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Diabetic foot ulcers (DFUs) are a devastating complication of diabetes mellitus, affecting approximately 15–25% of diabetic patients during their lifetime. The pathophysiology of DFUs is multifactorial, involving peripheral neuropathy, impaired angiogenesis, chronic inflammation, and microcirculatory dysfunction. Despite advances in wound care, offloading, and infection management, DFUs remain a leading cause of lower extremity amputation.

The complex wound environment in DFUs is characterized by persistent inflammation, poor tissue perfusion, and impaired cellular repair mechanisms. This article presents a clinical case in which hirudotherapy (medical leech therapy) was used as an adjunctive treatment for a chronic diabetic foot ulcer, resulting in improved healing outcomes.

Clinical Case Presentation

A 58-year-old male with a 12-year history of type 2 diabetes mellitus presented with a non-healing ulcer on the plantar aspect of his right foot. The ulcer had been present for eight months despite standard care, including regular debridement, offloading with a total contact cast, advanced moisture-retentive dressings, and systemic antibiotics for intermittent infections. The ulcer measured approximately 3.2 cm × 2.8 cm at initial assessment, with a fibrinous base, moderate exudate, and surrounding hyperkeratotic edges.

The patient had well-controlled blood glucose (HbA1c 7.2%) but exhibited signs of peripheral neuropathy (reduced monofilament sensation) and diminished pedal pulses. Ankle-brachial index (ABI) was 0.8, indicating mild peripheral arterial disease. Vascular surgery consultation confirmed that revascularization was not indicated at that time.

Treatment Approach

After informed consent and multidisciplinary discussion, the wound care team initiated adjunctive hirudotherapy alongside standard wound management. Three to four medical-grade leeches (Hirudo verbana) were applied to the periwound healthy skin surrounding the ulcer in each session. The patient received five sessions at one-week intervals.

As illustrated in the mechanism diagram, the bioactive substances in leech saliva target multiple pathological factors in DFU healing:

• Anti-inflammatory effects: Modulation of local inflammation to reduce tissue damage

• Improving tissue permeability: Enhanced diffusion of oxygen and nutrients into the wound bed

• Promoting local circulation: Increased blood flow velocity and microvascular perfusion

Standard infection control measures were employed, including prophylactic antibiotics (levofloxacin 500 mg daily during the treatment period) and strict sterile technique. Offloading and moisture-retentive dressings were maintained throughout.

Clinical Outcome

The patient demonstrated progressive improvement over the five-week treatment period:

• Week 1–2: Reduction in periwound erythema and edema; exudate decreased noticeably

• Week 3–4: Fibrinous base transitioned to healthy granulation tissue; wound margins showed epithelialization

• Week 5: Ulcer size reduced to 1.1 cm × 0.8 cm (approximately 90% reduction from baseline)

• Week 8 (follow-up): Complete wound closure achieved

The patient reported no pain during or after leech applications. No infectious complications, significant bleeding, or adverse reactions occurred. Offloading was continued throughout, and no surgical intervention was required.

Detailed Mechanism of Action

The therapeutic effects observed in this case can be attributed to the synergistic action of bioactive substances in medicinal leech saliva, as outlined in the accompanying illustration:

Anti-inflammatory Effects

• Eglin and anti-stasin: These protease inhibitors neutralize elastase, cathepsin G, and other inflammatory mediators that perpetuate chronic inflammation in DFUs

• Reduction in pro-inflammatory cytokines: Local application modulates the inflammatory cascade, allowing the wound to transition from a chronic inflammatory state to a proliferative healing phase

Improving Tissue Permeability

• Hyaluronidase: Breaks down hyaluronic acid in the extracellular matrix, reducing tissue edema and facilitating the diffusion of oxygen, nutrients, and therapeutic agents into the wound bed

• Collagenase: Helps remodel fibrotic tissue, softening hyperkeratotic margins and allowing for better wound contraction

Promoting Local Circulation

• Hirudin: A potent thrombin inhibitor that prevents microthrombosis within the compromised microvasculature

• Vasodilators (histamine-like substances, acetylcholine): Induce local vasodilation, increasing blood flow velocity and enhancing oxygen delivery to ischemic wound edges

• Platelet aggregation inhibitors (saratin, calin, apyrase): Reduce microvascular obstruction, improving overall tissue perfusion

These combined actions address three key barriers to DFU healing: persistent inflammation, poor tissue permeability, and microcirculatory insufficiency.

Safety Considerations and Limitations

Hirudotherapy in diabetic patients requires specific precautions:

• Infection risk: Diabetic patients have impaired immune responses; prophylactic antibiotics are strongly recommended

• Wound contamination: Leech application should be limited to periwound healthy skin, not directly into the ulcer bed

• Bleeding: Patients on antiplatelet or anticoagulant therapy require careful assessment

• Glycemic control: Poorly controlled diabetes (HbA1c > 8.5%) may impair healing regardless of adjunctive therapies

• Not a substitute for standard care: Offloading, glycemic control, and infection management remain foundational

In this case, the patient’s stable glycemic control and adherence to offloading contributed to the favorable outcome.

Discussion

This case illustrates that hirudotherapy, when integrated into a comprehensive wound care program, can accelerate healing in chronic diabetic foot ulcers. The multi-targeted mechanisms—anti-inflammatory, permeability-enhancing, and pro-circulatory—directly address the pathological features that distinguish DFUs from acute wounds.

While randomized controlled trials of hirudotherapy for DFUs are lacking, the biological plausibility is strong, and this case adds to the growing body of clinical observations supporting its potential role. Future research should focus on standardized protocols, optimal treatment frequency, and long-term outcomes.

Conclusion

Hirudotherapy may serve as a valuable adjunctive treatment for carefully selected patients with chronic diabetic foot ulcers that have failed to respond to standard care. When applied under medical supervision with appropriate infection control and patient selection, it can enhance wound healing through its anti-inflammatory, tissue permeability-enhancing, and microcirculatory-promoting effects. Self-application outside a clinical setting is not appropriate and carries significant risks.

Keywords: hirudotherapy, diabetic foot ulcer, chronic wound healing, microcirculation, anti-inflammatory, tissue permeability

Reference (for professional context):
This case report is informed by the established mechanisms of hirudotherapy and the clinical literature on adjunctive treatments for diabetic foot ulcers. For broader clinical context, see: Armstrong DG, et al. Diabetic foot ulcers: a review. JAMA. 2023.