Protein-losing enteropathy: causes, symptoms, tests and treatment

Proteins such as albumin circulate in the blood, where they help to hold fluid inside the blood vessels. In PLE, protein is lost across the wall of the gut or from the lymphatic channels that drain it, faster than the body can replace it. Patient.info says this results in hypoproteinaemia, which can be complicated by oedema, ascites (fluid in the abdomen), pleural and pericardial effusions (fluid around the lungs and heart) and malnutrition.

PLE is therefore a syndrome, not a single disease. The question for doctors is always why the protein is leaking, and the answer decides the treatment.

Patient.info describes three main mechanisms: mucosal disease with ulceration, lymphatic obstruction causing loss of protein-rich lymph, and changes in the permeability of the gut lining. It also notes that PLE is common after the Fontan procedure, a staged operation for children with a functional single ventricle, and can occur after graft-versus-host disease.

Patient.info says the clinical picture is very variable but mainly consists of swelling due to low blood protein, and that PLE should be considered in anyone with oedema, especially against a background of gut disease. Doctors also ask about diarrhoea, abdominal pain, heart history and alcohol.

The NHS page on swollen ankles, feet and legs says to see a GP if both ankles, feet or legs are swollen and it has not improved after treating it at home for a few days, it gets worse, or you have a heart, kidney or leg vein condition. It advises an urgent GP appointment or NHS 111 if swelling is severe, painful or starts suddenly, if there is swelling in other areas such as the face or tummy, or if you have a very high temperature. It says to call 999 if you are short of breath, have chest tightness or pain, or cough up blood.

The first step with low albumin is to exclude more common causes, including malnutrition, liver disease and kidney disease, using blood tests and function tests, as Patient.info explains. Gut protein loss is investigated in people with oedema, low albumin and normal kidney and liver function.

Faecal alpha-1 antitrypsin measured in a random stool sample, or more accurately as clearance from a 24-hour stool collection with a matching blood test, is used to assess gut protein loss. Scintigraphy using radio-labelled albumin or dextran is an accurate test but expensive and time-consuming, usually reserved for those with a negative alpha-1 antitrypsin test. Endoscopy and biopsy can show ulceration, inflammation, dilated lymphatics or tumours, and capsule endoscopy or enteroscopy can examine the small bowel.

Patient.info says there is no specific treatment for PLE, so management is directed at the underlying cause and at malnutrition and micronutrient deficiencies. Treating the cause can resolve it: examples given include treating chronic diarrhoea with loperamide in one study and using diuretics for congestive heart failure.

For primary intestinal lymphangiectasia, dietary therapy is the mainstay, consisting of a high-protein, low-fat diet. Octreotide has been useful in some patients, supplementation with fat-soluble vitamins may help, and parenteral nutrition has been used to support recovery. In patients who have had the Fontan operation, surgical changes to the circulation have helped some, and heart transplantation is occasionally used for intractable PLE. These decisions are made by specialist teams, and diets should not be changed to low fat without medical advice.

The outlook depends on the cause. Patient.info notes that PLE is a major cause of illness and death after the Fontan operation, whereas in other settings treating the underlying condition can resolve it.

Practical measures from NHS advice for swelling include raising the legs when you can, gentle exercise to improve circulation, wide comfortable shoes and avoiding standing or sitting for long periods. These ease swelling but do not treat the cause, so ongoing review by the specialist team is essential.

On the NHS, investigation is usually led by a gastroenterologist, with paediatric, cardiology or lymphatic services involved depending on the cause. Because PLE is rare, referral to a centre with experience is often appropriate.

Private gastroenterologists can arrange tests such as endoscopy and stool studies more quickly. The investigations are the same, so waiting time and continuity are the main differences. Ask which team will take responsibility for nutrition and for the underlying cause.