Amyloidosis: symptoms, treatment and prognosis

Amyloidosis is a generic term used to describe a group of diseases of diverse etiology and highly variable prognosis and treatment. This set of serious conditions has one characteristic in common, the deposition of an abnormal protein (amyloid) in various organs, which causes interference in its normal operation.

Its epidemiology is difficult to pin down, but it is estimated that between 5.1 and 12.8 patients per million people per year suffer from it. Due to its low incidence, it is considered a heterogeneous set of rare diseases. How does it manifest? What are the treatments available? In the next space we will tell you everything about it.

What is amyloidosis and what are its causes?

Amyloidosis refers to a set of rare diseases and not just a specific pathology. In any case, in all the variants the accumulation of a protein of its own with abnormal folding occurs in different organs and systems, which causes an alteration in their functioning.

As indicated by Hospital Puerta del Hierro, there are many proteins in the body that can misfold and cause this condition. The predisposition to this metabolic failure can be inherited, but there are cases in which it is produced by spontaneous DNA mutations without a family history. We tell you the main types.

The accumulation of amyloid protein in various parts of the body leads to amyloidosis.

Primary amyloidosis (AL)

Primary amyloidosis (AL) is the most common form of the disease, it represents 85% of the cases diagnosed in high-income countries. The cause of amyloid protein production is not known, but it is known to be related to abnormal antibody synthesis by a type of immune body known as "plasma cells."

In a normal situation, plasma cells (or plasma cells) produce whole antibodies (glycoproteins), and the body breaks them down and recycles them after a specified period of time. These glycoproteins, when working properly, protect against pathogenic infections.

When antibody chains are produced atypically, they cannot be degraded. Consequently, fibers are formed that accumulate in organs and tissues. The highest density of amyloid is found in the heart, kidneys, liver, spleen, nerves, intestines, and skin.

Secondary amyloidosis (AA)

Secondary amyloidosis appears related to a chronic inflammatory process. In this case, this is because the protein that accumulates is circulating serum amyloid A, which rises in natural response to inflammation and infection in the body. Chronic osteomyelitis, irritable bowel syndrome, and other conditions can lead to it.

Other types

As we have said previously, there are other types of amyloidosis. We summarize 2 more variants briefly in the following list:

  1. Family: it is the inherited form of amyloidosis. It is usually related to a genetic mutation in genes that code for a protein that is produced in the liver, transthyretin. This poorly synthesized protein accumulates over time in the heart. Studies estimate that 4% of African Americans carry one of these mutations.
  2. Senile systemic: it is acquired, not inherited. Protein accumulation in the heart usually occurs, especially in elderly patients. The transthyretin is once again the protagonist, but in this case its accumulation does not have to be associated with a family inheritance.

As you can see, there are many types of amyloidosis, based on the type of protein that accumulates in any given organ. Anyway, We emphasize that the most common variant is the primary one, triggered by improper production of immune antibodies.

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What are your symptoms?

The Mayo Clinic compiles the main clinical manifestations of amyloidosis. These include the following:

  • Swelling in the ankles and legs: This may be due, in part, to poor liver or kidney function, which causes an imbalance in the amount of fluids and substances that are stored in the body.
  • Fatigue, weakness, and shortness of breath with minimal effort: These are general symptoms of amyloidosis, regardless of where the abnormal proteins collect.
  • Abnormal heart rhythms and heart failure: this is characteristic of senile systemic amyloidosis. It is due to the natural accumulation of transthyretin (TTR) in the heart slowly and progressively, as the patient ages.
  • Tingling or numbness in the hands and feet: due to the accumulation of amyloids in nerve endings.
  • Bruises and a fuller tongue (macroglossia): These are the epidermal manifestations of amyloid accumulation.

The symptoms are nonspecific and, although they depend on the affected organ, many times they remain masked by the previous pathology that determines the appearance of amyloidosis.

Kidney damage is the most frequent in many cases, as up to 66% of patients with primary amyloidosis suffer from dysfunctionalities of varying severity in the kidneys, as indicated by the Revista Mexicana de Dermatología. Thus, swelling of the extremities and the presence of protein in the urine are the most common early signs.

Risk factor's

Talking about risk factors in such a heterogeneous set of diseases is complex, but There are certain conditions that could predispose a patient to suffer from amyloidosis. Among them, we find the following:

  • Age: According to studies, the average age of presentation of the condition is 65 years. Senile systemic amyloidosis is believed to be underdiagnosed, presenting with the aging process.
  • Sex: two-thirds of amyloidosis patients are men.
  • Other diseases: chronic inflammatory diseases (such as irritable bowel syndrome, chronic osteomyelitis, ankylosing spondylitis, among others) and certain infectious diseases can lead to the appearance of secondary amyloidosis.
  • Sick relatives: As we have commented, some variants of these pathologies are hereditary in nature.
  • Ethnicity: African-American people are more likely to have amyloidosis, since they carry certain genetic mutations at the genomic level in a greater proportion than other ethnic groups.

How is it diagnosed?

As indicated National Health Service (NHS), diagnosing amyloidosis is quite difficult, since the symptoms are very vague and tend to be confused with those caused by other diseases.

After a physical examination, routine tests (urine samples, blood tests, among others), computed tomography tests, and thyroid and liver function tests, the final diagnosis can only be made with a biopsy.

After obtaining a sample of the damaged tissue, it is stained with the Congo red staining salt. This method allows the characteristic green birefringence of amyloid protein to be observed under the microscope. The most suitable places to carry out the test are the fat of the abdominal panniculus, the rectal mucosa, the gums, the skin, the kidney and the liver.

Biopsy is necessary for the final diagnosis of amyloidosis.

Available treatments

Unfortunately, we are facing a series of diseases that do not have a good prognosis. Its survival rate after diagnosis ranges from 1 to 4 years. The most common causes of death are kidney failure and heart disease. Remission is only conceived when the causative agent is localized, such as a tumor.

Anyway, This does not mean that you do not have to fight for the life of the patient. The
MSD Manual details the most effective treatments based on the type of amyloidosis presented.

Primary amyloidosis

The combined action of chemotherapy, certain drugs, and peripheral stem cell transplantation can stop amyloid deposition. Radiation therapy may be the most appropriate option when amyloid accumulation only occurs in a specific area of ​​the body.

Secondary amyloidosis

Urgent treatment of the underlying disease is required. If the cause is an infection or a curable tumor, a possible remission is conceived. This does not happen in all cases, as we remember that the prognosis is very poor.

Hereditary and senile amyloidosis

It should be remembered that both conditions are produced by the accumulation of transthyretin protein (TTR) in the heart. Medications such as diflunisal and tafamidis can stabilize this protein molecule, slowing the progression of the disease. This delays the inevitable end, but does not suppose a total cure of the pathology at any time.

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We find it difficult to end on a positive note, as the general prognosis of most types of amyloidosis is very poor. Although the average life expectancy is 1-4 years, those patients with localized affectation or senile amyloidosis can live for up to 5-15 years, with a variable quality of life.

In many cases, the disease cannot be cured, but its progression can be delayed. Hopefully, with medical advances – and a greater understanding of the human body – primary amyloidosis and its variants can be effectively cured in the future.