Pain Management Case of the Month: Pumpkin—Managing Oral Pain in a Cat

An eight-year-old male neutered domestic shorthair cat presents for acute-onset, left-sided facial swelling of four days’ duration.

Figure 1: Pumpkin, an 8-year-old male neutered domestic shorthair cat, presented for evaluation of acute-onset, left-sided facial swelling

by Laura Sasser, DVM

Signalment and History

An 8-year-old male neutered domestic shorthair cat presented for acute-onset, left-sided facial swelling of four days’ duration. The patient received cefovecin 8 mg/kg subcutaneously at the referring veterinarian’s practice two days before evaluation, and the patient’s owners reported a significant improvement, but not resolution, in the facial swelling following the injection. Wellness care, including vaccinations and parasite prevention, was current.

The patient reportedly was eating well with no change in behavior at home. The patient was reportedly an indoor cat and was in a house with two other cats.

Physical Examination and Diagnostics

Physical examination revealed a patient who was bright and alert, and his general physical examination was normal. The patient’s body condition was moderately overweight with a body condition score of 7/9.

An awake oral examination revealed normal occlusion with moderate to severe dental calculus and focal areas of erythema and swelling centered over the left maxillary fourth premolar tooth (208). Preanesthetic blood profile was normal. The anesthetized oral examination revealed gingivitis, dental calculus, gingival recession, and a stage 3 furcation of the left maxillary fourth premolar tooth (Figure 2).

Full-mouth digital dental radiographs, cone beam computerized tomography (CBCT), and 3D reconstruction of the patient were obtained and evaluated chairside (Figures 3–5). The radiograph of the left maxilla revealed a missing left maxillary second premolar tooth (206), vertical and horizontal bone loss of the left maxillary fourth premolar (208) and left maxillary first molar tooth (209), and resorptive lesions of the left maxillary fourth premolar tooth (208).

Evaluation of the CBCT images revealed osteolysis and tooth resorption of the right and left maxillary fourth premolar teeth. Stage 4 periodontal disease of the left and right maxillary fourth premolar and first molar tooth and tooth resorptive disease were diagnosed based on oral examination and radiology findings.

Figure 2. The anesthetized oral examination revealed gingivitis, calculus, gingival recession, and a stage 3 furcation of the left maxillary fourth premolar tooth

Figure 3. An evaluation of digital dental radiograph of the left maxilla revealed a missing left maxillary second premolar tooth (206), vertical and horizontal bone loss of the left maxillary fourth premolar (208) and left maxillary first molar tooth (209), and resorptive lesions of the left maxillary fourth premolar tooth (208)

Figure 4. Evaluation of the CBCT images at the level of the maxillary fourth premolar teeth revealed osteolysis and tooth resorption of the right and left maxillary fourth premolar teeth

Treatment and Outcome

The patient was premedicated with buprenorphine (0.02 mg/kg) given intramuscularly 45 minutes before anesthetic induction based on lean body weight. A 22-gauge intravenous catheter was placed in the right cephalic vein. The patient was then induced with propofol (4 mg/kg) administered intravenously to effect. The patient was intubated with a 4.0 mm cuffed endotracheal tube. General anesthesia was maintained with a combination of 2 L/min oxygen and 1.5% to 2.0% isoflurane anesthesia. Anesthetic monitoring was performed by observation of jaw tone, mucous membrane color, capillary refill time, eye position and reflexes, respiratory rate, and pulse quality and with the use of a multiparameter monitor that included respiratory rate, pulse rate, electrocardiography, noninvasive blood pressure monitoring, rectal body temperature, pulse oximetry, and end-tidal carbon dioxide concentration.

A balanced isotonic fluid was administered intravenously at a rate of 3 mL/kg/h. A warm-water-circulating blanket and a warm-air-circulating system were used to help maintain body temperature during the anesthetic event. A full oral examination, including periodontal probing, was performed and recorded in the patient’s dental chart. Local anesthesia was achieved with a left infraorbital block using .25 mL of 0.5% bupivacaine (Figures 6 and 7), and an injection of robenacoxib (2 mg/kg) was administered subcutaneously. The patient received a complete professional dental cleaning procedure performed using a piezoelectric scaler and hand scaling of the supragingival tooth and subgingival space, followed by polishing. A surgical extraction of the left maxillary fourth premolar and first molar teeth (208, 209) was performed with a mucoperiosteal flap. The right maxillary fourth premolar and first molar teeth were extracted in a similar fashion. The patient was transferred to recovery, was normothermic, and was observed until alert and ambulatory.

The patient was discharged from the hospital with instructions to feed a soft diet for seven days. Buprenorphine (0.02 mg/kg) based on lean body mass was to be administered transmucosally twice daily for four days, and robenacoxib (1 mg/kg) tablets were dispensed once daily for two days following surgery. In a phone call 24 hours after surgery, the owner stated that Pumpkin was doing well and eating well. The two-week follow-up appointment demonstrated healing in the mouth and no evidence of facial swelling.

Figure 5. Evaluation of the 3D reconstruction confirmed the bone loss of caudal left maxilla and aided in educating the patient’s owner on their pet’s oral health

Figure 6. A 0.5% bupivacaine hydrochloride injection was dosed with a tuberculin syringe and a new 25-gauge needle was placed before injection

Figure 7. Demonstration of placement of a needle and syringe for an infraorbital nerve block in a feline skull. The needle is advanced only to the point of entry of the canal and the syringe and needle are held parallel to the dental arcade

Discussion and Conclusion

A multimodal approach to pain management is widely used in veterinary medicine in order to decrease the dose of individual analgesic drugs and ultimately decrease the side effects of individual drugs. By affecting the many steps in the pain pathway, pain can be minimalized and medications can be more effective than using one analgesic alone. In this patient, an opioid was combined with the use of a nonsteroidal anti-inflammatory (NSAID) medication and local anesthetic dental block to manage his surgical pain.

In this patient, analgesics and anesthetics were calculated based on lean body mass to avoid potential side effects due to overdose. Buprenorphine is an opioid that was used both as a premedication and during the postoperative period. The transmucosal delivery allows absorption by buccal mucosa and is well tolerated by most feline patients. Robenacoxib is a coxib class NSAID that is highly protein bound and persists at the site of inflammation longer than in the blood. It has been shown to reach peak blood concentrations within 30 minutes after administration.

Caution should be utilized with NSAID usage in cats, and NSAIDs shouldn’t be used in patients with known hypersensitivity or intolerance to them. If appropriate, robenacoxib should be administered before the start of surgery to allow sufficient time for it to reach peak levels. Bupivacaine is a commonly used local anesthetic agent. The use of local anesthetics will allow for lower vaporizer settings, which minimizes the hypotensive effects of inhalant anesthetics. Bupivacaine takes 6–10 minutes to take effect but results in four to eight hours’ duration of activity. Administering bupivacaine at the beginning of a dental procedure allows adequate time for it to take effect before the start of the surgery. The dose of bupivacaine should not exceed 2 mg/kg, and care must be taken to not administer intravenously because of potential cardiotoxic effects. In this patient, an infraorbital block was used by administering bupivacaine into the short infraorbital canal.

It is important to pursue further education in the form of wet-lab training if a clinician is not familiar with the techniques of administering local anesthetic agents. Other components of anesthesia that could be helpful to consider are feline-friendly techniques before anesthesia, such as low-stress handling, pheromone diffusers or spray, designated feline-only exam rooms, and the use of anxiety-reducing medications before arrival at the hospital.

References

Gracis, M. 2013. “The Oral Cavity.” In Small Animal Regional Anesthesia and Analgesia, edited by L. Campoy and M. R. Read, 119–147. Oxford: Wiley Blackwell.

Grubb, T., J. Sager, J. Gaynor, E. Montgomery, J. Parker, H. Shafford, and C. Tearney. 2020. “2020 AAHA Anesthesia and Monitoring Guidelines for Dogs and Cats.” Journal of the American Animal Hospital Association 56, no. 2:1–24.

Snyder, L. C., C. Snyder, and D. Beebe. 2019. “Anesthesia and Pain Management.” In Wiggs’s Veterinary Dentistry, 2nd ed., edited by H. B. Lobprise and J. R. Dodd, 177–192. Hoboken, NJ: Wiley Blackwell.

Discussion by Mike Petty, DVM, CCRT, CVPP, DAAPM

Anyone who has had dental pain can testify to the intensity of pain and the disruption it causes in normal daily routine. Animals are no exception, even though many of them seem to hide the pain as they soldier through every day. As Laura Sasser, DVM, describes above, being proactive with a multimodal approach is the best way to ensure rapid return to function and head off secondary neuralgic pain issues like trigeminal neuralgia.

Dental blocks seem complex until you have done one or two of them, and then they become easy. Although hands-on labs are not available during this pandemic, you can get great detail on performing dental blocks in both dogs and cats in the book Small Animal Regional Anesthesia and Analgesia, edited by Luis Campoy and Matt Read. It is my go-to book whenever I need to brush up on any local anesthetic technique that I don’t perform often.
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Michael C. Petty, DVM, CCRT, CVPP, DAAPM, is in private practice in Canton, Michigan. He is a frequent national and international lecturer on topics related to pain management. Petty offers commentary on each Pain Case of the Month (and occasionally writes one himself). He was also a member of the task force for the 2015 AAHA/AAFP Pain Management Guidelines for Dogs and Cats.

 

Laura Sasser
Laura Sasser, DVM, is in a private veterinary dental practice located in Aurora, Illinois. She is a graduate of the Purdue University College of Veterinary Medicine and is pursuing board certification at the American Veterinary Dental College.

 

Photo credits: Photos courtesy of Laura Sasser

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