📋 MOCK OSCE · FCPS, MCPS, MD PAEDIATRICS ⏱ 10 min · OBESITY

Obesity · Short Case

Candidate task: perform focused examination on a child with obesity, discuss differential diagnosis, investigations, management & follow‑up.
Pre‑exam Protocol
⏤ · Wash, Warm, Introduce, Position, Expose, Approach ▾

Standard pre‑examination protocol – must be demonstrated:

🖐 Wash hands with sterilizing solution.
🔥 Warm hands and stethoscope.
👋 Introduce yourself to child & parent.
🧍 Position child: standing for inspection, then supine for GPE.
👕 Exposure — chest, abdomen, and limbs exposed (maintain modesty).
➡️ Approach from the right side.
✔ CPSP marker: Pre‑exam Protocol is observed and scored.
1. Clinical Examination (≈6 min)
02 General Look (Inspection from end of bed) ▾

Key observations:

  • Body habitus: generalised vs truncal obesity (Cushing's), syndromic features (Prader‑Willi, Bardet‑Biedl).
  • Height: tall (exogenous obesity), short (endocrine – Cushing's, hypothyroidism, GH deficiency).
  • Nutritional status: BMI >95th percentile for age/sex.
  • Skin: acanthosis nigricans (insulin resistance), striae (Cushing's), hirsutism (PCOS).
  • Facial features: moon face (Cushing's), coarse features (hypothyroidism), dysmorphism (syndromes).
  • Activity: lethargy (hypothyroidism, Pickwickian), exercise tolerance.
👁 Red flags: short stature + obesity → endocrine cause (Cushing's, hypothyroidism, GH deficiency). Acanthosis nigricans → insulin resistance (T2DM, PCOS).
03 Measurements & Growth Parameters ▾

Anthropometry:

  • Height & weight: plot on growth chart; calculate BMI and BMI percentile.
  • BMI: >95th percentile = obese; >99th percentile = severe obesity.
  • Waist circumference: measure at midpoint between lower rib and iliac crest; elevated waist‑to‑height ratio >0.5 indicates central obesity.
  • Blood pressure: measure (obesity → hypertension).
  • Growth velocity: accelerated (exogenous obesity, precocious puberty), decelerated (endocrine causes).
📏 Key: BMI >95th percentile + short stature → screen for endocrine causes. Waist‑to‑height ratio >0.5 → higher metabolic risk.
04 General Physical Exam (Hands → Face → Abdomen → Limbs) ▾

Systematic examination:

  • Hands: small (Prader‑Willi), polydactyly (Bardet‑Biedl), short 4th metacarpal (pseudohypoparathyroidism).
  • Face: moon face (Cushing's), coarse features (hypothyroidism), triangular facies (Russell‑Silver – but short).
  • Skin: acanthosis nigricans (neck, axillae – insulin resistance), striae (purple – Cushing's), hirsutism (PCOS), bruising (Cushing's).
  • Neck: goitre (hypothyroidism), buffalo hump (Cushing's).
  • Chest: gynecomastia (Klinefelter, exogenous obesity), wide‑spaced nipples (Turner).
  • Abdomen: striae, hepatomegaly (fatty liver), umbilical hernia (Prader‑Willi).
  • Genitalia: hypogonadism (Prader‑Willi, Bardet‑Biedl, Klinefelter), cryptorchidism (Prader‑Willi, Noonan).
  • Lower limbs: small feet (Prader‑Willi), genu valgum (complication of obesity), tibia vara (Blount's disease).
  • Neurological: hypotonia (Prader‑Willi), delayed ankle jerk relaxation (hypothyroidism).
🔍 Key associations: obesity + short stature + hyperphagia + small hands/feet + hypotonia → Prader‑Willi. Obesity + acanthosis nigricans + hirsutism + menstrual irregularity → PCOS.
05 Developmental Assessment & Associated Signs ▾

Assess:

  • Motor milestones: may be delayed (Prader‑Willi – hypotonia).
  • Cognitive function: intellectual disability (Prader‑Willi, Bardet‑Biedl, Down).
  • Behaviour: hyperphagia, obsessive‑compulsive traits (Prader‑Willi), emotional eating, depression.
  • Vision: retinitis pigmentosa (Bardet‑Biedl, Alström).
  • Hearing: sensorineural deafness (Alström).
  • Sleep: snoring, sleep apnoea (obesity → Pickwickian syndrome).
🧠 Genetic clues: obesity + intellectual disability + hypogonadism + small hands/feet → Prader‑Willi (15q11.2‑13). Obesity + retinitis pigmentosa + polydactyly → Bardet‑Biedl.

📋 Case Presentation – (fill in during exam)

This is a _____-year-old _____ child, referred for _____ (obesity / weight gain). On examination, height _____ percentile, BMI _____ percentile, waist‑to‑height ratio _____. General exam: _____ (acanthosis nigricans, striae, dysmorphic features, genitalia). Developmental: _____ (appropriate/delayed). Associated signs: _____.

2. Viva Discussion (≈4 min)
06 Viva · Differential, Investigations, Management, Follow‑up ▾
🔹 Differential Diagnosis

Exogenous (Simple) Obesity
• Most common – calorie excess, sedentary lifestyle.
Endocrine Causes
• Cushing's syndrome (short, truncal obesity, striae)
• Hypothyroidism (short, goitre, dry skin, delayed reflexes)
• Growth hormone deficiency (short, cherubic facies)
• Pseudohypoparathyroidism (short, round face, short 4th metacarpal)
• Insulin resistance / T2DM (acanthosis nigricans)
Syndromic Causes
• Prader‑Willi (hypotonia, hyperphagia, small hands/feet, hypogonadism)
• Bardet‑Biedl (obesity, retinitis pigmentosa, polydactyly, renal anomalies)
• Alström (obesity, deafness, retinitis pigmentosa, T2DM)
• Down syndrome (short, dysmorphic, hypotonia)
• Klinefelter (tall, gynecomastia, hypogonadism)
• Lawrence‑Moon‑Biedl
Drug‑Induced
• Corticosteroids, antipsychotics (olanzapine, risperidone)

🔹 Investigations – Diagnosis

• Thyroid function – TSH, free T4 (exclude hypothyroidism).
• Fasting glucose, HbA1c – screen for T2DM.
• Lipid profile – dyslipidaemia (common).
• Liver function – ALT, AST (fatty liver).
• IGF‑1 / GH stimulation – if growth hormone deficiency suspected.
• Cortisol, dexamethasone suppression – if Cushing's suspected.
• Karyotype – if syndromic (Turner, Klinefelter).
• Genetic testing – if Prader‑Willi (methylation analysis), Bardet‑Biedl.

🔹 Investigations – Aetiology

• Genetic testing – Prader‑Willi (15q11.2‑13), Bardet‑Biedl (BBS genes).
• MRI brain – if hypopituitarism / Cushing's (pituitary adenoma).
• Pelvic ultrasound – if PCOS suspected.
• Sleep study – if obstructive sleep apnoea suspected.

🔹 Investigations – Exclude Others

• Thyroid function – exclude hypothyroidism.
• Cortisol – exclude Cushing's.
• Glucose, HbA1c – exclude T2DM.
• Lipids – screen for dyslipidaemia.
• Liver function – screen for fatty liver.

🔹 Investigations – Rule Out Complications

• Blood pressure – hypertension.
• Lipid profile – dyslipidaemia.
• HbA1c / OGTT – T2DM.
• Liver ultrasound – fatty liver / steatohepatitis.
• Sleep study – if sleep apnoea suspected.
• Orthopaedic – if Blount's disease or SCFE suspected (X‑ray).

🔹 Management – Across Organ Systems

Lifestyle

Dietary modification (healthy eating, portion control), physical activity (60 min/day), behavioural therapy.

Pharmacological

Metformin (if insulin resistance / T2DM), liraglutide (if ≥12 years, BMI >95th). Orlistat (limited use in children).

Endocrine

Thyroxine (hypothyroidism), hydrocortisone (adrenal insufficiency), GH (GH deficiency).

Surgical

Bariatric surgery (if severe obesity with comorbidities, and failed medical therapy – limited use).

Psychosocial

Counselling, family‑based intervention, address bullying / self‑esteem.

Complication Management

T2DM – metformin / insulin. Dyslipidaemia – statin (if >10 years). Sleep apnoea – CPAP. Blount's disease – orthopaedic referral.

Surveillance

Monitor BMI, BP, lipids, HbA1c; screen for T2DM every 1‑2 years.

Genetic Counselling

If syndromic – recurrence risk.

📈 Prognosis

  • Exogenous obesity: variable; early intervention improves outcomes.
  • Hypothyroidism: excellent with thyroxine; catch‑up growth.
  • Cushing's: depends on cause; good if treated early.
  • Prader‑Willi: lifelong management; risk of obesity, T2DM, sleep apnoea.
  • T2DM: progressive; may require insulin.

📋 Follow‑up Schedule

  • Exogenous obesity: 3‑6 monthly for weight management, annual BP/lipids/HbA1c.
  • Endocrine causes: endocrinology 3‑6 monthly; monitor growth, TFTs / cortisol.
  • Prader‑Willi: multidisciplinary 6‑12 monthly; monitor for scoliosis, sleep apnoea, T2DM.
  • T2DM: endocrinology 3‑6 monthly; monitor HbA1c, lipids, microalbuminuria.
  • Transition: to adult services (endocrinology, obesity medicine).
💡 Examiner expectation: differentiate exogenous (simple) obesity from endocrine / syndromic causes. Recognise complications – T2DM, dyslipidaemia, hypertension, NAFLD, sleep apnoea, orthopaedic issues. Know management – lifestyle first, with pharmacological / surgical options for severe cases.
📚 Visit paeds.online for more CPSP resources
Mock OSCE · Obesity · Based on Wyne‑Harris, Nelson & Pediatric Clinical Advisor