A simple case of cellulitis on the third finger is a lot more
Figure 1. Kanavel signs: fixed flexion with fusiform swelling.
Mr. K, a 58-year-old right-hand-dominant man, arrived at the ED with a five-day history of increased redness, pain and swelling in his left middle finger. He reported that the pain originated over the distal tip of the finger and rapidly spread proximally and volarly into his palm. Mr. K reported no fever, chills or recent illnesses, nor any trauma or penetration to the finger, but complained of unrelated pain in his right knee.
Mr. K was diagnosed with systemic lupus erythematosus (SLE) 25 years ago. He denied ever having any problems with joint pain or swelling, and noted that he takes his daily medications diligently. Mr. K maintains on several drugs for hypertension, including furosemide (Lasix). He is 6 foot 5 inches tall and is obese. Mr. K's surgical history includes bilateral orthopedic knee surgery.
Examination of the left middle finger revealed all four of Kanavel signs, indicative of septic flexor tenosynovitis (fusiform swelling, pain with passive extension, pain with palpation along the flexor tendon and fixed flexion).1 The finger also appeared cellulitic along both the volar and dorsal aspects and was erythematous (Figure 1).
Results of the tests were negative for lymphangitis or lymphedema, and there was no evidence of injury. The ED tests revealed a slightly elevated WBC count of 11.94 K/ml (4.5-11 normal range), an elevated ESR of 89 mm/hr, and an elevated CRP at 128.4 mg/L.
Infectious flexor tenosynovitis is an emergency and when left unattended, it can lead to skin loss, tendon necrosis or rupture, and eventually osteomyelitis and finger contracture.1,2 Due to Mr. K's rapid onset of symptoms, as well as the appearance of Kanavel's four signs, immediate incision and drainage of the flexor tendon was performed. Initial incisions over the volar PIP joint and proximal tendon sheath expelled murky secretions. Subsequently, a knee aspiration was performed on the affected knee.
Both the finger and knee synovial analyses were positive for urates — conclusive for gout. A secondary blood draw also revealed an elevated uric acid level of 8.9 mg/dL (3.4-7.0 mg/dL is normal for males). After 48 hours, cultures of the left middle finger revealed coagulase-negative staphylococcus; however, no growth was noted from the knee cultures.
4. Treatment and Outcome
The flexor tendon sheath was copiously irrigated with sterile saline, and a small amount of soft tissue was excised around the incisions to delay closure and encourage continued drainage from the tendon sheath (Figure 2).
The wounds were covered with Vaseline gauze and dry, sterile dressings. Mr. K was admitted to the hospital and IV vancomycin (Vanocin) was administered. He underwent hand soaks and dressing changes four times a day.