Chapter 32 - Hand Infections Flashcards
What are the most common bacteria found in hand infections?
Staph. aureus (50-80%) and Beta-hemolytic streptococci; >50% are polymicrobial
What is the basic treatment principle when dealing with infections in the hand?
DICE: Drainage and Debridement, Immobilization, Chemotherapy (antibiotics), Elevation
What is the most common site for infection (tissue of the hand)?
Dorsal subcutaneous tissue, followed by tendon, joint, bone and subfascia
What is the most common mechanism of hand infections?
Trauma (penetrating injuries or bites)
How do superficial hand infections tend to be treated?
Antibiotics (14-21 days), splinting (depending on severity)
How to deep hand infections tend to be treated?
Surgical irrigation and debridement, antibiotics, splinting
What patient risk factors predispose them to hand infections?
Immunocompromised states, IV drug use, DM, steroid use, microvascular disease and damaged blood supply (trauma). Infections tend to be virulent.
Whats are the common pathogens found in diabetic patients?
Gram negative and polymicrobial, subepidermal abscesses are unique to this population.
How do you treat a herpetic whitlow in an immunocompromised patient
Antivirals (will not resolve spontaneously)
What characterizes cellulitis of the hand?
Erythema, swelling, tenderness, associated lymphangiitis may indicate a more severe infection
What bacteria is most often seen with cellulitis?
Group A Beta-hemolytic streptococcus - S. Aureus may also be seen
What are the oral antibiotics of choice in cellulitis?
Nafcillin, dicloxacillin, and cephalexin; erythromycin if pen allergic
What are the most commonly isolated pathogen in human-bite infections?
alpha-hemolytic strep and s. aureus
What is the most commonly involved area in human bites
MCP joint (“fight bites”)
Where is the most common topography for occurence of hand infections?
Flexor tendon zone II
What organism is commonly isolated in one-third of human bite wounds?
Eikenella corrodens, 7-29%, must be cultured in 10% CO2, destroys articular cartilage quickly
What is the recommended treatment for human bite injury?
Surgical extension and debridement with arthrotomy, culture, antibiotics, leave the wound open
What organism commonly infects animal bites and scratch wounds?
Pasturella multilocida
What is necessary for diagnosis and treatment of an animal bite?
Xray (to assess bone and foreign objects such as teeth), antibiotics (augmentin or IV unasyn), irrigation
What are the common cultures requested in hand infections?
Aerobic, anaerobic, cultures in Lowenstein-Jensen medium for atypical mycobacterium
What are the common stains needed in hand infections?
Gram stain, Ziehl-Neelsen (mycobacterium), Tzanck smear (herpes)
When evaluating a hand infection and a fungus is suspected, what preparation is necessary?
KOH (potassium hydroxide)
What is the most common infection in the hand of HIV patients?
Herpes simplex
When using aminogylcoside (eg gentamicin), for gram negative coverage, what are potential side effects?
Nephrotoxicity and ototoxicity
What is the drug of choice for MSSA infections of the hand?
cefalexin, augmentin
Whats is the drug of choice for MRSA? IV/Oral
Vancomycin, Bactrim, clinda, cipro
What is the current reported incidence of MRSA hand infections?
34-73% and rising
What is the most common hand infection?
Paronychia - infection beneath the eponychial fold along the paronychial fold and nail plate.
Which is the area around the fingertip most resistant to infection?
hyponychium
How do you treat an acute paronychia without abscess?
warm water soaks (with or without iodine or chlorhexidine) and oral antibiotics.
How do you treat a paronychia with abscess?
I&D, routinely with removal of the nail plate
What is a runaround abscess?
a paronychial abscess that tracks around beneath the entire nail fold superficial to the nail plate
What type of patients have chronic paronychial infections?
People exposed to constant moisture (dishwashers, swimmers, medical professionals), children who dig in the dirt
What organism is seen in chronic paronychial infections and what is the treatment?
Candida albicans; Marsupialization and nail removal; topical corticosteroid-antifungal ointment (3% clioquinol in triamcinilone-nystatin (Mycolog))
In what subset of diabetic patients with hand infections is morbidity particularly high?
renal transplant patients
What is a felon?
Closed space infection of the digital pulp
What is the most common organism found in felons?
MRSA
What is the preferred incision for draining a felon?
Mid-volar and high lateral incisions. Longitudinal incisions from distal flexion crease to pulp apex allows for incision of septal compartments while protecting neurovascular bundles
What type of incision is used for draining a felon, is associated with vascular compromise of the digital pad?
Fishmouth
What are the consequences of undrained felons?
deep-space infections, septic arthritis, osteomyelitis, amputation, acute flexor tenosynovitis, painful/insensate pulp scars
How long does viral shedding and ability to infect others persist in people with herpetic whitlow?
until lesion epithelialization is complete
What is the natural course of a herpetic whitlow
self limiting, 3-4 weeks, presents with throbbing pain, tingling, swelling, and erythema (48-72hrs), then erythema and tenderness around clear vesicles which coalesce to form ulcers over 10-14 days. 20% recurrence.
Is irrigation and debridement helpful in herpetic whitlow?
No. May cause bacterial superinfection.
What is pyogenic flexor tenosynovitis of the hand?
Bacterial infection of the flexor sheath between the viceral epitenon layer and the outer parietal layer
What is the most common bacteria associated with pyogenic flexor tenosynovitis?
S. Aureus
What are the four cardinal signs of pyogenic flexor tenosynovitis?
- Flexed resting position
- Tenderness over the flexor sheath
- Severe pain of passive extension (commonly proximally along the finger tendon sheath)
- Fusiform swelling of the finger
All signs may not be present, especially early
What laboratory values are helpful in the diagnosis of flexor tenosynovitis?
WBC, ESR, CRP. Elevation of at least one of these values with +clinical exam is 100% specific (not as sensitive)
What type of bacterial flexor tenosynovitis usually results from hematogenous spread?
Gonococcal infection
Which two digital flexor sheaths communicate with bursae in the palm and thus can propagate proximal extension of the tenosynovial infections?
Flexor sheath of the thumb (radial bursa) and the small finger (ulnar bursa). The ulnar and radial bursae extend proximally in 50-80% of persons into the carpal tunnel
What is a horseshoe abscess?
Infection of either small finger or thumb flexor sheath with contiguous spread through communication of the radial and ulnar bursae
What has happened if a patient with suppurative flexor tenosynovitis of the small finger suddenly develops acute Carpal tunnel syndrome?
Extensive proximal spread of infection into Paronas space
What is Paronas space (borders)?
Quadrilateral potential space at the wrist bordered by pronator quadratus, pollicus longus and flexor carpi ulnaris
Can contiguous spread from the index finger sheath cause infection in the thenar space
yes
How do you treat early infections of suppurative flexor tenosynovitis (<24hrs)?
Elevation, splinting, and IV antibiotics.
How do you treat late infections of suppurative flexor tenosynovitis (<24hrs)?
Surgical irrigation of the tendon sheath and IV antibiotics
If limited incision and catheter irrigation are used, why is it important to make sure the catheter is within the digital sheath?
Digital compartment syndrome can occur. The presence of fluid in the interstitial tissue
What is the favored exposure for severe tenosynovitis infections with subcutaneous purulence or necrotic tendon?
Open exposure of the sheath and irrigation through windows sparing A2 and A4 pulleys, midaxial approach is preferred over Bruner incision to limit postoperative tendon exposure
What is the recommended empiric choice and duration of treatment for antibiotics for pyogenic flexor tenosynovitis?
Vancomycin and Zosyn for 2-3 weeks
What deep spaces of the hand can be involved in infection?
Dorsal subaponeurotic, thenar, midpalmar, Parona’s space, interdigital subfascial web spaces
Name the possible pertinent infected area for:
Midpalmar space
Infection of ring or middle finger flexor tendon sheath
Name the possible pertinent infected area for:
Thenar space
Infection of the index flexor tendon sheath
Name the possible pertinent infected area for:
Dorsal subaponeurotic space
Aponeurosis of the extensor tendons (deep)
Name the possible pertinent infected area for:
Dorsal subcutaneous space
Entire dorsum of the hand
What are the most common infectious agents for deep space hand infections?
Streptococcus, S. aureus, and coliform organisms
What is the name used when the interdigital subfascial webspace is infected?
Collar button abscess
What is the treatment for infection in the interdigital subfascial webspace (Collar button abscess)
I&D, broad spectrum antibiotics
In contrast to simple dorsal subcutaneous abscess, a collar button abscess is characterized by:
Abducted resting posture of the adjacent digits
An infection in the thenar space, first webspace, and dorsoradial aspect of the hand is known as?
Dumbbell or pantaloon abscess
The boundaries of the thenar space?
Volar: index finger flexor tendon
Dorsal: adductor pollicis musculature
Radial: insertion of the adductor pollicis into the proximal phalanx of the thumb and thenar muscle fascia
Ulnar: midpalmar space or oblique septum from the palmar fascia to the volar ridge to the third metacarpal (midpalmar septum)
Why is the thumb held in marked abduction in thenar-space infections?
This posture reduces pressure and pain
What are the mimickers of hand infection?
Gout, pseudogout, pyogenic granuloma, pyoderma gangrenosum, neoplasia
hat is the most common algae infection seen in fishermen? What antibiotic to use?
Prototheca wickerhammi
Tetracycline
What are the recommended incisions for drainage of thenar space infections?
Combined volar (thenar eminence belly) and dorsal incisions (1st webspace axial to 2nd MC)
Why are incisions parallel to the first-web commissure not recommended in thenar space infections?
To avoid webspace contracture
What is the only infection resulting in loss of palmar concavity?
Midpalmar space infection
What are the boundaries of the midpalmar space?
Volar: flexor tendons and lumbricals
Dorsal: middle and ring finger metacarpals and second and third palmar interosseous muscles
Radial: midpalmar septum
Ulnar: Hypothenar muscles
Exposure to what virus causes milker’s node in the hand (or granuloma)?
Pox virus
What is an interdigital pilonidal cyst?
When a foreign piece of hair enters the webspace and becomes secondarily infected
What is the usual rate of infections after elective hand surgery?
1-7%; 0.47% deep infection rate after CTR
What bacteria is associated with coastal or brackish water and what is the treatment?
Vibrio vulnificus
Tetracycline, chloramphenicol
What bacteria is associated with fresh water and what is the treatment?
Mycobacterium marinum
Rifampin, ethambutol TMP-SMX
What is sporotrichosis?
Chronic granulomatous infection caused by the saprophytic fungus (Sporothrix schenckii). Most common subcutaneous fungal lesion in North America, seen mostly in upper extremities.
What is the treatment of choice for sporotrichosis?
Oral potassium iodide, or itraconazole if allergic to iodine
What organisms are commonly found in septic arthritis of the hand? Cause?
S. aureus and streptococcus.
Haemophilus influenzae (young).
Gonococcus (young adult with monoarticular non traumatic septic arthritis).
Penetrating trauma.
What is the most common cause of osteomyelitis in the hand?
Open fractures
Where is the most common location of osteomyelitis in the hand?
Distal phalanx
What is the most common organism seen in necrotizing fasciitis?
Group A strep
What is the organism seen in gas gangrene?
clostridium perfringins
Are there pathognomonic physical findings for deep space infections of the hand?
No, but deep infections are frequently associated with abundant tenosynovitis or joint synovia
What unique infection can occur in the hands of a patient receiving taxol?
Subungual abscess of multiple digits (including toes) with painful onycholysis or nail plate separation
How is septic arthritis of the hand transmitted?
Commonly by penetrating trauma or spread of infection from contiguous sources
What are the physical findings in hand septic arthritis?
Fusiform swelling of the joint with erythema and pain upon active range of motion or passive motion
How is septic arthritis diagnosed?
Joint aspiration with analysis of cultures, cell count (>50,000 cells with >75% PMN leukocytes), crystal count
What is the treatment for hand septic arthritis?
I&D + antibiotics
What is the surgical approach for wrist septic arthritis?
Open through longitudinal incisions between 3rd and 4th extensor compartments or via arthroscopy
What is the surgical approach for MCP joint septic arthritis?
Longitudinal, dorsal incision with at least partial preservation of sagittal bands to prevent extensor tendon subluxation
What is the surgical approach for IP joint septic arthritis?
midaxial incisions
What duration of antibiotics is recommended for septic arthritis of the hand?
1-4 weeks of IV antibiotics
