Describe the effect of protein-energy malnutrition (PEM) on children: kwashiorkor and marasmus.

• Capillaries – absorb amino acids, glucose, water‑soluble vitamins and minerals.
• Lacteals – specialised lymphatic vessels that absorb long‑chain fatty acids and glycerol (as chylomicrons).

Protein‑Energy Malnutrition (PEM) (AO1)

PEM occurs when intake of protein and/or calories is insufficient to meet metabolic demands. It is most common in children under five years in low‑income regions where diets are low in quality protein and overall energy.

Key Clinical Forms

• Kwashiorkor – primarily a protein deficiency with relatively adequate caloric intake.
• Marasmus – severe deficiency of both protein and calories.

Kwashiorkor (AO1)

Typical presentation

• Onset usually after 6 months, when breast‑milk is replaced by a protein‑poor diet (e.g., starchy staples).
• Pitting oedema of feet and abdomen due to low plasma albumin.
• Dermatitis – “flaky‑paint” skin lesions, hyper‑pigmented patches.
• Hair becomes thin, brittle and may lose colour (depigmentation).
• Enlarged, fatty liver palpable under the ribs.
• Growth retardation may be less severe than in marasmus.

Marasmus (AO1)

Typical presentation

• Occurs in children with chronic severe calorie deficiency, often from birth.
• Marked wasting of muscle and sub‑cutaneous fat – “skin‑and‑bones” appearance.
• No oedema; the child appears emaciated.
• Thin, dry hair; reduced skin turgor.
• Severe growth retardation – both height and weight are low.
• Frequent infections due to weakened immunity.

Comparison of Kwashiorkor and Marasmus (AO1)

Pathophysiology (Brief) (AO2)

• Kwashiorkor: Insufficient amino acids impair synthesis of plasma proteins (especially albumin). Reduced oncotic pressure allows fluid to leak into interstitial spaces → oedema.
• Marasmus: The body catabolises its own protein stores for energy, leading to loss of muscle mass and sub‑cutaneous fat.

Management (AO2)

1. Stabilisation – correct dehydration, electrolyte imbalance and treat any infections.
2. Nutritional rehabilitation – start with low‑protein, high‑energy therapeutic feeds (e.g., F‑75, then F‑100) to avoid re‑feeding syndrome.
3. Micronutrient supplementation – especially zinc, vitamin A and iron where appropriate.
4. Long‑term dietary improvement – introduce balanced meals containing adequate protein (legumes, meat, dairy) and calories.

Prevention (AO2)

• Exclusive breastfeeding for the first 6 months.
• Introduce complementary foods rich in protein and energy (fortified cereals, legumes, animal‑source foods).
• Community education on nutrition, hygiene and the importance of micronutrients.
• Regular growth monitoring (weight‑for‑age, height‑for‑age) to detect early signs of under‑nutrition.

Glossary (AO1 – terminology)

• Macronutrients – nutrients required in large amounts (carbohydrates, proteins, fats).
• Micronutrients – vitamins and minerals needed in small quantities.
• Dietary fibre – indigestible plant material that aids digestion and regulates blood glucose.
• Oncotic pressure – osmotic pressure exerted by plasma proteins, mainly albumin.
• Re‑feeding syndrome – metabolic disturbances that can occur when nutrition is re‑introduced too rapidly.

AO2 – Data Handling Activity

Activity: Using a set of growth‑chart data for a group of 2‑year‑old children, calculate the weight‑for‑age percentiles. Identify any children whose weight is below the 60 % percentile and discuss whether they may be suffering from marasmus, kwashiorkor or another form of under‑nutrition.

AO3 – Practical Investigation Ideas

• Protein test – Use the Biuret test to compare the protein content of common foods (e.g., milk, beans, rice, wheat flour). Record colour change and relate to dietary protein sources.
• Vitamin C loss – Perform the iodine‑starch test on raw versus boiled vegetables to demonstrate the effect of cooking on vitamin C content.
• Calcium estimation – Use a simple precipitation method with ammonium oxalate to compare calcium levels in fortified milk versus plain water.