Failure to Thrive / Malnutrition

Inadequate nutritional intake or absorption resulting in unintentional weight loss, functional decline, and micronutrient deficiencies

Symptoms / Associated Sx

  • Unintentional weight loss (>5% body weight in 1 month or >10% in 6 months)

  • Fatigue, weakness, loss of muscle mass (sarcopenia)

  • Poor appetite, early satiety, dysphagia (access to food barriers)

  • Pressure ulcers, poor wound healing

  • Cognitive decline, depression (especially in elderly)

  • Edema, ascites (hypoalbuminemia)

  • Specific deficiency signs: angular cheilitis (B2/iron), glossitis (B12/folate/niacin), peripheral neuropathy (B12/thiamine), night blindness (vitamin A), tetany (calcium/magnesium), bruising (vitamin K)

Denies

  • Intentional weight loss with dietary changes (rules out diet-related weight loss)

  • Fever, night sweats (rules out infectious or malignant etiology if absent — but must still investigate)

  • Diarrhea, steatorrhea (rules out malabsorption syndrome if absent)

  • Dysphagia (rules out mechanical dysphagia as primary cause)

Social History (SHx)

Social isolation, food insecurity, poverty, alcohol/substance use, functional decline/disability limiting food access, depression, cognitive impairment (dementia), living alone, recent bereavement, institutionalization.

Main Etiology

  • Inadequate intake: Depression, dementia, dysphagia, food insecurity, social isolation, medications (nausea), poor dentition

  • Malabsorption: Celiac disease, Crohn's disease, short bowel syndrome, pancreatic exocrine insufficiency, small intestinal bacterial overgrowth (SIBO)

  • Increased metabolic demand: Cancer, chronic infection (TB, HIV), cardiac cachexia, COPD, end-stage organ failure

  • Protein-losing: Protein-losing enteropathy, nephrotic syndrome, burns

Most Common DDx

  • Malignancy (weight loss + anorexia + night sweats; CT body + cancer screening labs; CBC for anemia; malignancy workup in any unexplained weight loss >10% over 6 months)

  • Depression / psychiatric illness (poor appetite + weight loss + low mood + anhedonia; PHQ-9; responds to antidepressants and social support)

  • Celiac disease (malabsorption + diarrhea + bloating; anti-tTG IgA + total IgA; small bowel biopsy shows villous atrophy; gluten-free diet resolves)

  • Hyperthyroidism (weight loss + increased appetite + tremor + tachycardia; TSH low, free T4 high; responds to antithyroid medications)

  • Adrenal insufficiency (weight loss + fatigue + nausea + hypotension + hyponatremia; AM cortisol low; ACTH stimulation test confirms)

  • Pancreatic exocrine insufficiency (steatorrhea + weight loss; fecal elastase low; responds to pancreatic enzyme replacement)

  • SIBO (small intestinal bacterial overgrowth — bloating + diarrhea + malabsorption; hydrogen breath test; responds to rifaximin 550 mg TID × 14 days)

DATA

  • CBC (anemia — iron deficiency, B12/folate), CMP (albumin — severity marker; electrolytes; glucose; renal/liver function)

  • Prealbumin (more sensitive short-term nutritional marker than albumin)

  • Iron studies, ferritin, B12, folate, thiamine, 25-OH vitamin D, zinc, magnesium

  • TSH (hyperthyroidism), AM cortisol (adrenal insufficiency)

  • Anti-tTG IgA + total IgA (celiac disease)

  • Fecal elastase (pancreatic exocrine insufficiency)

  • Fecal fat (malabsorption — 72-hour stool collection or qualitative Sudan stain)

  • HIV test, TB skin test/IGRA (if infectious etiology suspected)

  • CT chest/abdomen/pelvis (malignancy, occult infection — in unexplained weight loss)

  • Upper endoscopy + small bowel biopsy (celiac, Crohn's, SIBO)

  • Depression screening (PHQ-9); cognitive assessment (MoCA, MMSE); functional assessment (ADLs)

Home Meds

  • Medications causing nausea/anorexia (metformin, digoxin, opioids, SSRIs — review and adjust)

  • Diuretics (aggressive diuresis → electrolyte depletion; assess dose)

  • Multiple medications (polypharmacy → reduced appetite)

Plan

  • Identify and treat underlying cause — this is the most important step

  • Dietitian consultation (ASPEN/AND malnutrition criteria; individualized nutrition plan)

  • Oral nutritional supplementation: High-calorie protein supplements (Ensure, Boost) TID between meals; fortify foods; address food access issues (social work consult)

  • Enteral nutrition (EN) — preferred over parenteral:

    • NG tube: short-term (<4 weeks); goal 25–30 kcal/kg/day; 1.2–2.0 g/kg/day protein

    • PEG tube: long-term (>4 weeks); consider for dysphagia, dementia with recurrent aspiration, head/neck cancer

    • NJ tube: if gastric motility impaired or aspiration risk

  • Parenteral nutrition (PN) — only when EN not feasible:

    • Total PN (TPN): central access (PICC or CVC); short bowel syndrome, intestinal failure, post-op when EN not possible >7 days

    • Peripheral PN: short-term bridge; limited by osmolarity (<900 mOsm/L

ORDERS

Labs

Admission Labs

  • CBC with diff

  • CMP

  • BMP

  • Magnesium

  • Phosphorus

  • Albumin

  • Prealbumin

  • CRP

Nutritional Labs

  • Iron studies

  • Ferritin

  • Vitamin B12

  • Folate

  • Thiamine (Vitamin B1)

  • Vitamin D (25-OH)

  • Zinc

  • Copper (if severe malnutrition)

  • Selenium (if severe malnutrition)

Endocrine Workup

  • TSH

  • Free T4

  • AM Cortisol

Malabsorption Workup

  • Anti-tTG IgA

  • Total IgA

  • Fecal elastase

  • Fecal fat study

Infectious Workup

  • HIV

  • TB Quantiferon/IGRA

Additional Labs

  • HbA1c

  • UA

  • ESR

  • CRP

Refeeding Syndrome Monitoring

  • BMP q12–24h initially

  • Mg daily

  • Phos daily

  • K daily

Trending Labs

  • CBC daily

  • CMP daily

  • Mg daily

  • Phos daily

  • Prealbumin weekly

Imaging

Malignancy Workup

CT Chest with Contrast

CT Abdomen/Pelvis with Contrast

Evaluate:

  • Occult malignancy

  • Chronic infection

  • Cachexia etiology

Dysphagia Evaluation

Barium Swallow

Modified Barium Swallow (SLP)

GI Workup

EGD

  • Celiac disease

  • Upper GI malignancy

  • Crohn's disease

Colonoscopy

  • Colon cancer

  • IBD

Procedures

Enteral Feeding Access

NG Tube

  • Short-term (<4 weeks)

PEG Tube

  • Long-term (>4 weeks)

NJ Tube

  • Aspiration risk

  • Gastroparesis

Parenteral Nutrition

PICC Placement

If:

  • TPN needed

  • EN not possible

Medications

Nutritional Support

Oral Nutrition Supplements

Ensure Plus

  • TID between meals

OR

Boost Plus

  • TID between meals

Vitamin Replacement

Thiamine

High Refeeding Risk

  • Thiamine 100 mg IV/PO daily

Start BEFORE feeding

Multivitamin

  • Daily

Folic Acid

  • 1 mg PO daily

Iron Deficiency

IV Iron

  • Ferric carboxymaltose 500–1000 mg IV

OR

Oral Iron

  • Ferrous sulfate 325 mg PO every other day

B12 Deficiency

Cyanocobalamin

  • 1000 mcg IM monthly

OR

  • Daily initially if severe

Vitamin D Deficiency

Vitamin D3

  • 1000–5000 IU daily

OR

Ergocalciferol

  • 50,000 IU weekly

Appetite Stimulants

(Not routine)

Mirtazapine

  • 7.5–15 mg PO qHS

Useful if:

  • Depression

  • Poor appetite

Megestrol

Generally avoid in elderly
(VTE risk)

Refeeding Syndrome Prevention

Monitor Closely

Replace aggressively:

Potassium

  • Goal >4

Magnesium

  • Goal >2

Phosphorus

  • Goal >3

High Risk

  • BMI <16

  • Minimal intake >7 days

  • Severe weight loss

Nutrition Orders

Dietitian Consult (Mandatory)

Calorie Goal

  • 25–30 kcal/kg/day

Protein Goal

  • 1.2–2.0 g/kg/day

Daily Calorie Count

Daily Weights

Hold Medications

Review and Reduce

Potential offenders:

  • Opioids

  • Digoxin

  • Metformin

  • SSRIs causing anorexia

  • Excess diuretics

Polypharmacy Review

Consults

Nutrition/Dietitian (All Patients)

Speech Language Pathology (SLP)

If:

  • Dysphagia

  • Aspiration concern

Gastroenterology

If:

  • Malabsorption

  • Weight loss

  • Endoscopy needed

Oncology

If:

  • Suspected malignancy

Psychiatry

If:

  • Depression

  • Eating disorder

  • Severe anxiety

Social Work

If:

  • Food insecurity

  • Poor support

  • Placement issues

PT/OT

If:

  • Sarcopenia

  • Functional decline

  • Fall risk

Palliative Care

If:

  • Advanced cancer

  • End-stage organ disease

Nursing Orders

Monitoring

  • Daily weights

  • Strict I&O

  • Calorie counts

Fall Precautions

  • Weakness

  • Frailty

Skin Care

  • Pressure injury prevention

  • Frequent repositioning

Notify Physician

  • Electrolyte abnormalities

  • Poor PO intake

  • Weight loss

  • Refeeding syndrome signs