Hand Case 3.1

Hand Icon

Presented by: Mike Fernandes, MD

Chief Complaint: “My thumb is swollen ”

History of Present Illness:
This is a 47 year-old male presents to the emergency department’s ARC.  His primary complaint is that his right thumb is swollen.  He states that he bumped his thumb about two weeks ago on some furniture.  He  had some pain and a little swelling but nothing else.  The pain had improved after a few days, however, it started to hurt again and swell.  After a about a week and half he started to notice some purulent drainage from a little sinus at the tip of his thumb. He has some difficulty flexing his thumb at the interphalangeal joint, he is however, able to oppose his thumb.  The digit is erythematous, and swollen.  The remainder of his hand and digits are completely unaffected, the swelling and erythema is limited to the thumb.

Past Medical History: Denies, any hypertension or diabetes mellitus
Past Surgical History: Eye surgery in 2007
Medications: Eye drops
Allergies: NKDA
Social History: He denies any drug use.  He does admit to smoking 1 pack of cigarettes every 2 days, and occasionally consumes alcohol.
Family History: Significant for heart disease and diabetes

Physical Exam:

Vital Signs: BP: 142/88, P: 84, RR: 18, SpO2: 99%RA T: 36.3

Extremities: FROM, strength is 5/5 proximately and distally in both upper and lower extremities.  He is able to flex and extend at the wrist joints without any difficulty.

Hands: His MCP, PIP and DIP are completely intact with full extension and flexion from the index to the pinky finger on both hands.  He is able to oppose this thumbs bilaterally.  He is able to fully extend and flex this left thumb at the IP joint as well as abduct and adduct.  His right thumb is swollen up almost to the MCP it is  not uniformly swollen and erythematous, or warm to the touch. He is able to abduct and adduct his thumb, however, can fully flex at the IP joint because of swelling. He has pain to palpation at the distal phalanx of of the thumb; there is a whitish discoloration to the tip of the distal phalanx with a draining sinus, which did not appear to extend beyond the distal phalanx.  The nail bed appears to not be involved.  He did not have pain on passive extension of the digit, he did not have tenderness along the tendon sheath.

Radiographs
X-ray of the right hand was completely within normal limits, no bony abnormalities were noted no fracture, dislocations, or signs of osteomyelitis.  Patient did have some soft tissue swelling of the first digit, which is evident on the x-ray film.

Discussion:
A Felon is an infection of the distal pulp space of the finger.  The culprit organism usually is S. aureus or S. pyogenes, which enters the pulp space following minor trauma.  Patients present with exquisite pain, erythema, and swelling of the finger pad that overlies the distal phalanx.  This is a suppurative infection, so an abscess may develop.

By definition, a felon does not include the DIP crease.  If the edema and erythema extend that far, there may be a more serious complication; the infection may have spread to the bone and joint, invaded the tendon sheath, or formed a sinus tract to the skin.

A felon usually is caused by inoculation of bacteria into the fingertip through a penetrating trauma. The most commonly affected digits are the thumb and index finger.  Common predisposing causes include wood splinters, bits of glass, abrasions, and minor puncture wounds.  A felon also may arise when an untreated paronychia spreads into the pad of the fingertip.  Felons have been reported following multiple finger-stick blood tests.

Early infection is characterized by inflammation alone and may be treated with an oral anti-staphylococcal antibiotic such as cephalexin (Keflex) (250 to 500 mg PO QID) or dicloxacillin (250 to 500 mg PO QID).  If penicillin-allergic, erythromycin (250 to 500 mg PO QID) or clindamycin (150 to 300 mg PO QID) can be used.  If a patient is hospitalized because of comorbid or other condition, either nafcillin (1 to 2 gm IV q4-6h) or cefazolin (Ancef) (1 gm IVq6h) is recommended.  If there is suspicion for MRSA, then vancomycin should be administered.

In general, patients present for medical care after the development of an abscess.  Treatment requires incision and drainage, but incisions of the distal finger can result in painful scars or damage to the nerves and vasculature of the distal finger pulp.

The pulp of the fingertip is divided into small compartments by 15 to 20 fibrous septa that run vertically and attach the skin to the periosteum, forming the compartments that serve as the nidus of infection.
Abscess formation in these relatively non-compliant compartments causes significant pain, and the resultant swelling can lead to tissue necrosis.  Because the septa attach to the periosteum of the distal phalanx, spread of infection to the underlying bone can result in osteomyelitis.

1.   When an incision and drainage procedure is performed, it is important to open these compartments to drain the abscess effectively.  There are several techniques for draining felons; however, most practitioners have narrowed it down to two.  These two techniques are thought to be most effective in controlling infection and minimizing the risk of neurovascular injury and painful scar formation:

Felon
Felon

Midvolar technique: images (A and B)

midvolar
Unilateral longitudinal technique: images (C, D and E)

2. Most abscesses point to the middle of the finger pad, making the midvolar approach ideal.  If a sinus tract is present, the incision should include it.  This facilitates complete exposure of the abscess and prevents necrosis of the skin between the incision and the sinus tract.

The incision is made in the midline of the finger pad over the area of maximal swelling and tenderness (distal to the DIP) crease).  The incision should be made long enough to allow drainage of pus and blunt dissection of the compartments of the pulp space, with care taken not to injure the underlying flexor tendon.
The unilateral longitudinal approach is recommended when a sinus tract is not present.  This incision is made on the unopposed of non-border surface of the finger (radial aspect of the thumb and little finger and the ulnar aspect of the index, middle, and ring fingers).  The incision is made 5 mm distal to the DIP crease and just volar to the nail fold, whit is to avoid the neurovascular bundle.  The incision should extend to the subcutaneous tissue, allowing complete drainage of the space.  Blunt dissection just like the midvolar approach is a component of this unilateral longitudinal approach, the goal is to break up the loculations of pus and to explore for foreign bodies, if deemed necessary.

3. After the incision and drainage, area is irrigated thoroughly and packed with sterile gauze.
Antibiotics are given, as previously discussed, and the wound should be reevaluated within 48 hours.
When the patient returns, the gauze is removed, the patient is instructed to soak the wound twice daily and to cover it with dry dressing after each soak; the incision is to heal by secondary intention.  Also, encourage the patient to perform range of motion exercises.

Case Conclusion:
The patient had a Felon, a digital block was performed to provide anesthesia.  Then the area was steriley prepared for incision and drainage.  The thumb was incised using the midvolar approach, drained and thoroughly irrigated in emergency department.  The wound was then packed with sterile gauze, and the patient was educated and sent home with Keflex and follow up in 3 days.

References:
1. Tintinalli Emergency Medicine: A Comprehensive Study Guide, 6th ed: Chapters 44, 268, 269
2. Emergency and Primary Care of the Hand (ACEP Hand Book): Hart, Uehara, Wagner
3. Rosen’s Emergency Medicine: Concepts and Clinical Practice, 6th ed: Chapters 46, 47, 48

“Hand Case Discussion” is an educational module that focuses on the diganosis and management of Hand pathology that commonly presents to the Emergency Department.

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