MED-NERD
Bulimia nervosa (BN)
Outline :
- Overview
- Key facts
- Incidence
- Aetiology and predisposing factors
- Diagnostic criteria
- Classification of bulimia nervosa
- Complications
- Investigations
- Differential diagnosis
- Treatment and management
- Prognosis and mortality rate
- Conclusion
- References
Overview :
Relatively, eating disorders including anorexia nervosa and bulimia nervosa (BN) are rare in the community as people delay seeking help due to denial, shame, and stigma.
Bulimia nervosa is an eating disorder characterized by recurrent episodes of binging behaviour (loss of control while eating large quantities of food) followed by compensatory behaviour (self-induced vomiting, fasting, exercise, withholding insulin "known as diabulimia or eating-disorder diabetes mellitus type-1", abuse caffeine and medications of attention-deficit/hyperactivity disorder, and misuse of diuretics or laxatives) in order to prevent weight gain and for shape concerns.
Key facts:
- Gerald Russel was the first one who described bulimia nervosa in 1979 .
- Detection and diagnosis of bulimia nervosa is difficult as most patients are young of normal weight or overweight.
- Bulimia nervosa affects both sexes but occurs more in females.
- More than 90% of purging behaviour are self-induced vomiting and laxative misuse.
- Common causes of morbidity and mortality in bulimia nervosa are electrolyte imbalance and metabolic disturbances .
- Common complaints of bulimia nervosa are gastrointestinal complaints including gastroesophageal reflux disease (GERD).
- Diabetic patients with manipulation of their blood glucose level are more prone to hyperglycaemia, ketoacidosis, and premature microvascular complications.
Incidence :
-Bulimia nervosa mainly affects adolescents and young adults in both males and females.
-About 3% females and more than 1% males suffer from bulimia nervosa in their lives .
-The peak incidence is the age ranging between 15 and 29 years .
-12.4 years old is the median age of onset of bulimia nervosa.
-About 1-3% of adolescents fulfill the diagnostic criteria for bulimia nervosa.
-Nearly 2-3% of adolescents may be subclinical cases of bulimia nervosa .
-Patients with bulimia nervosa are generally within the normal weight range or above that.
-Recently , there has been a decrease in the incidence of bulimia nervosa over time .
-Different diagnostic criteria, increased awareness leading to earlier detection, availability of treatment facilities could be causes for different rates over time .
Aetiology and predisposing factors :
-Abnormalities in interoceptive functions of insula, alterations in white matter structure, altered intrinsic functional brain architecture , and changes in the connections within appetite regulating centres may cause the binging behaviour of bulimia nervosa .
-Genetic, environmental, neurobiological, psychosocial, temperamental factors may be predisposing factors for bulimia nervosa.
-Impulsivity, puberty, weight and shape concerns, history of childhood trauma, physical, emotional, and sexual traumas may be associated with bulimia nervosa .
-Moreover, about 70% of patients with psychiatric comorbidities, substance abuse, anxiety, affective disorders, personality disorders are associated with eating disorders commonly, bulimia nervosa.
Diagnostic criteria :
-The fifth edition of the Diagnostic and Statistical Manual for Mental Disorders (DSM-5) declares that episodes of binge eating and compensatory behaviour must occur at a minimum frequency of once per week over the course of three months and not occur during episodes of anorexia nervosa.
-Binge eating occurs in a short period of time usually 2-hour period or less with loss of control.
-Binging behaviour is followed by compensatory behaviour to prevent weight gain including : self-induced vomiting, laxative or diuretics abuse, fasting, severe physical activity.
Classification of bulimia nervosa:
Bulimia nervosa is classified according to the severity of the condition which is determined by the frequency of purging behaviour as the following :
- Mild : an average of 1–3 episodes of inappropriate compensatory behaviours per week.
- Moderate: an average 4-7 episodes of purging behaviour weekly.
- Severe: an average 8-13 episodes .
- Extreme: 14 episodes or more .
Complications of bulimia nervosa :
1-skin:
Russel sign : Development of calluses on the dorsal aspect of the dominant hand.
Caused by : Repeated insertion of hand into the mouth to induce vomiting causes traumatic irritation of the hand by teeth.
*Indicate: self-induced vomiting .
2-Oral complications:
-Dental erosions (perimyolysis) and dental caries : The most common irreversible oral sign or chronic regurgitation. It affects the lingual surface of maxillary teeth.
Caused by: Contact between teeth and acidic vomitus (pH 3.8), changes in salivary composition, and changes in dietary intake.
-Trauma to oral mucosa, pharynx, and soft palate:
Caused by: Insertion of foreign body into the mouth to induce vomiting or the acidic effect of vomitus on the mucosa.
3- Subconjunctival haemorrhage and recurrent epistaxis: caused by forceful vomiting.
4-Pharyngitis, Hoarseness, cough, and dysphagia: Caused by acidic vomitus affecting pharyngeal mucosa.
5-Parotid gland hypertrophy (sialadenosis): Occurs in more than 50% of patients via self-induced vomiting. It manifests as bilateral painless enlargement of parotid gland involving other salivary glands as well.
Caused by: Cholinergic stimulation of the gland to increase the saliva production as demanded leading to hypertrophy of the gland.
6-Cardiac complications:
Caused by: Electrolyte disturbances especially hypokalaemia and acid-base disorder as a result of purging behaviour
Cardiac complications include arrhythmias, QT prolongation, and may lead to irreversible cardiomyopathy.
7-Pneumomediastinum:
Caused by: Self-induced vomiting increasing intrathoracic and intra-alveolar pressures and may be due to malnutrition.
8-Aspiration pneumonia: Due to pulmonary infection with Mycobacterium avium complex organisms.
9-Gastroesophageal reflux disease, Barrett oesophagus and oesophageal adenocarcinoma:
Caused by: Forceful vomiting leading to contact of gastric acid with oesophageal mucosa and damaging lower oesophageal sphincter.
Other rare complications are oesophageal rupture, known as Boerhaave syndrome, and Mallory-Weiss tears that presents as scant coffee ground emesis following recurrent episodes of vomiting .
10-Colonic inertia:
Caused by: Excessive laxative abuse and direct damage to myenteric nerve plexus of the gut. The colon becomes unable to move the stool forward.
11-Melanosis coli: It is black discoloration of the colon noticed during colonoscopy.
12-Irritable bowel syndrome (IBS): With prevalence of about 62% of patient with bulimia nervosa.
13-Achalasia - the inability of lower oesophageal muscles to relax
-Oesophageal spasm - irregular contractility of oesophageal muscles
14-Constipation and rectal prolapse : Cased by chronic abuse of laxatives leading to cathartic colon syndrome.
15-Endocrine complications such as irregular menses.
Investigations :
• Electrolytes, liver function tests, blood urea nitrogen, serum creatinine, and calcium level detection.
• Complete blood count and obtaining a vitamin B12 level.
• Urinalysis.
• Serum magnesium and phosphorous as well as the electrocardiogram in severe cases.
• Pregnancy test in female patients. In case of secondary amenorrhea in female patients, they should be tested for luteinizing hormone, beta-HCG, prolactin, and a follicle-stimulating hormone .
• Lab tests to detect stool or urine bisacodyl, aloe-emodin, emodin, and rhein although positive test does not necessary confirm the diagnosis.
Differential diagnosis:
• Biliary disease : It will frequently present with abnormal transaminases or bilirubin on a comprehensive metabolic profile.
• Irritable bowel syndrome: can increase the frequency of bowel movements but is usually not associated with episodes of binge eating.
• Neurological conditions, : Neurological examination to rule out a neurological origin for vomiting.
• Prader-Willi syndrome-: It is a genetic disorder presents with hyperphagia and obesity, mental disability and hypogonadism, angry outbursts, and oppositional behaviour. Compensatory purging behaviour is typically absent.
• Klein-Levin syndrome: A a disorder that primarily affects adolescent males and also causes increased appetite, hypersomnia, and behavioural disturbances. Compensatory purging behaviour is absent.
• Diabetes mellitus: A common cause of polyphagia. Blood glucose level should be checked.
• Anorexia nervosa: An important distinction is that a diagnosis of anorexia nervosa requires low body weight; BMI<18, whereas this is not a diagnostic criterion for bulimia nervosa.
• Binge eating disorder: It is also characterized by episodes of binge eating. These patients do not limit their dietary intake in-between the episodes.
• Major depressive disorder: May also present with episodes of overeating and with suicidal ideations but, , does not feature the inappropriate compensatory purging behaviour of bulimia nervosa.
See: Violence, Stress, and their relation to COVID-19
Treatment and management:
- The main aim of treatment is a cessation of the binging and purging behaviour.
- Selective serotonin reuptake inhibitors (SSRI) such as fluoxetine, citalopram, and sertraline may be used to reduce the symptoms of bulimia nervosa.
- The only medication approved by FDA is fluoxetine better in decreasing the frequency of vomiting episodes and binging.
- Monoamine oxidase inhibitors and tricyclic antidepressants are used in resistant cases due to their lethality and potential side effects.
- Saline administration for treatment of metabolic alkalosis and dehydration.
- Treatment of constipation include : adequate hydration, dietary fibre intake, and exercise.
- Patients with cardiac complications and severe electrolyte disturbance should obtain cardiology consultation.
- Antiepileptics such as topiramate may reduce binging episodes and should be used carefully due to their side effects especially weight loss and cognitive problems.
- A large number of randomized controlled trials (RCTs) testing psychotherapy, pharmacotherapy, or their combination, have shown the efficacy of cognitive-behavioural therapy (CBT) as compared with other active treatments.
- Increased risk of suicide is one of the associated problems using SSRI in adolescents and adults so patients must be monitored closely and doses must be prescribed carefully.
Prognosis and mortality rate:
-Must patients diagnosed having bulimia nervosa recover from the condition.
-The five-year remission rate is about 74%.
-About 47% of patients relapse within 5 years .
-Nearly, 33% of patients with bulimia nervosa experience non-suicidal self-harm.
-Bulimia nervosa patients are 8 times more likely to commit suicide compared to the general population.
-Mortality rates in bulimia nervosa elevate range from 1.5% to 2.5%.
Conclusion:
Eating disorders including bulimia nervosa generally affect young population mainly females. Bulimia nervosa can lead to serious complications, including metabolic alkalosis, dehydration, constipation, and cardiac arrhythmias. Psychotherapy, cognitive behavioural therapy in addition to pharmacotherapy can be used in treatment of bulimia nervosa. Improved awareness can help in earlier detection and treatment in groups that suffer from eating and psychiatric disorders.
See: Violence, Stress, and their relation to COVID-19
References:
(1) van Eeden AE, van Hoeken D, Hoek HW. Incidence, prevalence and mortality of anorexia nervosa and bulimia nervosa. Curr Opin Psychiatry. 2021 Nov 1; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8500372/
(2) Gorrell S, Le Grange D. Update on Treatments for Adolescent Bulimia Nervosa. Child Adolesc Psychiatr Clin N Am. 2019 Oct;.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6709693/#!po=6.25000
(3)Nitsch A, Dlugosz H, Gibson D, Mehler PS. Medical complications of bulimia nervosa. Cleve Clin J Med. 2021 Jun 2;
https://www.ccjm.org/content/88/6/333.long
(4)
https://www.ncbi.nlm.nih.gov/books/NBK562178/#!po=7.81250
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