A 18-month-old girl from an urban slum in Delhi is brought by her mother with a 4-month history of progressive weight loss, severe muscle wasting, and loose skin folds. On examination, she weighs 7.5 kg (expected ~12 kg for age), appears emaciated with visible ribs and spine, and has no edema. Her hair is dry and thin but not easily pluckable. Serum albumin is 3.2 g/dL, and hemoglobin is 7.8 g/dL. The child is alert and feeding well. What is the most likely diagnosis?

Explanation

## Clinical Diagnosis: Marasmus ### Key Clinical Features Present **Key Point:** Marasmus is protein-energy malnutrition with **proportionate deficiency of both protein and calories**. The hallmark is severe wasting with **absence of edema**. The child appears "old" or "wizened" due to loss of subcutaneous fat and muscle. ### Why This Case Is Marasmus This 18-month-old has: - **Severe wasting** — weight only 62% of expected for age (7.5 kg vs. ~12 kg) - **Visible ribs and spine** — marked loss of subcutaneous fat and muscle - **Loose skin folds** — result of rapid weight loss; skin hangs loosely over depleted muscle and fat - **Absence of bilateral pitting edema** — distinguishes marasmus from kwashiorkor - **Relatively preserved serum albumin (3.2 g/dL)** — albumin is maintained because the body preferentially preserves visceral protein at the expense of somatic protein (muscle) - **Dry, thin hair (not easily pluckable)** — hair changes are present but less severe than in kwashiorkor - **Progressive onset over 4 months** — marasmus develops insidiously with chronic inadequate total caloric intake - **Alert and feeding well** — mental status is often preserved in marasmus (unlike in severe kwashiorkor with apathy) **High-Yield:** The **absence of edema despite low weight-for-age is the key discriminator**. If edema were present, the diagnosis would shift toward kwashiorkor or marasmic kwashiorkor. ### Pathophysiology ```mermaid flowchart TD A[Inadequate total caloric intake<br/>Inadequate protein intake]:::outcome --> B[Adaptive metabolic response] B --> C[Reduced energy expenditure] B --> D[Preferential preservation of visceral protein] C --> E[Slow, progressive weight loss] D --> F[Serum albumin relatively preserved] E --> G[Severe wasting of muscle and fat]:::outcome G --> H[Absence of edema]:::outcome ``` ### Biochemical Markers: Marasmus vs. Kwashiorkor | Parameter | Marasmus | Kwashiorkor | Marasmic Kwashiorkor | |-----------|----------|-------------|----------------------| | **Weight-for-age** | < 60% | 60–80% | < 60% | | **Serum albumin** | Normal or mildly ↓ | ↓↓ (< 2.5 g/dL) | ↓↓ | | **Edema** | Absent | Present (bilateral, pitting) | Present | | **Subcutaneous fat** | Severely depleted | Preserved | Depleted | | **Muscle mass** | Severely wasted | Relatively preserved | Severely wasted | | **Hair changes** | Mild | Marked | Marked | | **Hepatomegaly** | Rare | Common | Common | | **Mental status** | Often alert | Often apathetic | Variable | | **Immune function** | Severely impaired | Severely impaired | Severely impaired | **Clinical Pearl:** In marasmus, the body "spares" visceral organs and plasma proteins (including albumin) at the expense of muscle and fat. This is why serum albumin may be near-normal despite severe wasting. In kwashiorkor, the loss of hepatic synthetic capacity leads to marked hypoalbuminemia. ### Clinical Presentation Timeline **Mnemonic: MARASMUS = Muscle loss, Absent edema, Reduced subcutaneous fat** - **M**uscle wasting (severe) - **A**bsent edema - **R**educed fat (subcutaneous depleted) - **A**lbumin relatively preserved - **S**evere wasting (proportionate) - **M**etabolic adaptation (slow weight loss) - **U**ndernourished (total calories inadequate) - **S**low onset (chronic) ### Why Anemia Is Present The hemoglobin of 7.8 g/dL reflects: - Protein deficiency (reduced hemoglobin synthesis) - Likely concurrent iron deficiency (common in malnourished children) - Chronic inflammation from malnutrition Anemia is common in both marasmus and kwashiorkor but does not change the primary diagnosis. ### Management Approach **Warning:** Unlike kwashiorkor, marasmus does not carry the same acute risk of refeeding syndrome, but careful gradual nutritional rehabilitation is still essential. Micronutrient supplementation (iron, vitamin A, B vitamins, zinc) is critical. [cite:Park 26e Ch 10; Harrison 21e Ch 72]