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Education Material for Health Care Professionals: Newsletter Version

THE FEET AND DIABETES

INFECTIONS

At the same time, one has to treat any infection at the earliest so that it does not proceed to a more severe form of morbidity. “Nip it in the bud” as they say!

The clinical diagnosis of infection usually consists of three aspects.

(1) Systemic signs of fever and leukocytosis.

(2) Classic signs of inflammation around the ulcer (eg, heat, redness, edema, and pain); and

(3) Presence of purulent discharge from the ulcer;

It should be realized that due to the presence of varying degrees of nerve and arterial involvement, one may not see these “classic” signs.  Pain and tenderness may be absent because of neuropathy. The response to injury in skin includes a local vasodilation mediated by sensory nerve fibers, which are impaired in diabetic neuropathy. Intact tissue responds to bacterial infection by increasing blood flow >20-fold in the area around the infection. However, erythema or redness may be absent in the diabetic foot because of the inability of the foot to increase its blood supply in response to infection. Furthermore, it is now established that up to 50% of patients with deep foot infections will not have leukocytosis or fever. Thus, one cannot wait for the classical signs before initiating management in all patients.

Principles of  treatment

Treating Cellulitis


Empiric Antibiotic therapy

Most of the foot infections are caused by mulitimicobrial  involvement. Thus, empiric treatment should cover Gram- negative aerobic as well as an aerobic organisms. The antibiotic chosen should be bactericiadal as opposed to bacteriostatic. In general, bacteriostatic antibiotics require an intact immune system to function properly. The latter is often compromised in a person with diabetes.

Selected empirical antibiotic regimens for mild and non–limb-threatening infections
Oral agents Topical agents
Cephalexin Silver sulfadiazine
Cefdinir Silver powder, gels
Amoxicillin-clavulanate Mafenide acetate
Clindamycin Ciprofloxacin drops
Dicloxacillin Mupirocin
Ciprofloxacin, levofloxacin Gentamicin
Trimethoprim-sulfamethoxazole Bacitracin
Linezolid Cadexomer iodine

Aminoglycosides should not be used in combination therapy, if possible. In diabetic patients, who may have some degree of underlying nephropathy, the potential toxic effects of these agents is a prime concern, especially since less toxic alternatives are available. In addition, aminoglycosides are inactivated in an acidic environment, such as that found in abscess cavities. They have minimal penetration into bone, thus making them a poor choice for patients with osteomyelitis.

Later, the antibiotic choice would depend on the culture and sensitivity reports.

A patient who presents with mild infection should be closely monitored and if healing does not take place or the conditions worsens, it would be much better to refer the patient  to people specializing in managing such problems.

Any person presenting with more serious infections or an abcess or ulcer should immediately be referred to others well versed in this management without wasting


precious time

I do not want to go into a detailed discussion about the treatment modalities as this is better left to people specializing in managing such problems.

At the same time, there have been some recent advances in the management of wounds and ulcers which should be known to all doctors as often even if patients are admitted to the hospital, they are discharged and dressings are done at home.

One such advance is the availability of  beclapermin gel.

Becaplermin gel is a platelet-derived growth factor (PDGF) of recombinant human origin. PDGF stimulates and recruits macrophages, neutrophils, and fibroblasts; stimulates angiogenesis; and stimulates granulation tissue formation, wound contraction, and wound remodeling. Becaplermin gel should be used in wounds that have adequate blood supply and a clean wound bed (one without infection or necrosis). When used in conjunction with appropriate wound care, becaplermin gel has been shown to increase the incidence of complete wound closure (50% versus 35% for placebo) and decrease the time to complete wound closure (86 versus 127 days).

The amount of becaplermin gel applied varies by wound size (see Table below). The amount should be measured out onto a clean surface and the gel applied using an application aid (Q-tip, etc.) to a thickness of 1/16 inch. The gel should be covered with a saline-moistened gauze pad and left in place for 12 hours. After 12 hours, remove the gauze, rinse the ulcer with saline, and apply a new moistened dressing (without becaplermin gel) for the remaining 12 hours. Repeat this application process once daily.


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