Numbness, weakness, or sudden drops in blood pressure can all be signs that ATTR amyloidosis is affecting your nerves. In this condition, misfolded amyloid proteins build up in the peripheral nervous system — the network of nerves outside the brain and spinal cord.

When many nerves are affected, it’s called polyneuropathy. Transthyretin amyloid polyneuropathy (ATTR-PN) is one specific type. Peripheral and autonomic neuropathy are most common in light-chain (AL) amyloidosis and hereditary transthyretin amyloidosis.

“I’m extremely lightheaded, walking has become somewhat troublesome, and my vision seems messed up.”
— A MyAmyloidosisTeam member

This article explains how ATTR-PN affects sensory, motor, and autonomic nerves and what symptoms you might experience.

How Do Amyloids Damage Nerves?

Amyloidosis is a rare condition in which abnormal proteins clump together in organs, tissues, and nerves. ATTR amyloidosis is one of several types of amyloidosis. This form develops when a protein called transthyretin (TTR) becomes unstable and misfolds.

The TTR protein can misfold due to an inherited genetic mutation, or change (hereditary ATTR), or may occur with age (wild-type ATTR). Researchers have identified more than 120 possible mutations in the TTR gene. ATTR-PN is most often linked to the hereditary form of ATTR amyloidosis.

“I'm in pain and off balance when I am walking."
— A MyAmyloidosisTeam member

When amyloid proteins build up around nerve fibers and blood vessels, they damage the axon — the part of the nerve that sends signals to the body and brain. This buildup disrupts how the nerves send messages and affects how well they work. ATTR-PN is a form of peripheral neuropathy caused by amyloid buildup in the peripheral nervous system.

Types of Nerves

The peripheral nervous system includes three main types of nerves, all of which can be affected by ATTR-PN:

• Sensory nerves — These carry signals to the brain that allow you to feel sensations like touch, pain, and temperature. Sensory nerves include both large and small fibers.
• Motor nerves — These carry signals from your brain and spinal cord to muscles, allowing your body to move.
• Autonomic nerves — These control automatic body functions, such as heart rate, breathing, and blood pressure.

How Amyloidosis Damages Sensory Nerves

ATTR-PN may first affect the small sensory fibers, which detect pain and temperature. Amyloid-related neuropathy symptoms usually begin in the hands and feet. The small nerve fibers in these areas tend to lack protective insulation, making them more vulnerable early in the disease. These small sensory fibers are the most commonly affected by amyloid buildup.

Symptoms of Sensory Nerve Damage

Sensory symptoms generally start in the feet and move up the body within four to five years of developing the condition. Motor symptoms in the lower limbs may appear about two years after sensory symptoms begin. Damage to small sensory fibers may cause:

• Burning
• Tingling
• “Pins and needles” or “electric shock” sensations
• Increased sensitivity to touch

One MyAmyloidosisTeam member described their symptoms as “stinging, stabbing, tingling sensations in the hands, feet and limbs.”

Over time, nerve damage may spread from small nerve fibers to larger ones, which help you sense vibration and know where your body is in space. Damage to large sensory nerves may cause numbness and loss of balance. “I’m in pain and off balance when I am walking,” one member shared.

Eventually, people may develop muscle weakness and more severe loss of sensation.

How Amyloidosis Damages Motor Nerves

When amyloid proteins build up around motor nerves, they can cause muscle weakness and loss of function in the hands or feet. This damage tends to happen the longer someone lives with amyloidosis.

Symptoms of Motor Nerve Damage

Damage to motor nerves can cause wide-ranging problems, including difficulty walking and joint pain. You may notice:

• Trouble walking
• Back, hip, knee, or shoulder pain
• “Trigger finger” (a finger stuck in a bent position)
• Carpal tunnel syndrome

“Rough morning, with shoulder, back, and leg pain,” a MyAmyloidosisTeam member wrote.

Carpal tunnel syndrome can be an early warning sign of nerve damage, usually developing more than 10 years before an ATTR amyloidosis diagnosis. Symptoms of carpal tunnel syndrome include:

• Wrist pain
• Weak grip
• Numbness in the hands
• Tendency to drop objects

How Amyloidosis Damages Autonomic Nerves

Autonomic nerves control body functions that you don’t have to think about, such as:

• Heart rate
• Blood pressure
• Digestion
• Circulation
• Bladder function
• Sexual function

Autonomic neuropathy occurs in up to 82 percent of people with hereditary ATTR amyloid peripheral neuropathy and up to 75 percent with AL amyloid peripheral neuropathy.

Symptoms of Autonomic Nerve Damage

Autonomic nerve symptoms can be an early red flag for ATTR amyloidosis, because they often appear before other signs. In about 10 percent of people, these signs appear before sensory or motor symptoms.

Amyloid buildup in autonomic nerves may cause:

• Orthostatic hypotension (feeling lightheaded or faint when standing)
• Diarrhea, poor appetite, constipation, or other stomach issues
• Sexual dysfunction
• Incontinence
• Reduced sensation, urinary tract infections, or other bladder problems

People with autonomic nerve damage may also have issues with their heart, kidneys, or eyes. Eye problems can include increased cloudiness, dryness, or glaucoma (increased pressure).

“I’m extremely lightheaded, walking has become somewhat troublesome, and my vision seems messed up,” a MyAmyloidosisTeam member shared.

Talk to Your Doctor About Treatment

Treatments for ATTR-PN can help slow the progression of the disease and may improve neuropathy symptoms over time. Your doctor might recommend medications to manage nerve pain or other symptoms. They may also suggest physical therapy, lifestyle changes, or alternative approaches such as acupuncture to help you feel more comfortable and stay active.

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