Michelle Muscat MD MRCS(Ed) MSc, PG Dip, FRCPath, PhD

Band: Superchick

Genre: Alternative pop/rock

Runtime: 4.01 minutes

Released: 2005/2006

 

The American rock band Superchick’s song “Courage” describes the struggle of an individual suffering from an eating disorder. The relevant lyrics of the song are used here as an introduction to a short discussion of some of the biochemical abnormalities which may be found in anorexia nervosa.

The lyrics of the song state:

“I don’t know the first time I felt unbeautiful

 The day I chose not to eat

 What I do know is how I changed my life forever”

 

Eating disorders, anorexia and bulimia, are commoner in females when compared to males, and hence a female vocalist for this song is an apt choice. The song itself seems to focus on the aspect of heighted self-consciousness of body image, physical looks, and fear of gaining weight. Anorexia is a psychological disorder which usually results in a body mass index (BMI) of less than 17.5 kg/m2.

From a more biochemical clinical perspective, in anorexia, there may be low plasma gonadotrophins resulting in amenorrhea, and also high plasma cortisol levels. Patients may also make use of laxatives, and occasionally diuretics. Electrolyte disturbances such as hypokalemia may be seen.  If urine potassium is also measured in a clinical biochemistry laboratory, this can help delineate etiology given urine potassium is diminished when there is laxative misuse and increased should there be vomiting. Acid-base abnormalities may develop. Individuals may exhibit a pseudo-Bartter’s syndrome biochemical pattern with hypokalaemic metabolic alkalosis. In anorexia other biochemical abnormalities may develop. Usually, creatinine and urea levels are on the low side. Patients may also have deficiencies in micronutrients. Hyponatremia may also be encountered and is usually dilutional in nature due to excess water intake. There may be alterations in liver function testing, typically high aminotransferases. Low levels of free thyroid hormones have been described with higher levels of reverse T3.  Hypoglycaemia may be present and abnormalities in lipid profiles have also been documented, with studies having found high levels of total cholesterol. Anorexic patients also have a higher likelihood to develop osteoporosis.

Management is usually in the hands of a multi-disciplinary team comprising amongst others, a psychiatrist and a dietician.  In the very severe cases where artificial nutritional support must be resorted to, close biochemical monitoring is needed to avert the development of refeeding syndrome. If nutrition is introduced too rapidly after prolonged periods of starvation, the patient may develop severe electrolyte abnormalities such as hypophosphatemia, hypokalemia and hypomagnesaemia. From a research-wise biochemical perspective, some studies focused on the correlation of the disorder with a prospective potential biomarker.1-6 One can evaluate biomarkers in eating disorders at the different ends of the spectrum from obesity to anorexia nervosa. Adipocytokines or adipokines are bioactive mediators released by fatty tissue, hence starvation may result in alteration of specific adipocytokine profiles. Further validated, reproducible and robust biochemical markers would have the potential to contribute to assessment and risk stratification.

This review is partially funded through the Endeavour Scholarship Scheme

 

References

  1. Cerasa A, Castiglioni I, Salvatore C, et al. Biomarkers of Eating Disorders Using Support Vector Machine Analysis of Structural Neuroimaging Data: Preliminary Results. Behav Neurol 2015;2015:924814.
  2. Koubaa S, Hallstrom T, Brismar K, et al. Biomarkers of nutrition and stress in pregnant women with a history of eating disorders in relation to head circumference and neurocognitive function of the offspring. BMC Pregnancy Childbirth 2015;15:318.
  3. Alguacil LF, Salas E, Gonzalez-Martin C. Identification of new drug targets and biomarkers related to obesity and eating disorders: an approach based on reward deficit and addiction. Curr Pharm Des 2011;17(5):462-70.
  4. Leoni MC, Pizzo D, Marchi A. Adipocytokines: potential biomarkers for childhood obesity and anorexia nervosa. Minerva Pediatr 2010;62(2):171-8.
  5. Janas-Kozik M, Mazurek U, Krupka-Matuszczyk I, et al. The transcript expression profile of the leptin receptor-coding gene assayed with the oligonucleotide microarray technique–could this be an anorexia nervosa marker? Cell Mol Biol Lett 2006;11(1):62-9.
  6. Yasuhara D, Naruo T, Nagai N, et al. Insulinogenic index at 15 min as a marker of nutritional rehabilitation in anorexia nervosa. Am J Clin Nutr 2003;77(2):292-9.