Researchers have reported the case of a Portuguese man with late-onset familial amyloid polyneuropathy (FAP) and a rare combination of heart failure with a severe accumulation of fluids in the abdominal cavity.
The case report, “Val30Met Familial Amyloid Polyneuropathy, Heart Failure, and Chylous Ascites: An Unexpected Combination,” was published in the Spanish Journal of Cardiology.
FAP, also known as hereditary transthyretin (TTR) amyloid polyneuropathy, is a rare disease caused by genetic mutations in the TTR gene. Val30Met is the most common mutation.
The disease was first identified in several families in Portugal in the early 1950s, and in some areas of northern Portugal it affects one in 500 people, although it’s considered a rare disease in the U.S. and most countries of the world.
FAP has a wide range of symptoms, including motor and sensory impairment due to nerve damage (neuropathy). But heart abnormalities have been increasingly recognized as serious and potentially life-threatening manifestations.
In the report, a Portuguese research team presented the case of a 70-year-old man who had been diagnosed with FAP triggered by the TTR Val30Met mutation.
The first symptoms of the disease appeared 10 years earier (called late-onset disease) with symptoms of nerve cell damage. He had a clinical history of heart problems and chronic kidney disease, and he had been referred to the hospital due to decompensated congestive heart failure — a sudden worsening of heart failure symptoms.
In the month before he was admitted to the hospital, the patient developed generalized edema, which is the accumulation of fluids. He was initially treated with oral diuretics but these failed to improve his condition, which got progressively worse, leading to difficulty breathing and low blood pressure.
He was in bad shape when he was admitted, with severe fluid accumulation in the abdominal cavity, requiring urgent care.
Some of the abdominal liquid was collected for analysis. To the researchers’ surprise, the liquid had a milky appearance and was rich in fatty molecules called triglycerides.
Also, an evaluation of his heart through an echocardiogram revealed that the walls were severely increased with signs of immune cell infiltrates. The heart’s pumping activity was also found to be impaired.
These symptoms did not exactly fit the common features of the FAP Val30Met mutation, so the team conducted additional tests to exclude other possible conditions, such as cancer.
These evaluations also revealed increased deposits of transthyretin amyloids in the heart wall, which was consistent with cardiac manifestations of FAP rather than another heart disorder.
Supported by these findings, the team concluded the patient had heart failure derived from FAP, which led to severe accumulation of fatty fluids (chylous ascites) in the abdominal region.
Since the patient was not responding to treatment with diuretics and developed low blood pressure, resolving the fluid accumulation became a challenge to the clinical team.
They were able to achieve a clinical balance by administering subcutaneous injections of Lasix (furosemide) combined with oral Zaroxolyn (metolazone) and Aldactone (spironolactone), all medicines with properties for the treatment of high blood pressure or heart failure, as well as fluid accumulation.
Also, the patient’s fluid intake was restricted, and the accumulated fluids were removed by paracentesis (a hollow needle was used to remove the fluids).
After three weeks, he showed a significant improvement and was discharged from the hospital. At home, he continued to self-administer Lasix using a catheter that was placed subcutaneously and changed every week.
“Careful diuretic dosing and subcutaneous furosemide [Lasix] were crucial to overcome the decreased oral absorption and improve edema [fluid accumulation],” the researchers wrote.