NG Tube Feeding and Anorexia Nervosa: Why and When?

By Stuart Kaplan, MD, FAAP, and Wendy Foulds Mathes, MS, PhD, LPCA, NCC

Nasogastric (NG) tube feeding is used as a form of nutritional supplementation and rehabilitation in a variety of medical settings. It requires the insertion of a tube through the nasal passage, down the esophagus, and into the stomach.  Nutrition is delivered directly to the stomach either in bolus (one large infusion of liquid food delivered over a 10-60 minute period) or continuously over an 8-24 hour period via a pump.  NG tube feeding is indicated for medical conditions that render a patient unable to acquire sufficient nutrition through oral feeding. Examples of such conditions are cystic fibrosis, Crohn’s disease, neuromuscular disorders that impair chewing and swallowing, and anorexia nervosa.

NG tube feeding offers many benefits in the treatment of anorexia nervosa.  It can be used in conjunction with oral feeding during the initial stages of treatment to facilitate weight gain for medical stability and to improve an individual’s cognitive function to promote readiness for and engagement in treatment toward psychological recovery. Similarly, NG tube feeding can augment oral feeding during later stages of recovery when caloric need is high due to increased metabolic need. When NG tube feeding is used to supplement and not replace oral feeding in the treatment of individuals with anorexia nervosa, it can help promote both physical and psychological recovery. Just as someone with a broken leg needs to use crutches to walk while their bone heals, NG tube feeding can support an individual with anorexia nervosa as they move forward toward recovery…until they are able to stand on their own two feet again.

EARLY REFEEDING AND MEDICAL STABILIZATION

The hallmark of anorexia nervosa, restriction of energy intake leading to significantly low body weight (American Psychiatric Association, 2013), leads to physical and psychological consequences that make treatment extremely challenging. Severe malnutrition and low body weight contribute to cardiac irregularities (including cardiac failure and arrhythmia) and endocrine abnormalities (including hypoglycemia) that can be life threatening.  In addition, severe malnutrition contributes to cognitive impairment that may hinder an individual’s ability to comprehend the severity of their condition, delaying treatment and reducing adherence to treatment recommendations. As such, restoring nutritional status and body weight facilitates treatment response and recovery.

Studies examining nutritional rehabilitation in individuals with anorexia nervosa have reported that oral refeeding during the early stages of treatment may not be sufficient to maintain body weight and individuals may lose weight during the first week of treatment (Garber, Michihata, Hetnal, Shafer, and Moscicki, 2012). NG tube feeding in addition to oral feeding has been shown to increase weight gain during the first few weeks of treatment compared to oral feeding alone (Robb et al., 2002, Silber et al., 2004). As such, supplemental caloric intake via NG tube feeding during the early stages of recovery can facilitate medical stabilization and improve cognitive function in severely malnourished individuals.

Individuals that struggle with anorexia nervosa suffer physical and psychological consequences that make it difficult to ingest food.  Anorexia nervosa-related behaviors such as prolonged food restriction or laxative abuse wreak havoc on the gastrointestinal system. It can take weeks of nutritional rehabilitation before healthy GI function is restored. Anorexia nervosa patients often suffer from delayed gastric emptying, decreased gastric motility, and gastroparesis (paralysis of the GI tract). These phenomena cause patients to feel full sooner after eating and this sensation lasts longer in patients with anorexia nervosa than in individuals without anorexia nervosa. These GI consequences also contribute to physical discomfort, such as gastrointestinal distention, pain, gas, and feeling bloated, as well as psychological distress, such as increased anxiety around eating and heightened body image concerns. Experiencing these side effects of eating during the early stages of treatment may impede progress toward recovery, prolong medical instability, and extend the duration of hospitalization. NG tube feeding can alleviate some of this distress. Liquid nutrition is well-tolerated and leads to less GI distress than solid nutrition in patients with slowed gastric motility (Marzola, Nasser, Hashim, Shih, and Kaye, 2013). Oral caloric intake through meals and snacks can be supplemented with caloric intake through the NG tube. Thus, caloric intake can be distributed over a 24 hour period, decreasing the physical and psychological consequences of larger caloric intakes in the form of meals and snacks alone. Oral intakes can be gradually increased as the individual adapts to the physical sensations of eating.

Many patients with pervasive eating disorder-related thoughts, even when able to understand the importance of nutrition, face a constant internal battle between the recognition of the importance of increased nutrition and the distress of actively ingesting food. NG tube feeding can, in the short term, mitigate this struggle by medicalizing increased nutrition through “doctor’s orders” as opposed to placing the full responsibility of re-nourishment on the patient. Occasionally, patients may initially agree to NG tube feeding and then refuse the feed in times of psychological distress. In certain cases, there is the need to proceed with NG tube feeding despite active refusal by the patient. For example, NG tube feeding becomes medically necessary when a patient fails to progress medically and psychologically, such that the patient continues to lose weight and his condition decompensates. At the point when patient and provider agree that NG tube feeding is the appropriate course of treatment, it is often useful to obtain consent (and assent in the case of minors) to provide NG tube feeding when medically indicated, undeterred by the patient’s refusal in times of psychological distress.

MAINTAINING WEIGHT GAIN THROUGH HYPERMETABOLIC STATES

NG tube feeding can be an excellent tool for assisting patients in restoring body weight and maintaining weight gain throughout the recovery process. As individuals being treated for anorexia nervosa regain body weight, they often experience an increase in metabolism that requires a significantly greater caloric intake to continue to maintain weight gain and continue to restore body weight (Marzola et al., 2013). Some individuals will need to consume 4000-5000 kcals a day to overcome this increase in metabolic need without losing weight (Mehler, Winkelman, Andersen, and Guadiani, 2010, Marzola et al., 2013). Consuming such a large amount of calories as meals and snacks can be physically uncomfortable and psychologically challenging beyond the patient’s current level of coping. In such cases, NG tube feeding can be used to augment oral feeding. Patients continue to eat meals and snacks during the day, adding calories slowly as they continue to reinforce their skills to manage anxiety and emotional distress, and receive NG tube feeding overnight to meet their increased caloric needs. As the patient adapts, both physically and psychologically, to increased food intake, NG tube feeds can be gradually decreased. Using NG tube feeding in this way helps to normalize eating and limit physical and psychological discomfort while the patient is receiving sufficient calories to continue to progress toward body weight restoration.

POTENTIAL CHALLENGES TO NG TUBE FEEDING

Controversy exists about the use of NG tube feeding in anorexia nervosa. It has been suggested that NG tube feeding only be used when a patient’s mental and physical health and body weight continue to decline despite oral refeeding efforts (Mehler et al., 2010). Some practitioners believe that NG tube feeding addresses the physical requirements for weight restoration without addressing the psychological aspects of the disorder (Zuercher, Cumella, Woods, Eberly, and Carr, 2003). At the same time, many argue that restoration of body weight and healthy nutritional status facilitates psychological recovery through enhanced cognitive function and decreased physical consequences of the disorder (Mehler et al., 2010). Anecdotal clinical data suggests that the opportunity for NG tube feeding may have negative consequences on anorexia nervosa patients. Patients may view NG tubes as a badge of honor, demonstrating that they are more ill than other patients and thus may refuse to comply with oral food intake prescriptions in order to have an NG tube inserted.  Nevertheless, data from research examining the psychological and physical implications of tube feeding in patients struggling with anorexia nervosa have failed to support the hypothesis that NG tube feeding impairs psychological recovery (Zuercher et al., 2003, Nehring, Kewitz, von Kries, and Thyen, 2014).

It is important to note that refeeding patients struggling with AN can be life-threatening. Increasing caloric intake too quickly can lead to refeeding syndrome, marked by hormonal imbalances that, without proper supplementation and monitoring, can lead to heart failure. Refeeding and increasing caloric intake through both oral and NG routes should be approached gradually, monitored closely, and based upon the metabolic need of the patient (Mehler et al., 2010).