Rapidly Progressing Cellulitis of the Hand Following a Feral Cat Bite

Case at a Glance

A 32-year-old female presented with worsening pain and swelling in her right index finger less than 24 hours after a feral cat bite. Despite the initiation of oral antibiotics, her symptoms progressed rapidly, raising concern for a deep space infection or septic arthritis.

Patient's Story

A 32-year-old female with extensive experience in animal rescue was bitten and scratched on her right hand while handling a feral kitten. She performed immediate wound care, washing the area with antibacterial soap and applying a topical antibiotic ointment. The following morning, she awoke to find the knuckle of her right index finger was significantly swollen, tender to palpation, and she was unable to fully flex the digit. Concerned, she sought medical attention.

Initial Assessment

The patient presented to an urgent care clinic approximately 24 hours after the injury. On examination, the right index finger exhibited marked edema, erythema, and tenderness over the dorsal aspect of the metacarpophalangeal (MCP) joint. The original puncture wound appeared small and had already closed. The clinical picture was consistent with cellulitis secondary to a cat bite.

The Diagnostic Journey

The urgent care physician prescribed a course of oral amoxicillin, to be taken twice daily. The patient took her first dose at approximately 5:00 PM. However, by 11:00 PM the same evening, her condition had deteriorated. The finger began to throb without provocation, and the swelling had visibly increased. The patient noted that the topical antibiotic ointment she had initially applied seemed ineffective, as the puncture wound had closed too quickly for it to penetrate. The rapid worsening of symptoms despite the initiation of oral antibiotics strongly suggested that the infection was more severe than a simple superficial cellulitis and was likely involving deeper structures, such as the joint capsule or tendon sheath.

Final Diagnosis

Initial Diagnosis: Cellulitis of the right index finger. Working Diagnosis upon Worsening Symptoms: Suspected septic arthritis of the right index MCP joint and/or infectious tenosynovitis. Cat bites are notorious for inoculating deep structures with virulent bacteria, most commonly Pasteurella multocida, leading to rapidly destructive infections.

Treatment Plan

The initial treatment plan of oral amoxicillin proved insufficient. The standard of care for a rapidly progressing infection of the hand following a cat bite, especially one overlying a joint, requires more aggressive management. The recommended plan would be immediate referral to an Emergency Department for further evaluation. This would likely include admission for intravenous (IV) antibiotics (e.g., ampicillin-sulbactam) to achieve higher systemic drug levels and a consultation with an orthopedic or hand surgeon for consideration of surgical irrigation and debridement of the affected joint and tissues.

Outcome and Follow-up

This case underscores the critical nature of cat bite injuries to the hand. The patient was advised to seek immediate re-evaluation due to the progression of her symptoms. Prompt escalation to IV antibiotics and potential surgical intervention is paramount in preventing long-term complications such as cartilage destruction, osteomyelitis, permanent joint stiffness, and chronic pain. Close follow-up after such an event is necessary to monitor for resolution of the infection and to manage any residual functional deficits with physical therapy if needed.