What is the recommended work-up for a patient presenting with weight gain and fatigue?

Work-up for Weight Gain and Fatigue

Begin by quantifying fatigue severity using a 0-10 numeric rating scale, with scores of 4-10 warranting immediate focused evaluation including complete blood count with differential, comprehensive metabolic panel, thyroid-stimulating hormone, erythrocyte sedimentation rate, and C-reactive protein. 1, 2

Initial Severity Assessment

• Use a 0-10 numeric rating scale over the past 7 days, where 0 = no fatigue and 10 = worst fatigue imaginable 1, 2
• Scores 0-3 indicate mild fatigue requiring only education and periodic rescreening 1
• Scores 4-10 indicate moderate to severe fatigue requiring comprehensive workup 1, 2
• Scores ≥7 typically indicate marked functional impairment requiring urgent evaluation 3, 2

Medication Review (First Priority)

Review all current medications first, as this is the most commonly overlooked contributor to fatigue. 2

• Document all prescription medications, over-the-counter drugs, herbal supplements, and vitamins 4, 2
• Identify recent medication changes that temporally correlate with symptom onset 4
• Assess for medications causing fatigue: β-blockers (bradycardia-induced fatigue), SSRIs (63% experience fatigue), combinations of narcotics, antidepressants, antiemetics, and antihistamines causing excessive drowsiness 4, 2
• Consider dose adjustments or medication discontinuation when appropriate 4

Focused History for Red Flags

• Document fever, drenching night sweats, and unexplained weight loss >10% over 6 months (B symptoms) 1, 3
• Assess onset, pattern, duration, and temporal changes in both fatigue and weight gain 1
• Evaluate pain, pulmonary complaints, and interference with normal daily functioning 1, 3
• Screen for lymphadenopathy, hepatosplenomegaly, and skin manifestations on physical examination 1, 3

Laboratory Workup

For patients with moderate to severe fatigue (scores 4-10), obtain the following initial screening tests: 1, 2

• Complete blood count with differential (assess for anemia) 1, 2
• Comprehensive metabolic panel including electrolytes, hepatic and renal function 1, 2
• Thyroid-stimulating hormone 1, 2
• Erythrocyte sedimentation rate and C-reactive protein for inflammation 1, 2
• Imbalances in sodium, potassium, calcium, iron, and magnesium are often reversible and may reduce fatigue with appropriate supplementation 4, 2

Nutritional Assessment

• Document weight changes, current weight, and calculate body mass index 4
• Evaluate caloric intake changes and impediments to nutritional intake 4, 2
• Assess for nausea, vomiting, loss of appetite, food disinterest, mucositis, odynophagia, bowel obstruction, diarrhea, and constipation 4
• Consider consultation with a nutrition expert if substantial abnormalities are identified 4

Sleep and Mental Health Evaluation

• Assess sleep quality, quantity, and sleep hygiene practices systematically 1, 2
• Screen for sleep apnea, particularly if the patient has gained weight or has other risk factors 1
• Screen for depression using PHQ-9 (present in 25-33% of fatigued patients) 1
• Screen for anxiety using GAD-7 1
• Evaluate for alcohol and substance abuse, which can lead to or aggravate sleep disturbance and fatigue 4, 3

Physical Activity and Deconditioning Assessment

• Query about functional status, including changes in exercise or activity patterns 4
• Determine if patients can accomplish normal daily activities and participate in exercise programs 4
• Document amount and frequency of current exercise 4
• Assess conditioning level before recommending exercise interventions 4

Special Population Considerations

• For new immigrants or recent travelers: document country of origin and regions visited, and consider screening for malaria, tuberculosis, HIV, schistosomiasis, dengue fever, and rickettsial diseases 1, 3
• For cancer survivors: consider disease recurrence or late treatment effects 1

Common Pitfalls

• Do not overlook medication review—this is the most frequently missed contributor to fatigue 2
• Sleep disturbances occur in 30-75% of fatigued patients and must be systematically evaluated 1
• Weight gain following treatment of hyperthyroidism can be substantial (mean 5.42 kg), with continued weight gain over time 5
• Sleep problems, particularly trouble falling asleep and waking up several times per night, are independently associated with major weight gain (≥5 kg) in women 6