A TEENAGER WHO WON’T EAT
History
Claire is a 15-year old girl who is urgently referred to the paediatric clinic because of weight loss, nausea and a poor appetite. She is accompanied by her mother and father, who do most of the talking. They were shocked when they took her on holiday 3 weeks ago and they saw how little Claire ate. When they forced her to join them for meals in restaurants, she complained of feeling sick and having no appetite. She has become an increasingly picky eater over the last year or so, first becoming vegetarian and then rarely eating with her parents because mealtimes clashed with her running training. During that time she became the county cross-country running champion, and she trains at least once every day. Her mother thinks she goes to the toilet more often than normal and is worried that she has not menstruated for the last 4 months. Claire has lost a lot of weight and all her clothes from 1 year ago are very loose on her. Claire is quiet while her parents talk, but when asked directly she says that she doesn’t think there is a problem. She says that she has lost some weight over the last year, but that was necessary for her running. She eats when she is hungry and is very careful about her diet because she needs the right foods to optimize her performance. She says that she feels healthier than she ever has, although she admits that her running performance has deteriorated over the last two months. She enjoys her school, works hard and achieves top grades. She says that things are fine at home and that her parents should be proud of her rather than worried. She is quite pleased that she hasn’t menstruated for 4 months as periods are quite a nuisance. She says she is not sexually active and denies any drug use. She is otherwise healthy and just takes laxatives occasionally for constipation. She has a 12-year-old brother whom she likes. Her father manages his own company and her mother is a dance teacher.
Examination
Claire’s weight is 39 kg ( second centile) and her height is 166 cm (75th centile). Her skin is dry and her bones appear very prominent. She has fine downy hair over her face. Her heart rate is 55 beats/min and regular, but otherwise cardiovascular, respiratory, abdominal and ear, nose and throat examinations are normal.
Questions
• What is Claire’s body mass index?
• What is the most likely diagnosis and what questions would help to confirm this?
• What other diagnoses must be considered?
• What physical complications can arise from this condition?
Medicine
Body mass index (BMI) is calculated as weight (kg)/height2 (m2 ). Claire’s BMI is 14.2 kg/m2 . BMI centile charts are available for boys and girls and demonstrate the variation with age. A BMI less than the fifth centile is considered underweight, and Claire falls well below this. The most likely diagnosis is anorexia nervosa. Claire is severely underweight, she exercises excessively, may abuse laxatives, has secondary amenorrhoea and denies the seriousness of the problem. Specific questions about her attitude to her body shape, eating and weight gain should be asked. Symptoms of depression and obsessive compulsive disorder should be sought, as these may coexist with anorexia. Other diagnoses to consider include thyrotoxicosis, inflammatory bowel disease and bulimia nervosa, although none of these would have all of the features described above.
Features of anorexia nervosa and bulimia nervosa
Anorexia nervosa Bulimia nervosa
Body weight well below normal Body weight normal or overweight
Intense fear of weight gain Recurrent binge eating
Abnormal perception of body Abnormal compensatory behaviour
Amenorrhoea Fear of weight gain
Either restriction of intake or
binge eating and purging
Physical complications of anorexia nervosa
• Cardiovascular – bradycardia, hypotension, conduction abnormalities
• Neurological – cognitive impairment, poor concentration
• Renal – fluid and electrolyte abnormalities, pre-renal failure
• Endocrine – amenorrhoea, delayed/arrested puberty, osteoporosis
• Gastrointestinal – abnormal motility and absorption, damage from purgatives
• Haematological – anaemia, thrombocytopenia, leucopenia
• Skin – dry skin, lanugo hair, brittle nails
Management of anorexia nervosa requires specialist expertise and may involve inpatient treatment to establish weight gain and to correct any dangerous metabolic derangements. During re-feeding, life-threatening changes in electrolytes and a cardiomyopathy may develop. Outpatient management tries to address the longer-term issues of abnormal body perception and fear of weight gain.
KEY POINTS
• Anorexia nervosa is characterized by being severely underweight, a fear of weight gain and an abnormal body perception.
• Anorexia nervosa can lead to dangerous physical complications.
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