Hand Infections

DEFINITION

Hand infections including specific conditions (refer management)

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EPIDEMIOLOGY

See below

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AETIOLOGY

Various agents common and uncommon can be implicated

Note occupational and exposure risks:
- e.g. herpes simplex infx common in dental workers
- Mycobacterium in fishermen and marine workers
- Sporothrix schenckii in gardeners
- Eikenella corrodens in human bites / hand vs tooth trauma
- Pasturella multocida after cat and dog bites

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BIOLOGICAL BEHAVIOUR

See management below

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MANIFESTATIONS

See management for individual conditions

History
Determine hand dominance, occupation
Pre-existing and concurrent diseases
- diabetes and immunosuppression important
Precise chronology of hand symptoms

Exam
Inspect
Size and contour of affect vs unaffected hand
Focal swelling, abrasions, skin changes
- areas of erythema, blistering, ecchymosis, necrosis, fresh or partly healed wounds
Palpation
Entire hand, from uninvolved to involved areas
Elicit focal tenderness over joints, tendons, noting crepitus, firmness, fluctuance,

Complete neurovascular and functional exam of hand and forearm

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INVESTIGATIONS

Imaging
Plain films to look for foreign body, bony pathology, gas in soft tissues.
Other tests sometimes necessary, e.g. CT, USS, MRI.

Lab Tests
CBC, CRP,
Blood cultures as indicated
Collection of specimen / pus for gram stain, fungi and mycobacteria


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MANAGEMENT

Prophylaxis
Tetanus prophylaxis if wound and not up to date

Cellulitis
Elevation, splinting, antibiotics

Abscess or Collection
Surgical drainage.

Surgical Management
(At fingertip or superficial soft tissues)
LA - ring block to digital nerves at finger bases via dorsal puncture
- no vasoconstriction(!)
cf complicated deep tissue space infections --> need GA (and injections then compromised lymphatic outflow as well)
Tourniquet finger with a penrose-type drain or finger glove wrapped around it.
Plan incision ot account for need for proximal distal extension.
Enter space, debride, tenosynovectomy if indicated
Irrigate and wash well.

Joint space involvement
Debride spongy bone and send for pathological evaluation to confirm diagnosis of osteomyelitis
--> requires 6w+ of Abx

Specific Conditions

1. Paronychia
Infx of soft tissue folds around lateral aspects of fingernail.
Us. staph aureus, often after minor trauma or nail biting.
--> if not treated, can progress proximally into deep spaces and become serious
If at proximal nail fold, termed eponychia
Assoc. with edema, erythema, tenderness
Early
Splint, immobilize, elevate, oral antibiotics
Advanced
Drain with ring block and tourniquet
image
- laternal nail on affected side elevated off nail bed
- longitudinal nail strip removed with small pointed scissors
--> if not adequately drained, enter margins of nail fold to adjacent soft tissues.
- irrigate, spint, elevate 24h, antibiotics 14d, review in 3-5d

2. Felon
Painful infection of volar pulp
felon
Initially contained by fibrous septa of the volar finger, causing a mini compartment syndrome
--> exquisitely tender
image
Usually from penetrating injury, e.g. with thorn, splinter, needle etc
If not treated, infection can again track along deep planes, causing serious problems and osteomyelitis
Early
Treat with splinting, elevation, antibiotics
More Advanced
Digital block
Need free drainage of compartments of volar pulp
Perform bilateral incisions parallel to and 3mm from edges of nail.
Spread scissors in volar tissue space to release pus
Irrigate and place a single drain.
Incisions heal by secondary intention
image

3. Herpetic Whitlow
Painful infection, 1+ fingers, caused by HSV 1 or 2
After infection by contaminated fluids
- sucking fingers near oral lesions, contact with patients etc.
Incubation period 2-14d
- fever and malaise may precede burning finger pain and eruption
- at 7-10d, small clear vesicles form and coalesce, vesicles rupture and ulcerate
Self-limiting. But recurrence up to 50%
Treatment
Rule out paronychia
Viral cultures can be done
Symptomatic treatment only
- unroofing blisters can promote secondary bacterial infx
Acyclovir can reduce duration of infection and abx if secondary infx.

4. Suppurative Flexor Tenosynovitis
Us. after penetrating injury to volar finger
Bacterial infx of flexor sheath, b/n first annual pulley and metacarpal head and FDP on prox phalanx = closed potential space.
In thumb and little finger, sheath communicates with bursa, allowing proximal extension of infection.
Staph aureus and Strep are the most common species.
Cardinal signs
Symmetric swelling of affected digit
Semiflexed digit
Pain along tendon sheath
Severe pain on passive extension
Treatment
image
Early: splinting, elevation, IV Abx.
Do not delay.
Failure to respond in 24h --> surgical drainage.
2cm transverse incision at proximal end of A1 pulley.
- if infx in sheath, counter-incision on midlateral line of digit; prox to DIP jt
--> thread a small drain or catheter in this tract, flex finger several times to drain sheath.
--> if minimal output, can remove and free drain.
--> else can leave and irrigate.

Deep Infections

image
A. Thenar space; B. Adductor pollicus; C. Midpalmar septum;
D. Dorsal aponeurotic space;
E. Extensor tendon; F. Midpalmar space; G. Hypothenar space.

Usually result from penetrating injury and Strep or Staph introduction.

1. Interdigital Web Space Infection
Through breaks in skin b/n finger or secondary infection
Painful distal palmar swelling
May be abscess and fingers separating away from the swelling
Treat with incision and drainage, through ventral, dorsal, or combined approach.
- can access palmar space with zig-zag incision
--> bluntly dissect subcut tissues
--> identify and protect the digital neurovascular bundle
Loosely close over a penrose drain and secure, splint, elevate, ABx.
image

2. Dorsal Space Infections
Often IV drug users
Pain, erythema and swelling of the dorsal hand
Tenderness elicited on extension.
Antibiotics, elevation, immobilisation.
Incision and drainage when fluctuant.
- incise fascia between extensor tendons
- occasionally, 2 parallel incisions are needed
- ensure skin bridge has adequate blood supply

3. Palmar space infections
Incision and open deep spaces with blunt dissection, e.g. opening mosquito haemostat
Thenar

Between interosseus muscles and abductor policus longus and midpalmar septum and thumb metacarpal (triangular region)
- can spread dorsally over back of interosseus creating a pantaloon abscess
Inflamed and pain on thumb active motion
Thumb may be held in abduction.
Incision like this:
image
- dorsal counter drainage when necessary

Midpalmar Space

Deep to palmar fascia
Bordered by oblique septum, and hypthenar septum
Uncommon site of infection.
Oedema of the volar and dorsal hand surfaces
Tender palm and pain on passive finger motion
Drain with transverse or longitudinal incision (or both):
image

Hypothenar Space
Between hypothenar fascia and hypothenar muscles.
Pain on flexing little finger.
Drain with simple lontiduinal incision over space.

Paronar Space
Deep to forearm flexors, bounded by pronator quadratus and interosseus membrane
Communicates with radial and ulnar bursae, and midpalmar space infections may join
Longitudinal incision between flexor tendons, ending at the wrist crease.

Septic Arthritis
Swollen painful joint, pain and restriction on motion.
Confirmed by aspiration of infected joint fluid
May be systemically unwell
Early treatment needed
Treatment
Dorsolateral incision, lateral to finger extensors, for finger joint infections
For wrist, longitudinal incision between 3rd and 4th finger extensor compartments, avoid the extensor tendons.
- further incisions as indicated

Osteomyelitis
Penetrating injury or haemotogenous spread.
Often staph; debride and long-term antibiotics.
Ortho and occasionally finger amputation in severe cases.

Bites
Commonly punch wounds over metacarpophalyngeal jt
Ciommunicate with joint space, having septic arthritis in 60%
Most common bug is Eikenella corrodens
Radiographs for body injury and tooth fragments
Dog bites often have Strep viridans or staph aureus, cat may have Pasturella multocida
Careful hand exam required
If joint involved, needs washout in a bloodless field with copious irrigation
Human bite infections are particularly aggressive, need urgen incision and drainage and high-dose ABx
- hand elevation and tetanus
Dog bites can usually be irrigated and closed, but not cat bites - often become infected. Oral ABx indicated, consider tetanus and rabies.

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REFERENCES

Cameron 10th

Jerome Notes

Hand infections

What is cellulitis of the hand

Usually a diffuse infection caused by group A Beta haemolytic strep

As a rule, surgery is contraindicated in the presence of a spreading streptococcal infection.

However, for localized infections, other than cellulitis or lymphangitis of streptococcal origin, incision and drainage is carried out.

Most infections arising on the volar surface of the hand produce maximal swelling on the dorsum; however, dorsal drainage is used only when suppuration presents on the dorsum.

What is Paronychia

Infection of paronychium. Acute infection is caused by S. Areus. A chronic fungal infection by C. Albicans may develop in dishwashers

Acute unilateral paronychia requires elevation of the cuticle from the nail at the site of infection

If the infection is advanced or with subungual abscess, removal of the proximal portion of the nail is preferred

If necessary to ensure adequate drainage, an incision may be made in the skin below the corner of the nail, placed laterally to avoid damage to the nail bed

What is Eponychia

Infection of the eponychium.

What is a Felon

Infection of the pulp of the finger tip. At each skin crease, the skin is bound to the flexor sheath so that the pulp of each phalanx is in a separate compartment. The branches of the digital artery that supply the epiphysis of the distal phalanx tranverse the pulp space. Infection of the pulp space may occlude these vessels and cause necrosis.

Immediate drainage is imperative to relieve the increased tension

Superficial infections may be drained through incisions directly overlying the site of infection.

For a deeply situated abscess, the incision should be made to one side of the fingernail, across under the free edge of the nail, and extended well down into the pulp of the finger anterior to the terminal phalanx until all compartments have been opened and the abscess cavity has been completely drained

 

What are tendon sheath infections

• Infections in the synovial flexor sheaths

• Those associated with trauma – the most common organisms are staph and strep. Lacerations and bites are associated with polymicrobial infection including gram negative organisms

• Common antibiotic regimen include Vancomycin and ciprofloxacin

• Associated with dog/cat bites:  should include prophylactic oral augmentin. For active infection IV ceftriaxone plus metronidazole or  IV Tazocin.

• Human bites: Cefuroxime and metronidazole or augmentin

• Pathogens associated with haematogenous spread include N. gonorrhea and mycobacteria

• Injuries associated with fresh or salt water – suggest levoflaxacin (cover M. Marinum)  and doxycycline (cover vibrio species). 

• Kanaval’s sign is elicited: flexed posture of finger, circumferential swelling of digit, tenderness along sheath and pain on passively extending the finger.

• There is a risk of tendon sloughing and adhesion formation.

• Treatment is elevation, with splintage in safe position, Abx.

• If infection is extensive at presentation or does not respond promptly to conservative treatment, incision, drainage and washout is required.

How is surgery performed for tendon sheath infections

Drainage is carried out through transverse incisions, as indicated by the dotted lines in Figure 6, opening the sheath distally and proximally.

The distal incision should be placed just proximal to the interphalangeal crease and the proximal incision about a finger-breadth below the metacarpophalangeal crease for the index, middle, ring, and little fingers. The proximal transverse incision for the thumb must be placed just proximal to the wrist, at the base of the radial bursa, and a similar incision may be required in the ulnar bursa for drainage of infection in the flexor tendon sheath of the little finger if it has spread into the palm.

A small catheter may be introduced into the sheath for irrigation with saline or the appropriate antibiotic solution.

What is a web space infection

Infection in the web space of the hand.

Often produce marked swelling extending to the back of the hand and associated with systemic upset

Treatment is with elevation, IV Abx and early incision and drainage if no improvement

May be drained through incisions placed directly over the site of abscess, with care taken not to spread the infection to the tendon sheaths. The incision is zig-zag in shape

What are palmar space infections

• Infection in the potential midpalmar or thenar spaces.

• These spaces lie between the flexor tendons and the metacarpals.

• Present with gross and rapid swelling in the dorsal and palmar aspects of the hand.

• A septum passed from the palmar aponeurosis to the third metacarpal to define a thenar and mid-palmar space:

• Thenar: Anterior to the transverse head of adductor longus and contains the long flexor to the index finger and first lumbical

• Midpalmar space: Deep to the long flexors of the middle, ring and little fingers and anterior to the interosseous muscles of these fingers. Contains the 2nd, 3rd and 4th lumbicals.

• Because the synovial sheaths of the thumb and little fingers extend into the palm and forearm via the radial and ulna bursa

The proximal transverse incision for the thumb must be placed just proximal to the wrist, at the base of the radial bursa, and a similar incision may be required in the ulnar bursa for drainage of infection in the flexor tendon sheath of the little finger if it has spread into the palm.

 

What is the safe or ‘intrinsic plus’ position of the hand

• MCP flexed at 70 degrees

• PIP and DIP extended

• Wrist extended at 20-30 degrees

• Thumb is extended and abducted.

• This is the position at which the collateral ligaments are taught and so no shortening of these ligaments will occur with immobility which cannot be overcome with physiotherapy.

• This is slightly different from the position of optimal function – where the flexor and extensor tendons are at maximal mechanical advantage.

What is the microbiology of hand infections

• Tendon sheath infections – most commonly S. Areus

• Cellulitis most commonly caused by Beta haemolytic strep

• Contaminated wounds contain E.coli, proteus, pseudomonas

• Paronychia – most commonly S. Areus if acute, candida if chronic

• Spontaneous tenosynovitis – N. Gonorrhea

• Human bites – Eikenella Corrodens – best treated with augmentin.

• Other organisms in the human mouth alpha and beta haemolytic strep, staph, nisseria, anaerobes (bacteroides, fusobactum, clostridia, viellonella, peptostreptococcus.

• Dog and cat bites – Pasturella Multocida – best treated with Augmentin

• Thorn injuries in garden – sporothrix schenckii

• Fishermen – mycobacterium Marinum