Mr. H, age 45 years, presented to the clinic following a cat bite to his right hand 14 hours prior. The family cat lunged at him and bit and scratched his hand. Pulling away, Mr. H fell back and landed on a coffee table with his open right hand hyperextended. There was minimal pain and bleeding. Immediately after the incident, Mr. H. washed his wounds with soap and water, applied antibiotic ointment, and took ibuprofen for pain relief.
Mr. H was unsure of the date of his last tetanus shot and reported that the cat is up to date on all immunizations. He described a nonradiating pain in the tip of the second digit with limited flexion. There was full range of motion in the right wrist and all other digits of the right hand. No fever, chills, shortness of breath, cough, wheeze, chest pain, or palpitations were reported. Mr. H’s medical history included hypertension, hypercholesterolemia, and tobacco abuse. Current medications included lisinopril 10 mg daily and pravastatin 20 mg daily.
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1. Physical examination
At the initial visit, Mr. H was alert and oriented. BP was 120/78 mm Hg, pulse 98 beats per minute, pulse oxygenation 97%, temperature 98.8˚F, and weight 290 lbs. The skin was warm and dry to touch. The second digit of the right hand was mildly edematous with five nondraining puncture wounds noted: two puncture wounds located between the proximal interphalangeal (PIP) and metacarpophalangeal joint of the second digit and three on the palmar aspect of the right hand. Multiple scratch wounds of various lengths across the dorsum of the right hand were nondraining and erythematous. There was limited range of motion to the second digit on the right hand (partial flexion). Capillary refill to the upper extremities measured fewer than three seconds. Positive tactile response to the digits of the right hand was achieved.
Mr. H was sent to radiology for an x-ray to rule out fracture, dislocation, and signs of osteomyelitis. Results were negative for fracture, dislocation, and lytic or blastic lesions. Joint spaces were preserved, and bony structures were in good alignment.
An initial assessment of early cellulitis and right-hand pain secondary to the cat bite and fall was made.
2. Treatment
Mr. H’s right-hand wounds were cleansed with antibacterial soap, betadine wash, and sterile water rinse. The right arm was placed in a sling for elevation of the extremity. A tetanus shot was administered. A prescription was given prophylactically for amoxicillin (Augmentin) 875 mg one orally b.i.d. for 10 days. Hydrocodone (Vicodin) and naprosyn (Naproxen) were also prescribed for pain and inflammation.
It was strongly advised that the patient follow up the next day, but Mr. H declined. After being advised of the risk for infection, Mr. H agreed to follow up in three days or sooner if symptoms worsened. Signs and symptoms warranting earlier evaluation (e.g., fever, chills, increasing edema, erythema, numbness, drainage, and pain) were discussed. Discharge instructions and wound-care handouts were provided.
3. Follow-up
Mr. H returned in three days as instructed. He described severe nonradiating pain to his right hand and second digit unrelieved by Vicodin or Naprosyn. The pain was markedly worse during second-digit flexion attempts or when pressure was applied. The second digit was warm to touch, red, and swollen. Mr. H was unable to perform full flexion of the second digit. No drainage, fever, chills, shortness of breath, chest pain, or wheeze was reported. Mr. H noted a progression of redness and swelling over the past three days, and admitted inconsistent use of the sling. He was on day three of Augmentin and taking it as directed.
On physical examination, BP was 118/80, pulse 106, respiratory rate 20 breaths per minute, temperature 99.9˚F, and pulse oxygenation 98%. The patient appeared ill and uncomfortable. The skin on the second digit of the right hand showed significant edema and erythema circumferentially (Figure 1). There was limited range of motion at the PIP joint on the second digit.
4. Diagnostic workup
Laboratory findings showed erythrocyte sedimentation rate 28 mm/hour, high-sensitivity C-reactive protein
14.5 mg/L, WBC 10,0000/μl, RBC 3.77 106/μl, hemoglobin 12.3 g/dL, and hematocrit 35.3%.
Mr. H was advised to stop taking Vicodin and started on oxycodone (Percocet) 5/325 mg one or two orally every six hours as needed. Mr. H. was then sent for immediate orthopedic surgical evaluation.
5. Diagnosis
Mr. H was diagnosed with a septic joint, scheduled for incision and drainage, and admitted to the hospital overnight for observation. Wound cultures were significant for Pasteurella multocida. An infectious disease consultation was ordered. A peripherally inserted central catheter line was placed and IV ceftriaxone (Rocephin) administered.
Mr. H was discharged the next day and told to return to the infusion center every day for the next two weeks for IV Rocephin. A continued decrease in range of motion of the second digit was demonstrated at the two-week follow-up, but the pain was significantly improved. No fevers, chills, increased redness, or swelling was noted. The patient was switched to cefuroxime (Ceftin) 500 mg b.i.d. for two weeks.
At six-weeks postoperative, Mr. H had full range of motion and increased strength in the right hand. There were no signs of infection and no pain. The patient was able to return to work.
6. Discussion
There is no such thing as a simple cat bite, yet most patients are unaware of the potential for harm, and they delay or fail to seek immediate evaluation and treatment. Dog or cat bites to the hands are the most severe injuries, often requiring surgical intervention and hospitalization.1 Infectious complications occur in approximately 50% of cat bites whereas with dog bites, the overall estimated infection rate is 2% to 20%. Early treatment reduces the severity of many animal bites.
Infections occur as a result of a combination of the oral flora of the animal and the human skin flora. Common pathogens include Pasteurella species, Staphylococcus aureus, streptococci, anaerobes, Capnocytophaga, Moraxella, Corynebacterium, and Neisseria. Pasteurella multocida is the most common isolated pathogen transmitted from cats.2 The animal’s long and sharp canine teeth penetrate the skin, causing deep puncture wounds and providing an avenue for the induction of bacteria.
7. Recommendations
Early treatment is beneficial in decreasing the risk of infection. Prescribing an antibiotic prophylactically has shown to reduce the rate of infection from cat bites. The drug of choice is amoxicillin/clavulanate 875 mg/125 mg b.i.d. for three to five days. If the patient is allergic to penicillin, recommend doxycyline 100 mg b.i.d. for three to five days or one double-strength trimethoprim/sulfamethoxazole tablet b.i.d. for three to five days. Stress the importance of immediately washing the wound with antiseptic solution and water and seeking immediate evaluation. Follow-up evaluation should focus on early detection and diagnosis of tenosynovitis, septic arthritis, and osteomyelitis.
8. Conclusion
Pet owners must be made aware of the seriousness of a cat bite. Educating the patient about the importance of early management and immediate follow-up can reduce the risk of adverse sequelae and the potential costs of hospitalization and post-bite management. Obviously, the best bite is the one that has been prevented. Avoidance of bites, prompt wound management, and judicious use of antibiotics decrease antimicrobial resistance and infection incidence.
Ms. Henderson is a family nurse practitioner at Wheaton Franciscan Healthcare–All Saints in Racine, Wisc. Dr. Kaul is the MSN and DNP Program Director and an associate professor at Concordia University Wisconsin in Mequon.
References
1. Benson LS, Edwards SL, Schiff AP, et al. Dog and cat bites to the hand: treatment and cost assessment. J Hand Surg Am. 2006;31:468-473.
2. Uphold CR, Graham MV. Clinical Guidelines in Family Practice. 4th ed., Gainesville Fla.: Barmarrae Books; 2003.
