Amyloidosis - Symptoms and Causes- Medtalks

Amyloidosis

Amyloidosis is a set of diseases in which a misfolded protein called amyloid accumulates in the body. Amyloid accumulation can potentially cause organ damage and failure. Amyloid deposits can form in the following organs:

• Spleen

• Liver 

• Kidney

• Nerves

• Heart

• Blood vessels

Amyloid may build up in your body at times. This is referred to as systemic amyloidosis. It is basically extracellular deposits, causing structural and functional damage.

Different Forms of Amyloid Protein

Although all amyloids have the same morphology and staining properties, amyloidosis is not a single illness. It is a collection of disorders that share the deposition of similar-looking proteins but differ in molecular structure (more than 20 distinct proteins) and process of production. 

Physical Characteristics of Amyloid Protein

• Amyloid is made up of non branching fibrils 7–10 nm in diameter.

• Each fibril is made up of beta pleated sheet polypeptide chains that are coiled around one another.

• Congo red dye binds to these fibrils, resulting in characteristic apple-green birefringence (dichroism).

Factors Attributing to Amyloidosis

In general, amyloidosis is caused by an amyloid accumulation in your organs. The organs or parts of the body that are affected are determined by the type of amyloid deposits you have. Some varieties of amyloidosis are inherited, while others can be caused by:

• Chronic disease

• Inflammatory illnesses

Signs & Symptoms of Amyloidosis

Amyloidosis may not create symptoms in its early stages. When it worsens, the symptoms you experience will be determined by the type of amyloidosis you have and the organ or organs that are affected.

For instance, if your heart is damaged, you may experience:

• Difficulty in breathing

• Tachycardia

• Irregular breathing

• Chest discomfort

• Low blood pressure, which may induce dizziness

If your kidneys are damaged, you may suffer swelling in your legs as a result of fluid buildup (edema) or foamy urine as a result of excess protein. If your liver is damaged, you may have discomfort and swelling in your upper abdomen.

If your gastrointestinal tract is compromised, you may experience:

• Nausea

• Diarrhea

• Constipation

• Lack of appetite

You may encounter the following symptoms if your nerves are affected:

• Lower leg discomfort

• Numbness

• Tingling sensation

• Standing up causes dizziness

• Nausea

• Diarrhea 

• Insensitivity to cold or heat

The following are some general symptoms that may occur:

• Fatigue

• Bruises on your skin or around your eyes

• Swollen tongue 

• Joint discomfort

• Carpal tunnel syndrome, often causes numbness and tingling in the hands and thumbs

Types of Amyloidosis 

Each variety of amyloidosis requires a somewhat different therapy, so it is critical to obtain an accurate diagnosis. About 95% of the amyloid consists of fibril proteins and the rest 5% contains proteoglycans, serum amyloid P, glycosaminoglycans etc.

Light Chain Amyloidosis (AL)

One of the most prevalent kinds of amyloidosis identified is AL amyloidosis, also known as immunoglobulin light chain amyloidosis. It is referred to as primary amyloidosis.

AL amyloidosis arises when aberrant amyloid proteins known as light chains accumulate in organs such as your:

• Heart

• Kidney

• Liver

• Skin

Autoimmune Amyloidosis (AA)

This kind of amyloidosis can develop following a prolonged infection, such as TB, or an inflammatory condition, such as rheumatoid arthritis or inflammatory bowel disease. Rheumatoid arthritis affects almost half of those with AA amyloidosis. The kidneys are the most affected by AA amyloidosis. It can potentially harm your intestines, liver, or heart. This condition was formerly known as secondary amyloidosis.

Beta-2 Microglobulin Amyloidosis (Abeta2m)

This type of amyloidosis affects patients who have been on dialysis for a long time due to renal difficulties. Amyloid builds up in joints and tendons, causing discomfort and stiffness.

ATTR Amyloidosis

A mutation in a gene that runs in families causes this rare type of familial amyloidosis. Hereditary amyloidosis can affect the:

• Liver

• Kidney

• Heart

Localized Amyloidosis (ALoc)

There are several forms of localised amyloidosis. ALoc amyloidosis often causes amyloid deposits in the trachea or bronchus, eye, or bladder. They can, however, be linked to endocrine proteins or proteins generated in the skin and heart.

Wild-type ATTR

Wild-type ATTR is usually seen in men over the age of 75, and is related to the ageing process. The heart is the most commonly affected organ by wild-type ATTR, and carpal tunnel syndrome is one of the earliest indications of this illness.

Risk Factors for Amyloidosis 

Although amyloidosis may affect anybody, several variables can raise your risk, like:

• Age: The most prevalent kind of amyloidosis, AL amyloidosis, is usually diagnosed in people over the age of 50.

• Gender: Despite the fact that this illness is thought to affect both men and women equally, 60% of persons referred to amyloid clinics are men.

• Race: African Americans are more likely than other races to get hereditary amyloidosis.

• Hereditary: Hereditary amyloidosis is passed down via families.

• Medical background: A prolonged infection or inflammatory condition might increase your risk of developing AA amyloidosis.

• Renal Failure: You may be at greater risk if your kidneys are damaged and you require dialysis. Dialysis may not be as successful as your own kidneys in removing large proteins from your blood.

Diagnosis of Amyloidosis

• Urine and blood testing: These assays can be used to determine the amounts of amyloid protein. Thyroid and liver function can also be checked using blood testing.

• Echocardiogram: Sound waves are used in this imaging exam to produce images of your heart.

• Biopsy: A doctor takes a sample of tissue from your liver, nerves, kidneys, heart, belly fat, or other organs for this test. Analyzing the tissue sample might assist your doctor in determining the sort of amyloid deposit you have.

• Aspiration and biopsy of bone marrow: A needle is used to withdraw a little quantity of fluid from inside your bones during bone marrow aspiration. A bone marrow biopsy involves the removal of tissue from within your bone. These tests can be performed concurrently or independently. 

The Bottom Line

Amyloidosis refers to a group of disorders induced by an amyloid protein accumulation. Some of these illnesses are inherited, while others are the result of persistent infection or autoimmune disorders. Amyloidosis is not curable, however, it can be controlled with medication in many cases. Discuss your treatment choices with your doctor, and work with them if you discover that your present treatment plan isn't working. They can make changes to help minimize your symptoms and enhance your quality of life as required.

References:

1. https://www.healthline.com/health/amyloidosis#diagnosis