11.9 Eating Disorders, Sleep Disorders & Sexual Health

1. Anorexia Nervosa

Restriction of energy intake leading to significantly low body weight, with intense fear of weight gain and disturbance in the experience of body weight or shape. Two subtypes: restricting and binge-eating/purging.

Anorexia nervosa has the highest mortality rate of any psychiatric disorder except opioid use disorder, from cardiac complications and from suicide.

Medical complications by system

Bradycardia in a young woman with low body weight is a warning sign, not athletic conditioning. Severe bradycardia, hypotension, orthostasis, hypothermia, electrolyte disturbance, arrhythmia and very low weight are indications for inpatient medical stabilization.

Osteoporosis in anorexia nervosa is not treated primarily with bisphosphonates. The effective intervention is weight restoration and resumption of menses. Oral contraceptives do not improve bone density in this population and can mask the return of spontaneous menstruation, which is an important marker of recovery.

Refeeding syndrome

The acute hazard of treatment. As carbohydrate is reintroduced, insulin drives phosphate, potassium and magnesium intracellularly in a patient whose total body stores are already depleted.

• Hypophosphatemia is the hallmark, and can cause rhabdomyolysis, hemolysis, respiratory muscle failure, arrhythmia, seizures and death
• Also hypokalemia, hypomagnesemia, thiamine deficiency and fluid overload
• Typically occurs within the first several days of refeeding

Prevention: start at a conservative caloric level and advance gradually, give thiamine before feeding, and monitor and replete phosphate, potassium and magnesium daily during the initial period. The exam answer to how do you avoid killing this patient is nearly always start low, go slow, replete electrolytes and give thiamine.

2. Bulimia Nervosa and Binge-Eating Disorder

Bulimia nervosa: recurrent binge eating with compensatory behaviors — vomiting, laxatives, diuretics, fasting, excessive exercise — with weight typically normal or above normal, which is why it is missed.

Physical clues: parotid enlargement, dental enamel erosion on the lingual surfaces, Russell sign (calluses on the dorsum of the hand from self-induced vomiting), and menstrual irregularity.

Laboratory signature of purging: hypokalemic, hypochloremic metabolic alkalosis from vomiting, and a low urine chloride. Laxative abuse instead produces a non-anion-gap metabolic acidosis with hypokalemia.

Treatment: cognitive behavioral therapy is first-line; fluoxetine is the only antidepressant approved for bulimia and is used at higher doses than for depression. Bupropion is contraindicated in eating disorders with purging because of an increased seizure risk.

Binge-eating disorder involves binges without compensatory behavior, and is the most common eating disorder. Treatment is cognitive behavioral therapy, with lisdexamfetamine and some antidepressants as options.

Screening question worth knowing: the SCOFF questionnaire is a brief validated screen usable in primary care.

3. Insomnia

Chronic insomnia is difficulty initiating or maintaining sleep with daytime consequences, occurring at least three nights weekly for at least three months.

Evaluate for secondary causes first: obstructive sleep apnea, restless legs syndrome, depression and anxiety, chronic pain, nocturia, gastroesophageal reflux, and medications and substances — caffeine, alcohol (which fragments sleep despite hastening onset), stimulants, corticosteroids, beta-blockers, decongestants.

Cognitive behavioral therapy for insomnia (CBT-I) is first-line and is superior to hypnotics for durable benefit. Its components:

1. Stimulus control — bed only for sleep and sex; leave the bed if awake beyond about 20 minutes
2. Sleep restriction — compress time in bed to actual sleep time, then extend as efficiency improves
3. Sleep hygiene — consistent wake time, dark cool room, no screens, no clock-watching
4. Cognitive restructuring of catastrophic beliefs about sleep
5. Relaxation training

Pharmacotherapy is adjunctive and short-term. Benzodiazepines and Z-drugs (zolpidem, eszopiclone) cause tolerance, dependence, next-day impairment, complex sleep behaviors and falls and fractures in older adults — both classes appear on the Beers Criteria. Diphenhydramine and other anticholinergic sleep aids should be avoided in older adults. Melatonin receptor agonists and orexin receptor antagonists are alternatives.

4. Narcolepsy and Other Sleep Disorders

Narcolepsy results from loss of hypothalamic hypocretin (orexin) neurons.

The tetrad:

1. Excessive daytime sleepiness — universal; irresistible sleep attacks
2. Cataplexy — sudden bilateral loss of muscle tone triggered by emotion, especially laughter, with preserved consciousness. Pathognomonic when present, and defines type 1
3. Sleep paralysis
4. Hypnagogic or hypnopompic hallucinations

Diagnosis: overnight polysomnography (to exclude sleep apnea and confirm adequate sleep) followed by a multiple sleep latency test showing short mean sleep latency and two or more sleep-onset REM periods. Low cerebrospinal fluid hypocretin confirms type 1.

Treatment: scheduled naps and sleep hygiene, wake-promoting agents (modafinil, armodafinil, solriamfetol, pitolisant), stimulants, and sodium oxybate for cataplexy and disrupted nocturnal sleep. Cataplexy also responds to serotonergic and noradrenergic antidepressants, and abrupt withdrawal of these can cause status cataplecticus.

Other parasomnias worth recognizing:

• REM sleep behavior disorder — dream enactment with loss of normal REM atonia. A strong predictor of future alpha-synucleinopathy (Parkinson disease, Lewy body dementia, multiple system atrophy). Treated with melatonin or clonazepam and by making the sleep environment safe.
• Restless legs syndrome — urge to move with unpleasant sensations, worse at rest and in the evening, relieved by movement. Check ferritin and supplement iron if it is low; also associated with pregnancy, kidney disease and dopamine antagonists. Alpha-2-delta ligands are now preferred over dopamine agonists because of augmentation.

5. Sexual Disorders and Gender Dysphoria

A named blueprint subsection. The internist role is recognizing medical and pharmacologic contributors, providing non-judgmental care, and knowing the basic principles of gender-affirming care.

Sexual dysfunction

Common medical and pharmacologic contributors:

Antidepressant-associated sexual dysfunction is common, is a leading cause of non-adherence, and is frequently not volunteered. Strategies include dose reduction, switching to bupropion or mirtazapine, or adding bupropion.

In women, evaluate for genitourinary syndrome of menopause, which causes dyspareunia from vulvovaginal atrophy and responds well to low-dose vaginal estrogen — a treatment with minimal systemic absorption that is appropriate even for many women in whom systemic hormone therapy is not.

In men, see the discussion of erectile dysfunction; the key safety point is that phosphodiesterase-5 inhibitors are absolutely contraindicated with nitrates.

Gender dysphoria and gender-affirming care

Gender dysphoria is clinically significant distress associated with incongruence between experienced gender and sex assigned at birth. Being transgender is not itself a mental disorder; the diagnosis describes distress, and many transgender people do not have it.

Principles of respectful care, which are themselves testable:

• Use the patient's stated name and pronouns consistently across the record and the team
• Take an organ inventory rather than assuming anatomy from gender identity
• Screen based on the organs present, not on gender marker: a transgender man who retains a cervix needs cervical cancer screening; a transgender woman who retains a prostate is subject to prostate-related considerations
• Ask about hormone therapy and surgical history when clinically relevant, not out of curiosity

Medical aspects of hormone therapy the internist should know:

• Feminizing therapy (estrogen with an antiandrogen such as spironolactone): monitor for venous thromboembolism — risk is highest with ethinyl estradiol and with smoking — hypertriglyceridemia, hyperkalemia from spironolactone, and prolactin elevation.
• Masculinizing therapy (testosterone): monitor hematocrit for erythrocytosis, lipids, blood pressure, and hepatic enzymes. Testosterone is not a contraceptive, and pregnancy remains possible in a patient with a uterus and ovaries.
• Laboratory reference ranges should be interpreted according to the hormonal milieu and organ inventory; creatinine and hemoglobin ranges in particular shift with sustained hormone therapy.

Health disparities in transgender populations — higher rates of depression, suicidality, HIV, substance use, and avoidance of care because of prior discriminatory experiences — are recognized targets of the health equity content that ABIM has stated will appear in its assessments.