Hand Infections

Areas that may become infected:

  • Superficial
    • Finger tip (Paronychia)
    • Pulp space (Felon)
    • Web Space (Collar stud abscess)
    • Subdermal
  • Deep
    • Flexor sheaths → Radial & Ulnar bursae
    • Parona’s space
    • Mid palmar space
    • Thenar space
    • Hypothenar space
    • Joint Spaces
  • Most common pathogen: Staphylococcus aureus

Paronychia

  • Nail fold infection
  • Treatment: Incision & drainage (I&D) with incision at edge of nail
  • May require partial or complete nail removal
  • Resistant cases: Consider Candida albicans

Felon

  • Infection of pulp space
  • Treatment: I&D with mid-lateral incision in pulp space
    • Ulnar side except for thumb and little finger
  • Main concern: Multiple loculations requiring breakdown
    • Peel off volar aspect of distal phalanx

Collar Stud Abscess

  • Characteristics: Two separate abscesses in web space
    • Hourglass-shaped appearance
    • Larger on dorsal surface, can extend proximally
    • Fingers appear slightly spread apart
  • Treatment:
    • Avoid incision through web space (prevents bad scarring)

Flexor Sheath Infections

Kanavel’s Signs:

  1. Flexed posture
  2. Pain along flexor sheath
  3. Fusiform swelling
  4. Pain on passive stretch

Management:

  • Early cases: Antibiotics if short-duration presentation
  • Unclear diagnosis: Consider further evaluation
  • Incision & Drainage (I&D) in case of soft tissue infection:
    • Two transverse incisions over A1 and A5 pulleys
    • Dissect flexor sheath proximal & distal to pulley
    • Longitudinal incision & pus culture
    • Insert umbilical catheter to irrigate sheath proximally to distally (prevents infection spread)
    • Consider leaving catheter for irrigation or relook at 48 hours
    • Severe infections: May require full sheath exploration via mid-lateral incisions (avoids exposing flexor tendons)

Radial & Ulnar Bursae

  • Anatomy:
    • Continuations of flexor sheaths of little and thumb digits
    • Meet just proximal to flexor retinaculum
  • Horseshoe Abscess: Infection tracking down from thumb/little finger

Palmar Spaces

  • Lie deep to flexor tendons but superficial to metacarpals
  • Rare but difficult to diagnose
  • Three spaces:
    1. Mid-palmar space (Over middle and ring MC, contains 2nd–4th lumbricals)
    2. Thenar space (Overlies 2nd MC, contains 1st lumbrical)
    3. Hypothenar space (Overlies little finger MC, contains hypothenar muscles)
  • Mid-palmar & thenar spaces separated by a fibrous septum from 3rd MC
  • Signs of infection:
    • Severe pain
    • High fever
    • Absence of fusiform swelling (unlike flexor sheath infections)
    • Does not involve fingers

Parona’s Space

  • Potential space at wrist level (deep to radial & ulnar bursa confluence)
  • Bound by: FCU, PQ, FPL, flexor tendons
  • Concern: Pus can compromise median nerve

Bites & Infections

Common Organisms by Bite Type:

  • Cat: Pasteurella multocida
  • Dog: Streptococcus viridans, Pasteurella multocida
  • Human: Eikenella corrodens
  • Other anaerobes possible but above are most common

Dog & Cat Bites (Order of Frequency):

  1. Streptococcus viridans
  2. Pasteurella multocida
  3. Staphylococcus aureus

Fight Bites (Clenched Fist Injuries)

  • Exploration of underlying joint is essential, even if not obviously involved
  • Puncture wound in joint capsule is distal to skin wound (due to flexion at time of injury)
  • Common organisms:
    1. Group A Streptococcus
    2. Staphylococcus aureus
    3. Eikenella corrodens
    4. Other anaerobes

Other Infections

Herpetic Whitlow

  • Herpes simplex virus
  • Vesicular lesions on children’s fingers
  • History of herpes
  • Treatment: Acyclovir

Necrotizing Fasciitis

  • Rare but high mortality
  • Mixed aggressive pathogens:
    • Group A Streptococcus ± Staphylococcus
    • Anaerobes ± Staphylococcus
  • Intra-operative findings:
    • Dishwater pus
    • Fat liquefaction
    • Muscle necrosis

Fungal Infections

  • Consider fungal causes (Candida albicans) in chronic, non-responsive cases

Onychomycosis

  • Fungal nail bed infection
  • Common, chronic
  • Signs:
    • Yellow/brown discoloration
    • Purulent discharge in severe cases
  • Organism: Trichophyton rubrum

Subcutaneous Fungal Infections

  • Typical Organism: Sporothrix schenckii
  • Source: Inoculation from soil/plants (e.g., rose thorn)
  • Presentation: Starts as papule at inoculation site
  • Treatment: Topical potassium iodine solution

Mycobacterial Infections

  • Most common chronic infection of the hand
  • Tend to attack synovium → Can mimic inflammatory arthropathy
  • Diagnosis:
    • Culture on Lownstein-Jensen medium (for mycobacteria)
    • Ziehl-Neelsen stain (for acid-fast bacilli)
    • CXR (to rule out hematogenous spread)

Typical Mycobacterial Organisms:

  • Mycobacterium marinum → Fresh/saltwater exposure
  • Mycobacterium kansasii → Soil exposure
  • M. avium-intracellulare → Soil, poultry (most common in HIV)

Leprosy

  • Mycobacterium leprae
  • Primarily a nerve disease, skin lesions on hands are secondary

Syphilis

  • Treponema pallidum
  • Signs: Ulcers on fingers (chancre)
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