Overview
Definition:
Eating disorders (EDs) such as anorexia nervosa (AN), bulimia nervosa (BN), and eating disorder not otherwise specified (EDNOS) are severe psychiatric conditions characterized by disturbed eating behaviors and a distorted body image, leading to significant nutritional deficiencies and physiological consequences, impacting bone health significantly in adolescents.
Epidemiology:
Eating disorders affect approximately 0.5-3% of adolescent girls and 0.1-1% of adolescent boys, with significant overlap in symptoms and impact
Bone density reduction is common, with prevalence rates of osteopenia and osteoporosis reported in 20-60% of adolescents with AN, and significant risk in other EDs.
Clinical Significance:
Adolescence is a critical period for bone accrual, with up to 50% of peak bone mass achieved during these years
Impaired bone health during this time can lead to irreversible deficits, increasing the risk of fractures and osteoporosis later in life
Early identification and intervention are paramount for long-term skeletal integrity and patient well-being, making this a crucial topic for pediatric and adolescent medicine specialists preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Weight loss or failure to gain weight as expected for age and height
Loss of menstrual periods (secondary amenorrhea) or delayed menarche
Fatigue and generalized weakness
Irritability or mood changes
Complaints of bone pain or fractures
Cold intolerance
Constipation or other gastrointestinal complaints
Excessive exercise or caloric restriction
Perfectionistic traits or obsessive thoughts about food/body weight.
Signs:
Low body mass index (BMI) for age
Amenorrhea
Lanugo hair growth
Bradycardia and hypotension
Peripheral edema
Dry, brittle hair and nails
Skin changes (e.g., carotenemia)
Signs of dehydration
Muscle wasting
Diminished secondary sexual characteristics.
Diagnostic Criteria:
Diagnosis relies on clinical assessment based on DSM-5 criteria for specific eating disorders
Bone health assessment is guided by established guidelines for pediatric osteoporosis and osteopenia, typically involving dual-energy X-ray absorptiometry (DXA) if indicated
Key indicators for concern include amenorrhea, significant weight loss, and prolonged nutritional deficiencies.
Diagnostic Approach
History Taking:
Detailed dietary history including restriction patterns, binge-purge behaviors, and compensatory actions
Menstrual history (age of menarche, regularity, duration)
Family history of osteoporosis or eating disorders
Psychosocial history including stressors, body image concerns, and perfectionism
History of prior fractures or bone pain
Medication history (e.g., long-term steroid use)
Assess for signs of malnutrition and electrolyte imbalances.
Physical Examination:
Measure height, weight, and calculate BMI
plot on growth charts
Assess for signs of malnutrition (e.g., lanugo, dry skin)
Palpate for tenderness over bones
Assess for muscle strength and wasting
Perform a cardiovascular examination (check for bradycardia, hypotension)
Examine skin, hair, and nails for signs of nutritional deficiency
Assess for peripheral edema.
Investigations:
Laboratory tests: Complete blood count (CBC) to assess for anemia
Electrolytes, renal function tests (RFTs), and liver function tests (LFTs) to assess for dehydration and organ involvement
Thyroid function tests (TFTs) to rule out thyroid disorders
Vitamin D and calcium levels to assess for deficiencies
Folate and B12 levels
Hormonal evaluation: Estradiol, FSH, LH (especially in amenorrheic patients)
Bone mineral density (BMD) assessment: Dual-energy X-ray absorptiometry (DXA) scan to measure bone mineral content and density, reporting Z-scores for adolescents
Interpretation: Z-scores below -2.0 are suggestive of osteopenia/osteoporosis in this age group.
Differential Diagnosis:
Other causes of amenorrhea (e.g., PCOS, premature ovarian insufficiency)
Other causes of weight loss (e.g., inflammatory bowel disease, malignancy, hyperthyroidism)
Other causes of bone pain or fractures (e.g., genetic bone disorders, rickets, trauma)
Psychiatric disorders with somatic symptoms.
Management
Initial Management:
Multidisciplinary approach involving pediatricians, adolescent medicine specialists, psychiatrists, registered dietitians, and orthopedic specialists
Medical stabilization focusing on correcting malnutrition, electrolyte imbalances, and refeeding syndrome risk
Psychological therapy initiated to address the underlying eating disorder.
Medical Management:
Nutritional rehabilitation: Gradual increase in caloric intake to promote weight restoration and support bone mineralization
Calcium and Vitamin D supplementation: Recommended daily intake for adolescents is 1300 mg calcium and 600 IU Vitamin D
supplementation is crucial given dietary deficits
Doses typically range from 1000-1500 mg elemental calcium and 800-1000 IU Vitamin D daily, adjusted based on serum levels
Bisphosphonates: May be considered in severe cases of osteoporosis or recurrent fractures unresponsive to nutritional therapy, though evidence in adolescents is limited and use is off-label
typically zoledronic acid or alendronate under specialist guidance
Hormonal therapy: Estrogen replacement for prolonged amenorrhea may be considered, but its efficacy in improving bone density in AN is debated and nutritional rehabilitation is primary
Pharmacotherapy for comorbid psychiatric conditions: Antidepressants (SSRIs) for anxiety or depression.
Surgical Management:
Generally not indicated for bone health issues related to eating disorders
Fracture management follows standard orthopedic principles (casting, surgical fixation if required).
Supportive Care:
Close monitoring of weight gain, nutritional status, and bone mineral density
Regular electrolyte and cardiac monitoring
Psychological support and counseling for the adolescent and family
Education on healthy eating patterns and bone health maintenance
Management of comorbidities like anxiety and depression.
Complications
Early Complications:
Refeeding syndrome (electrolyte disturbances, fluid overload, cardiac complications)
Hypoglycemia
Arrhythmias
Seizures
Dehydration
Gastrointestinal distress
Amenorrhea
Osteopenia.
Late Complications:
Osteoporosis
Increased risk of fragility fractures
Long-term skeletal deformities
Infertility
Chronic gastrointestinal dysfunction
Cardiovascular sequelae
Psychological sequelae
Increased mortality.
Prevention Strategies:
Early recognition and intervention for eating disorders
Aggressive nutritional rehabilitation and weight restoration
Adequate calcium and Vitamin D intake during adolescence
Regular monitoring of bone mineral density in at-risk individuals
Addressing psychological factors contributing to bone loss
Prompt management of amenorrhea.
Prognosis
Factors Affecting Prognosis:
Severity and duration of the eating disorder
Degree of nutritional deficit
Presence and severity of amenorrhea
Age of onset and duration of illness
Adequacy of treatment and adherence to nutritional rehabilitation
Presence of comorbid psychiatric conditions
Early intervention leads to better outcomes.
Outcomes:
With comprehensive treatment, many adolescents can achieve weight restoration and resumption of menses, leading to gradual improvement in bone mineral density
However, some degree of irreversible bone loss may occur, especially in cases of prolonged severe illness, increasing long-term fracture risk
Psychological recovery is a significant determinant of overall outcome.
Follow Up:
Long-term follow-up is essential, including regular medical evaluations, nutritional assessments, and monitoring of bone mineral density (e.g., annually or biannually until skeletal maturity and BMD normalization)
Continued psychological support and relapse prevention strategies are crucial.
Key Points
Exam Focus:
Adolescence is a critical period for bone accrual
EDs severely impair this
Amenorrhea in EDs is a key indicator of hypothalamic dysfunction and estrogen deficiency, directly impacting bone
DXA Z-scores below -2.0 are significant in adolescents
Refeeding syndrome is a life-threatening complication requiring careful monitoring
Calcium and Vitamin D supplementation is essential, not optional.
Clinical Pearls:
Always inquire about menstrual history in adolescents with weight concerns or eating pattern disturbances
Consider bone density scans in any adolescent with prolonged amenorrhea ( > 6 months) or significant weight loss due to an ED
Multidisciplinary team care is non-negotiable for optimal outcomes
Educate families on the long-term skeletal consequences of EDs.
Common Mistakes:
Underestimating the severity of bone loss in adolescents with EDs
Focusing solely on weight restoration without addressing psychological aspects
Inadequate calcium and Vitamin D supplementation
Delaying bone density assessment in at-risk individuals
Not anticipating and managing refeeding syndrome.