MayoClinic.com defines gangrene as the decay of tissues that have lost vitality due to an interruption in their blood supply. Gangrene most commonly affects the limbs, including fingers and toes. Dry gangrene refers to a variety of gangrene where the dead tissues become dry, black, and leathery, as opposed to the swelling that occurs in the wet gangrene. Dry gangrene usually develops insidiously over a period of time. It most commonly occurs in people with atherosclerosis and other blood vessel diseases. Patients with dry gangrene may suffer from serious complications if not treated adequately.
Limb Loss
As indicated by the Merck Manuals Online Library, gangrene may progress until the dead tissue separate and fall off. This self-separation is referred to as auto-amputation in the medical community. Sometimes when it is impossible to rescue a limb afflicted with dry gangrene, the physician will opt to cut the affected limb off---a procedure called an amputation. An amputation may be the last resort for patients with severe pain caused by the underlying peripheral arterial disease. The UK National Health Service reports that every year 5,000 patients undergo amputation because of dry gangrene.
Inadequate Wound Healing
According to the Association for the Advancement of Wound Care, the same underlying condition that caused the dry gangrene, severe arterial insufficiency, can cause disastrous consequences for wound healing after the dead gangrenous tissue is removed. The patient with arterial disease causing reduced blood supply in the extremities might be unable to withstand any surgical removal of the dead tissue, which is one of the standard procedures in the care of dry gangrene. Whether the blood flow in the lower limbs can promote wound healing or not is not arbitrarily determined. The score the patient receives on an ultrasound determination of the blood pressure in the ankle versus the upper limb determines the Ankle Brachial Index. A low Ankle Brachial Index indicates that the circulation is very poor and that wound healing may be significantly impaired.
Secondary Infection
MayoClinic.com notes that dry gangrene is not caused by or usually associated with infections, unlike wet gangrene. However, in a patient with impaired immunity, bacteria may colonize the dead tissues, resulting in a secondary infection. If secondary infection of a gangrene occurs, the treatment becomes urgent before the bacteria spreads to the blood stream, causing a generalized life-threatening condition called septicemia.
