Robert L. Cloutier
Depending on the disease, patients with chronic or complicated foot problems generally should be referred to a dermatologist, orthopedist, general surgeon, or podiatrist.
Tinea pedis and onychomycosis are discussed in Chapter 157, Other Dermatologic Disorders. Puncture wounds of the foot are discussed in Chapter 17, Puncture Wounds and Bites.
CORNS AND CALLUSES
CLINICAL FEATURES
Calluses represent a dermatologic reaction to focal pressure whether external (ill-fitting shoe) or internal (bunion) creating focal hyperkeratosis.
Calluses initially grow outward but with continued pressure will grow inward to form corns.
Hard corns develop over bony protuberances and soft corns in softer areas between toes.
Corns can be differentiated from calluses by examining the dermal lines. Corns will violate dermal lines; calluses form along, but do not cross, dermal lines.
Corns may be painful and can be differentiated from warts when incised; warts will bleed and corns will not.
DIAGNOSIS AND DIFFERENTIAL
Keratotic lesions may be indicative of more severe underlying disease, a mechanical problem, or local disease.
The differential diagnosis may include syphilis, tinea, psoriasis, lichen planus, rosacea, arsenic poisoning, basal cell nevus syndrome, and malignancy.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Treatment involves paring with a number 15 blade; the incision should include removal of the central keratin plug.
PLANTAR WARTS
CLINICAL FEATURES
Plantar warts are common, contagious, and caused by the human papillomavirus. They may be painful and tend to develop over the bony protuberances of the foot.
DIAGNOSIS AND DIFFERENTIAL
Diagnosis is clinical and the differential diagnosis may include corns or melanoma.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Topical treatment with 15% to 20% salicylic acid is most effective. Warts may require repeated treat ments. Nonhealing lesions may represent undiagnosed melanoma and should be referred to a dermatologist or podiatrist.
ONYCHOCRYPTOSIS (INGROWN TOENAIL)
CLINICAL FEATURES
Onychocryptosis is characterized by increased inflammation or infection of the lateral or medial aspects of the toenail. This occurs when the nail plate penetrates the nail sulcus and subcutaneous tissue; most commonly this involves the great toe.
Patients with underlying diabetes, arterial insufficiency, cellulitis, ulceration, or necrosis are at risk for amputation if treatment is delayed.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Toenail is uninfected: Often, all that is required is a combination of nail elevation (eg, with a wisp of cotton between the nail plate and the skin), daily foot soaks, and avoidance of pressure on the area. A second option is digital block followed by removal of a spicule of the nail, with debridement of the nail groove. Partial removal of the nail will be necessary if there is either granulation tissue or infection (see Fig. 185-1).
FIG. 185-1. Partial toenail removal (infection present). This method is used for onychocryptosis in the setting of significant granulation tissue or infection.
Toenail is infected: After digital block, one-fourth of the nail should be cut longitudinally (including beneath the cuticle) and removed. A non-adherent bulky dressing should be placed and the wound checked in 24 to 48 hours (see Fig. 185-1).
BURSITIS
CLINICAL FEATURES
Pathologic changes of the foot bursae are subdivided as follows: (1) noninflammatory, (2) inflammatory, (3) suppurative, and (4) calcified.
Noninflammatory bursae become painful as a result of direct pressure.
Inflammatory bursae become painful as a result of gout, syphilis, or rheumatoid arthritis.
Suppurative bursae become painful due to pyogenic organisms from adjacent wounds.
DIAGNOSIS AND DIFFERENTIAL
Inflammatory bursitis: gout and rheumatoid arthritis.
Retrocalcaneal bursitis may mimic Achilles tendinitis.
Suppurative bursitis: pyogenic organisms (ie, Staphylococcus spp.) from adjacent wounds.
Ultrasound (US) and magnetic resonance imaging (MRI) are useful diagnostically but not vital to ED evaluation.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Complications include a hygroma, calcified bursae, fistula, and ulcer formation.
Patients should be non-weightbearing and the affected area should be rested.
Treatment for septic bursitis includes nafcillin 500 milligrams QID or oxacillin 500 milligrams QID.
PLANTAR FASCIITIS
CLINICAL FEATURES
The plantar fascia is connective tissue anchoring the plantar skin to the bone, protecting the arch of the foot.
Plantar fasciitis is the most common cause of heel pain due to overuse. Patients have deep point tenderness, worse on arising and after activity, over the anterior-medial calcaneus at the point of insertion of the plantar fascia.
DIAGNOSIS AND DIFFERENTIAL
The differential diagnosis may include abnormal joint mechanics, poorly cushioned shoes, Achilles tendon pathology, and rheumatoid disease.
Diagnosis is clinical, but MRI and US may be useful but are not critical in ED setting.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Treatment includes rest, ice, and nonsteroidal anti-inflammatory drugs (NSAIDs). Eighty percent of cases are self-limited.
Plantar-specific stretches are helpful. Other options to unload the plantar fascia include foot strapping, nighttime splints, arch supports, and short-leg walking casts.
Glucocorticoid injections are not indicated in the ED.
TARSAL TUNNEL SYNDROME
CLINICAL FEATURES
Tarsal tunnel syndrome involves compression of the posterior tibial nerve as it courses inferior to the medial malleolus causing foot and heel pain.
Causes include running, restrictive footwear (eg, ski boots, skates), edema of pregnancy, posttraumatic fibrosis, ganglion cysts, osteophytes, and tumors.
The pain of tarsal tunnel syndrome involves the more medial heel and arch and worsens with activity.
Pain may also be worse at night at the medial malleolus, the heel, the sole of the foot, and the distal calf.
DIAGNOSIS AND DIFFERENTIAL
The differential diagnosis may include plantar fasciitis and Achilles tendinitis.
Tinel’s sign is positive; eversion and dorsiflexion of foot worsens symptoms.
US, computed tomography (CT), and MRI may aid in diagnosis.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Treatment includes NSAIDs, rest, and possible ortho pedic referral.
DEEP PERONEAL NERVE ENTRAPMENT
CLINICAL FEATURES
Occurs most frequently where the nerve courses beneath the extensor retinaculum. Recurrent ankle sprains, soft tissue masses, and restrictive footwear represent the most common causes.
Symptoms include dorsal and medial foot pain as well as hypesthesia in the web space between the first two toes. Nighttime pain is common.
DIAGNOSIS AND DIFFERENTIAL
Pain may be exacerbated by palpation of the peroneal nerve at the site of entrapment and with plantar flex ion and inversion of the foot.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
US, CT, or MRI may aid in diagnosis. Treatment includes NSAIDs, rest, and possible orthopedic referral.
GANGLIONS
A ganglion is a benign synovial cyst, typically 1.5 to 2.5 cm in diameter, attached to a joint capsule or tendon sheath. The anterolateral ankle is a typical site.
Ganglions may appear suddenly or gradually, enlarge or diminish in size, and may be painful or asymptomatic.
A firm, usually nontender, cystic lesion is seen on examination. The diagnosis is clinical, but MRI or US can be used if in doubt.
Initial treatment includes aspiration and injection of glucocorticoids, but most require surgical excision.
TENDON LESIONS
TENOSYNOVITIS AND TENDINITIS
Tenosynovitis or tendinitis is usually due to overuse and presents with pain over the involved tendon. Treatment includes ice, rest, and NSAIDs.
The flexor hallicus longus, posterior tibialis, and Achilles tendons are those that are most frequently affected.
Flexor hallicus longus tenosynovitis typically affects ballet dancers, but is also seen in runners and non-athletes. The presentation is similar to plantar fasciitis and tarsal tunnel syndrome. Management is often surgical.
TENDON LACERATIONS
Tendon lacerations should be explored and repaired if the ends are visible in the wound.
Due to the high complication rate, specialty consulta tion is often necessary. After repair, extensor tendons are immobilized in dorsiflexion and flexor tendons in equinus.
TENDON RUPTURES
Achilles tendon rupture presents with pain and a palpable defect in the area of tendon. Patients are unable to stand on tiptoes, and display an absence of plantar flexion with squeezing of the calf (Thompson sign).
Treatment is generally surgical in younger patients and conservative (casting in equinus) in the elderly.
Anterior tibialis tendon rupture results with a palpable defect and mild foot drop. These tendon ruptures are rare, usually not as painful as Achilles ruptures, and occur after the fourth decade of life. Surgical repair is often unnecessary.
Posterior tibialis tendon rupture is usually chronic and insidious and presents with a flattened arch and swelling over the medial ankle. It usually occurs after fourth decade with two-thirds of cases being in women. Examination may show weakness on inversion, a palpable defect, and inability to stand on tiptoes. Treatment is either surgical or conservative.
Flexor hallicus longus rupture presents with loss of plantar flexion of the great toe. Need for surgery depends on patient occupation and lifestyle.
Disruption of the peroneal retinaculum occurs with a direct blow during dorsiflexion, causing localized pain behind the lateral malleolus and clicking while walking as the peroneal tendon is subluxed. The treatment is surgical.
PLANTAR INTERDIGITAL NEUROMA (MORTON’S NEUROMA)
Neuromas form in plantar digital nerves just proximal to their bifurcations and are thought to occur from entrapment of the plantar digital nerve due to tight-fitting shoes.
Women between the ages of 25 and 50 years are the most commonly affected patients with the third interspace being the most commonly affected area.
Patients may present with burning, cramping, or aching over the affected metatarsal head.
Diagnosis is clinical, but US, MRI, and nerve conduction studies may be helpful.
Conservative treatment includes wide shoes and glucocorticoid injections, which may be curative. Surgical neurolysis is occasionally required.
COMPARTMENT SYNDROMES OF THE FOOT
CLINICAL FEATURES
Nine compartments have been identified in the foot.
Compartment syndromes in the foot are most commonly associated with high-energy crush injuries. Other causes include post-ischemic swelling after arterial injury, ankle fractures, burns, bleeding disorders, and exercise. Chronic compartment syndromes have been noted with overuse.
At-risk patients include those with increasingly severe pain exacerbated by active and passive motion, coupled with paresthesias and neurovascular deficits.
DIAGNOSIS AND DIFFERENTIAL
At-risk patients must have compartment pressures checked. Any difference of less than 30 mm Hg between the Stryker STIC device (Stryker Kalamazoo, MI) and diastolic blood pressure is considered positive.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Prompt consideration of emergent fasciotomy.
PLANTAR FIBROMATOSIS
Plantar fibromatosis (Dupuytren contracture of the plantar fascia) involves small, asymptomatic, palpable, slowly growing, firm masses on the non-weight-bearing plantar surface of the foot.
Onset is usually during adolescence. MRI may be helpful for diagnosis. Toe contractures do not occur, lesions tend to reabsorb spontaneously, and treatment is conservative.
MALIGNANT MELANOMA
Melanoma of the foot accounts for 15% of all cutaneous melanomas.
Many present as atypical nonpigmented or pigmented lesions including the nail with a predilection for plantar surfaces.
Vigilance is key as these lesions often mimic more benign conditions such as fungal infection, plantar warts, and foot ulcers.
Patients with atypical or nonhealing lesions should be sent for biopsy.
For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed., see Chapter 282, “Soft Tissue Problems of the Foot,” by Franz R. Melio.