Diode laser coagulation for the treatment of epistaxis in a Scottish fold cat

Abstract

We report the case of a 4-year-old, castrated 4.2-kg Scottish fold cat with recurrent epistaxis that was unresponsive to medical therapy. Diathermocoagulation of the nasal mucosa with a diode laser controlled the epistaxis and there was no significant recurrence of epistaxis during 1 year of follow-up.

Epistaxis in cats is caused by bleeding disorders, hypertension (1), hyperviscosity syndrome (2), hamartomas (3), neoplasia, and infectious rhinitis; however, its prevalence is low. In humans, especially children, recurrent epistaxis related to excessive low-grade inflammation of vessels and thin-walled arterioles (4) and hereditary hemorrhagic telangiectasia (5) has been reported. Although anterior epistaxis, such as bleeding from Kiesselbach’s plexus, is common in humans (6), the sites of bleeding have not been reported in cats with epistaxis.

While recurrent epistaxis is treated with silver nitrate cauterization when the bleeding site has not been identified in humans, this approach is not suitable in cats because of possible septal perforation; a severe complication (4,5,7). However, electrocautery or diathermy with a pulsed dye (8), neodymium:yttrium-aluminium-garnet (Nd:YAG) (9), argon (10), or diode (11) laser may be attempted when the bleeding site has been identified. Chemical, electrical, diathermic, or laser coagulation for epistaxis has not been reported in cats.

We report a case of recurrent epistaxis in a young Scottish fold cat, and describe the bleeding site and its treatment with diode laser coagulation.

Case description

A 4-year-old, castrated male, Scottish fold cat weighing 4.2 kg was evaluated for mild sneezing and intermittent bilateral epistaxis preceded by right epistaxis without melena. The epistaxis had occurred occasionally from the time the cat was 1 year old, although the amount and frequency had been mild. Physical examination revealed a grade 4/6 systolic heart murmur in the left parasternal region. The indirect systolic blood pressure measured by Doppler was 237 mmHg when the cat was slightly excited. A complete blood (cell) count (CBC) revealed leucopenia [3780/μL; reference range (RR): 5500 to 19 500/μL], and serum biochemistry revealed an elevated creatinine level (185.6 μmol/L; RR: 70.7 to 159.1 μmol/L). The prothrombin time (8 s; RR: 8 to 11 s) and activated partial thromboplastin time (27 s; RR: 20 to 27 s) were normal. Tests for feline immunodeficiency and feline leukemia viruses were negative. Analysis of urine obtained by cystocentesis showed hematuria and proteinuria; however, the urine protein-to-creatinine ratio (UPC) was 0.21. The urine specific gravity was 1.030. The urine was not cultured. Echocardiography showed that the end-diastolic basilar septal thickness was 6.5 mm, and the left ventricular outflow tract velocity (2.52 m/s) was increased due to systolic anterior motion of the septal leaflet; hypertrophic obstructive cardiomyopathy (HOCM) was diagnosed. The cat was prescribed benazepril (Fortekor; Novartis Animal Health, Tokyo, Japan), 0.6 mg/kg body weight (BW) PO, q24h, for approximately 1 mo because hypertension was suspected as the cause of the epistaxis.

At 35 d after first presentation, computed tomography angiography (CTA) was performed because epistaxis occurred up to once or twice a week even though the cat’s indirect systolic pressure was decreased to 196 mmHg. The CTA did not reveal any abnormalities such as a mass, chronic rhinitis, or foreign body. Nasal flushing samples were cultured, but no pathogens were detected. Real-time polymerase chain reaction (RT-PCR) tests (IDEXX, Tokyo, Japan) on nasopharyngeal and conjunctival swabs for feline herpes virus, feline calicivirus, Chlamydophila felis, Mycoplasma felis, Bordetella bronchiseptica, and H1N1 influenza virus were all negative. The cat was prescribed benazepril (0.6 mg/kg BW, PO, q24h) and amlodipine (Amlodin; Sumitomo Dainippon Pharma, Osaka, Japan), 0.625 mg, PO, q24h, because hypertension was again suspected.

At 58 d after first presentation, a rhinoscopy was attempted because mild sneezing and epistaxis occurred approximately 2 wk after antihypertensive treatment. Caudal rhinoscopy revealed excessive and tortuous vessels in the nasopharynx that bled easily (Figure 1). The region containing the abnormal vessels was sampled for pathological investigation. Moderate bleeding was arrested with cold saline. Microscopically, we observed many irregularly shaped blood vessels of various wall thicknesses lined by a flattened mature endothelium (Figure 2). Prednisolone (Predonine; Shionogi, Osaka, Japan) was probatively prescribed for 1 mo because vascular malformation was suspected. Prednisolone was started at 1.25 mg/kg BW, PO, q24h for 7 d, reduced to 1.25 mg/kg BW, q48h for 7 d, and then continued at 0.625 mg/kg BW, q48h for 2 wk. The frequency of epistaxis decreased to once a month; however, the owner decided to stop administering prednisolone because of its adverse effects: namely polyuria/polydipsia.

Figure 1.

Caudal rhinoscopy of the nasopharynx. Excessive and tortuous vessels were observed in the nasal mucosa.

Figure 2.

Nasal submucosa. Irregularly shaped blood vessels with various wall thicknesses lined by a flattened mature endothelium (hematoxylin and eosin staining). Bar = 100 μm

At 93 d after first presentation, diathermocoagulation was attempted with a diode laser via a caudal rhinoscopy. The cat was anesthetized with fentanyl (Fentanyl Injection; Janssen Pharmaceutical, Tokyo, Japan), 5 μg/kg BW, IV and propofol (Propofol; Mylan Seiyaku, Tokyo, Japan), 5 mg/kg BW, IV, for induction and fentanyl (Janssen Pharmaceutical), 5 μg/kg BW per hour constant-rate infusion (CRI), and isoflurane (1.5% to 2.0%) for maintenance of anesthesia. Lactated Ringer’s solution (5 mL/kg BW per hour, IV) was given as a maintenance fluid. A diode laser (DVL-20; Asuka Medical, Kyoto, Japan) was used to cauterize the nasal mucosa. A flexible 6-mm endoscope (VQ TYPE 6092A, Olympus, Tokyo, Japan) was used to visualize the excessive and tortuous vessels in the nasopharynx. A 400-μm bare optical fiber was guided to the abnormal vessels through the channel of the endoscope. The tip of the bare optical fiber was partially peeled off and manually carbonated to coagulate the tissues by heat. Laser coagulation was performed at 2.5 to 6.00 W output power and was continued until the abnormal vessels had disappeared (Figure 3). The tip of the fiber was re-carbonated when the carbonized substance was dropped or burned off. If bleeding occurred from the vessels during laser coagulation, it was arrested using the carbonated tip. The duration of the operation was 85 min, and the cat recovered from anesthesia without complications. Fentanyl, 2 μg/kg BW per hour CRI, was continued for 24 h for analgesia, and cefalexin (Laryxin; Toyama Chemical, Tokyo, Japan), 18 mg/kg BW, PO, q12h, was prescribed as an antibacterial agent. Tramadol (Toramal; Nippon Shinyaku, Kyoto, Japan), 0.1 mg/kg BW, PO, q12h, was prescribed for analgesia for 3 d after surgery. The cat had a good appetite and did not appear to have lost his sense of smell, even immediately after surgery. Intermittent mild sneezing and a small amount of epistaxis occurred during the 10 d following laser treatment. Significant epistaxis had disappeared by the 1-year follow-up.

Figure 3.

A — Rhinoscopy during diathermocoagulation with a diode laser. The arrow indicates the carbonated tip of the laser fiber. This procedure was performed until the abnormal vessels had disappeared. B — Rhinoscopy after laser cautery. The disappearance of the abnormal vessels was confirmed.

Discussion

Although epistaxis is rare, it can be caused by bleeding disorders, hypertension (1), hyperviscosity syndrome (2), hamartomas (3), neoplasia, infectious rhinitis, lymphoplasmacytic rhinitis, and foreign bodies in cats. In the present case, we did not detect any mass, infection, or foreign body. The indirect systolic blood pressure was above the reference range and chronic kidney disease, which is common in cats, might be considered as the cause of the hypertension (12). However, hypertension does not appear to be the cause because epistaxis was observed even when the cat was young and a “white coat hypertension” was commonly observed in cats at the hospital (12). Indeed, the antihypertensive treatment did not resolve the cat’s epistaxis although medical control of hypertension might not have been sufficient.

The owner requested a more detailed examination via rhinoscopy because she was distressed by the nosebleeds that occurred when her cat sneezed. In addition, the cat might require anti-platelet and/or antithrombotic therapy in the future because he is affected by HOCM. The rhinoscopy revealed excessive and tortuous vessels in the nasopharynx indicative of posterior epistaxis, whereas anterior epistaxis, such as Kiesselbach’s plexus, is common in humans (6). A biopsy was attempted despite the risk of severe hemorrhage. Fortunately, the moderate hemorrhage that did occur was arrested by the use of cold saline. Indeed, protracted hemorrhage was reported as an uncommon complication in dogs that underwent rhinoscopy-assisted biopsy (13). The cat had experienced recurrent epistaxis from 1 y of age. Recurrent epistaxis is common in children, although its causes have not been elucidated. Several case reports have shown that thin-walled arterioles and capillaries with a surrounding inflammatory infiltrate are the prominent vessels, and neovascularization due to chronic low-grade inflammation has been proposed as a mechanism of recurrent epistaxis (4). In addition, hereditary hemorrhagic telangiectasia characterized by epistaxis and red-violet cutaneous lesions has been noted as a cause of epistaxis in humans, particularly children (5). In this cat, the latter disease does not appear to have been the cause of epistaxis because pathological investigation did not reveal any signs of telangiectasia and cutaneous lesions were not detected. Inflammation is suggested as an alternative explanation because prednisolone was slightly effective in treating the epistaxis and sneezing, although allergic or lymphocytic-plasmacytic rhinitis is rare in cats. Therefore, neovascularization due to chronic low-grade inflammation might have been the cause of epistaxis in this cat. Steroids might have been inadequate in this case, however, as they might have induced heart failure (14) and/or aortic thromboembolism (15) in a cat affected by HOCM.

In humans with both of the diseases described above, electrocautery or diathermy is attempted when the bleeding site is identified, whereas silver nitrate cauterization is attempted when the bleeding site has not been identified (4,5,7). In this cat, silver nitrate cauterization might have been an option to arrest the nosebleeds because the bleeding sites during epistaxis were not identified, although excessive and tortuous vessels bleed easily. Silver nitrate, however, particularly at high concentrations, may cause severe complications, including septal perforation (16). These side effects might be more severe in cats because they have a thinner nasal septum than humans. Therefore diode laser coagulation was selected for use in this cat. This approach appears to be suitable for cats with epistaxis because the fiber is very thin and can easily pass through the channel of even a small flexible endoscope, although many different types of lasers, such as pulsed dye (8), Nd:YAG (9), and argon (10), are available to arrest bleeding. Indeed, as has been reported in humans (11), the diode laser induced sufficient diathermocoagulation in the abnormal vessels in the nasal mucosa of this cat. After diode laser coagulation, the cat’s epistaxis was resolved over the 1-year follow-up period, which significantly improved the quality of life of both the cat and his owner. However, the procedure may need to be repeated if epistaxis recurs.

Although the diode laser is not a novel tool and is commonly used for various bleeding abnormalities in veterinary practice, to our knowledge, this is the first report of successful laser coagulation with a diode laser to treat epistaxis in a cat. Laser coagulation with a diode laser can be considered a valid choice in the treatment of epistaxis in cats; however, the near-circumferential coagulation of the nasopharynx, as was observed herein, might be a cause of nasopharyngeal stenosis following scar tissue retraction. In addition, the significance of the relationship between epistaxis and abnormal vessels that was observed in this cat is unclear because tortuous vessels are observed even in healthy cats. However, diathermocoagulation of these abnormal vessels was effective in this cat. Further investigations are required to determine the relationship between abnormal vessels and epistaxis, the appropriate interval between repeat procedures, and the long-term benefits and possible side effects of laser coagulation. CVJ