Pages S46-S48 of Methods of Treatment

Neuropathic ulcer disease: Patient MM was a 46 year old women with type 1 diabetes mellitus that had been poorly controlled over 22 years. On the 8th of January, her podiatrist debrided an infected plantar callus beneath her 5th metatarsal head and started her on antibiotics and Epsom foot soaks. Her infection progressed over the next ten days leading to hospitalization on the vascular surgery service. She was begun on intravenous gentamicin and tetracycline with no effect on her fever (101 degrees F) or her leukocytosis (17.7 to 20.2). Her ulcer appeared to be enlarging and the possibility of leg amputation was considered. On the 4th hospital day a boot consultation was requested (Figure 3).
Figure 3. Patient MM. Plantar and dorsal aspects of foot on presentation for boot therapy 1/18/89.
Hammer toes suggested the presence of her underlying neuropathy. Necrotic fat beneath the proximal phalanges of the 3rd to 5th toes, blackening of the 5th toe, a slight purpling of the 3rd toe and modest reddening of the whole dorsum of the foot pointed to the gravity of her infection. Her dorsalis pedis and posterior tibial pulses were both easily palpable. Light touch and position sense were absent and 2-point discrimination was over 25 cm. Her antibiotics appeared to be appropriate according to her cultures. Our routine program for such patients was begun: (a) appropriate oral or intravenous antibiotics to prevent septic emboli, (b) a cleansing foot soak in dilute peroxide or Betadine to remove superficial pus and debris, (c) local antibiotic injections, here with gentamicin, into the necrotic areas under the 3rd-5th toes and into the top of the 3rd toe and the side of the 5th toe and (d) Mini-Boot therapy with the foot immersed in 200 ml multielectrolyte solution (Sea Soaks) and gentamicin (80 mg/half gallon). The local antibiotic injection were given once daily with an insulin syringe while the boot therapies in the antibiotic solution were given three to four times a day. She appeared to be responding but Dr. Dillon went on vacation for a week during which her therapy was again limited to intravenous antibiotics. Her fever returned and again her foot infection seemed to be progressing leading the surgeons to urge leg amputation. She refused insisting on waiting a week to restart boot therapy. The latter was restarted and her foot did well. Her left toe was left atrophied but she lost no parts and was discharged ambulatory to receive boot therapy as an outpatient (Figure 4).
Figure 4. Patient MM: On 5/26/89 her foot was healed. Her fifth toe was atrophied and had a small residual scab. New callus had formed at the pressure point under her fifth metatarsal head.
Comment: Patients with diabetic neuropathy are susceptible to necrotizing cellulitis in the absence of macrovascular disease. Denervation of the small muscles in the foot results in hammer toe deformities and abnormal pressure points. Sweating and reactive hyperemia may be absent due to loss of postganglionic cholinergic innervation. Loss of sympathetic innervation diverts arterial blood flow through A-V shunts. Fissures and cracks in dry skin and callus provide entry for bacteria. In the absence of pain sensation, the infection may be unappreciated. Elaboration of bacterial enzymes may digest the tissue and produce a chemical arteritis depriving the infected area of arterial blood with its immune factors and any administered antibiotics. Bypass procedures are useless in the presence of palpable pulses. Incision and drainage procedures are useless early in the process when only large reddened cellulitis areas may be present; later if abscesses develop such procedures are important. In this patient, the local injection of antibiotics delivered effective therapy when both oral and intravenous routes were ineffective. The therapy with the Mini-Boot both disseminated the antibiotic throughout the infected tissue and helped maintain and restore blood flow through the inflamed areas of the foot thus assisting the delivery of leukocytes and systematically administered antibiotics. Pumping the foot in the multielectrolyte solution containing antibiotics effectively scrubbed, cleaned and debrided the foot daily. No further sharp debridements were done and no large incisions that would require time and additional procedures to heal were made. In this fashion, we have treated and salvaged many feet that appeared to be lost. The adverse effect of infection on effective blood flow is discussed further below; here, the adverse effect of neuropathy is added to our formula.

III. Effective blood flow = f (variables)/ neuropathy or EBF = f (V) / Neur or EFB=f(V) / (VP)(IFP)(Neur)

Pages S48-S51 of Methods of Treatment.
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