What is the recommended workup for a patient presenting with loss of appetite?

Recommended Workup for Loss of Appetite

The recommended workup for a patient presenting with loss of appetite should include assessment of weight and height history, comprehensive review of systems, physical examination with vital signs, complete blood count, comprehensive metabolic panel, and screening for eating disorders, with additional targeted testing based on clinical suspicion. 1

Initial Assessment

History Taking

• Weight history assessment:
  • Document recent weight changes (percentage and timeframe)
  • Maximum and minimum weight
  • Pattern of weight loss (intentional vs. unintentional) 1
• Eating pattern evaluation:
  • Quantify food intake reduction (percentage of normal intake)
  • Duration of appetite changes
  • Presence of food avoidance or restrictive eating
  • Changes in food repertoire or elimination of food groups 1, 2
• Associated symptoms:
  • Gastrointestinal symptoms (nausea, vomiting, early satiety, dysphagia)
  • Psychological symptoms (depression, anxiety, body image concerns)
  • Pain, fatigue, or other systemic symptoms 1, 3

Physical Examination

• Vital signs including temperature, heart rate, blood pressure, and orthostatic measurements
• Height, weight, and BMI calculation
• Assessment for signs of malnutrition:
  • Loss of subcutaneous fat
  • Muscle wasting (temporal, interosseous, quadriceps)
  • Skin and mucous membrane integrity 1
• Abdominal examination for masses, organomegaly, or tenderness
• Neurological examination if indicated

Laboratory and Diagnostic Testing

Initial Laboratory Tests

• Complete blood count (CBC) 1
• Comprehensive metabolic panel including:
  • Electrolytes
  • Liver enzymes
  • Renal function tests
  • Glucose 1
• Thyroid-stimulating hormone (TSH) 4
• Urinalysis 4
• Fecal occult blood test 4

Additional Testing Based on Clinical Suspicion

• Electrocardiogram (ECG) for patients with significant weight loss, restrictive eating patterns, or severe purging behaviors 1
• Upper gastrointestinal studies for patients with dysphagia, early satiety, or persistent abdominal symptoms 4
• Screening for depression using validated tools 1
• Nutritional assessment using tools like the Subjective Global Assessment (SGA) or Mini Nutritional Assessment (MNA) for elderly patients 1

Screening for Specific Conditions

Eating Disorders

• Screen all patients with unexplained weight loss or appetite changes for eating disorders 1, 2
• Assess for:
  • Restrictive eating patterns
  • Binge eating behaviors
  • Compensatory behaviors (purging, excessive exercise)
  • Body image disturbance
  • Fear of weight gain 1, 2, 3

Diabetes and Metabolic Disorders

• Screen for disordered eating in patients with diabetes when hyperglycemia and weight loss are unexplained 1
• Review medication regimen for effects on hunger/caloric intake 1

Cancer

• Consider cancer screening, particularly for lung and gastrointestinal malignancies, in elderly patients with unintentional weight loss 4
• Focus on age-appropriate cancer screening tests based on risk factors

Psychiatric Conditions

• Screen for depression and anxiety, which are common causes of appetite loss 1, 4
• Consider medication side effects, particularly from psychotropic medications 4

Special Considerations

Elderly Patients

• Use age-appropriate screening tools like the Mini Nutritional Assessment (MNA) 1
• Consider polypharmacy as a potential cause of appetite loss 4
• Evaluate social factors including isolation, inability to prepare meals, and financial constraints 5

Cancer Patients

• In patients with cancer and appetite loss, consider corticosteroids or progestins for short-term appetite stimulation, while being aware of potential side effects 1
• Consider supplementation with long-chain N-3 fatty acids in advanced cancer patients undergoing chemotherapy 1

Patients with Chronic Disease

• Assess for disease-specific causes of appetite loss
• Consider nutritional support when dietary intake is chronically insufficient 1, 6

Common Pitfalls to Avoid

• Misdiagnosis: Failing to distinguish between different causes of appetite loss can lead to ineffective treatment 2
• Delayed diagnosis: Focusing exclusively on GI symptoms without considering eating disorders can delay proper treatment 3
• Overlooking medication effects: Many medications can cause anorexia, nausea, or altered taste 4
• Assuming weight loss method indicates cause: The rate or method of weight loss does not reliably indicate whether an eating disorder is present 3
• Premature nutritional intervention: Indiscriminate use of nutritional support without identifying underlying causes may be ineffective or harmful 6

By following this structured approach to evaluating loss of appetite, clinicians can systematically identify underlying causes and implement appropriate interventions to address both the symptom and its etiology.