# Severe Acute Malnutrition

Recognize severe acute malnutrition by anthropometry or nutritional edema, distinguish marasmus from kwashiorkor, triage complications requiring inpatient stabilization, and transition feeding deliberately to avoid metabolic and fluid-related deterioration.

**Clinical question:** How should physicians identify, triage, and manage marasmus, kwashiorkor, and marasmic kwashiorkor in young children?

Updated: 2026-08-24T16:08:52.853684+00:00

## What matters in practice
- Classify severe acute malnutrition in children 6–59 months by mid-upper arm circumference <115 mm, weight-for-height/length z score <−3, or bilateral pitting edema; edema alone establishes severe disease even when weight-based measures appear less abnormal. [19][23]
- Marasmus is severe wasting without edema; kwashiorkor is edematous malnutrition, and marasmic kwashiorkor combines edema with severe wasting. [10][12]
- Children requiring inpatient care need stabilization before rehabilitation feeding because usual protein, fat, and sodium loads may not be tolerated during acute illness. [24]
- For inpatient children 6–59 months who are stabilized, have appetite, and have reduced edema, transition from F-75 to ready-to-use therapeutic food over 2–3 days as tolerated. [24]
- Rapid nutritional reintroduction in a severely malnourished child can precipitate electrolyte deficits, sodium and fluid retention, organ dysfunction, and arrhythmias; monitor closely during early feeding. [6]

## Identify severe acute malnutrition despite edema

Use objective anthropometry and bilateral pitting edema; weight alone is unreliable in edematous disease.

For children 6–59 months, diagnose severe acute malnutrition (SAM) when any one of the following is present: mid-upper arm circumference (MUAC) <115 mm, weight-for-height/length z score (WHZ/WLZ) <−3, or bilateral pitting edema. These criteria identify children with severe wasting or nutritional edema who require prompt clinical assessment. [19][23]

Do not use a reassuring weight or MUAC to exclude SAM when bilateral pitting edema is present. Nutritional edema can falsely elevate both weight and arm circumference, masking depleted lean and fat mass. [16]

Document edema distribution and severity at presentation and serially. Bilateral lower-extremity pitting edema supports kwashiorkor; generalized edema may occur in more severe edematous malnutrition and should prompt inpatient assessment for coexisting complications. [10][12]
- Measure MUAC with a standardized tape and record the value in millimeters; <115 mm meets a SAM criterion in children 6–59 months. [19][21]
- Calculate WHZ/WLZ against WHO child-growth standards; <−3 meets a SAM criterion. [19][23]
- Test for bilateral pitting edema by sustained thumb pressure over the dorsum of each foot; bilateral edema meets a SAM criterion irrespective of weight-for-height. [19][23]

*Clinical phenotype distinguishes marasmus, kwashiorkor, and mixed disease; edema may distort weight-based and MUAC assessments. [10][12][16]*

| Phenotype | Key bedside finding | Classification implication | Immediate next action |
| --- | --- | --- | --- |
| Marasmus | Marked wasting or emaciation without nutritional edema. [10][12] | SAM if MUAC <115 mm or WHZ/WLZ <−3. [19][23] | Assess appetite and medical complications to determine inpatient versus ambulatory treatment pathway. [24] |
| Kwashiorkor | Bilateral pitting edema; skin desquamation and hair changes may coexist. [10][12] | Edema establishes edematous SAM even if weight-based measures are elevated by fluid. [16][19] | Assess edema burden, appetite, infection, hypoglycemia, hypothermia, and fluid status before feeding advancement. [9][24] |
| Marasmic kwashiorkor | Severe wasting plus bilateral pitting edema. [10] | Mixed severe phenotype; do not allow edema to obscure wasting severity. [10][16] | Use inpatient stabilization when medical complications or inability to tolerate rehabilitation feeding are present. [24] |

## Triage for immediate stabilization before rehabilitation

The first decision is whether the child can safely tolerate rehabilitation feeding.

Treat a child with SAM as medically high risk until hypoglycemia, hypothermia, infection, dehydration or fluid imbalance, and feeding intolerance have been assessed. SAM predisposes to hypoglycemia, hypothermia, severe infection, and micronutrient deficiencies, and these threats can be clinically occult. [9]

Inpatient management is indicated for children with SAM who have medical complications or cannot tolerate usual nutritional loads. During this phase, protein, fat, and sodium tolerance is reduced; standard inpatient care therefore begins with stabilization rather than immediate high-energy catch-up feeding. [24]

Assess for concurrent infection at presentation. WHO guidance has recommended routine broad-spectrum antibiotic treatment, including amoxicillin, because children with SAM often have subclinical bacterial infection; this practice remains controversial because of antimicrobial-resistance and adverse-effect concerns. Local protocols and the child’s clinical findings should determine agent selection and disposition. [9]
- Obtain and trend bedside temperature and glucose during initial stabilization because hypothermia and hypoglycemia are recognized life-threatening SAM complications. [9]
- Evaluate respiratory status, perfusion, mental status, vomiting, stool losses, and ability to take prescribed feeds before selecting an ambulatory pathway. Children with medical complications require inpatient care. [24]
- Interpret edema cautiously: fluid retention and impaired organ function can accompany early nutritional therapy and can complicate assessment of volume status. [6]

### Refeeding-risk surveillance

Marasmus, kwashiorkor, prolonged starvation of 10–14 days, and chronic malnutrition are recognized risk states for refeeding syndrome. Risk is not limited to parenteral nutrition: electrolyte and metabolic complications can follow oral, enteral, or parenteral reintroduction of nutrition. [6]
- During early nutritional therapy, monitor for electrolyte deficiencies, sodium retention, peripheral edema, hyperglycemia, rising hepatic enzymes or triglycerides, arrhythmias, and renal, respiratory, or heart failure. [6]
- Consider thiamine and folate depletion among the metabolic hazards of refeeding; abnormalities require active surveillance during nutrition advancement. [6]

*Stabilization and rehabilitation have distinct objectives in inpatient SAM. [24]*

| Phase | Clinical trigger | Therapeutic feeding approach | Advancement rule |
| --- | --- | --- | --- |
| Stabilization | Medical complications or inability to tolerate usual protein, fat, and sodium loads. [24] | Use F-75, a low-protein milk-based therapeutic formula. [24] | Do not advance solely because a prescribed volume was tolerated; reassess clinical stabilization, appetite, and edema. [24] |
| Transition | Child is stabilized, has appetite, and has reduced edema. [24] | Transition from F-75 to RUTF over 2–3 days as tolerated when RUTF is the rehabilitation therapeutic food. [24] | Advance over the transition interval while watching for intolerance and fluid or electrolyte complications. [6][24] |
| Rehabilitation | Stabilized child ready for nutritional recovery. [24] | Use RUTF in settings where it is provided; RUTF has replaced liquid F-100 in many rehabilitation programs. [24] | Introduce ad libitum rehabilitation feeding only after the restricted transition period as tolerated. [24] |

## Sequence feeding according to clinical stability and edema response

Avoid treating initial feeding as simple calorie replacement.

For inpatient children 6–59 months with SAM, use F-75 during stabilization, then transition only after stabilization, return of appetite, and reduction in edema. F-75 is a low-protein milk-based formula designed for the stabilization phase; rehabilitation diets provide higher protein and energy. [24]

Where RUTF is used for rehabilitation, transition from F-75 to RUTF over 2–3 days as tolerated. RUTF is generally a lipid-based paste containing milk powder, electrolytes, and micronutrients and provides nutrient intake comparable to F-100 with added iron. [24]

Do not equate persistent edema with nutritional recovery. Kwashiorkor is associated with edema and fatty liver, while evidence syntheses describe more severe depletion of antioxidants, vitamins, and minerals than in marasmus. Reduced edema and improved appetite are the clinical prerequisites for rehabilitation transition, not an isolated gain in body weight. [1][11][24]
- Use appetite and edema trajectory as explicit transition checkpoints rather than advancing on a fixed calendar alone. [24]
- Avoid abruptly introducing unrestricted rehabilitation feeding in a high-risk child; current WHO guidance describes restricted introduction during transition before ad libitum feeding. [24]
- Monitor for worsening edema, arrhythmias, hyperglycemia, and organ dysfunction during nutritional escalation, especially in children with prolonged starvation or edematous SAM. [6]

*Feeding decisions should follow clinical response rather than body weight alone, particularly in edematous SAM. [16][24]*

| Finding during treatment | Interpretation | Action |
| --- | --- | --- |
| No medical stability, absent appetite, or substantial edema | Child has not met the stated readiness features for rehabilitation feeding. [24] | Continue stabilization-phase management and reassess clinical complications. [24] |
| Stabilized, appetite present, edema reduced | Meets WHO-described readiness features for transition to rehabilitation feeding. [24] | Transition F-75 to RUTF over 2–3 days as tolerated. [24] |
| New edema, electrolyte disturbance, hyperglycemia, arrhythmia, or organ dysfunction after feeding begins | Possible refeeding-related metabolic or fluid complication. [6] | Reassess nutrition advancement and urgently evaluate fluid, electrolyte, cardiac, respiratory, renal, and hepatic status. [6] |

## Look beyond food insecurity when phenotype or course is atypical

SAM classification establishes severity; history and targeted evaluation identify modifiable drivers and complications.

Obtain a focused nutritional history, past medical history, vaccination history, and family history in every child with suspected malnutrition. These elements are specifically identified as part of the clinical evaluation and can reveal restricted diets, recent weaning, chronic illness, recurrent infections, or household constraints that will determine relapse risk after nutritional recovery. [12]

Differentiate phenotypes clinically, but do not assume that kwashiorkor is explained by protein intake alone. Comparative analyses associate kwashiorkor with fatty liver, edema, methionine and glutathione depletion, greater antioxidant and micronutrient depletion, and altered gut microbial patterns; these findings reinforce the need to assess infection and nutritional adequacy during management. [1][11]

Acute infection changes metabolic behavior in SAM. In one isotope-tracer study of children with acute infection, whole-body protein breakdown and synthesis were higher in marasmus than in kwashiorkor, despite similar C-reactive protein concentrations; phenotype should therefore inform risk assessment but not replace direct clinical evaluation of infection or organ dysfunction. [4]
- When edema is present, document skin desquamation and hair changes because these support the edematous kwashiorkor phenotype. [10]
- When wasting and edema coexist, classify as marasmic kwashiorkor rather than relying on weight-based severity alone. [10][16]
- If nutritional edema is present, assess for fatty liver as a recognized associated feature of kwashiorkor when clinical findings warrant hepatic evaluation. [1][11]

*Phenotype directs the interpretation of anthropometry and complication risk, not a separate empiric feeding regimen. [1][10][16][24]*

| Pattern | What changes the assessment | Clinical consequence |
| --- | --- | --- |
| Predominant wasting without edema | Low MUAC and WHZ/WLZ directly reflect tissue depletion. [19][23] | Use anthropometric thresholds to identify SAM and assess for acute complications before rehabilitation feeding. [9][24] |
| Edematous malnutrition | Fluid can falsely increase weight and MUAC. [16] | Bilateral pitting edema is independently diagnostic of SAM; use edema reduction and appetite when considering feeding transition. [19][24] |
| Mixed wasting and edema | Edema may conceal the degree of wasting. [10][16] | Classify as marasmic kwashiorkor and prioritize inpatient stabilization when complications are present. [10][24] |

## Monitor clinical recovery, not weight gain alone

Serial findings should determine feeding advancement and identify early metabolic deterioration.

During inpatient treatment, monitor appetite, edema, tolerance of prescribed feeds, and signs of refeeding-related electrolyte, fluid, glucose, cardiac, respiratory, renal, and hepatic complications. This monitoring is most important during early reintroduction and transition because refeeding syndrome can impair organ function and precipitate arrhythmias. [6][24]

Use the change in edema as a treatment marker rather than interpreting early weight gain as unequivocal nutritional recovery. The WHO transition criterion specifically requires reduced edema along with stabilization and appetite before moving from F-75 to RUTF. [24]

Before discharge or transfer to outpatient nutritional rehabilitation, ensure that the child has completed stabilization, can tolerate the rehabilitation plan, and has a follow-up structure that can detect recurrent edema, faltering intake, infection, or failure to regain nutritional status. SAM historically carried wide treatment-center mortality variation, with lower mortality associated with adherence to staged management principles. [10][14]
- Recheck MUAC and weight-for-height/length using the same standardized technique used at baseline; interpret values alongside edema status. [16][19]
- Escalate reassessment for new peripheral edema, respiratory deterioration, altered perfusion, arrhythmia, or rising glucose after nutrition is introduced. [6]
- Maintain infection vigilance throughout treatment because SAM compromises host defenses and is associated with severe infection risk. [9]

## References
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## Editorial note

Prepared from cited clinical literature using Astra's research workflow. Verify recommendations against current guidance and patient-specific factors.