Refeeding EdemaLooking Beyond the Symptoms

Refeeding edema in patients with anorexia nervosa is still a poorly understood condition. A recent case of edema in a Singapore patient demonstrated the need for further investigation of the condition (Singapore Med 2005;46:308).

A 19-year-old college student with restricting type AN was being seen on follow-up visits to her psychiatrist. Because her weight had fallen from 48 kg to 36 kg over the past year, she was referred to the medical unit for nutritional rehabilitation and medical stabilization. She had symptomatic sinus bradycardia, with a heart rate of 40 beats per minute.

As she was started on nutritional rehabilitation, she developed edema in both feet. Then the edema became moderately severe and the patient was very upset because of the physical discomfort and her inability to walk without pain. Her physicians ruled out hypoalbuminemia, renal failure, liver failure, cardiac failure, proteinuria, hypothyroidism, and obstruction to venous drainage due to an abdominal mass. CT scans showed no abdominal masses, and chest films were normal. She did have low levels of estradiol (24.9 IU/l), leutinizing hormone (0.1 IU/l), and follicular stimulating hormone (0.5 IU/l). Urine cortisol (24 hr) and prolactin measurements were within normal ranges.

The patient was treated with multivitamins and thiaminwith little improvement. Furosemide was given and her legs were elevated, but little change was seen. As she was continued on nutrition, she slowed gained weight and the swelling in both feet eventually resolved spontaneously about a month after it first appeared.

What leads to edema during refeeding?

According to the authors, two basic mechanisms cause edema formation, namely a change in capillary hemodynamics that favors the movement of fluid from the vascular space into the interstitium, and the retention of sodium and water by the kidneys. During refeeding, insulin secretion normally increases and it has been proposed that insulin release can result in significant edema.

Glucagons have also been implicated in edema formation. Increased levels of glucagons during starvation have a natriuretic effect, whereas decreased levels during refeeding enhance antinatriuresis in the distal tubule.

The authors suggest that it is important to rule out possible causes of edema when an anorexic patient undergoing treatment develops edema. One of the most important conditions to rule out with refeeding edema is cardiac failure. Patients with anorexia nervosa lose a large amount of body mass during starvation and this, coupled with the reduced demand, can lead to reduced ventricular mass and myofibrillary atrophy. During refeeding, the sudden ingestion of relatively large amounts of nutrients can overwhelm the diminished capacity of the cardiovascular system and result in heart failure.

Other patients may abuse diuretics and the resultant hypovolemia activates the rennin-angiotensin-aldosterone system. This may not reverse as quickly when diuretics are stopped abruptly and can cause initial edema with spontaneous resolution.

In most cases edema will resolve without treatment

Most patients will not need treatment and their edema will resolve spontaneously as refeeding continues. However, when the edema is severe, the authors suggest low doses of diuretics given in the early morning (since edema usually accumulates during the day when the patient is upright. Another benefit of this treatment is that it confers psychological reassurance to patients who are already finding it difficult to cope with the changes that have occurred in their body shape.

Even though most cases of edema in patients with anorexia nervosa will resolve with refeeding, the authors note that it is important to rule out possibly serious underlying causes of edema, such as cardiac failure, and to prepare the patients psychologically by directly addressing the problem.