Case 1
A 5-year-old, Thoroughbred gelding racehorse with a 1-week history of epiglottic entrapment causing poor performance and upper respiratory noise was presented to the Cornell University Equine Hospital for treatment. No history of dysphagia was reported by the trainer; however, the horse had coughed while exercising and eating for approximately 3 wk.
On physical examination, no abnormalities of significance were noted. An upper airway videoendoscopic examination revealed focal swelling of the rostral third of the epiglottis, ulceration on the dorsal surface of the epiglottis, and loss of the scalloped edge of the epiglottic cartilage with the appearance of a concomitant aryepiglottic entrapment (). Indeed, loss of the scalloped edge of epiglottic cartilage and a mucous membrane that appeared to attach to the lateral aspect of the corniculate process gave the false impression of an aryepiglottic entrapment. However, a slightly more dorsal view () showed a rather inflamed and enlarged mucous membrane of the epiglottic cartilage, not the aryepiglottic membrane. Intermittent dorsal displacement of the soft palate (DDSP) was observed during the examination. Finally, a white structure protruded for approximately 1 cm beyond the dorsal surface of the epiglottic cartilage through an ulcerated area of the epiglottis; this was presumed to be a necrotic section of cartilage surrounded by abscessation. A tentative diagnosis of septic chondritis of the epiglottic cartilage was made.
The animal was sedated with detomidine hydrochloride (Dormosedan; Pfizer, Exton, Pennsylvania, USA), 0.012 mg/kg body weight (BW), IV, and butorphanol tartrate (Torbugesic; Fort Dodge Animal Health, Iowa, USA), 0.008 mg/kg BW, IV, to facilitate further investigation of the epiglottic cartilage (
1). Local anesthetic, 50 mL of 2% lidocaine hydrochloride solution (Lidocaine; Phoenix Scientific, St Joseph, Missouri, USA) was applied to the dorsal aspect of the epiglottic cartilage and nasopharynx through the videoendoscope biopsy channel. Under videoendoscopic visualization, approximately 1.25 × 0.75 cm of necrotic epiglottic cartilage protruding through the ulcerated area was removed with bronchoesophageal forceps (Richard Wolfe Medical Instrument Corp., Vernon Hills, Illinois, USA) inserted through the right nostril. The sample was submitted for histopathologic examination, culture, and sensitivity testing. A cranial pedunculated tag of epiglottic mucosa, measuring approximately 1.25 × 1.0 cm, was removed, using a diode laser and bronchoesophageal forceps. The tag’s removal enhanced exposure to the ulcerated area on the dorsal aspect of the epiglottic cartilage, allowing better local debridement and removal of smaller pieces of necrotic debris from the abscess with forceps. Polyethylene (PE) tubing was passed through the videoendoscope biopsy channel into the epiglottic cartilage defect, which was then lavaged with 250 mL of a solution of sterile physiological saline solution containing 1g of sodium ampicillin (Amicillin; American Pharmaceutical Partners, Schaumburg, Illinois, USA) per liter. Histopathological examination of the sample revealed sheets of degenerated cartilage that had undergone ischemic necrosis. Colonies of mixed bacterial rods and cocci covered and extended into the chondroid lacunae.
Streptococcus pneumoniae, sensitive to ampicillin and enrofloxacin, was isolated from the aerobic culture.
A diagnosis of septic chondritis of the epiglottic cartilage with abscessation was made and the following treatment was instituted: nonsteroidal antiinflammatory medication, phenylbutazone (Vedco; St Joseph, Missouri, USA), 2.2 mg/kg BW, PO, q12h for 10 d postoperatively, and enrofloxacin (Baytril; Bayer Animal Health, Shawnee, Kansas, USA), 7.5 mg/kg BW, PO, q24h for 21 d. A 20-mL “throat spray” consisting of 250 mL glycerin (Humco; Texarkana, Texas, USA), 250 mL dimethyl sulfoxide 90% (DMSO; Butler Company, Columbus, Ohio, USA), 500 mL furacin (nitrofurazone powder USP; PCCA, Houston, Texas, USA), 50 mL dexamethasone sodium phosphate (25 mg/mL) (American Regent, Shirley, New York, USA), and ticarcillin and clavulonate (Timentin; SmithKline Beecham, Philadelphia, Pennsylvania, USA), 3 g, was applied to the nasopharynx through a flexible, soft rubber, 10 French catheter via the ventral nasal meatus twice daily for 14 d. The horse was confined to a stall with daily hand walking as exercise until being reevaluated 2 mo later.
At the approximately 2-month postoperative, reevaluation physical examination, all vital signs were within normal limits. Videoendoscopy of the larynx revealed that the soft palate was persistently positioned dorsal to the epiglottic cartilage. After sedation and administration of local anesthetic, as described previously, further examination with the aid of bronchoesophageal forceps revealed a shortened and deformed epiglottic cartilage and an aryepiglottic entrapment. The aryepiglottic folds were edematous and thick, with prominent margins, and they covered 1/3 of the short, edematous, misshapen, and discolored epiglottis, which was approximately half its normal length, presumably as a result of its previous infection. A grave prognosis for return to racing was given, and the horse was prepared for surgery to correct the epiglottic entrapment and DDSP.
Because of the very thick aryepiglottic folds and deformed epiglottic cartilage, removing a section of aryepiglottic membrane by laryngotomy was judged to be less likely to cause injury to the remaining deformed epiglottic cartilage and to have less likelihood of recurrence of the epiglottic entrapment than making a linear incision of the membrane with a hook blade or laser. The DDSP treatment planned was a partial Llewellyn procedure (
2), because a tie-forward procedure cannot be done at the same time as a laryngotomy (
3). The horse was placed in dorsal recumbency, a 2-cm section of the sternothyroideus tendon and associated muscle was removed bilaterally, and the entrapping aryepiglottic membrane was resected through a laryngotomy. Recovery from anesthesia was uneventful.
The colt also received nonsteroidal antiinflammatory medication, phenylbutazone (Vedco), 2 mg/kg BW, PO, q12h for 5 d, and the “throat spray” described above for 14 d. In addition, the following treatment was recommended: trimethoprim/sulfamethoxazole (Tribissen; Teva Pharmaceuticals, Sellersville, Pennsylvania, USA), 30 mg/kg BW, PO, q12h for 10 d, and a period of rest with controlled exercise/walking for 2 wk. Endoscopic examination 5 mo later revealed a persistent DDPS. The horse returned to racing, but he was unable to compete successfully in 2 starts and was retired from racing.
Case 2
A 3-year-old, male Thoroughbred racehorse was presented to the Cornell University Equine Hospital for evaluation and treatment of DDSP associated with epiglottic swelling. The colt had performed poorly in his most recent race (1 wk prior to presentation), made an abnormal respiratory noise while exercising, and was referred after epiglottitis and associated intermittent DDSP had been diagnosed by endoscopic examination. A few weeks prior to his poor performances, the colt had coughed intermittently.
Results from a complete physical and visual examination, palpation of the colt’s head and neck, and auscultation of the upper and lower respiratory tract and cardiovascular system were within normal limits. The horse was comfortable and no abnormal upper respiratory noise could be heard at rest. Videoendoscopic examination of the upper respiratory tract, performed with the use of a lip chain for restraint, showed that the dorsal aspect of the epiglottis was swollen and ulcerated (). In addition, the soft palate was noted to displace frequently during the examination, and multiple swallowing episodes were needed to replace it to its correct anatomical position. The scalloped edge of the epiglottic cartilage could still be seen. A lateral radiograph of the laryngeal area with the horse standing revealed a thick epiglottis, a blunted rostral third of the epiglottic cartilage, and the caudal free edge of the soft palate in the normal subepiglottic position. The horse was restrained in stocks, sedated, and had local anesthetic applied to the nasopharyngeal structures, as described for Case 1. The ulcer on the dorsal aspect of the epiglottic cartilage was explored with bronchoesophageal forceps. Purulent exudate found deep within the ulcer was submitted for bacterial culture. Further exploration revealed that the tip of the epiglottic cartilage was loose from the main cartilage; it was removed with the bronchoesophageal forceps. The remaining purulent exudate was lavaged, as described in Case 1. A diagnosis of septic chondritis of the epiglottic cartilage with abscessation was made. It was expected that shortening of the epiglottic cartilage as a result of the chondritis would lead to persistent DDSP. Therefore, surgical advancement of the larynx (laryngeal tie-forward) with partial sternothyroideus muscle tenectomy was performed under general anesthesia (
2,
3). The animal recovered uneventfully from anesthesia.
Aerobic bacterial culture of the epiglottic cartilage revealed a moderate number of Actinobacillus spp. In response to the results from culturing and sensitivity testing, the colt was treated initially with ampicillin (Ampicillin Na; American Pharmaceutical Partners), 15 mg/kg BW, IV, q8h, and gentamicin sulfate (GentaVed, Vedco), 6.6 mg/kg BW, IV, q24h for 10 d, followed by oral enrofloxacin (Baytril; Bayer Animal Health), 7.5 mg/kg BW, PO, q24h for 10 d. Postoperative treatment also included “throat spray” and phenylbutazone, as described in Case 1.
The horse was kept in a box stall with daily hand walking for 3 mo postsurgery. Endoscopic evaluation at 3 and 6 mo revealed an almost persistent DDPS without dysphagia. The epiglottic cartilage was observed to be blunt and reduced in size by approximately 50%. The horse made 3 unsuccessful starts 6 mo after presentation.
