Define Kwashiorkor. Describe its pathogenesis, clinical features, investigations and management.

Definition

• Kwashiorkor is a form of severe protein-energy malnutrition caused by a relatively greater deficiency of protein (with some calorie intake), classically seen in children aged 1–3 years after weaning.
• The term (Ga language, Ghana) means 'the disease of the displaced child' — the child weaned when the next baby arrives.

Pathogenesis

• Protein deficiency → hypoalbuminaemia → ↓ plasma oncotic pressure → oedema.
• Impaired lipoprotein synthesis → fat accumulates in the liver → fatty hepatomegaly.
• Oxidative stress, aflatoxin exposure and cell-membrane dysfunction contribute to oedema and skin changes.

Clinical Features

• Oedema (pitting, dependent — feet, then generalised) — the defining feature.
• Growth retardation (partly masked by oedema).
• Skin changes — 'flaky-paint' dermatosis with hyper/hypopigmentation, especially in flexures.
• Hair changes — sparse, brittle, depigmented; the 'flag sign' (alternating light/dark bands); easily pluckable.
• Hepatomegaly (fatty liver); moon face; muscle wasting with some retained subcutaneous fat.
• Mental changes — apathy, irritability, anorexia.
• Anaemia, diarrhoea, and features of associated vitamin deficiencies.

Investigations

• Low serum albumin & total protein; anaemia; low blood glucose; electrolyte disturbances (low K, Mg).
• Screen for infection and associated deficiencies (vitamin A, zinc).

Management

Managed as SAM using the WHO 10-step protocol — cautious feeding with F-75 then F-100/RUTF, antibiotics for infection, correct micronutrients (no iron in the stabilisation phase), and never use diuretics for the oedema.

Prognosis

• With correct SAM management, the oedema resolves and the child recovers, though mortality is high if complications (infection, electrolyte imbalance, heart failure) are not anticipated.
• Marasmic-kwashiorkor (features of both) carries the worst prognosis.

A Note on WHY the Hair and Skin Change

• A vivid diagnostic set of signs is explained by understanding why protein deficiency shows itself in the hair and skin.
• Both are made of rapidly dividing cells producing structural protein (keratin) — so they are among the first tissues to fail when protein is unavailable.
• The hair becomes thin, sparse, dry and brittle; it loses its pigment (because melanin synthesis requires tyrosine, and its enzymes require protein) — turning it reddish-brown or grey; and it is easily plucked, without pain, because the follicles are atrophic.
• And because protein deprivation may be intermittent, alternating bands of pale and normal hair appear along the shaft — the 'flag sign' — which is, in effect, a historical record of the child's nutrition.
• The skin develops the characteristic 'flaky-paint' dermatosis: areas of hyperpigmentation which then desquamate, leaving raw, pale, easily-infected areas — particularly in the napkin area, the groins and over pressure points.
• It is thin, dry and ulcerates readily.
• Together with the oedema, apathy, anorexia, moon face and a fatty, enlarged liver, these produce the unmistakable picture of kwashiorkor — a child who is miserable, will not eat, and looks deceptively 'plump' because of the oedema.