Anorexia (appetite loss)

Anorexia is a physical symptom also known as appetite loss causing an inability to eat.

Prevalence
The prevalence of anorexia in people with ME/CFS is unknown.

Symptom recognition
Anorexia is recognized as a possible symptom in the Canadian Consensus Criteria for ME, but is not regarded as a diagnostic symptom. 

Possible causes
While ME/CFS can cause significant appetite loss in some people, other ME/CFS symptoms may also cause changes in eating behaviors or significant weight loss include:
 * digestive problems
 * nausea
 * abdominal pain
 * new food or medication sensitivities
 * irritable bowel syndrome is often comorbid with ME/CFS
 * diarrhea
 * gastroparesis can be caused by Ehlers-Danlos syndromes (EDS), and many people with EDS also have ME/CFS
 * mast cell activation syndrome (MCAS) and mast cell activation disorder (MCAD) are not uncommon in people with ME/CFS, and may cause food or medication intolerances, resulting in a person using a restricted diet to reduce symptoms

Severe ME
Severe myalgic encephalomyelitis/chronic fatigue syndrome can also cause
 * dysphagia (swallowing difficulties or an inability to swallow)
 * dysphagia is also found in some people after a stroke, in multiple sclerosis and Parkinson's diseases


 * vomiting, which may be linked to vertigo
 * food intolerances, food or medication intolerances are found in approximately 50% of people with ME/CFS, and may become severe
 * food intolerances may cause a reluctance to eat/swallow in severe cases

Feeding tubes
Some people severely affected by ME/CFS need feeding tubes or artificial nutritional, and may become severely underweight purely as a result of their ME/CFS symptoms, and may starve to death. This is also the case for some people with anorexia or eating disorders.

Merryn Crofts was bedbound and unable to eat when she died of very severe ME. Merryn relied on a feeding tube for nutrition, and weighed just six stone (84 lbs) at her death but she did not have an eating disorder, she had severe gastrointestinal symptoms causing severe weight loss. Merryn's autopsy revealed ganglia inflammation. It is suspected that in the later years of her illness Merryn also suffered from EDS and MCAD. Her death certificate is the second in the UK publicly known to have been attributed to ME.

Misdiagnosis
Swallowing and eating symptoms in ME/CFS can lead to the person becoming severely underweight; this can cause a misdiagnosis of anorexia nervosa or another eating disorder, which may lead to inappropriate treatment.

A number of patient groups have raised concerns that the eating disorders including anorexia nervosa may be incorrectly diagnosed in some patients who actually have weight loss caused by ME/CFS symptoms, particularly in children, young people, and people with severe ME.

Some children with severe ME have been misdiagnosed with Pervasive Refusal Syndrome, based on the assumption that they are refusing to eat, refusing to speak, and refusing to attend school or do normal activities.

Notable studies
There do not appear to be any significant studies assessing swallowing or eating issues in patients with ME/CFS, or investigating the presence of comorbid eating disorders, or the potential misdiagnosing of eating disorders, although there are many different accounts from patients or their carers/parents.

Byron Hyde has started that enteroviruses may disrupt swallowing reflexes in ME/CFS.

See more

 * Digestive system
 * Ehlers-Danlos syndrome
 * Mast cell activation syndrome (MCAS)
 * Mast cell activation disorder (MCAD)
 * Severe and very severe ME
 * Anorexia and eating disorders
 * Psychologization
 * Ethical issues
 * Mental illness
 * Pervasive Refusal Syndrome

Learn more

 * |title=ME - The Illness and Common Misconceptions: Abuse, Neglect, Mental Incapacity. A summary originally produced for the legal profession - The Young ME Sufferer's Trust
 * |title = Knowledge in the Hope of Protecting M.E. Sufferers from Unnecessary Sectioning IN - The Grace Charity for M.E. and The 25% ME Group