WEIGHT LOSS / MALNUTRITION

Unintentional weight loss ≥5% in 6–12 months or clinically significant undernutrition impairing function — requires systematic evaluation for underlying disease

SYMPTOMS / ASSOCIATED SX

  • Documented weight loss (compare prior chart weights); clothes fitting loose; patient/caregiver report

  • B symptoms: fever, night sweats (malignancy, TB, lymphoma, HIV)

  • Anorexia, early satiety, nausea (GI malignancy, gastroparesis, hepatic disease)

  • Diarrhea, steatorrhea, bloating (malabsorption — celiac, IBD, pancreatic EPI)

  • Exam: muscle wasting (temporalis, interossei, quadriceps), edema (hypoalbuminemia), glossitis/cheilosis

DENIES

  • Intentional dietary restriction or increased exercise (eating disorder, voluntary)

  • Abdominal pain/early satiety (GI mass or obstruction)

  • Night sweats/lymphadenopathy (lymphoma, TB, HIV)

  • Changes in stool caliber or frequency (colorectal malignancy)

SOCIAL HISTORY

  • Food access, finances, ability to prepare meals; social isolation; alcohol; tobacco

  • Cultural/religious dietary practices; prior eating disorder history

MAIN ETIOLOGY

  • Malignancy (>40% in elderly with significant unintentional weight loss) — GI, lung, lymphoma, RCC

  • Psychiatric: depression, anxiety, anorexia nervosa, bulimia

  • GI: IBD, celiac, pancreatic EPI, PUD, gastroparesis

  • Endocrine: hyperthyroidism, uncontrolled DM, adrenal insufficiency

  • Social/functional: food insecurity, dysphagia, inability to self-feed, dementia

MOST COMMON DDX

  • Malignancy (CT CAP + age-appropriate screening; B symptoms raise pre-test probability)

  • Depression (PHQ-9; anhedonia, decreased appetite)

  • Hyperthyroidism (TSH suppressed; weight loss with preserved or increased appetite)

  • Malabsorption (steatorrhea; anti-tTG IgA for celiac; fecal elastase for EPI)

  • IBD (diarrhea + abdominal pain; ESR/CRP; colonoscopy)

  • Eating disorder (BMI <18.5; SCOFF questionnaire ≥2 positive; psychiatry)

DATA

  • BMI; weight trend; CBC, BMP, LFTs, TSH, HbA1c, ESR/CRP, LDH

  • Albumin, prealbumin (albumin half-life ~20 days; prealbumin 2–3 days = better acute marker)

  • Anti-tTG IgA (celiac) + total IgA; fecal elastase (<200 mcg/g = EPI)

  • HIV Ag/Ab; Hep B/C; IGRA + CXR (TB); SPEP; PSA (men)

  • CT chest/abdomen/pelvis with contrast (malignancy screen)

  • EGD/colonoscopy (GI malignancy, IBD); PHQ-9; SCOFF questionnaire

HOME MEDS

  • Metformin, SSRIs, digoxin — GI intolerance/appetite suppression; reassess

  • All herbal supplements — stop (high GI toxicity risk)

PLAN

  • Refeeding syndrome prevention (NICE guidelines) — for significantly malnourished patients:

    • Start at 10–20 kcal/kg/day for first 24–48h

    • Check and replace Phos, K, Mg BEFORE feeding and q6–12h for first 72h

    • Thiamine 100 mg IV/PO daily ×5–7 days BEFORE and DURING refeeding

    • Advance calories slowly over 3–7 days to goal (30–35 kcal/kg/day)

  • Malabsorption:

    • Celiac: strict gluten-free diet; GI referral; replace iron, B12, D, folate

    • EPI: pancreatic enzyme replacement (lipase 40,000–72,000 units with each meal)

    • IBD: GI consult; 5-ASA/biologic therapy per disease type

  • Malignancy: oncology referral; nutritional support; consider mirtazapine/megestrol

  • Eating disorders: psychiatry + eating disorder specialist; medical stabilization; NG refeeding if BMI <14 or cardiac instability

  • PT/OT: resistance training + protein supplementation for sarcopenia

  • DISCHARGE:

    • Malignancy workup completion; oncology referral

    • Dietitian outpatient; Meals on Wheels

    • Refeeding targets communicated to transitional team; PCP follow-up 1–2 weeks

RED FLAGS

  • Refeeding syndrome: severe hypophosphatemia (<1.5 mg/dL) after nutrition → cardiac arrhythmias, respiratory failure; slow feeding, aggressive Phos replacement

  • BMI <14 or rapid weight loss with bradycardia in eating disorder → cardiac telemetry, ICU, mandatory hospitalization

  • B symptoms + lymphadenopathy → lymphoma/TB/HIV; CT CAP; excisional LN biopsy

  • Severe hypoalbuminemia (<2.0) → high infection/wound risk; consider TPN if enteral not feasible

  • Suspected elder neglect contributing to malnutrition → mandatory reporting; APS

SENIOR IM RESIDENT PEARLS

  • ASPEN/ESPEN 2012: diagnose malnutrition with ≥2 of: weight loss, inadequate intake, fat loss, muscle loss, fluid accumulation, reduced grip strength

  • Albumin reflects inflammation more than nutrition — negative acute-phase reactant; use prealbumin for short-term monitoring

  • Refeeding syndrome: hypophosphatemia is the hallmark — prevention requires slow caloric introduction + prophylactic electrolyte replacement

  • Common mistake: high-calorie feeds too rapidly in malnourished patients without Phos monitoring — can be fatal

  • Common mistake: not checking anti-tTG IgA in unexplained weight loss — celiac underdiagnosed in adults

  • CHF cardiac cachexia: TNF-α, IL-6 mediated; treat with HF optimization + nutritional support

  • SCOFF questionnaire: ≥2 positive = likely eating disorder