INFECTIONS OF THE HAND
Before the
introduction of antibiotics, infections of the hand often led to prolonged
morbidity, severe deformity, amputation, and even death. Kanavel’s classic
article in 1939 on the pathways of purulent infection within the anatomic
compartments of the hand opened the modern era of treatment for these problems.
Although injuries in the industrial workplace are less prevalent than in
Kanavel’s time, wounds of the hand still account for a large percentage of hand
infections. A high incidence of hand infections is also associated with
societal problems, such as intravenous injection of drugs with contaminated
needles, wounds inflicted with various weapons in gang-related incidents, and
complications of treatment with immunosuppressive agents. Human and animal
bites may also have severe consequences.
The evaluation of a hand wound must include the
duration of time since the injury, the contamination likely at the site of
injury, and the severity of the wound. After the initial evaluation of the
patient’s neurovascular and musculoskeletal status, the examiner must make a
decision about further evaluation and treatment. It is generally better to err
on the side of caution and thoroughly inspect the wound under surgical control
in the operating room. Regional, intravenous, or general anesthesia is induced.
In a fresh wound, exsanguination is performed with an elastic bandage; if the
wound is already infected, elevating the limb for 2 minutes reduces the risk of
forcing the inflammation deeper into normal tissue. Hemostasis is obtained with
an upper arm pneumatic or an Esmarch forearm tourniquet.
Foreign material and devitalized tissue are debrided,
and the wound is thoroughly irrigated. Pulsed lavage with 3 L or more of saline
solution significantly reduces bacterial contamination. Reducing the bacterial
population below 1 million organisms/mm3 allows the normal immune defenses to
control contaminants. After debridement, exposed tendons, vessels, nerves, and
joints should be protected, but wound closure should be delayed. Fine-meshed
gauze impregnated with petroleum and 3% bismuth tribromophenate and then gauze
dampened with saline solution provides a non- stick, antibacterial, and moist
dressing to protect the exposed tissues. The hand is overwrapped in gauze and
immobilized with a splint and elevated, which is extremely effective in halting
infection. This open treatment followed by repeat debridement at 3 to 5 days and
with delayed primary closure produces excellent results. Some smaller wounds
are left open and treated by whirlpool baths daily with damp to dry dressings changed twice daily until granulation and
epithelialization gradually closes the wound from the inside out preventing
anaerobic bacteria from being trapped in a prematurely closed, subsequently
anoxic wound.
The same approach to postoperative care is appropriate
after incision and drainage of abscesses. In the immediate postoperative
period, the wrist is generally immobilized in dorsiflexion, the metacarpophalangeal joints in 30 to 40
degrees of flexion, and the proximal interphalangeal joints in relative
extension. A bulky dressing provides pressure to reduce edema and capillary
drainage to extract exudate. These measures minimize the likelihood of joint
contractures due to immobility.
If possible, cultures should be obtained before beginning
antibiotic therapy for any hand infection. Gram- positive cocci are responsible
for most abscesses, particularly those resulting from infections incurred
around the home or in the industrial workplace. Wounds due to agricultural or
garden accidents are more likely to be contaminated with gram-negative or mixed
organisms.
Felon
A felon, or whitlow, may begin as a subepidermal
abscess that penetrates a pulp space of the finger. Further extension into
adjacent fibrofatty spaces causes distention with severe pain and throbbing. If
the spread continues, osteomyelitis of the distal phalanx may result in loss of
the tuft, septic arthritis of the distal interphalangeal joint, or infective
tenosynovitis of the flexor tendon sheath.
In the earliest phase, release of the subepidermal
abscess and antibiotic treatment may abort the infection. However, when the
felon is well established, incision and drainage are imperative. A longitudinal
incision is made directly over the site of drainage or necrosis to minimize the
chance of injuring a digital nerve. Blunt breakdown of septa with a hemostat
allows for thorough drainage. A fishmouth incision or through- and-through
incision is seldom necessary. A wick of gauze is left in the wound for 1 or 2
days, after which irrigation or soaks may be started.
Paronychia
Paronychia usually originates with an undetected break
in the eponychium (cuticle) or with a hangnail. Dryness of the skin may be a
factor, and the infectious organisms are often supplied from the patient’s
nasopharynx. The early signs are redness and burning that spread along the nail
fold. Pain is often inordinate for the apparent degree of inflammation. At this
early stage, gently lifting the eponychium with a No. 11 blade evacuates the
pus, allowing the inflammation to resolve without further treatment. A partial
finger block suffices for anesthesia.
If untreated, the infection may progress beneath the
nail, causing it to loosen. At this stage, excision of the proximal nail
produces satisfactory decompression. A radial incision in the nail fold should
be avoided. Some- times an incision halfway between the eponychium and the
distal interphalangeal skin crease allows for direct drainage, accompanied by
nail plate removal. Rarely, a mucous cyst simulates a paronychia or actually
becomes infected. The infection may progress up the stalk of the cyst to the
joint cavity, resulting in a septic distal interphalangeal joint.
Subcutaneous Abscess
Subcutaneous abscesses may occur anywhere in the fingers
or hand and usually result from minute breaks in the skin that becomes
infected. These infections present as pain, swelling, redness, and turgor. On the
dorsum of the hand, abscesses are likely to originate in a hair follicle, or
there may be several drainage sinuses that coalesce into a carbuncle.
Subcutaneous abscesses often have a purulent center,
which aids identification. Incision and drainage are performed, with suitable
regional anesthesia induced proximal to any obvious inflammation and avoiding
areas of lymphangitis. The incision is centered over the fluctuant area, placed
in skin creases, or angled at them obliquely. The incision should avoid
underlying structures, particularly cutaneous nerves.
Also called subepidermal or vesicular cellulitis, pyoderma
is most often seen in children and usually involves the dorsal aspect of the
two distal segments of a finger. This infection is often due to Streptococcus
from the nasopharynx, although both Staphylococcus and Pseudomonas
species may also be present. The blebs may be aspirated and the fluid
cultured to obtain definitive diagnosis, but the lesions invariably respond to
antibiotics and protection from contact with the mouth. Pyoderma is highly
contagious, and precautions should be taken to avoid spreading it to family
members or schoolmates.
Herpes Simplex Cellulitis
A vesicular cellulitis of the hand or fingers due to
infection with herpes simplex virus occurs most often in dentists and health
care workers. Although the infection is contagious and often quite
uncomfortable, it tends to run a benign course: several crops of vesicles
develop slowly and heal over 2 to 3 weeks. The vesicles may be punctured under
sterile conditions. Involved hands must be kept clean and dry, and the patient
must be very careful to avoid further self-contamination or
cross-contamination.
Tenosynovitis And Infection Of Fascial Space
Tenosynovitis
Purulent tenosynovitis can be a devastating infection
because it produces adhesions within the tenosynovial canal that markedly limit
finger motion. If the infection affects one of the ulnar three fingers, the
quadrigia effect may limit motion of the adjacent fingers as well. Once a
granulation response has begun, the ability to restore full function is
compromised. If treatment is delayed or the antibiotics used are insufficient
or ineffective, the infection may convert to a subacute state that produces
progressive destruction.
The infection is usually secondary to a puncture
wound, and initial onset is insidious. Infection with a virulent organism such
as Staphylococcus, however, can produce severe pain within a few hours.
The four cardinal signs of tendon sheath infection (described by Kanavel) are
uniform swelling, fixed flexion, pain on attempted passive extension of the
finger, and tenderness along the course of the tendon sheath into the distal
palm.
In the thumb and little finger, the tendon sheath
usually extends into the radial and ulnar bursae, respectively, allowing
infection to spread well into the distal forearm (see Plates 4-37 and 4-38). A
communication between the two bursae allows the establishment of a horseshoe abscess that affects both the thumb and the
little finger, although effective treatment with antibiotics has made this
complication rare. By the time the horseshoe abscess occurs, irrevocable damage
to the delicate gliding tissues of the tenosynovial sheath may have occurred.
Avascular necrosis of the tendons follows quickly from vincular occlusion and
intracompartmental pressure. Less virulent organisms cause a less acute infection, but if they are unrecognized and untreated,
the residual effect may be no less detrimental.
A subcutaneous abscess directly over the tendon sheath
may be confused with true purulent tenosynovitis. Therefore, if the diagnosis
is not clear, incision and drainage should be performed. The initial incision
is made over the site of maximum tenderness. If a subcutaneous abscess is found
and the underlying sheath appears transparent and free of effusion, further
dissection is not necessary. However, if there is effusion, purulence,
distention, or thickening and opacity of the sheath, the incision should be
extended as a Brunner zigzag incision.
To ensure adequate drainage and perfusion of the
sheath, one or more flaps are raised at the sites of the cruciate pulleys. Any
fluid should be aspirated and cultured immediately. If the tenosynovial sheath
is inflamed, tissue samples should be sent for culture, Gram stain, and
histologic examination. Determining the causative organism is essential because
a number of unusual organisms, including Brucella, Pasteurella multocida, and
various Mycobacterium species, may also induce tenosynovitis.
The tendon sheath can be milked by passive movements
of the fingers. The sheath may also be irrigated through a small catheter,
which is left in place for 1 or 2 days, and the effusion allowed to drain. The
skin may be closed loosely to protect the underlying tendon. Active movement of
the finger should be started once daily after surgery and continued under
supervision but splinted and elevated between treatments. If the ulnar or
radial bursa is involved, separate incisions are made at the wrist or the
digital incisions extended, with care to preserve the transverse carpal
ligament.
Sporotrichosis
Sporotrichum schenckii, a fungus frequently found in soil or on garden plants, produces
cutaneous and subcutaneous lesions and inflammation of the lymph vessels
(lymphangitis). This indolent infection is characterized by a pilot lesion at
the site of inoculation, followed by the appearance of a succession of
satellite lesions, which progress proximally along a lymphatic chain. The
lesions are raised, red, swollen, and usually about 1 cm in diameter; the
center may ulcerate and drain. Pain is minimal. Diagnosis requires isolating
the organism from the ulcerations.
The treatment of choice is topical application of
potassium iodide, which is effective in the benign form of the disease. Lesions
heal in 2 to 3 weeks. Sporotrichosis may remain localized or spread
systemically to involve other organ systems.
Infection Of Deep Compartments
The deep compartments of the hand may become infected
by direct inoculation via penetrating wounds or by extension of infection in
adjacent areas. Such infections are relatively infrequent, but when present
they cause rapid deleterious changes and are prone to spreading. Unless treated
with incision and drainage, deep infection may cause permanent deformity.
Infection of Midpalmar Space
The midpalmar space lies under the flexor tendons of
the ulnar three fingers and over the deep fascia covering the intrinsic
muscles. Ulnarly, the hypothenar muscles and, radially, the adductor pollicis
muscle define the space, which is partially separated by fibrous septa that
attach the palmar floor to the central ridges of the metacarpal shafts. Purulence may enter or extend through the
lumbrical canals or break through into the carpal canal or thenar space.
Symptoms such as pain on movement, swelling, and
marked tenderness may rapidly increase in severity. The dorsum of the hand
swells as the lymphatic drainage becomes involved. Tenosynovitis may also
develop. The diagnosis is suggested by exquisite tenderness over the palm.
Treatment is by incision, which follows skin creases
and is centered to allow access to the midpalmar space and retraction of the
flexor tendons. The neurovascular bundles must be carefully identified and
retracted. Usually, the purulence is under pressure when the mid- palmar space
is opened and can be aspirated and the space irrigated. Extensions into
adjacent spaces can be identified by massaging the palm, starting at the perimeter.
Drains are inserted and kept in place for 1 or 2 days.
Infection of Thenar Space
The thenar space lies under the flexor tendons of the
index finger and over the adductor pollicis muscle. The septum to the third
metacarpal defines the ulnar border, and the thenar muscles define the radial
border. The infection may extend into the lumbrical canal of the index finger
and over the distal aspect of the adductor pollicis muscle. A dorsal thenar
space infection on the dorsal aspect of the adductor pollicis muscle may dissect
under the first dorsal interosseous muscle. An incision along the thenar space
must avoid the recurrent motor branch of the median nerve. The nerve is
identified by surface anatomic landmarks, using Kaplan’s cardinal line
intersection with the thenar crease. The incision can be extended distally as a
Z-plasty over the first web space.
Collar Button Abscess
These types of abscesses derive their name from the
dumbbell-shaped contour of the abscess around the margin of the superficial
transverse metacarpal ligament in one of the web spaces. Thus, they may present
on both dorsal and volar aspects of the hand. Drainage is through a zigzag
incision over the distal web space.
Infection of Parona Space
The Parona space lies deep to the flexor tendon
sheaths in the distal forearm and volar to the pronator quadratus muscle.
Infections are usually due to direct inoculation or extension from an infection
of the tendon sheaths. An abscess may be drained through a direct palmar
incision if the radial and ulnar bursae are involved. The median nerve must be
identified and protected. If the tendon sheaths are not involved, an incision
between the flexor tendons and ulnar neurovascular bundle allows access to the
Parona space, as does a direct ulnar incision sliding along the pronator quadratus muscle.
Infections from Human and Animal Bites
Teeth carry a variety of virulent organisms, and a
bite may inoculate these organisms deeply into tissues of the hand. Most dogs
and cats are carriers of Pasteurella multocida, an organism that
produces a rapidly spreading inflammation that may penetrate subcutaneous and
subfascial spaces as well as tendon sheaths and deep compartments. More
aggressive and earlier treatment is required for cat bites because delayed surgical treatment leads to
very slow resolution of infection. Human bites carry streptococcal,
staphylococcal, spirochetal, and gram-negative organisms. Eikenella
corrodens is an especially invasive organism that is difficult to
eradicate. Penetration of the metacarpophalangeal joint by an incisor may lead
to a destructive septic arthritis and dissemination of infection into the
adjacent spaces. Treatment of this type of infection requires early recognition, adequate
incision, and irrigation.
Lymphangitis
Lymphangitis often originates from an insignificant
break in the skin or a small wound in the hand. Pain and a burning erythema
develop at the site of inoculation. Lymphangitic erythematous streaks begin to
form over the dorsum of the hand, progressing in just a few hours into the
forearm and then into the arm. Pain intensifies and fever and chills develop.
The axilla and epitrochlear areas become tender and swollen.
On examination, the patient appears anxious, protects
the involved arm, and may shiver with chills. The wound and the lymphangitic
streaks are tender to the touch, as are the soft, swollen epitrochlear and
axillary nodes. There may be a small serous drainage at the wound site, which
should be cultured and Gram stained. Because streptococci are the usual
causative organisms, treatment with penicillin or cephalosporin is started
immediately. The perimeter of the erythema at the wound site and the
lymphangitic streaks can be marked with a pen for later reference, and the size
of the nodes is noted. If the infection does not respond to treatment with
antibiotics or if the signs worsen in 12 to 24 hours, a culture sample should
be obtained by aspiration or incision or the antibiotic regimen should be
changed.
Necrotizing Fasciitis
Also called a Meleney ulcer, necrotizing fasciitis is a
severe manifestation of lymphangitis that progresses in a frightening manner
within a few hours. Anaerobic or microaerophilic streptococci are believed to
be the usual cause, but these microorganisms are difficult to culture. Tissue necrosis develops rapidly behind an advancing
wall of inflammation that limits penetration by antibiotics. Desquamation followed
by gangrene may be relentless. The clinical signs of pain, hyperpyrexia, and
chills are severe.
The skin lesions are incised and drained or aspirated
to obtain fluid for culture. Intravenous infusion of aqueous penicillin must be
instituted immediately; additional antibiotics may be recommended by an
infectious disease specialist. The progress of the inflammation and necrosis
must be carefully monitored. Surgical intervention within hours is often
required to save life and limb. Even when the necrotizing lymphangitis is
controlled early, however, autoamputation may be a sequela and death is an
occasional outcome.
Other Hand Infections
The preceding discussion is merely an introduction to
the greater scope of infections of the hand. Mycobacterial tenosynovitis and
arthritis still occur. Mycobacterium marinum is an organism frequently associated with
injuries due to marine activities. Gonococcal septic arthritis rapidly destroys
involved joints. Rare invaders of the musculoskeletal system are fungal
infections, including coccidioidomycosis and blastomycosis. Clostridium
perfringens may colonize crushed muscle in the hand, producing gas
gangrene. Rare viral infections transmitted from domestic animals occasionally
produce lesions on the hand, and inflammation that mimics infection (e.g., calcium pyrophosphate dihydrate
disease) should also be considered in the differential diagnosis.
The introduction of antibiotics has dramatically
improved the prognosis for infections of the hand. For optimal treatment,
however, the correct diagnosis must be established, the organism identified,
the purulence drained, and an appropriate rehabilitation program instituted.
