Amyloid A Amyloidosis - Causes, Symptoms, Diagnosis and Management

Introduction

Amyloidosis is a rare health condition that is marked by the collection of specific proteins over a lot of organs. This protein settling (deposition) can happen either in single or multiple organs. Amyloid A amyloidosis is a health condition that can negatively impact the functioning of vital organs in the human body.

What Is Amyloidosis?

Amyloidosis is a specific group of disorders characterized by atypical protein deposits in organs. Though other proteins can also form deposits, amyloid proteins are the ones that result in serious health issues. When proteins get to build up in the tissues and organs, it greatly influences the normal functioning of the organs. Amyloidosis can be of different types:

• Immunoglobulin light chain amyloidosis.

• Amyloid A amyloidosis.

• Dialysis-related amyloidosis.

• Familial amyloidosis.

• Age-related amyloidosis.

• Organ-specific amyloidosis.

What Is Amyloid A Amyloidosis?

Amyloid A amyloidosis (AA amyloidosis) is a specific class of amyloidosis that develops as a consequence of an underlying long-standing infection or inflammation (immune response). Secondary amyloidosis is the synonym for AA amyloidosis as it develops secondarily to other health conditions. In AA amyloidosis a specific protein called serum amyloid A (SAA) is gathered in the tissues and organs.

What Is Serum Amyloid A?

Serum amyloid A (SAA) is a typical protein produced chiefly by the liver cells (hepatocytes). SAA exhibits certain key roles during various inflammatory and infectious conditions. Inflammatory conditions are accompanied by a sudden hike in the SAA level in the circulatory blood. In addition, it has some immunomodulatory functions.

What Causes Amyloid A Amyloidosis?

The clear mechanism leading to this rare condition's development is still unknown. However, it develops secondary to various conditions accompanied by lingering inflammation. When there is a long-standing inflammatory (immune response) condition, a higher concentration of SAA circulates in the bloodstream over a longer period, eventually precipitating in the tissues and organs in the form of insoluble fibrils. Amyloid protein collection may completely disrupt the structure and function of organs and potentiates the complications of chronic (long-standing) conditions. In most instances, AA amyloidosis is seen in connection with conditions like:

• Rheumatoid arthritis.

• Crohn’s disease.

• Ulcerative colitis.

• Ankylosing spondylitis.

• Familial periodic fever syndrome.

• Bronchiectasis.

• Cystic fibrosis.

• Chronic osteomyelitis.

• Tuberculosis.

• Hairy cell leukemia.

• Multiple myeloma.

• Hodgkin lymphoma.

• Vasculitis.

Which Are the Organs That Are More Frequently Affected by A A Amyloidosis?

Though SAA proteins can accumulate anywhere in the body, they routinely affect the kidney and significantly impair kidney functions. In addition, the liver, intestine, spleen, and stomach are also affected occasionally. It affects the heart less frequently, but it is potentially dangerous.

What Are the Signs and Symptoms Associated With Amyloid A Amyloidosis?

• The affected organs largely influence the symptoms exhibited in AA amyloidosis and vary accordingly.

• Kidney involvement gets reflected in the ballooning of legs and arms. Apart from that, proteinuria (protein in urine) can also be detected as the kidney is improperly functioning.

• When the stomach and intestines are affected, it produces symptoms like diarrhea and bloating. Sometimes the tongue enlarges, obstructing the swallowing of food. Occasionally constipation is also reported with gastrointestinal tract association.

• Amyloid buildup in the nerve endings causes tingling and numbness, especially in the hands and feet.

• Protein collection in the skin makes it weak and delicate, thus increasing the tendency to bleed (bruising) through the skin.

• Amyloid fibrils in the heart muscle significantly impair the rhythm of the heartbeat. In addition, it reflects short - shallow breaths and a dramatic reduction in blood pressure.

Other routinely encountered symptoms include the following:

• Frothy feces (pee).

• Weight loss.

• Weakness.

• Rash.

• Weak grip.

• Abdominal pain.

How Is Amyloid A Amyloidosis Diagnosed?

Along with medical history and clinical findings, certain tests and procedures are advised to confirm the diagnosis of AA amyloidosis.

1. Blood Tests: To assess urea, nitrogen, and creatinine levels in the blood.

2. Urine Analysis: To detect the presence of protein in the urine.

3. Biopsy: Biopsy specimens are collected from the involved organ to detect amyloidosis changes.

4. Aspiration Cytology: To assess the fat under the skin layer.

5. Ultrasound: Ultrasound of the abdomen reveals structural changes in the organs like the liver.

6. Nerve Conduction Velocity: To assess the transmission of impulses through the nerves.

7. Echocardiogram: To assess the heart's functioning and detect damaged areas.

8. Electrocardiogram: To detect irregularities in the heart's electrical conduction.

9. Nuclear Imaging: To identify damage in heart muscle using radioactive agents as tracers.

10. Magnetic Resonance Imaging (MRI): Magnetic field provides a clear picture of the organ.

11. Computed Tomography: To visualize the organ structure.

What Are the Available Treatment Methodologies?

• AA amyloidosis is not a completely curable condition. However, symptomatic management effectively controls the disease by checking protein accumulation.

• As the disorder is precipitated by an underlying disease, treating the primary condition is vital in managing AA amyloidosis.

• The involved organs and the underlying disease tend to guide treatment strategies.

• Occasionally, immunosuppressive medicines are suggested to control the immune response and, thereby, SAA protein deposition.

• Dialysis is considered if the kidney function is severely affected.

• Cardiac medicines are prescribed to maintain the rate and rhythm of the heartbeat.

• If the organs are damaged to the extent that further corrective treatments do not seem fruitful, it is better to consider organ transplantation as an effective treatment intervention. However, organ transplantation is a complex surgical procedure; hence it is initiated only if all the patient factors are favorable for the surgery.

What Are the Potential Complications That Could Arise From A A Amyloidosis?

• Kidney failure.

• Respiratory failure.

• Heart failure.

• Internal bleeding.

• Perforation in the bowel.

• Endocrine failure.

• End-stage renal disease.

• Multiple organ failure.

What Is the Prognosis for A A Amyloidosis?

The prognosis of AA amyloidosis revolves around certain factors like:

• Affected organs.

• Severity and nature of the underlying disease.

Conclusion

AA amyloidosis is a serious condition that originates due to a long-standing infectious condition, expressed as an accumulation of amyloid fibrils. Protein deposits in tissues and organs leading to disrupted functioning over time. So it needs to be treated at the right time; otherwise, it can potentially cause multiple organ failure and death. However, it can be prevented by properly managing and treating other systemic conditions.