Amyloidosis

Amyloidosis is an umbrella term that describes diseases caused by abnormal deposits in the body of the protein amyloid. These rare and incurable diseases are more common in people over the age of 40 years, for reasons unknown. Amyloidosis can be classified according to its cause: primary, secondary and familial. There are two more subclassifications according to degree of severity: localised and systemic. Localised amyloidosis means that only one area or body part is affected, while systemic amyloidosis means that abnormal protein deposits are scattered throughout the body. Systemic amyloidosis can be serious or even life-threatening, depending on which parts of the body are affected. Research has established that there is no link to dietary proteins, but the exact cause of amyloidosis remains unknown.

Symptoms
The symptoms of amyloidosis vary widely, depending on which tissues and organs are affected. In some cases, amyloidosis has no symptoms until extensive tissue damage has occurred. Some of the symptoms may include:

• Ankle and leg swelling (oedema)
• Muscular weakness
• Unexplained weight loss
• Pins and needles or numbness in the extremities
• Memory loss
• Diarrhoea
• Swollen tongue
• Dizziness when standing up suddenly (orthostatic hypotension).

• Primary amyloidosis - the disease develops by itself without apparent cause. Parts of the body commonly affected include the heart, lung, skin, tongue, intestines, liver, kidney and spleen.
• Secondary amyloidosis - the disease develops as a complication of another disease such as rheumatoid arthritis, multiple myeloma, tuberculosis, osteomyelitis or ankylosing spondylitis. Parts of the body commonly affected include the adrenal glands, lymph nodes, liver, kidney and spleen.
• Familial amyloidosis - this type is particularly rare. If a person has the flawed gene that causes familial amyloidosis, they have a 50 per cent chance of passing the same condition on to their offspring. Parts of the body commonly affected include peripheral nerves, the nerves of the wrist and the eyes.

• Heart - the heart is a four chambered pump that circulates blood around the body. Amyloid deposits within the heart muscle restrict its function, leading to heart failure (cardiomyopathy). Symptoms may include breathlessness and irregular heartbeat.
• Kidneys - the kidneys filter wastes from the bloodstream and help to regulate the body’s water balance. Amyloidosis damages the small filtering units of the kidney and causes them to leech protein into the urine. The drop in blood protein causes oedema (fluid retention) in the feet and ankles. Ultimately, the damage to the kidneys impairs their function so that wastes build up in the bloodstream. For reasons unknown, kidneys affected by amyloidosis also tend to trigger higher levels of blood cholesterol.
• Nervous system - the nervous system helps all the parts of the body to communicate with each other. It also reacts to changes both outside and inside the body. Around one in four people with amyloidosis experience carpal tunnel syndrome, which is a ‘pinching’ of the main nerve that services the hand as it runs through the wrist. Other generalised nervous system symptoms include pins and needles and numbness. More specific symptoms depend on which nerves are affected. For example, if the nerves that service your bowel are affected, you may experience constipation or diarrhoea, or both.

• General tests - including blood and urine tests.
• Bone marrow biopsy - a small tag of bone marrow is removed and examined for abnormalities.
• Tissue biopsy - a small tag of abdominal fat or rectal tissue is removed with a slender needle and examined in a laboratory.

• Adequate rest.
• Treatment for any underlying disorder such as rheumatoid arthritis.
• Drugs to slow amyloid activity.
• A special diet tailored to your needs - for example, a person with affected kidneys will benefit from a low salt diet.
• Dialysis, if the kidneys are affected.
• Drugs to stabilise the heartbeat, if the heart is affected.
• Transplants of affected organs may be considered.
• Current trials include the use of particular chemotherapy medications and bone marrow transplants.

• Your doctor

• Amyloidosis is an umbrella term that describes diseases caused by abnormal deposits of the protein amyloid.
• The symptoms of amyloidosis vary widely, depending on which tissues and organs are affected.
• There is no cure.
• The aims of treatment are to prevent further deposits of amyloid proteins and ease the symptoms.