIGNIFICANCE

To the authors' knowledge, this case report represents the first detailed description of the surgical procedure and clinical outcome for a total laryngectomy in a cat.

Gastroesophageal intussusception and extreme esophageal dilatation secondary to bilateral laryngeal paralysis in a cat

Gastroesophageal intussusception, extreme esophageal dilatation, and laryngeal paralysis are individually rare clinical entities in cats and the simultaneous occurrence in a single animal has not been described. We describe these 3 conditions occurring concurrently in a geriatric cat, and resolution of the cat's clinical signs after treatment with unilateral arytenoid lateralization. This finding supports the need for thorough history taking and examination in cats with extreme esophageal dilatation to determine if upper respiratory tract abnormalities are present, as appropriate treatment might resolve the esophageal dilatation.

Infiltrative laryngeal disease in dogs

OBJECTIVES

To describe the clinical features and outcome of neoplastic and inflammatory infiltrative laryngeal disease in dogs.

MATERIALS AND METHODS

Medical records at a single referral centre were retrospectively reviewed for dogs diagnosed with infiltrative laryngeal disease by CT or laryngoscopy.

RESULTS

Fifteen dogs were included, with a median age of 6 years (range 1-14 years). Thirteen dogs were diagnosed with inflammatory disease including granulation tissue (n = 4) and neutrophilic (n = 2), septic neutrophilic (n = 2), eosinophilic (n = 1) lymphocytic/plasmacytic (n = 1) and mixed/unclassified (n = 3) inflammation. One dog was diagnosed with large cell lymphoma and one dog was diagnosed with mast cell tumour. Twelve dogs survived to discharge. Follow-up was available for 10 dogs diagnosed with inflammatory disease. Four had fully recovered (7, 10, 23 and 32 months) and one dog developed acute leukaemia and was euthanased at 2 months. Five dogs had recurrence of clinical signs at 1, 1, 5, 17 and 26 months. The dog with lymphoma was euthanased at 8 months and the dog with mast cell tumour died at 5 months.

CLINICAL SIGNIFICANCE

In this cohort, infiltrative inflammatory lesions of the larynx were more common than neoplastic infiltration. For dogs that survived to discharge, outcome was fair although relapse was common.

Clinical and radiographic findings in cats with aspiration pneumonia: retrospective evaluation of 28 cases

OBJECTIVES

To describe the clinical syndrome of aspiration pneumonia in cats and record potential predisposing factors.

MATERIALS AND METHODS

A retrospective medical records search for cats with a diagnosis of "aspiration pneumonia" or "bronchopneumonia" was performed. Cases were included if they had a complete medical record and three-view thoracic radiographs with pulmonary changes consistent with aspiration pneumonia and no other radiographic or physical examination findings suggestive of another cause of pulmonary or cardiac disease.

RESULTS

We identified 28 cases. Potential predisposing conditions included: vomiting (12 of 28; 43%), anaesthesia (five of 28; 18%), enteral nutrition (five of 28; 18%), preexisting oesophageal disease (four of 28; 14%), neurologic disease (two of 28; 7%) and laryngeal disease (one of 28; 3.6%); 15 of 28 (53%) had more than one potentially predisposing condition. The most common lung lobe affected was the right middle (18 of 28; 64%), followed by the left cranial (16 of 28; 57%); multiple lung lobes were affected in 16 of 28 (57%) cases. Most cats (25 of 28; 89%) survived to discharge, with a median hospitalisation of 3 days.

CLINICAL SIGNIFICANCE

Potential predisposing factors for developing aspiration pneumonia in cats are similar to those recorded in dogs and people. Aspiration pneumonia occurred in cats following vomiting, anaesthesia or after receiving enteral nutrition. Survival rates are high following treatment with antibiotics and supportive care, with 89% of cats in this study surviving to discharge.

A cat with suspected laryngeal metastasis with mucosal irregularity resulting from apocrine/salivary gland adenocarcinoma in the head

A 16-year-old castrated male mongrel cat presented with swelling under the left pinna and a 3-month history of voice change. Laryngeal endoscopy revealed circumferential oedema around the arytenoid cartilages and hypersecretion of saliva. Histopathological examination of the mass around the left ear canal was considered the primary lesion that originated from cutaneous apocrine adenocarcinoma or parotid gland adenocarcinoma, and it metastasized to the larynx, lung and medial retropharyngeal lymph nodes. This report provides new insights into feline laryngeal diseases which could result in laryngeal metastasis with slight mucosal irregularity alone and without obvious radiographic abnormalities. Therefore, histopathological examination should be performed when a cat presents clinical signs such as stridor, dysphonia or voice change without any mass-forming laryngeal lesion.

Redundant arytenoid mucosa: clinical presentation, treatment and outcome in three cats

Three cats showing chronic, intermittent respiratory distress associated with increased noise on inspiration were examined. Head, neck and thoracic radiographs were unremarkable and laboratory findings were within normal ranges. In all three cats direct laryngoscopy revealed bilateral redundant arytenoid mucosa, which collapsed into the supraglottic and glottis airways during inspiration. Temporary tracheostomy and endoscopic diode laser excision of the excessive mucosa resolved symptoms in all three cats. Redundant arytenoid mucosa is a rare condition that may cause signs similar to laryngeal paralysis or laryngeal mass in cats. According to our results, diode laser surgery in association with temporary tracheostomy appears an appropriate mode of therapy.

Laryngeal disease in dogs and cats

The most common disease process involving the larynx is laryngeal paralysis, which occurs much more frequently in dogs than in cats. Diagnosis of laryngeal paralysis requires close attention to anesthetic plane and coordination of respiratory effort with laryngeal motion. Surgical arytenoid lateralization improves respiration and quality of life in dogs with laryngeal paralysis; however, aspiration pneumonia is a recognized complication, and generalized neuropathy can progress. Laryngeal collapse can result from any cause of chronic upper airway obstruction, but is most often associated with unaddressed brachycephalic airway syndrome. Laryngeal neoplasia, while generally uncommon, occurs more frequently in cats than in dogs.

Unilateral laryngeal paralysis subsequent to surgical ligation of a patent ductus arteriosus in an 8-week-old domestic shorthair cat

CASE DESCRIPTION

An 8-week-old female domestic shorthair cat was treated for patent ductus arteriosus (PDA) with surgical ligation. Seven weeks postoperatively, the cat was evaluated because of increased upper respiratory noise, inspiratory stridor, wheezing, and episodes of intermittent open-mouth breathing that had developed 1 week following the surgical ligation.

CLINICAL FINDINGS

The cat was sedated, and examination of the larynx revealed left-sided laryngeal paralysis.

TREATMENT AND OUTCOME

At the time left-sided laryngeal paralysis was diagnosed, the clinical signs of laryngeal dysfunction were not considered severe enough to warrant surgical intervention. No treatment was administered, and the owner monitored the cat for respiratory distress and worsening of clinical signs for an additional 5 months. During those 5 months, the clinical signs improved but persisted. Seven months after PDA ligation, the cat was again sedated and the larynx examined. The examination revealed persistent left arytenoid dysfunction, which was believed to be the result of permanent damage to the recurrent laryngeal nerve that was sustained during the surgical ligation of the PDA. The owner was counseled about surgical and medical treatment options for laryngeal paralysis but elected to forego treatment at that time.

CLINICAL RELEVANCE

Unilateral laryngeal paralysis caused by iatrogenic damage to the recurrent laryngeal nerve is a potential complication subsequent to surgical ligation of a PDA. The frequency of iatrogenically induced laryngeal paralysis is likely underestimated in small animal patients. Laryngoscopy should be performed in any small animal with a history of PDA attenuation and clinical signs of respiratory tract disease.