Most common organisms involved in hand infections
S. aureus or Streptococci
Why is early identification essential in hand infections?
Risk of damage to local structures and subsequent loss of function
Investigations for suspected hand infection?
Routine blood tests to aid diagnosis, including include CRP, WCC, and urate levels.+ Plain film radiographs+ wound swabs if producing pus to aid Abx choice
Why are plain film radiographs used in suspected hand infections?
As penetrating trauma is often a contributing factor in most hand infections, plain film radiographs are routinely used to exclude foreign bodies and assess for underlying fractures or evidence of osteomyelitis.
Management of suspected Hand infection
- Areas erythema marked to determine rate of spread - Abx
Paronychia
<ost common infection of the hand. Infection of the perionychium (the soft tissue fold around the nail plate) can occur secondary to contamination with oral flora from nail biting or sucking
Paronychia - risk factor
Previous trauma or injury causing a disruption to the perionychium can be a significant risk factor
Paronychia - pathophysiology / clinical features
Pus can track along the perionychium in a horse-shoe shape, producing a characteristic abscess at the skin-nail plate junction- fingertip may be swollen, inflamed, and very tender- pus can collect subungually, even cause necrosis of the nail bed and untreated paronychia can result in osteomyelitis of the distal phalanx
Paronychia - treatment
- Abx- Incision & drainage of pus - Nail plate removal MIGHT be necessary to allow sufficient pus drainage- Thorough washout normal saline + antiseptic
Infectious Tenosynovitis
inflammation of tendon sheath caused by infection
Infectious Tenosynovitis - cause (most common)
Direct inoculation of bacteria (commonly S. aureus) secondary to penetrating trauma
Tendosynovitis - most common type
Flexor sheath infections
Flexor sheath infections - emergency or not?
Surgical emergency: raised pressure within the tendon sheath can impair blood flow and lead to eventual tendon necrosis and rupture.
Tenosynovitis - features
Pain, swelling, and erythema of the affected digit
Strong indicator of flexor sheath infection
Kanavel's signs (4 cardinal features)
Kanavel's signs (4 cardinal features)
- Tenderness along the flexor sheath- Flexed finger posture- Pain on passive extension (early sign) - Fusiform swelling of the affected digit (sausage finger)
Tenosynovitis - management
Thorough washout of the flexor sheath in theatre followed by strict elevation and close monitoring
Felon Infections
Subcutaneous infection of the fingertip pulp, most commonly occur in the thumb or index finger and are caused by S. aureus.
Felon Infections - pathophysiology
Fibrous vertical septae run from the periosteum to the epidermis of the pulp, creating a closed system of microcompartments that are susceptible to rising pressure from inflammation
Felon Infections - features
Swelling of the pulp distal to the distal phalangeal crease and severe pain
Felon Infections - most common cause?
Direct contamination, e.g via splinters or garden thorns.
Felon Infections - management
- Simple, resolve spontaneously - Occasionally Abx may be required
Deep Hand Spaces
Thenar, mid-palmar, and hypothenar spaces.
Deep Hand Space Infections
Thenar, mid-palmar, and hypothenar spaces become swollen, tender, and erythematous, with hand movements limited.
Deep Hand Space Infections - Thenar space
Overlies adductor pollicis and is bound ulnarly by the insertion of the adductor onto the metacarpal; when infected, pus may track dorsally around the adductor and in-between its two heads
Deep Hand Space Infections - Mid Palmar space
Continuation of the carpal tunnel, deep to the palmar aponeurosis and superficial to the deep palmar interossei; it has multiple septa distally that separate the space and direct the flexor tendons to their digits
Deep Hand Space Infections - Hypothenar Space
Located palmar to the fifth metacarpal and dorsal to the hypothenar fascia
Differential Diagnosis hand infection
- Gout- Pseudogout- Cellulitis- Herpetic Whitlow- Pyoderma Gangrenosum- Retained foreign body
Complications of hand infections
- Tracking cellulitis- Subsequent sepsis - Damage to local structures