What is Acute Limb Ischemia?
A blood clot in a vessel (thrombus or embolus) of the limbs (upper ~ arm, forearm and hand, lower ~ thigh, leg, feet) starves the area of oxygen (hypoxia) and leads to tissue damage (ischemia).This is known as acute limb ischemia. It should always be taken seriously as a blood clot at this site may eventually lead to cell death (infarct) and necrosis.
Thrombosis in Leg, Arm
A thrombus is a blood clot which forms and stays at a specific site in the body. The formation or presence of this type of blood clot is referred to as thrombosis. Deep vein thrombosis (DVT) is a common cause of acute limb ischemia in the leg.
Some of the features of a thrombus in the leg or arm :
- Occlusion (extent of blockage) is usually partial.
- Symptoms develop more slowly – hours or days.
- Affects only one site in most cases.
- History of previous signs and symptoms.
Refer to Thrombosis Causes for more information.
Embolism in the Leg, Arm
An embolus is where an abnormal mass travels through the blood stream and lodges elsewhere in the body. Most of the time, the embolus is a thrombus that has broken away from its original site. This process is known as an embolism.
- Occlusion (extent of blockage) usually complete.
- Onset of symptoms are sudden – seconds or minutes.
- May affect more than one site.
- Previous signs and symptoms at the site will be absent.
Refer to Causes of Embolism for more information.
Signs and Symptoms of Acute Limb Ischemia
Acute limb ischemia is more likely to occur in the lower limb (leg) rather than the upper limb (arm) whether it is due to thrombosis or embolism. The six P’s (Pain, Pallor, absent Pulse, Perishing cold, Paresthesia, Paralysis) are an indication of ischemia but may also be due to other causes like diabetes and heart disease.
- More likely to occur with thrombosis and may be chronic in nature.
- Pain worsens upon movement and excessive activity or pressure and in the event of thrombosis this will be ongoing for a period of time (claudication).
- In the leg, calf pain and burning foot pain are commonly reported.
- Pain may be absent in a case of acute limb ischemia due to an embolism.
- May not be obvious in an embolism because of the sudden onset.
- Limb appears pale to white in color.
- Redness of the skin may also be evident.
- Weak or Absent Pulse.
- Wrist, elbow, foot and ankle pulses.
- Distal pulses are more likely to be affected.
- Feels faint or undetectable.
- Perishing Cold.
- Difficult to conclusively ascertain as the limbs often take on the environmental temperature.
- Numbness or tingling – “pins and needles”.
- Usually indicates that the ischemia is progressing.
- Loss of motor function or severe muscle weakness.
- Indicative of progressing ischemia which may be irreversible.
Other Signs and Symptoms of a Blood Clot
- Heat of the skin
- Dry, smooth and shiny skin
- Redness of the skin (acute)
- Darkening of the skin (chronic)
- Ulcers (chronic)
- Loss of body hair on the limb (chronic)