Hyperbaric Oxygen Therapy in Neglected Felon

The hand is one of the most vulnerable appendages to trauma during everyday activities. Any trauma to the hand, especially a penetrating one, may introduce pathogens to the subcutaneous tissues. Abscess in the pulp of any digit or felon, differs from the abscess located at the other parts of the body, because of the anatomic compartments of the pulp. Small compartments within the pulp are divided by 15 to 20 fibrous septa that extend from the periosteum to the skin. An infection within these compartments can lead to edema, increased compartment pressure, and abscess formation. The increased pressure in the compartments may compromise blood flow and lead to necrosis of the skin and pulp. Failure to treat this condition can result in serious complications.1–3
The authors present a case of a felon that was treated with a wound dressing and antibiotherapy for 6 weeks that did not heal, but healed after 6 weeks of treatment with the adjuvant HBOT.

Case Report
A 45-year-old man with diabetes, employed as a press-worker, presented to the authors’ clinic with a nonhealing, necrotic, infected wound on the second digit of the left hand. He had a 6-week history of hyperemia and induration in the distal phalanx and nail bed of the index finger of the left hand. He denied any trauma to the finger. He observed some discharge from the distal pulp of the fingertip 3 days after the first symptoms arose and unsuccessfully attempted to drain the discharge by squeezing the finger. The patient went to the emergency room (ER) since the erythema, edema, and pain had increased in the distal half of the digit in the 10 days leading up to the ER visit. An incision was made to drain the fingertip. The patient was prescribed oral naproxen sodium 275 mg tablet twice a day and sent home. The patient then went to the Department of Plastic Surgery 10 days post-incision when he noticed necrotic changes in the distal end of the finger. Plastic surgeons recommended wound care with topical antibiotic (mupirocin) and antibiotherapy (500 mg oral cephalexin) twice a day. Plain radiography revealed no evidence of osteomyelitis. Since healing was not obtained in 6 weeks with topical antibiotic treatment and wound care, the patient was referred to the authors’ clinic to be evaluated for HBOT.
The patient was being treated for diabetes mellitus with gliclazide and metformin. Physical examination revealed a normal appearing Caucasian male, except for hypopigmentation on both arms and the left index finger wound. The distal part of his left index finger had edema, erythema, tenderness, and was necrotic (Figure 1). Laboratory examination was remarkable for a serum glucose level of 231 mg/dL; cholesterol 260 mg/dL; triglycerides 399 mg/dL; erythrocyte sedimentation 66 mm/h; and HbA1c of 8.53%. Three-phased bone scintigraphy identified increased osteoblastic activity in all phases. Initial bacterial culture remained sterile and oral cephalexin treatment was discontinued.
The case was diagnosed as a complicated felon and HBOT was started after evaluating the patient for any possible contraindications to HBOT. His treatment protocol was set as daily 100% oxygen inhalation for 90 minutes at 2.4 ATA (atmosphere absolute) pressure, 6 days a week. Daily debridement of necrotic tissues was performed. The benefits of HBOT and wound debridement were noticeable in the first week. The second bacterial culture revealed Group A Streptococcus pyogenes after 1 week. Antibiotherapy (oral amoxicillin and clavulanic acid) was resumed at 1 g/twice a day, in accordance with the antibiogram. The patient’s symptoms improved over the next 10 days. In the fourth week, after the 20th HBOT session, infection in the wound regressed and granulation tissue in the wound bed increased remarkably (Figure 2). At the 40th session of HBOT (6 weeks), the patient had no signs of infection and the wound was completely healed. The patient was symptom-free during the control examination that was performed after 3 months (Figure 3).

Discussion
A felon is usually caused by the inoculation of the bacteria into the fingertip through a penetrating trauma. The digits most commonly affected are the thumb and the index finger. It differs from other types of subcutaneous abscess because of the fibrous trabeculae or septa dividing the pulp into several small compartments. The expanding abscess may deter the septa and the infection may extend to the phalanx and cause osteomyelitis. If the abscess extends to the skin, it may cause necrosis in the effected tissues. If diagnosed early, a felon may be treated with oral antibiotics and elevation of the hand. When abscess formation occurs, adequate drainage usually provides good results. If drainage is not performed, increased compartment pressure may cause necrosis and gangrene. Complicated infections usually occur in immunosuppressed patients or when adequate treatment is delayed. Staphylococcus aureus and Streptococci are the pathogenic agents that most commonly cause a felon.² These pathogens can pass thru the skin via a minor wound (eg, a splinter, bits of glass). A felon also may arise from an untreated paronychia that spreads into the fingertip pad. Felons have also been reported following multiple finger-stick blood tests.^2,3 The patient in the present case had diabetes and an occupation that were risk factors that predisposed him to infection. His fingernails and perionychial tissues had experienced multiple traumas, even though the patient denied that trauma was the cause of injury.
Injury and infection, as well as various pathological conditions, can markedly decrease tissue oxygen level, whereas exposure to hyperbaric oxygen (100% O2 at 2.4 ATM) increases oxygen tension in wounds to levels > 1000 mmHg.⁴ HBOT has been reported to increase the oxidative killing of polymorphonuclear leukocytes, presumably by promoting reactive oxygen species production⁵ while decreasing lymphocyte proliferation.⁶ HBOT also promotes the production of collagen by fibroblasts,⁷ thereby allowing wound healing in hypoxic tissues. During HBOT, tissue oxygen levels increase to the level that is necessary to meet the metabolic needs of tissues. HBOT restores functionality to the abnormalities caused by hypoxia. Therefore, HBOT has been used as an adjunctive therapy to medical and surgical treatment of nonhealing wounds. In the present case, notable progress was achieved in the first week after initiating HBOT.

Conclusion
This particular case is an example of successful use of HBOT in the treatment of late complications of a felon. Adjunctive HBOT should be considered when dealing with a complicated felon, as with other nonhealing wounds.