Acute attacks almost always start with severe pain which is usually in the abdomen but may also be felt in the back or thighs. Nausea, vomiting and constipation are common. Some people may become very confused during an acute attack and behave in ways that are unusual for them. They may later find it difficult to remember details of their illness. Convulsions and muscular weakness, which may lead to paralysis, are less common symptoms. Your pulse rate and blood pressure may increase but rarely to dangerous levels. An acute attack usually lasts for no longer than one or two weeks. If paralysis occurs, recovery is gradual but slow.
Acute attacks are often provoked by drugs, alcohol or hormonal changes, for example, those associated with the menstrual cycle. The most common age for an acute attack is from the late teens to the mid-thirties. They are extremely rare in children before puberty. Most people have only one or a few acute attacks; only a minority suffer repeated attacks, sometimes over several years. Although acute attacks can be very severe, particularly if precipitated by drugs or alcohol, nowadays they are rarely fatal.
Most people who have one or a few attacks of acute porphyria make a full recovery. They are then able to lead a normal life except that they need to take a few simple precautions to reduce the risk of having another attack.