Hand infections

Treatment

Medical

• • First 48 hours - favour elevation, rest, Abx
  • If no improvement at this time, highly unlikely that Abx alone will work

Cellulitis

• • Mark extent of infection
  • Hand immobilisation
  • Elevation
  • Abx
  • Removal of offending object
  • Avoid using affected limb for venepuncture
  • Hospitalise if: increasing cellulitis, no response to PO abx, purulence

Paronychia

• • Infection along paronychium - lateral folds of the fingernail
    • If both paronychium and eponychium are involved, called 'runaround infection'
  • Purulence dorsal to nail plate indicates involvement of nail matrix
  • If no purulence: PO Abx, warm soapy soaks, and splint immobilisation
  • If abscess:
    • Ring block
    • Use needle to get beneath the nailfold and lift the nailfold off nail plate
    • Puncture abscess
    • Part of nail may need to be removed if abscess is under nail or ingrown nail is causative factor
    • Pack wound with betadine soaked ribbon gauze/kaltestat
    • Twice daily soaks and packing with PO Abx

Herpetic whitlow

• • Cytolytic infection of pulp and nailfold caused by HSV
  • 48-72 hours of severe pain, followed by erythema. 10-14 days later, small clear vesicles form and then coalesce, with skin slough.
  • Usually self-limiting in 3-4 weeks
  • Antivirals not indicated
  • Cover area with a clean, dry dressing
  • 20% will get recurrence

Felon

• • Subcutaneous abscess in finger pulp
  • Mostly due to penetrating trauma from a needle, wood splinter or minor cut
  • Generally staph aureus
  • Can get quite gnarly if untreated with necrosis and proximal OM/septic arthritis
  • Oral Abx if within 48 hours, warm soapy soaks and elevation
  • Drainage if failure to improve, worsening symptoms or fluctuance in finger pulp

Pyogenic flexor tenosynovitis

• • Serious infection that can destroy the flexor sheath and its frictionless gliding surface, leading to scarring and poor tendon function
  • Anatomy
    • Infection within potential space formed by visceral and parietal layers of the tenosynovium that constitute the flexor tendon synovial sheath
    • The synovial sheath begins just proximal to the first annular pulley (A1) at the distal metacarpal neck and ends at the insertion of FDP distal to the A5 pulley
    • At little finger, this sheath is continuous with ulnar bursa
    • At thumb, the flexor sheath is continuous with radial bursa
  • Aetiology
    • Most commonly direct penetrating trauma to flexor tendon
    • Contamination from adjacent infection
    • Seeding from distant infection
  • Presentation
    • Pain and swelling along flexor sheath, especially with history of penetrating injury
    • Cardinal signs of Kaval: exquisite tenderness over the path of the flexor sheath, marked symmetrical swelling of the finger 'sausage finger', flexed posturing of the involved fingers, pain on passive extension of involved fingers (last one is most important and earliest sign)
  • Treatment
    • First 24-48 hours: non-op
    • Indications for surgery: failure to improve, infection >48 hours duration, gross purulence. 'However, in realistic practice, suspicion mandates immediate procedural intervention in the vast majority of cases.'
    1. Limited exposure with catheter placement for irrigation
       • Effective in most cases
       • Proximal incision over A1 pulley. A1 identified and incised to allow placement of 16 or 18 gauge soft angiocatheter or a 5Fr paediatric feeding catheter into the tendon sheath.
       • Distal incision over the A5 pulley in the midaxial location.
       • Catheter sewn into place and tendon sheath irrigated with 500mL saline. Need to visualise wash draining through the distal incision.
       • Loosely dress hand with abundant gauze, immobilise in splint, elevate.
       • Continue irrigation for 48 hours as 25mL/hr or 50mL bolus every 2 hours.
       • Begin hand therapy and remove dressing at 48 hours.
    2. Extensive dissection with complete exposure of flexor tendons
       • Mainly required when there has been poor response to limited exposure, or gross purulence initially noted within the tendon sheath
       • Midaxial or volar zigzag incision
       • Incisions made at cruciate pulleys and in the palm, and these are used to excise the inflamed synovium without damaging the annular pulleys and sent for culture
       • Incisions loosely closed over an indwelling catheter for post-op irrigation

Deep space infections

• • Thenar space
    • Anatomy
      • Dorsal floor: interosseous muscles and the APL, which insert into the volar aspect of the long finger metacarpal
      • Ulnar: separated from the midpalmar space by the oblique fascial septum
      • Radial: convergence of adductor pollicis tendon and fascia at the thumb proximal phalanx
    • Clinical
      • Swollen and exquisitely tender thenar region/first webspace
      • Thumb motion, both passive and active, induces severe pain
      • Swelling often results in thumb abduction as the volume of the thenar space increases due to the expanding purulence or swelling
      • Swelling and purulence may be more noticeable dorsally
    • Treatment
      • I+D through a combination of volar and dorsal incisions
      • (Dorsal incision alone offers incomplete access to the tissue plane deep to the index finger tendons)
      • Volar incision is best done along the thenar crease (longitudinal approach). Protect the palmar cutaneous branch of the median nerve in subcutaneous tissue here, as well as recurrent branch of the median nerve which lies deeper at the distal border of the transverse carpal ligament.
      • Blunt dissection between the first and second metacarpal entering through the palmar fascia; also decompress the dorsal compartment between the adductor and the first dorsal interosseous muscle.
      • Dorsal incision, preferably longitudinal, placed just proximal to the web, centred over the dome of the dorsal extension of the infection and then extended proximally by 1 to 2 cm. Don't extend incision to web edges so as to avoid a potential webspace contractures. Direct blunt dissection deeply towards the palm to evacuate the space. Wound should then be debrided, irrigated and packed.
  • Mid-palmar space
    • Anatomy
      • Deep (dorsal) to the palmar fascia and FDS/FDP tendons
      • Superficial to volar interosseous muscle fascia and metacarpals
      • Radial border - oblique septum, which separates the mid-palmar space from the thenar space
      • Ulnar border - hypothenar septum
      • Distal boundary - vertical septae of the palmar fascia
      • May be continuous with the radial bursa
    • Clinical
      • Dorsal hand often more swollen than the palm due to the vertical fibrous septae of the palm, but there will also be signs on the palm
      • Palmar concavity is notably lost
      • MF and RF flexed
      • Passive motion very painful
    • Treatment
      • Drainage required
      • Palmar approach - either transverse, longitudinal, or combination
      • Transverse: parallel to the distal palmar flexion crease from the radial border of MF to ulnar border of RF. Dissection taken deep, going on either side of the RF flexor tendons until the abscess is reached.
      • Longitudinal: proximal to the distal palmar flexion crease and extends proximally along MF metacarpal and stops short of the radial border of the hypothenar musculature. Blunt dissection deep to the palmar fascia until the mid-palmar space is entered.
      • Evacuate, irrigate, pack.
  • Hypothenar space
    • Anatomy
      • Potential space within the region defined by the hypothenar fascia and hypothenar musculature
      • Radial border - hypothenar septum
      • Floor - LF metacarpal and fascia of the deeper hypothenar muscle
      • Ulnar border - hypothenar musculature
    • Clinically
      • Very rare
      • Swelling and tenderness of the hypothenar space
      • Pain on LF metacarpophalangeal flexion
    • Treatment
      • Single longitudinal incision, either on the ulnar aspect of hand at the junction between the glabrous and the dorsal skin, OR on the palmar surface centred on the ulnar border of the RF metacarpal axis above the hypothenar eminence
      • Blunt dissection continued until the space is reached
      • Care for ulnar nerve and artery in Guyon's canal
      • Don't cross wrist crease
  • Interdigital space
    • Anatomy
      • Triangular spaces at bases of fingers
      • Roof - dorsal hand fascia and skin
      • Radial and ulnar borders are composed of the extensor tendon mechanism and MCPJ joint/capsular structures
      • Vertical septae of the palmar fascia for the distal boundary, thus limiting extension into hand
    • Clinically
      • Occurs with direct penetrating trauma, or irritation by fissures
      • Swelling tracks dorsally around the palmar fascia into the dorsal subcutaneous web space, producing a collar-button abscess
      • Finger abduction is seen if purulence is predominately volar aspect
      • Lack of abduction suggests a dorsal location
    • Treatment
      • Volar zigzag incision proximally to MCPJ and distally to base of involved web
      • Gentle blunt dissection. Connect the dorsal and palmar spaces, protecting neurovascular structures.
      • If there is a collar button abscess, a dorsal incision is made.
      • Irrigate and pack
  • Dorsal subaponeurotic space
    • Anatomy
      • Potential space located on the dorsum of the hand composed of loose areolar tissue deep to the extensor tendons and superficial to the interosseous muscle fascia and metacarpal periosteum
    • Clinically
      • Infections usually due to penetrating injury
      • Imaging is helpful due to overlapping presentations of cellulitis and deep space infection
      • Dorsal hand swollen and erythematous with warmth, fluctuance and tenderness, similar to cellulitis
      • Finger extension difficult and painful
      • Palm is usually non-tender
    • Treatment
      • Indications for drainage - either failure of conservative management or high suspicion of subaponeurotic space infection
      • Small and well-localised abscesses - one dorsal longitudinal incision
      • More diffuse and extensive infection - two longitudinal incisions, made over the second and fourth metacarpals
      • Don't injure extensor tendons, but make incisions in fascia to allow entry into the subaponeurotic space
  • Space of Parona
    • Anatomy
      • Distal forearm, deep to FDP tendons and volar to pronator quadratus
      • Continuous with radial and ulnar bursae and the midpalmar space (susceptible to infections from continuous spread)
    • Clinically
      • Swelling, tenderness, fluctuance in distal volar forearm
      • Flexion of fingers is difficult and painful
      • New-onset numbness and weakness in thumb, IF, RF (acute carpal tunnel syndrome)
    • Treatment
      • Longitudinal incision, ulnar to palmaris longus from wrist flexion crease to the distal third of the forearm (protect median nerve)
      • Nerve and flexor tendons retracted radially to gain access to space
      • Evacuate, irrigate
      • If also washing out mid-palmar space, use two separate incisions to leave carpal ligament intact

Septic arthritis

• • Unusual in the hand
  • Penetrating trauma can cause it, also haematogenous or contiguous
  • Low-grade fever, chills, night sweats. Pain, erythema, swelling in the joint. Active or passive movement will result in pain.
  • XR usually normal
  • Aspiration of purulence from joint confirms the diagnosis - send for cell counts and microscopy (exclude crystalline arthropathy)
  • Treatment
    • Arthrotomy preferred
    • Wrist - longitudinal incision between third and fourth dorsal compartments
    • MCPJ - dorsal midline incision and joint exposed through an incision in the extensor hood, with care taken to preserve the sagittal bands
    • PIPJ - midaxial incision from the DIPJ to the webspace is used to avoid injury to the central slip, and the tranverse retinacular ligament and accessory collateral ligaments are identified and incsed to expose the PIPJ.
    • A penrose drain should be left for 24 hours, and hand motion and therapy started on day 2 or 3.