Acute limb ischaemia (ALI) is a surgical emergency where the blood flow to a limb is disrupted and no oxygen rich blood can reach the tissues of the limb.
The cause of disrupted blood flow is usually thrombosis (where atherosclerosis of blood vessels leads to blockage of a blood vessel) or due to embolism (where a blood clot blocks a blood vessel). In most cases ALI is caused by atherosclerosis (85% of cases) with risk factors that include:
1. Diabetes
2. Smoking
3. Heart conditions like arrhythmias, heart attacks
4. High cholesterol
Other factors that might enhance the risk of ALI includes cancers, blood clotting disease, previous intravenous drug abuse and hypertension.
Usually patients with established blood vessel disease report pain with walking (claudication). This is a very important clue and doctors should always ask about pain with movement and also the presence of pain when not walking.
Read: Claudication
Patients will typically present to their doctor with significant pain, a cold limb and the inability to walk due to pain. The patient will also report that the limb may differ in colour from the other limb.
The doctor will check for the following which is indicative of ALI:
1. Swelling
2. Temperature difference (cold limb)
3. Pain
4. Weakness
5. Loss of sensation
6. The absence of pulses
If any or some of the above signs are present, urgent referral to a specialist vascular surgeon is needed. The vascular surgeon will evaluate the limb, do special investigations like checking blood flow to and from the limb and prepare the patient for surgery if needed.
It is important to determine where the occlusion is located in order to restore blood flow to the limb. CT angiography is a method doctors use to check where the blockage might be located an also plan surgery.
Surgery aims to restore blood flow. This can either be done by removing the occlusion or by bypassing the occlusion and restoring blood flow. In patients unsuitable for surgery, medication may be given to break up the occlusion.
Read: Dark chocolate may improve blood flow to the legs
Treating ALI as early and quick as possible is important as delay in treatment and diagnosis worsens the prognosis for the patient. If left untreated, amputation of the limb or even death of the patient may follow. Outcome is determined by the size of the occlusion, the location of the occlusion, the duration of the symptoms, the risk factors of the patient and the suitability for intervention.
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