Bulimia dan Anoreksia Nervosa
Published on September 11, 2026
Risk Factors
Adolescent females, perfectionistic personality traits, family pressure regarding body image, ballet dancers, models, athletes in weight-class sports
Etiology
Psychopathological distortion of body image leading to deliberate, self-maintained weight loss
Presentation
Severe weight loss (>15% below expected), amenorrhea, refusal to maintain normal weight, denial of illness
Classic Exam
Emaciation, lanugo hair, bradycardia, hypotension, dry skin, hypothermia, delayed puberty if pre-pubertal onset
Diagnostics
BMI , endocrine axis disruption (low LH/FSH, amenorrhea, elevated cortisol, elevated GH), electrolyte abnormalities
Management
Nutritional rehabilitation, psychotherapy (CBT, family-based therapy), correct electrolytes; hospitalize if medically unstable
01Pathophysiology
Anorexia Nervosa
The core psychopathology in anorexia nervosa, as defined in the PPDGJ-III, is a distortion of body image where the patient harbors a persistent, irrational dread of becoming fat. This drives the patient to deliberately reduce and maintain body weight well below a healthy threshold. The weight loss is not passive or accidental; it is actively induced and sustained by the patient through avoidance of calorie-dense foods and one or more compensatory behaviors such as self-induced vomiting, purgative use, excessive exercise, or the use of appetite suppressants and diuretics.
The sustained caloric deficit triggers a cascade of hypothalamic-pituitary-gonadal (HPG) axis suppression. The hypothalamus reduces pulsatile GnRH secretion, leading to low LH and FSH, which in women manifests as amenorrhea and in men as loss of libido and potency. This is a functional, starvation-induced hypogonadism, not a primary gonadal defect. The PPDGJ-III notes one important exception: menstrual bleeding may persist in anorexia patients receiving exogenous hormonal therapy (oral contraceptive pills), so amenorrhea alone is not a reliable screening tool in that population.
Beyond the gonadal axis, chronic starvation leads to elevated cortisol (the body's stress response to energy deprivation), increased growth hormone (a counter-regulatory attempt to mobilize fuel stores), altered peripheral thyroid hormone metabolism (low T3 "euthyroid sick syndrome"), and abnormal insulin secretion. These endocrine derangements explain much of the clinical picture: bradycardia, hypothermia, dry skin, hair loss, and lanugo.
When onset occurs before puberty, the PPDGJ-III highlights that pubertal milestones are delayed or arrested entirely. In girls, breast development stalls and primary amenorrhea occurs. In boys, genital development remains prepubertal. With recovery, puberty resumes, though menarche may be delayed.
Bulimia Nervosa
Bulimia nervosa shares the same underlying psychopathological fear of fatness, but the behavioral pattern is fundamentally different. The PPDGJ-III describes the cardinal feature as a persistent preoccupation with eating accompanied by episodes of irresistible craving (craving) for food. The patient experiences recurrent binge eating episodes, consuming abnormally large quantities of food in a short period while feeling a complete loss of control.
Following the binge, the patient attempts to counteract the expected weight gain through compensatory behaviors: self-induced vomiting, laxative or diuretic abuse, intermittent starvation, or the use of appetite suppressants and thyroid preparations. The PPDGJ-III adds a clinically important note: in patients with diabetes mellitus, the compensatory behavior may take the form of deliberate omission of insulin therapy to prevent caloric assimilation.
The repeated vomiting leads to hypokalemia and metabolic alkalosis (loss of H+ and Cl-), parotid gland hypertrophy from repeated stimulation, and erosion of dental enamel from gastric acid exposure. Laxative abuse instead produces metabolic acidosis with volume depletion.
The PPDGJ-III explicitly notes that a prior episode of anorexia nervosa is often present in the patient's history. The interval between the anorexia episode and bulimia ranges from several months to several years. The prior anorexia episode may have been clinically obvious or may have been "hidden," presenting only as modest weight loss, a transient phase of amenorrhea, or both.
An important distinction the PPDGJ-III makes: bulimia nervosa must be differentiated from depressive disorder, because bulimic patients frequently exhibit comorbid depressive symptoms. The test-writer may present a patient with binge-purge behavior and prominent sadness to see if you correctly identify bulimia as the primary diagnosis rather than depression with eating changes.
02Classification and Clinical Manifestation
PPDGJ-III Classification of Eating Disorders
Diagnosis | Key Features |
|---|---|
Anorexia Nervosa | All criteria met: BMI or weight 15% below expected, self-induced weight loss, body-image distortion, endocrine disorder, pubertal delay if pre-pubertal onset |
Atypical Anorexia Nervosa | One or more key features of anorexia nervosa are absent (e.g., amenorrhea or significant weight loss is missing), but overall clinical picture is still suggestive. Also includes patients who have all key symptoms but at a mild degree |
Bulimia Nervosa | All criteria met: preoccupation with food and irresistible craving, binge episodes, compensatory purging behaviors, morbid fear of fatness with self-imposed weight threshold, often prior anorexia episode |
Atypical Bulimia Nervosa | One or more key features of bulimia nervosa are absent, but clinical picture is still recognizable. Commonly applies to patients with normal or above-normal body weight who have typical binge-purge periods followed by vomiting or laxative use |
Clinical Manifestation
Feature | Anorexia Nervosa | Bulimia Nervosa |
|---|---|---|
Body weight | Severely underweight (BMI ) | Usually normal or near-normal |
Eating pattern | Restrictive avoidance of calorie-dense foods | Binge eating episodes with loss of control |
Compensatory behavior | Vomiting, laxatives, excessive exercise, appetite suppressants, diuretics | Vomiting, laxatives, fasting periods, appetite suppressants, thyroid drugs, insulin omission (diabetics) |
Body image | Distorted; sees self as fat despite emaciation | Fear of fatness with strict self-imposed weight ceiling |
Menstrual status | Amenorrhea (unless on hormonal therapy) | Often preserved, though may be irregular |
Endocrine disruption | Widespread HPG axis, cortisol, GH, thyroid, insulin | Less prominent; typically not a diagnostic criterion |
Mood | May have flat affect, social withdrawal | Frequently comorbid depressive symptoms |
Insight | Poor; denies illness | Often has shame and guilt; may seek help |
Relationship to prior eating disorder | Primary presentation | Often preceded by an anorexia nervosa episode |
03Diagnostic Workup
Test | Anorexia Nervosa | Bulimia Nervosa |
|---|---|---|
Best Initial Test | BMI calculation () and clinical history of deliberate weight loss | Clinical history of recurrent binge-purge episodes with fear of fatness |
Confirmatory Approach | Fulfillment of all PPDGJ-III criteria (weight, behavior, body-image distortion, endocrine disorder, pubertal status) | Fulfillment of all PPDGJ-III criteria (preoccupation, binge episodes, compensatory behaviors, psychopathology) |
Key Labs | Electrolytes (hypokalemia, hypophosphatemia), CBC (leukopenia), LH/FSH (low), cortisol (elevated), TFTs (low T3), glucose (low), albumin | Electrolytes (hypokalemia, hypochloremia), serum amylase (elevated from parotid), BUN (elevated if dehydrated), blood gas (metabolic alkalosis or acidosis) |
Supporting Studies | ECG (bradycardia, QT prolongation), DEXA scan (osteoporosis in chronic cases) | ECG (arrhythmia risk from hypokalemia), dental examination (enamel erosion) |
For anorexia nervosa, the PPDGJ-III requires that the diagnosis not be made casually. The guideline states that for a definite diagnosis, all five criteria (a through e) must be present. The initial step is calculating the BMI. A value of 17.5 or lower is the quantitative threshold established in the guideline. In pre-pubertal patients who have not yet reached their expected growth trajectory, the equivalent criterion is a failure to achieve expected weight gain during the growth period, rather than a percentage loss from a prior baseline.
Next, you must establish that the weight loss is self-induced. The vignette will typically describe dietary restriction of fatty or calorie-dense foods combined with at least one additional behavior (vomiting, purgative use, excessive exercise, or pharmacological suppression of appetite). The critical point is that the weight loss is intentional and maintained by the patient, not due to an organic cause.
Body-image distortion is the psychopathological hallmark. Look for statements in the vignette such as "the patient believes she is overweight despite being underweight" or "expresses intense fear of gaining weight." The PPDGJ-III phrases this as an "overvalued dread of fatness."
The endocrine workup is confirmatory. Expect to see low gonadotropins (LH, FSH), amenorrhea, elevated cortisol, elevated growth hormone, low T3, and abnormal insulin secretion. These findings are secondary to the starvation state and are expected to normalize with weight restoration.
For bulimia nervosa, diagnosis is primarily clinical. The PPDGJ-III requires documentation of (a) persistent food preoccupation with uncontrollable craving and binge episodes, (b) compensatory anti-fattening behaviors, and (c) the characteristic psychopathology of fat-phobia with a self-imposed weight ceiling. Laboratory findings support the diagnosis but do not define it. Hypokalemia is the most high-yield lab abnormality to recognize. An elevated serum amylase (from parotid hypertrophy, not pancreatitis) is a classic clue in a vignette. Blood gas analysis helps distinguish the type of purging: vomiting produces metabolic alkalosis, while laxative abuse produces metabolic acidosis.
The PPDGJ-III makes the important point that a prior episode of anorexia nervosa frequently exists in the history. The test-writer may include this as a timeline detail to help you confirm bulimia over other differentials.
Differential Diagnoses per PPDGJ-III
Differential | Description |
|---|---|
Organic loss of appetite | Loss of appetite due to a medical condition (e.g., malignancy, chronic infection, GI disease). The key difference is the absence of body-image distortion and deliberate weight-loss behaviors. |
Psychogenic loss of appetite | Appetite loss driven by psychological factors other than body-image distortion (e.g., depression, grief, adjustment disorder). The patient does not fear becoming fat and does not engage in purging behaviors. |
For bulimia nervosa, the PPDGJ-III explicitly flags depressive disorder as the primary differential, since bulimic patients frequently have comorbid depressive symptoms.
04Management and Treatment
Phase | Anorexia Nervosa | Bulimia Nervosa |
|---|---|---|
Acute Stabilization | Medical stabilization (correct electrolytes, cardiac monitoring), nutritional rehabilitation with gradual caloric increase to prevent refeeding syndrome | Interrupt the binge-purge cycle, correct electrolyte derangements (especially potassium), assess for suicidality |
First-Line Psychotherapy | Family-Based Treatment (FBT/Maudsley) for adolescents; CBT or psychodynamic therapy for adults | Cognitive-Behavioral Therapy (CBT) is the gold standard; structured eating plan with meal normalization |
Pharmacotherapy | No first-line medication for weight restoration; SSRIs may be used for comorbid depression/anxiety after weight is partially restored | Fluoxetine 60 mg/day is the only FDA-approved medication; higher dose than typical antidepressant dosing |
Long-Term | Weight restoration to goal BMI, relapse prevention, monitoring of bone density, endocrine normalization | Relapse prevention through ongoing CBT, maintenance fluoxetine if effective, nutritional counseling |
Anorexia Nervosa
Step 1: Assess medical stability. The first priority is determining whether the patient requires inpatient admission. Indications for hospitalization include BMI below 15, heart rate below 40 bpm, systolic blood pressure below 90 mmHg, significant electrolyte disturbances (especially hypokalemia and hypophosphatemia), or active suicidal ideation.
Step 2: Nutritional rehabilitation. Begin refeeding cautiously, typically starting at 1000 to 1200 kcal/day and increasing by 200 kcal every 2 to 3 days. The critical danger during this phase is refeeding syndrome, which results from rapid insulin-mediated cellular uptake of phosphate, potassium, and magnesium when carbohydrate intake resumes after prolonged starvation. Monitor serum phosphate, potassium, and magnesium daily during the first 1 to 2 weeks. Supplement phosphate prophylactically if levels trend downward.
Step 3: Psychotherapy. For adolescent patients, Family-Based Treatment (FBT), also known as the Maudsley approach, is the most evidence-supported intervention. Parents are empowered to take control of the patient's nutrition in Phase 1, then gradually return autonomy to the adolescent as weight is restored. For adults, CBT addressing body-image distortion and maladaptive eating behaviors is the primary approach.
Step 4: Pharmacotherapy. There is no medication proven to induce weight gain in anorexia nervosa. Do not start SSRIs in the acutely malnourished patient, as serotonergic medications are less effective (and potentially more harmful) in the setting of nutritional depletion. Once partial weight restoration has occurred, fluoxetine or other SSRIs may be considered for comorbid anxiety or depressive symptoms, or for relapse prevention.
Step 5: Endocrine monitoring. Expect amenorrhea to resolve with weight restoration. Do not prescribe estrogen replacement solely to restore menses, as this does not address the underlying hypothalamic suppression. Monitor bone density with DEXA in patients with prolonged amenorrhea (greater than 6 to 12 months), as osteoporosis is a significant long-term complication.
Bulimia Nervosa
Step 1: Interrupt the binge-purge cycle. The immediate goal is breaking the behavioral loop. Structured meal planning with regular meals and snacks (typically 3 meals and 2 to 3 snacks daily) reduces the physiological hunger that triggers binges.
Step 2: Correct electrolyte abnormalities. Potassium replacement is often necessary. Oral supplementation (20 to 40 mEq KCl daily) is usually sufficient unless the patient is severely hypokalemic (below 3.0 mEq/L) or symptomatic, in which case intravenous replacement with cardiac monitoring is indicated.
Step 3: CBT. Cognitive-Behavioral Therapy is the first-line treatment for bulimia nervosa and has the strongest evidence base. A standard course involves 16 to 20 sessions over 4 to 5 months. The therapy targets the cognitive distortions around body shape, the behavioral pattern of dietary restriction leading to binge episodes, and the use of compensatory purging.
Step 4: Pharmacotherapy. Fluoxetine at 60 mg/day is the recommended pharmacological agent. This dose is notably higher than the 20 mg/day used for depression. It reduces binge frequency and purging behavior independent of its antidepressant effect. If fluoxetine is not tolerated, other SSRIs may be tried, though evidence is strongest for fluoxetine. Bupropion is contraindicated in bulimia nervosa due to an increased risk of seizures in purging patients.
Step 5: Monitor for complications. Regular dental examinations are important for patients with chronic vomiting. Esophageal tears (Mallory-Weiss) and, rarely, esophageal rupture (Boerhaave syndrome) are life-threatening complications of forceful vomiting.
05Differential Diagnosis and Distractors
Differential | Why It Is Similar | Key Discriminator |
|---|---|---|
Major Depressive Disorder | Both can present with weight loss, decreased appetite, and social withdrawal | In depression, there is no body-image distortion or fear of fatness. The patient does not deliberately restrict food intake or engage in purging. Weight loss is passive, driven by anhedonia and loss of appetite. |
Bulimia Nervosa (when differentiating from anorexia) | Both involve fear of fatness and compensatory behaviors (vomiting, laxatives) | In anorexia, the patient is significantly underweight (BMI ). In bulimia, weight is usually normal or near-normal. Bulimia is defined by the binge-purge cycle, while anorexia is defined by sustained restriction and low weight. |
Organic causes of weight loss (malignancy, hyperthyroidism, Crohn disease, celiac disease) | Weight loss, fatigue, and nutritional deficiency overlap with anorexia nervosa | In organic disease, there is no deliberate food avoidance driven by body-image distortion. The patient typically wants to eat but cannot (or loses weight despite eating). Lab and imaging findings point to the underlying medical cause. |
Psychogenic loss of appetite | Reduced food intake due to psychological distress | The underlying driver is emotional distress (grief, adjustment, anxiety), not a distorted perception of body weight. The patient does not express fear of becoming fat and does not purge. |
Binge Eating Disorder | Recurrent episodes of binge eating similar to bulimia nervosa | In binge eating disorder, there are no regular compensatory behaviors (no purging, no laxative abuse, no fasting). Patients are frequently overweight or obese. |
Depressive disorder with bulimic features (PPDGJ-III flagged differential) | Bulimic patients often have depressive symptoms; depressed patients may overeat | In bulimia, the binge-purge cycle with fear of fatness is the primary psychopathology, and depression is secondary. In primary depression, mood disturbance dominates, and overeating (if present) is not followed by systematic compensatory purging. |
06Traps and High-Yield Pearls
The most common way students lose points on eating disorder questions is by confusing the weight criterion. The PPDGJ-III draws a hard line: anorexia nervosa requires the patient to be significantly underweight (BMI or weight 15% below expected). If the vignette describes a patient with binge-purge behavior but a normal BMI, the answer is bulimia nervosa, not anorexia. Many students default to "anorexia" whenever they see vomiting or food restriction, but the weight status is the decisive discriminator.
A second frequent trap involves the endocrine findings. Students may see amenorrhea, elevated cortisol, and low T3 in a vignette and be tempted to pursue an endocrine workup for Cushing syndrome or hypothyroidism. The key is recognizing that these hormonal derangements in the context of severe underweight and deliberate food restriction are secondary to the starvation state, not primary endocrine disease. They resolve with nutritional rehabilitation.
Third, the PPDGJ-III explicitly states that a prior anorexia nervosa episode is commonly part of the history in bulimia patients. If the vignette includes a timeline where the patient was severely underweight years ago and now presents at normal weight with binge-purge behavior, this historical detail confirms bulimia nervosa and should not confuse you into choosing anorexia.
Fourth, watch for the bupropion contraindication. A vignette may describe a bulimic patient with comorbid depression and ask about appropriate pharmacotherapy. Bupropion lowers the seizure threshold and is contraindicated in patients who purge. The correct answer is fluoxetine at 60 mg/day.
Finally, in the PPDGJ-III framework, atypical variants exist for both disorders. If a vignette describes a patient who meets most but not all criteria (e.g., all features of anorexia but menstruation is preserved, or all features of bulimia but binge episodes are infrequent), the correct classification is the atypical form. Do not dismiss the diagnosis entirely just because one criterion is absent; the PPDGJ-III accommodates partial presentations through the atypical categories.
The core competency being tested is your ability to (1) distinguish anorexia from bulimia based on weight and behavioral pattern, (2) recognize that endocrine abnormalities in anorexia are secondary and reversible, and (3) select the correct first-line therapy for each condition (FBT/nutritional rehabilitation for anorexia, CBT plus fluoxetine 60 mg for bulimia).