Child Health · Dehydration
Child Dehydration — CDS & MUAC
Clinical Dehydration Scale (CDS): 4 items, 0-8 score. Red flags, ORS (Dioralyte) treatment, when to A&E. Plus MUAC for malnutrition screening. Friedman 2004 / WHO.
Last reviewed 2 June 2026
MUAC + Clinical Dehydration Scale
Paediatric malnutrition + dehydration assessment
Mid-Upper Arm Circumference (MUAC) — 6-59 months
cm
Cutoffs (in mm): SAM < 115; MAM 115-125; Normal ≥ 125.
Clinical Dehydration Scale (CDS) — Gorelick / Friedman
Enter MUAC or score the CDS items.
Educational tool only — not medical advice. MUAC is a key indicator of acute malnutrition in 6-59 month-olds, used worldwide by WHO/UNICEF/MSF (independent of weight scales, no need for height/age). The Clinical Dehydration Scale (Friedman 2004) is validated for 1-36 month-olds presenting with gastroenteritis.
What does this mean?
MUAC is one of the simplest, most powerful screening tools in child health. A simple coloured tape around the upper arm identifies severe acute malnutrition (SAM, < 11.5 cm) and moderate acute malnutrition (MAM, 11.5–12.4 cm) in 6–59 month- olds — without scales or height boards, anywhere in the world. WHO/UNICEF use MUAC alongside weight-for-height z-score and bilateral pitting oedema to define SAM and direct children into community-based or inpatient therapeutic feeding (RUTF like Plumpy’Nut). The Clinical Dehydration Scale (Friedman 2004) is a 4-item bedside score for paediatric gastroenteritis that performs better than “skin turgor” alone (Cochrane 2015): general appearance, eyes, mucous membranes, tears. Score 0 none; 1–4 some dehydration (oral rehydration plan B); 5–8 moderate–severe (consider NG or IV plan C, urgent assessment).
Clinical Dehydration Scale (CDS)
Friedman 2004. 4 items scored 0-2 each:
- General appearance.
- Eyes.
- Mucous membranes (tongue).
- Tears.
Total 0-8.
- 0-1: mild / no dehydration.
- 2-4: moderate.
- 5-8: severe.
Red flags — same-day medical review
- Dry mouth / sunken eyes / no tears.
- <4 wet nappies/24h (infants) or no urine 8+ hours (older).
- Lethargy / unusually sleepy.
- Irritable / inconsolable.
- Fast heart rate.
- Rapid / deep breathing.
- Cold hands / feet; mottled skin.
- Capillary refill >2 sec.
- Weight loss (>5% acute).
- Sunken fontanelle (infants).
MUAC for malnutrition
Mid-upper arm circumference. Children 6 months-5 years.
- ≥125 mm: normal.
- 115-124 mm: moderate malnutrition.
- <115 mm: severe (global emergency standard).
Treatment
- Mild-moderate: ORS (Dioralyte) 50 mL/kg over 4 hours + replacement of losses. Sip 5-10 mL every 5-10 min. Breastfeeding continued.
- Severe / shocked: hospital; IV fluids; electrolyte correction.
ORS (Dioralyte) basics
Specific glucose + salt mix for gut absorption. Dissolve in EXACT water amount. Refrigerate; use within 24h. NOT sports drinks (too sugary, wrong electrolytes). NHS prescribes free for under-5s.
Fluid maintenance (Holliday-Segar)
- First 10 kg: 100 mL/kg/day.
- 10-20 kg: +50 mL/kg/day.
- >20 kg: +20 mL/kg/day.
Plus replacement for dehydration losses.
Hospital admission criteria
- CDS ≥5.
- Shock signs.
- Persistent vomiting.
- Bloody / black stool.
- Altered mental status.
- Underlying illness.
- <6 months significantly unwell.
- Failed home / community ORS.
Anti-diarrhoea / anti-vomit meds in children?
- Loperamide (Imodium): avoid in children <12 generally.
- Ondansetron: sometimes paediatric A&E; doctor-prescribed.
- Metoclopramide: not for children.
- Zinc: WHO recommends for diarrhoea in children.
- Probiotics: some evidence reducing diarrhoea duration.
Gastroenteritis specifics
- Viral usually (rotavirus, norovirus).
- Duration 5-7 days.
- Normal age-appropriate food when tolerating (BRAT diet outdated).
- Continue breastfeeding / formula.
- Avoid sugar-heavy drinks (juice, fizzy).
- Temporary lactose intolerance possible.
- 48-hour stay-home rule for nursery / school (UK).
Different scenarios
Scenario 1: Toddler with vomiting + diarrhoea x 2 days, CDS 3
Moderate dehydration. ORS slowly + frequently. Recheck signs.
Scenario 2: 18-month-old, fever, refusing fluids, lethargic, CDS 6
A&E. Possible IV fluids. Investigate cause — UTI workup, gastro screen.
Scenario 3: 6-year-old, hot weather, headache, mild thirst
Mild dehydration. Cool environment. Frequent small drinks. Recheck.
Scenario 4: Infant with poor feeding, dry mouth, <4 wet nappies/24h
Same-day medical review. Possible serious illness behind.
Scenario 5: Toddler 5-day diarrhoea, weight loss 6%, MUAC 113 mm
Severe malnutrition. Specialist input. Refeeding cautiously to avoid refeeding syndrome.
Care guidance — child dehydration
- Watch nappies / urine output.
- Sip ORS frequently.
- Continue breastfeeding.
- Don’t withhold food when tolerating.
- No anti-diarrhoea meds typically.
- 48-hour stay-home rule.
- Low threshold for medical review especially <6 months.
- UTI in young children — check urine.
Sources
- Friedman JN, et al. Development of a clinical dehydration scale for use in children 1-36 months. J Pediatr 2004.
- NICE NG84. Suspected sepsis in under-5s.
- NICE CG84. Diarrhoea and vomiting in under-5s.
- WHO / UNICEF. Integrated Management of Childhood Illness.
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Frequently asked questions
What is the Clinical Dehydration Scale (CDS)?
VALIDATED tool to assess CHILD DEHYDRATION severity. 4 ITEMS scored 0-2 each: GENERAL APPEARANCE, EYES, MUCOUS MEMBRANES (tongue), TEARS. TOTAL 0-8. Friedman 2004 (Pediatrics) — Canadian paediatric. STRENGTHS: simple, reliable, no special equipment, ages 1 month-3 years primarily. INTERPRETATION: 0-1 mild/no dehydration; 2-4 moderate; 5-8 severe. USED in: paediatric A&E, primary care, parents at home (with guidance).
When should I worry about my child being dehydrated?
RED FLAGS: (1) DRY MOUTH / sunken eyes / no tears; (2) DECREASED URINE — fewer than 4 wet nappies in 24h (infants) or no urine for 8+ hours (older children); (3) LETHARGY / unusually sleepy; (4) IRRITABLE / inconsolable; (5) FAST HEART RATE; (6) RAPID / DEEP breathing; (7) COLD HANDS / FEET, mottled skin; (8) CAPILLARY REFILL >2 sec (press fingertip, count to release); (9) WEIGHT LOSS (acute >5%); (10) SUNKEN FONTANELLE in infants. ANY: GP / NHS 111 / A&E same-day.
Common causes of child dehydration?
(1) VOMITING + DIARRHOEA (gastroenteritis — viral commonly): most common; (2) POOR ORAL INTAKE (sore throat, mouth ulcers, refusing); (3) FEVER (increased fluid loss); (4) HEAT exposure (hot weather, dehydration); (5) DIABETES (new diagnosis or DKA — polydipsia, polyuria); (6) BURNS; (7) PROLONGED INFECTION; (8) URINARY losses (DI, certain medications); (9) GI conditions (cholera, severe gastroenteritis, IBD). FREQUENT in babies + toddlers — small fluid reserves.
What's MUAC?
MID-UPPER ARM CIRCUMFERENCE — measuring tape around the middle of the upper arm. USED FOR: MALNUTRITION SCREENING (not just dehydration) in children 6 months-5 years. CUT-OFFS: ≥125 mm normal; 115-124 mm moderate malnutrition; <115 mm severe (red flag — global emergency standard). ALSO USED for dehydration in some protocols (modest correlation). QUICK + EFFICIENT screening in low-resource / emergency settings; WHO + UNICEF standard for malnutrition.
How is dehydration treated?
(1) MILD-MODERATE (CDS 1-4): ORAL REHYDRATION — DIORALYTE or similar (NHS-prescribed) — 50 mL/kg over 4 hours + replacement of losses. Sip frequently — small + often (5-10 mL every 5-10 min). BREASTFEEDING continued in infants. (2) SEVERE (CDS 5-8 or shocked): HOSPITAL — IV FLUIDS; correct electrolytes; monitoring. (3) UNDERLYING cause addressed (antibiotic if bacterial, etc.); (4) PREVENT recurrence: education.
What's ORS / Dioralyte?
ORAL REHYDRATION SOLUTION — sachets of specific glucose + salt mix that maximises gut absorption. PRECISE OSMOLARITY balances water absorption + electrolyte replacement. BRANDS: Dioralyte (UK), Pedialyte (US), generic ORS sachets. PROCEDURE: dissolve in EXACT amount of water (200 mL usually); refrigerate; use within 24h. NOT 'sports drinks' — too sugary, wrong electrolyte balance. DEFINITELY NOT just water (worsens hyponatraemia). NHS prescribes free for under-5s.
How much fluid does my child need?
MAINTENANCE: HOLLIDAY-SEGAR formula — 4-2-1 rule. First 10 kg: 100 mL/kg/day. Next 10 kg (10-20 kg): +50 mL/kg/day. Above 20 kg: +20 mL/kg/day. EXAMPLE: 15 kg child = 1000 mL (first 10kg) + 250 mL (next 5kg) = 1250 mL/day maintenance. PLUS REPLACEMENT for dehydration losses. ILL CHILDREN: more if fever + losses. SICK + REFUSING: gentle frequent small amounts (5 mL every 5 min) often works better than larger volumes.
What signs indicate hospital admission?
(1) CDS ≥5 (severe dehydration); (2) SHOCK signs (capillary refill >3 sec, cold mottled, low BP); (3) PERSISTENT vomiting + can't tolerate oral fluids; (4) BLOODY / black stool; (5) CONTINUOUS pain; (6) ALTERED MENTAL STATUS; (7) UNDERLYING illness (diabetes, kidney disease); (8) <6 MONTHS with significant illness; (9) FAILED home / community ORS trial; (10) UNCERTAIN diagnosis; (11) PARENT concern. EARLIER intervention better in young children — small reserves.
Should I give my child anti-diarrhoea / anti-vomit medicines?
MOSTLY NO. LOPERAMIDE (Imodium): avoid in children — slows gut + extends infection; contraindicated under 12 generally; rare exceptions. ONDANSETRON (anti-emetic): sometimes used in paediatric A&E for acute vomiting (single dose); not routine OTC; doctor-prescribed. METOCLOPRAMIDE: not for children. NHS approach: focus on rehydration. ZINC supplementation: WHO recommends for diarrhoea in children especially low-resource; UK practice varies. PROBIOTICS: some evidence for reducing diarrhoea duration.
What about gastroenteritis specifically?
VIRAL most common (rotavirus, norovirus). DURATION 5-7 days usually. TREATMENT: REHYDRATION first-line; PARACETAMOL for fever / discomfort; GENTLE REINTRODUCTION of food (BRAT diet — bananas, rice, apple, toast — no longer needed; normal age-appropriate food fine when tolerating); CONTINUE BREASTFEEDING / formula. AVOID: SUGAR-HEAVY drinks (juice, fizzy); empty calorie intake; restricting food unnecessarily. RECOVERY phase: some lactose intolerance temporary (consider lactose-free milk briefly).
Can my child get dehydrated from heat?
YES — especially: babies, young children, those with chronic illness. EARLY signs: thirst, headache, fatigue, irritability. PROGRESSIVE: dizziness, fast heart rate, cool skin, eventually heat stroke (red flags). PREVENTION: shade, cool environment, light clothing; FREQUENT small drinks; AVOID midday heat; WATER + SOME electrolytes for prolonged heat. NEVER leave child in car. INFANTS especially vulnerable — extra breastfeeds in hot weather.
When can my child go back to nursery?
GASTROENTERITIS: STAY HOME 48 hours after last episode of vomiting / diarrhoea (UK Health Protection guidance). MOST UK NURSERIES require this. KEEPS others from getting ill. HYDRATION + FEEDING returned to normal before return. SCHOOL: same advice. INFORM nursery / school about cause if known (helps them monitor outbreaks).
What's BRAT diet — is it still recommended?
NO — outdated. BRAT (Bananas, Rice, Applesauce, Toast) was traditional 'bland' post-illness diet. CURRENT GUIDANCE: NORMAL age-appropriate diet as soon as child tolerates (gentle reintroduction). HELPS gut heal faster. AVOIDS calorie deficit. BREASTMILK / formula continued throughout. KEY: ANY oral intake better than withholding food while rehydrating.
Could it be a UTI causing dehydration?
UTI in young children common — sometimes presents with fever, vomiting, poor feeding (without typical urinary symptoms in pre-verbal). ALWAYS CHECK urine if child unwell + fever + dehydrated + no obvious GI cause. NHS guidance: urine dipstick + send for culture in any febrile young child without clear source. ESPECIALLY IMPORTANT in babies + toddlers. TREATMENT: antibiotics + rehydration. CAN BE serious — pyelonephritis (kidney infection).
How does this relate to other calculators on BumpBites?
Companion: /calculators/ors-rehydration; /calculators/baby-fever; /calculators/pediatric-dose; /calculators/baby-constipation; /calculators/pews-paediatric; /calculators/baby-cough (overlap illness); /calculators/hand-foot-mouth (cause); /calculators/oral-thrush.