GI red flags: When diarrhea and weight loss may signal hATTR-PN
Fact-checked by Gastrointestinal (GI) problems can happen for many different reasons, but if you experience diarrhea and weight loss alongside nerve symptoms, it may point to something more than a digestive issue.
In hereditary transthyretin amyloidosis with polyneuropathy (hATTR-PN), GI symptoms can be early signs of nerve damage. If you are experiencing diarrhea and weight loss, especially with other nerve-related symptoms, it may be time to talk to your doctor.
How hATTR-PN affects the digestive system
In hATTR-PN, a protein called transthyretin is unstable and misfolds. This can lead to protein clumps, called amyloid deposits, building up in various parts of the body, including the nerves and GI tract.
Your GI tract depends on nerves to help move food, signal hunger and fullness, and control bowel movements. When hATTR-PN affects the autonomic nerves, which control bodily functions that happen without conscious control, digestion can be affected. Food may move too quickly or too slowly through the digestive tract, leading to a range of GI symptoms in hATTR-PN, including:
- diarrhea
- constipation
- nausea and vomiting
- bloating
- early fullness (satiety)
- unintended weight loss
Depending on the specific gene mutation involved, GI problems are estimated to affect about 56% to 69% of people with hATTR-PN. For some people, these symptoms appear early in the disease course, before more noticeable nerve symptoms develop.
Why diarrhea and weight loss are often misdiagnosed
Diarrhea and weight loss in hATTR-PN can be easy to overlook because these symptoms are often linked to more common digestive conditions. Before considering hATTR-PN, doctors may first rule out other gastrointestinal diseases, such as:
- food intolerance or allergies
- colitis (colon inflammation)
- irritable bowel syndrome
- celiac disease
- gastroesophageal reflux disorder
Because hATTR-PN is rare, it might not be the first condition a doctor considers. In addition, symptoms can vary widely from person to person, and many people do not have a known family history of the disease, which can make diagnosis more difficult.
Additionally, symptoms that seem unrelated may be evaluated by different specialists, making it harder to recognize the broader pattern behind the disease.
Other gastrointestinal symptoms
GI symptoms of hATTR-PN can change over time and do not always follow a consistent pattern. For example, some people alternate between loose diarrhea and constipation, rather than experiencing one ongoing bowel issue.
They may also experience nausea and vomiting in hATTR-PN due to delayed stomach emptying, meaning food remains in the stomach longer than expected. Other gastrointestinal red flags linked to hATTR-PN include:
- feeling full too soon
- excessive bloating after a meal
- poor absorption of nutrients
- bowel incontinence
Symptoms can range from mild to severe and can worsen over time, potentially affecting your daily routines, social plans, or comfort level when leaving the house. Because GI symptoms can shift over time, experts recommend monitoring digestion, weight, and early fullness as part of ongoing care.
When GI symptoms point to autonomic nerve damage
GI symptoms may raise greater concern when accompanied by signs involving the autonomic nervous system, which controls automatic functions the body carries out without conscious effort. These functions include:
- digestion
- blood pressure
- sweating
- bladder function
- sexual function
- heat regulation
In hATTR-PN, autonomic nerve damage can develop early in the disease, sometimes before more obvious nerve damage (neuropathy) symptoms appear. A pattern of unexplained weight loss and neuropathy can be especially important if it occurs with other signs such as:
- dizziness or fainting when standing
- urinary issues, such as trouble emptying the bladder
- erectile dysfunction or other sexual changes
- sweating changes or heat intolerance
- carpal tunnel syndrome, especially in both wrists
A combination of persistent unexplained diarrhea and weight loss can also point to worsening autonomic involvement, particularly when other symptoms are also present.
Diagnostic tests that may be considered
If GI symptoms are ongoing or worsening over time, your doctor may start by looking for common causes before considering hATTR-PN. For diarrhea, this evaluation might include:
- stool tests
- blood tests
- breath tests for certain food intolerances or bacterial overgrowth
- endoscopy or colonoscopy
If early fullness, nausea, or vomiting are more prominent, your doctor may also consider tests that measure how quickly food leaves the stomach and moves through your bowel.
Although diagnostic tools for GI symptoms in hATTR-PN remain limited and are not always routinely used, tracking nutrition, weight, and symptoms can provide important clues about how your digestive system is affected. Recognizing these changes early may help support faster evaluation, more informed conversations with doctors, and earlier diagnosis and care.
Amyloidosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
