Amyloidosis

Amyloidosis
Amyloidosis symptoms are often vague and require different physician specialists for diagnosis. Telltale symptoms may include an enlarged tongue (macroglossia) or bruising around the eyes (purpura)[1]
Specialty	Internal Medicine
Symptoms	Feeling tired, weight loss, swelling of the legs, shortness of breath, bleeding, feeling light headed with standing[2]
Usual onset	55–65 years old[2]
Causes	Genetic or acquired[3]
Diagnostic method	Tissue biopsy[2]
Treatment	Supportive care, directed at the underlying cause, dialysis, organ transplantation[3]
Prognosis	Improved with treatment[3]
Frequency	3–13 per million per year (AL amyloidosis)[2]
Deaths	1 per 1,000 people (developed world)[3]

Amyloidosis is a group of diseases in which abnormal proteins, known as amyloid fibrils, build up in tissue.^[4] There are several non-specific and vague signs and symptoms associated with amyloidosis.^[5] These include fatigue, peripheral edema, weight loss, shortness of breath, palpitations, and feeling faint with standing.^[5] In AL amyloidosis, specific indicators can include enlargement of the tongue and periorbital purpura.^[5] In wild-type ATTR amyloidosis, non-cardiac symptoms include: bilateral carpal tunnel syndrome, lumbar spinal stenosis, biceps tendon rupture, small fiber neuropathy, and autonomic dysfunction.^[5]

There are about 36 different types of amyloidosis, each due to a specific protein misfolding.^[6] Within these 36 proteins, 19 are grouped into localized forms, 14 are grouped as systemic forms, and three proteins can identify as either.^[6] These proteins can become irregular due to genetic effects, as well as through acquired environmental factors.^[6] The four most common types of systemic amyloidosis are light chain (AL), inflammation (AA), dialysis-related (Aβ₂M), and hereditary and old age (ATTR and wild-type transthyretin amyloid^[7]).^[2]

Diagnosis may be suspected when protein is found in the urine, organ enlargement is present, or problems are found with multiple peripheral nerves and it is unclear why.^[2] Diagnosis is confirmed by tissue biopsy.^[2] Due to the variable presentation, a diagnosis can often take some time to reach.^[3]

Treatment is geared towards decreasing the amount of the involved protein.^[2] This may sometimes be achieved by determining and treating the underlying cause.^[2] AL amyloidosis occurs in about 3–13 per million people per year and AA amyloidosis in about two per million people per year.^[2] The usual age of onset of these two types is 55 to 60 years old.^[2] Without treatment, life expectancy is between six months and four years.^[2] In the developed world about one per 1,000 deaths are from systemic amyloidosis.^[3] Amyloidosis has been described since at least 1639.^[2]