Two Cases of Micro-Arteriovenous Fistula in the Lower Extremity with Misdiagnosis of Refractory Cellulitis

Abstract

We report our experience of two cases of refractory cellulitis caused by peripheral micro-arteriovenous fistulas (AVFs) in the lower extremity. The micro-AVFs were so small that they could not be located accurately; further, the patients’ symptoms differed markedly from those previously reported for AVF. AVF is known to cause ischemic symptoms. In contrast, micro-AVF causes congestive symptoms and remains undetected in the majority of patients. Identification of this pathology is crucial to enable effective treatment by the ligation of the incompetent perforator vein that increases venous hypertension, leading to congestive symptoms.

Abnormalities of the hallux skin and nail in the course of very rare arteriovenous malformation

“…[1][2][3] In micro-arteriovenous fistulas in the lower extremities, unusual symptoms such as refractory cellulitis resistant to standard treatment have also been described. 8 AVMs can cause changes to nails, which are rarely reported in the literature. It is known, however, that venous stasis, venous hypertension, and also chronic limb ischemia can provoke nail changes.…”

“…[1][2][3] AVMs can also be caused by acquired factors: trauma, iatrogenic factors, catheterization, percutaneous invasive procedures, surgery, degenerative vascular changes, fragility of vessels caused by vasculitis, chronic steroid therapy, or dialysis. 1,6,8 In view of the increasing frequency of percutaneous endovascular interventions, complications manifesting with AVMs are to be expected. 4 AVMs in the foot can be asymptomatic, especially if they are small.…”

“…General symptoms of large AVM are the result of hyperkinetic circulation and may lead to right ventricular failure. [1][2][3][4]8 Physical examination may sometimes show a pulsatile or non-pulsatile mass, increased skin temperature, tremor of the vessel wall, and vascular murmur. AVMs can cause various skin lesions: hyperpigmentation, spots, bluish or purple nodules, port wine stains, and brownish or rusty skin discoloration, similar to chronic venous insufficiency.…”

“…Therefore, if AVM is suspected, CT angiography, MRI angiography, or digital subtraction angiography should be performed. [1][2][3][4][5][6][7][8] In clinical practice, such tests are usually considered if ischemic symptoms predominate. However, if AVMs are located distally, then symptoms of venous hypertension may prevail.…”

“…An AVM can cause a variety of abnormalities involving the skin, nails, bones, and nerves of the foot or toes that can coexist or may appear as isolated symptoms. [1][2][3][4][5][6][7][8] The disease often has an unpredictable course and so the diagnosis is usually delayed, resulting in tissue loss or permanent deformities of the foot or toes. 1,8…”