Decrease in appetite with weight loss under evaluation
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Decreased Appetite with Weight Loss - Under Evaluation
Definition and Clinical Significance
Significant unintentional weight loss is defined as >5% of usual body weight over 6-12 months. It is a harbinger of serious underlying disease. Studies have documented significantly increased mortality in men with unintentional weight loss compared with weight-stable men (36% vs ~15%).
A practical note: 25-50% of patients who complain of unintentional weight loss have not actually lost weight. Weight loss should be verified by:
- Comparing prior measured weights
- Significant decrease in clothing/belt size
- Corroborating history from family/caregivers
- Specific estimated amount from the patient
Epidemiology
- 15-20% of adults over 65 years have unintentional weight loss
- Prevalence rises to 50-60% in nursing home residents
- Body weight normally peaks around age 60, then decreases gradually (normal: <1 lb/year after age 70)
- In the elderly, weight loss often represents frailty syndrome (weakness, slowness, low physical activity, exhaustion, weight loss) - which carries substantially higher morbidity and mortality
Causes (by Frequency)
| Category | Frequency |
|---|---|
| Malignancy (GI most common, then lung, lymphoma) | ~19-36% |
| Depression / alcoholism | ~16% |
| Non-malignant GI disease | ~13% |
| Unknown ("no organic cause found") | ~22% |
| Endocrine disorders | ~7% |
Differential Diagnosis by System
A. Cardiovascular
- Severe heart failure
- Subacute bacterial endocarditis (SBE)
B. Endocrine
- Adrenal insufficiency
- Diabetes mellitus (uncontrolled)
- Hyperthyroidism
C. GI (mouth to rectum)
- Poor dentition (accounts for up to 9% of unintentional weight loss in adults >65)
- Anosmia / altered gustation
- Esophageal stricture, dysmotility, or cancer
- PUD, gastric cancer, gastroparesis, gastric outlet obstruction
- Chronic mesenteric ischemia, Crohn disease, celiac disease, chronic pancreatitis, malabsorption syndromes
- Colorectal cancer, inflammatory bowel disease
D. Liver / Biliary
- Cirrhosis
- Cholangiocarcinoma
E. Neurologic
- Dementia (increased energy expenditure from agitation and pacing + decreased intake)
- Parkinson disease
- Prior stroke
- Dysphagia from any neurologic cause
F. Oncologic (must-not-miss)
- GI malignancies (stomach, pancreas, colon)
- Lung cancer
- Lymphoma / hematologic malignancies
- Renal cell carcinoma
- Breast/gynecologic malignancies
G. Psychiatric
- Major depressive disorder
- Anxiety disorders
- Dementia with behavioral disturbance
- Anorexia nervosa (in younger patients; also occurs in older adults)
H. Infectious / Inflammatory
- HIV/AIDS
- Tuberculosis
- Chronic infections
- Rheumatoid arthritis, SLE, Sjogren syndrome
I. Renal
- Advanced chronic kidney disease / uremia
J. Pulmonary
- Severe COPD (increased metabolic demand + dyspnea reducing appetite)
K. Medications (important and often overlooked)
- Digoxin, loop diuretics, diltiazem, levodopa, metformin, opioids, certain SSRIs, many others
- Medical diets, radiation therapy, chronic pain
Four Pivotal Evaluation Steps
Step 1 - Verify that weight loss is real
Document with prior weights or corroborating evidence (clothing/belt size). Do not proceed with an exhaustive workup if weight loss cannot be confirmed.
Step 2 - Screen for malabsorption
Ask about diarrhea, large/malodorous/floating stools. This points toward small bowel or pancreatic disease. Also ask about changes in stool caliber or defecation difficulty (colorectal cancer red flag).
Step 3 - Decreased intake vs. increased expenditure
Most patients lose weight because of decreased intake. Weight loss with normal or increased appetite suggests substantial catabolism - seen in hyperthyroidism, uncontrolled diabetes, severe COPD, malabsorption, or malignancy.
Step 4 - Identify the "company it keeps"
The most productive strategy is to find associated symptoms/signs that point to a specific cause. A truly comprehensive history, psychosocial history, medication review, and head-to-toe physical exam (including mental status exam) will reveal clues in most cases.
Initial Evaluation
History
- Past medical history, prior weights
- Psychosocial: financial or social stressors, living arrangements, bereavement, anhedonia, hopelessness, alcohol use, illicit drug use, tobacco use
- Full review of systems (every organ system)
- Medications: all prescription and OTC drugs
Physical Exam
- Full comprehensive exam
- Special attention to: oral cavity, thyroid, lymph nodes, breast, abdomen (hepatosplenomegaly, masses), rectal exam, skin/musculoskeletal, neurologic including mental status exam
Initial Laboratory Workup
| Test | What It Screens For |
|---|---|
| CBC with differential | Anemia (iron deficiency may signal GI cancer), cytopenias |
| Urinalysis | Hematuria (renal/bladder cancer), proteinuria |
| Comprehensive metabolic panel | Renal function, LFTs (metastatic disease), glucose (DM) |
| Calcium | Hypercalcemia of malignancy |
| Fasting glucose | Uncontrolled diabetes |
| TSH | Hyperthyroidism |
| ESR or CRP | Elevated in malignancy, myeloma, TB, SBE, vasculitis |
| HIV test | HIV/AIDS |
| Fecal occult blood test (FOBT) | GI malignancy |
| Chest radiograph | Lung cancer, TB, severe COPD |
Age-appropriate cancer screening
Update any overdue preventive health exams: mammogram, Pap smear/HPV, colonoscopy, PSA (in selected men), low-dose chest CT (for smokers with ≥30 pack-year history who currently smoke or quit within the past 15 years).
Second-line imaging (if initial evaluation unrevealing)
- Upper endoscopy
- Abdominal ultrasound (or CT abdomen/pelvis depending on clinical concern)
Prognostic Point
An unrevealing initial evaluation is reassuring for malignancy. One study found that among patients with weight loss who had no abnormal findings on initial evaluation, none were subsequently diagnosed with cancer during the study period. However, a more recent larger study found cancers may still be present but undiagnosed antemortem, suggesting that ongoing clinical follow-up is warranted even after a negative initial workup.
Weight Loss Severity Thresholds (Nutritional)
| Degree of Loss (over 6 months) | Classification | Clinical Significance |
|---|---|---|
| <5% | Mild | Often clinically insignificant |
| 5-10% | Moderate | Warrants evaluation |
| >10% | Severe | Associated with ~15-20% decrease in total body protein; impaired physiology, poor outcomes, extended hospitalization |
Note: A >10% unintentional weight loss is the threshold at which patients are most likely to benefit from intensive nutritional support. - Sleisenger and Fordtran's Gastrointestinal and Liver Disease
Sources: Symptom to Diagnosis: An Evidence-Based Guide, 4th Edition, Chapter 32; Sleisenger and Fordtran's Gastrointestinal and Liver Disease
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