Peripheral Neuropathy and Amyloidosis

What is amyloidosis?

Amyloidosis can develop as a primary or secondary condition to a different health condition. In fact, some forms of this disease are more likely to affect people living with existing infections or conditions that cause chronic inflammation.

Amyloidosis is a disease that involves an excess or buildup of atypical amyloid deposits. These deposits can accumulate in the brain, kidneys, heart, spleen or other parts of the body. An individual with amyloidosis could have buildup in multiple organs.

There are a few types of amyloidosis, some of which are hereditary. The most common are light-chain amyloidosis, AA amyloidosis and transthyretin amyloidosis.

Symptoms

The signs and symptoms of amyloidosis are progressive and can worsen as the buildup worsens. The deposits can eventually harm the affected organs and cause other issues like swelling or kidney failure due to deposits blocking the filters in the kidney.

Signs and symptoms of amyloidosis include:

• Increased tongue size
• Losing weight unintentionally
• Swelling in the legs, ankles, feet and belly
• Feeling tired or weak
• Easily bruising
• Excessive bleeding after an injury
• Shortness of breath
• Numbness, tingling or pain in the hands and feet
• Purpura (purple spots) or bruised-looking skin around the eyes

Causes

Some forms of amyloidosis, like transthyretin amyloidosis (ATTR), are inherited from family members. It can also develop as a secondary condition to another condition characterized by chronic inflammation. It can develop due to a gene mutation or the cause could be entirely unknown.

Risk factors

Certain factors increase an individual’s risk of developing a form of amyloidosis. However, diagnosis of this disease is not mutually exclusive with these risk factors and can develop outside of these factors or groups.

• Other diseases: Risk is increased for individuals that suffer from inflammatory or chronic infectious diseases, mostly older but include individuals 18+.
• Family history: Certain types of amyloidosis are inherited.
• Sex: Men are at a higher risk for amyloidosis, making up nearly 70 percent of current cases.
• Kidney dialysis: Though less common with modern dialysis techniques, irregular proteins can build up in the blood of someone on dialysis and be deposited into the tissue.
• Race: Individuals of African descent are seemingly more at risk of transthyretin amyloidosis due to a genetic mutation.

Complications

Complications associated with systemic amyloidosis are commonly peripheral nerve disorders. This disease can affect motor or autonomic nerves, peripheral sensory and degeneration and dysfunction in these nerves.

Amyloid neuropathy as a result of autonomic and sensory dysfunction has signs and symptoms, including:

• Numbness
• Balance issues
• Painful paresthesia
• Diarrhea, incontinence and constipation
• Continuous nausea or vomiting
• Sexual dysfunction
• Sweating abnormalities

Treatments

The treatment for amyloidosis is dependent on the type. The goal of these therapies is to prolong life by slowing the progression of the disease. Active research and clinical trials exist for new therapies, treatments and procedures to treat amyloidosis. Currently, the treatments for amyloidosis include bone marrow transplants, chemotherapy and various medications. Medications depend on the form of amyloidosis and will be determined by the exhibiting symptoms and family history.

What is the connection between peripheral neuropathy and amyloidosis?

The connection between amyloidosis and peripheral neuropathy has often been overlooked. Peripheral neuropathy results from damage to the peripheral nerves outside the brain and spinal cord. Common symptoms are numbness, weakness and pain, typically in the feet and hands.

The connection between peripheral neuropathy and amyloidosis is cause and effect. Peripheral neuropathy is a common presenting symptom of (AL) light-chain amyloidosis and marks the early onset of the disease.

Peripheral neuropathy may provide a precursory warning to amyloidosis before it can infiltrate the vital structures of the kidneys, GI tract and heart, causing a downward trajectory of these organs. Identifying amyloidosis at this early stage may broaden the potential treatments and further prolong life.

What causes peripheral neuropathy in amyloidosis?

Peripheral neuropathy and amyloidosis have a common histopathological feature, deposits of amyloid-forming proteins in the body’s tissues. Peripheral neuropathy can be present in both inherited or acquired amyloidosis.

The amyloid deposits may cause tissue damage and dysregulation, as well as nerve damage. Damage to the peripheral nerves from amyloid deposits may cause peripheral neuropathy.

Amyloidosis is just one of many diseases that could cause peripheral neuropathy. Other diseases with the presence of amyloid proteins and the resulting peripheral neuropathy are still being studied and are not yet considered amyloid neuropathies, though they share similarities in molecular and cell biological defects caused by amyloid proteins.

Final thoughts

A great deal is still being learned about the association between peripheral neuropathy and amyloidosis. New treatments and therapies are being actively researched. Continue to speak with your doctor about symptoms you experience and their possible connections to other diseases, so the best course of action can be determined.

WinSanTor is a clinical-stage biotechnology company focused on the discovery and development of treatments for peripheral neuropathies. We believe in creating a solution that works and brings relief to millions who are struggling with this disease. Learn more about our company, our drug and subscribe to our newsletter.

Sources

• “Amyloidosis – Symptoms and causes – Mayo Clinic”. Mayo Clinic
• “Amyloidosis | Johns Hopkins Medicine”. Johns Hopkins Medicine
• “Amyloidosis: What It Is, Symptoms, Types & Treatment”. Cleveland Clinic
• “Light-Chain Amyloidosis With Peripheral Neuropathy as an Initial Presentation – PMC”. National Library of Medicine

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