A 2-year-old boy from rural Maharashtra presents with a 6-month history of poor weight gain and recurrent infections. On examination, he appears wasted with visible ribs, sparse hair that is easily pluckable, and bilateral pitting edema over the dorsa of feet. His mother reports he has been eating a diet predominantly of rice and dal with minimal protein intake. Serum albumin is 2.1 g/dL (normal 3.5–5.0), and total serum protein is 4.8 g/dL. What is the most likely diagnosis?

Explanation

## Clinical Diagnosis: Kwashiorkor ### Key Clinical Features Present **Key Point:** Kwashiorkor is protein-energy malnutrition with **relative protein deficiency** in the context of adequate or near-adequate total caloric intake. The classic triad is: 1. Bilateral pitting edema (often dependent, worsens with gravity) 2. Hepatomegaly (fatty infiltration) 3. Skin and hair changes (hyperkeratosis, depigmentation, easy hair pluckability) ### Why This Case Is Kwashiorkor This 2-year-old has: - **Bilateral pitting edema** — hallmark of kwashiorkor, due to hypoalbuminemia and reduced plasma oncotic pressure - **Sparse, easily pluckable hair** — sign of protein deficiency affecting hair follicle integrity - **Low serum albumin (2.1 g/dL)** — reflects hepatic protein synthesis failure from inadequate amino acid substrate - **Diet of rice and dal** — adequate carbohydrate (rice) but insufficient protein quantity or quality (dal alone is incomplete) - **Preserved subcutaneous fat** — wasting is less severe than in marasmus; the child retains some fat because total calories are not severely restricted **High-Yield:** The **edema distinguishes kwashiorkor from marasmus**. Marasmus presents with severe wasting, loss of subcutaneous fat, and absence of edema; kwashiorkor presents with edema, hepatomegaly, and relative preservation of subcutaneous fat. ### Pathophysiology ```mermaid flowchart TD A[Protein deficiency<br/>Adequate carbohydrate intake]:::outcome --> B[Reduced hepatic albumin synthesis] B --> C[Decreased plasma oncotic pressure] C --> D[Fluid shifts to interstitium] D --> E[Bilateral pitting edema]:::outcome A --> F[Impaired immune function] F --> G[Recurrent infections]:::outcome A --> H[Fatty infiltration of liver] H --> I[Hepatomegaly]:::outcome ``` ### Biochemical Markers | Parameter | Kwashiorkor | Marasmus | Marasmic Kwashiorkor | |-----------|-------------|---------|----------------------| | **Serum albumin** | ↓↓ (< 2.5 g/dL) | Normal or mildly ↓ | ↓↓ | | **Total protein** | ↓ | Normal or mildly ↓ | ↓ | | **Edema** | Present (bilateral, pitting) | Absent | Present | | **Subcutaneous fat** | Preserved | Severely depleted | Depleted | | **Hair changes** | Marked | Mild | Marked | | **Hepatomegaly** | Common | Rare | Common | **Clinical Pearl:** Kwashiorkor often presents acutely or subacutely with edema, whereas marasmus develops insidiously over months with progressive wasting. The presence of edema is the single most discriminating feature. ### Management Implications **Warning:** Rapid refeeding in kwashiorkor carries risk of **refeeding syndrome** (hypophosphatemia, hypokalemia, hypomagnesemia). Careful, gradual nutritional rehabilitation with monitoring of electrolytes is essential. **Mnemonic: KWASHIORKOR = Protein deficiency with Edema** - **K**washi = Protein (Akan language) - **E**dema (bilateral, pitting) - **P**reserved fat - **H**epatomegaly - **A**lbumin ↓↓ [cite:Park 26e Ch 10]