31st January 2024

Diagnosis and investigations

For the psychiatrist, the presentation is usually made by encouragement from a concerned family member, who encourages the sick patient to see a GP, who will usually refer to an appropriate secondary mental health team for assessment and management. Onset is typical in adolescence or early adulthood, with later onset quite rare. Usually, it is gradual, following a stressful life event, and onset so insidious it can often be missed for many months. For the physician, presentation is often on the advice of the psychiatrist due to weight loss and the physical health impact of starvation or dehydration, with careful monitoring of bone profile with gradual refeeding to avoid refeeding syndrome. Sometimes, the person will present due to the physical health complications, especially in those who live alone or whose family and friends are in denial, and can present with significant dehydration and acute kidney injury. 

Physical health examinations and investigations inform risk of refeeding syndrome and risk of death in a person suffering from any eating disorder. This can then inform the medical management of the patient and where the patient would be managed, as general inpatient psychiatric units are often ill-equipped to manage physical ill health. These are informed by the Royal College of Psychiatrists “MEED” guidelines, which replaced the “MaRSIpAn” guidance in May 2022. It does not provide a score but a series of red flags, with local teams often having their own set of guidelines on how meeting these will trigger an admission to medical beds. These red flags indicate a serious risk of physical health complications of the eating disorder, including severe malnutrition and risk of refeeding syndrome. 

Physical observation – red flags

It is important to examine for dehydration and severe starvation syndrome, as these are red flags for admission for refeeding within a physical health capacity. 

Dehydration

• Decreased skin tugor
• Dry mucosal membranes
• Sunken eyes

Starvation Syndrome

• Weight loss >1kg over 2 weeks
• BMI<13
• HR <40
• Systolic BP <90 OR postural hypotension with systolic difference >20mmHg
• Temperature <35.5C
• A raised or normal heart rate in the context of other red flags may be falsely reassuring and often a sign of concurrent infection or dehydration. 

Blood tests

• U&Es – hyponatraemia may indicate water loading, where a patient tries to disguise weight loss by drinking large amounts of water prior to their appointments. This can be checked by testing urine osmolality. Hypokalaemia could indicate purging or laxative abuse, and <2.5mmol/L is a red flag. Both can occur in malnutrition. Also, look for acute kidney injury. A normal creatinine might reassure, but note the low muscle mass and low protein intake, a creatinine within reference ranges may be raised for that individual.
• VBG: metabolic acidosis can indicate laxative abuse, whereas alkalosis can indicate vomiting.
• Liver function tests – transanimases are often raised. This is thought to be due to the process of gluconeogenesis, especially from body proteins. Transanimases 3x the baseline is a reg flag. A raised gamma GT could indicate vomiting, as could a raised amylase. 
• Bone profile: Hypomagnesemia is found in malnutrition. Phosphate is key to monitor for refeeding syndrome. A normal phosphate is not necessarily reassuring, as does not indicate body stores. It can suddenly drop without warning, especially in someone who has not eaten for more than 48 hours. 
• Thyroid function tests: hypothyroid picture caused by low iodine diet
• Vitamin D: if low can exacerbate psychological symptoms and give a depressive picture
• Blood glucose: hypoglycaemia usually indicates poor body reserves, a red flag is <3mmol/L
• FBC: WCC can drop, especially neutrophils in starvation. Also to look for anaemia, a Hb <10g/L is a red flag.
• B12, Folate and Ferritin: to investigate the nutritional deficiency that can cause anaemia
• Creatinine Kinase: can sometimes be done to investigate excessive exercise
• HbA1c – useful if a patient had diabetes and omitting insulin. >86mmol/mol is a red flag for admission.

ECG

Often, to investigate bradycardia and inform management, especially looking for a prolonged QTc (450ms in females or 430ms in males, mildly longer is acceptable in under 18s). Might also see ECG changes associated with hypokalaemia. 

Bone density scanning

Bone density scanning is not to be done routinely, as the initial management does not change if osteopenia exists or not. The key message should be that eating healthily and maintaining a healthy BMI is the key to prevent or treat osteopenia. In women, an adolescent (13-18) is underweight for 1 year, or an adult underweight for 2 years (practically, without a period for this time) or they have a history or recurrent fractures of bone pain, then a DEXA scan may be useful, with consideration of oestradiol with cyclic progesterone, or bisphosphonates in adults who have a chronic low body weight, and unrealistic to expect a full recovery to a healthy BMI.

Screening questionnaire

Like most psychiatric conditions, there is a lack of screening questionnaires, severity scores and other useful tools. The only useful screening tool is the SCOFF questionnaire, indicative of Bulimia Nervosa, where the score is >2. Someone with anorexia should also score at least 2, and is recommended for use in screening for anorexia by NICE. However, it has a very low sensitivity. It can be useful to quote in making referrals to psychiatric liaison teams or distinguishing between differentials, but should not be used as a diagnosis or an alternative to a full psychiatric assessment:

Do you make yourself SICK because you feel uncomfortably full?

Do you worry you have lost CONTROL over how much you eat?

Have you lost more than ONE stone in a 3-month period?

Do you believe yourself to be FAT when others say you are too thin?

Would you say that FOOD dominates your life?

References

• World Health Organization (2019). International Statistical Classification of Diseases and Related Health Problems, Chapter 6: Feeding or eating disorders (11th ed.). https://icd.who.int/
• National Institute for Health and Care Excellence (2017). Eating disorders: recognition and treatment. (NICE Guideline number 69). https://www.nice.org.uk/guidance/ng69
• Royal College of Psychiatrists (2022). MEED. Medical Emergencies in Eating Disorders. RCPsych Guideline CR 233
• Morgan JF, Reid F and Lacey JH (1999)). The SCOFF questionnaire: assessment of a new screening tool for eating disorders. BMJ, 219, 1467-8.