title: "Week 5: Cardiology, Developmental, Dermatology & Endocrinology"
Week 5: Cardiology, Developmental, Dermatology & Endocrinology
1. Cardiology
Fetal Circulation Review
In the fetus, pulmonary vascular resistance is high. The ductus arteriosus and foramen ovale allow oxygenated blood to bypass the lungs.
| Fetal Shunt | Description | Closure Stimulus |
|---|---|---|
| Foramen Ovale | RA to LA | Increased LA pressure from pulmonary venous return |
| Ductus Arteriosus | Pulmonary trunk to aorta | Increased PaO2, removal of prostaglandins |
| Ductus Venosus | Umbilical vein to IVC | Passive, decreased flow |
Neonates have RV dominance. This slowly transitions to LV dominance throughout childhood.
PGE1 can reopen the ductus arteriosus as a temporising measure in duct-dependent conditions (e.g., aortic coarctation).
Acquired Heart Disease
| Condition | Key Points |
|---|---|
| Acute Rheumatic Fever | 10 days - 6 weeks post-GAS pharyngitis/pyoderma. High-risk: Indigenous communities |
| Rheumatic Heart Disease | From recurrent ARF. Penicillin prophylaxis essential |
| Kawasaki Disease | Can cause coronary artery aneurysm. Treat with IVIg |
| Endocarditis | Usually mouth commensals on damaged endocardium. 6 weeks IV antibiotics |
Congenital Heart Disease
Incidence: 6-8 per 1000 live births (approximately 1 in 100).
- Tetralogy of Fallot (most common cyanotic CHD)
- Transposition of Great Arteries
- Truncus Arteriosus
- Total Anomalous Pulmonary Venous Return
- Tricuspid Valve Abnormalities
Chromosomal Associations:
- Down syndrome: AVSD
- Turner syndrome: Coarctation
- DiGeorge/Velo-Cardio-Facial: Conotruncal defects
Clinical Assessment
Signs of heart failure in children: tachypnoea, poor feeding, sweating (catecholamines), failure to thrive. Note: Kids don't get peripheral oedema like adults - check for hepatomegaly!
Apex beat location:
- <7 years: Left 4th intercostal space, MCL
- >7 years: Left 5th intercostal space, MCL
Heart Sounds and Murmurs
Wide fixed split S2 = Atrial Septal Defect. Anything increasing right-sided blood flow will split S2.
| Murmur Character | Example |
|---|---|
| Crescendo | Pulmonary/aortic stenosis, HCM |
| Decrescendo | Aortic/pulmonary regurgitation |
| Continuous "machinery" | Patent Ductus Arteriosus |
| Harsh pansystolic | VSD |
Common Defects
| Defect | Murmur | CXR | Features |
|---|---|---|---|
| VSD | Harsh pansystolic | Cardiomegaly, increased pulmonary markings | Presents 4-8 weeks as PVR falls |
| ASD | Wide fixed split S2, systolic flow murmur | RA/RV enlargement | May present with recurrent respiratory infections |
| PDA | Continuous machinery murmur | Cardiomegaly | Bounding pulses, wide pulse pressure |
| TOF | Harsh systolic ejection murmur | Boot-shaped heart | Progressive cyanosis by 5-6 months, "tet spells" |
| TGA | Single loud S2, no murmur | Egg on string | Most common cyanotic CHD presenting in first week |
A VSD murmur won't be apparent until PVR falls (around 4-8 weeks) and there's a pressure differential between LV and RV.
Tet spells (hypercyanotic episodes) in TOF require urgent management: knee-to-chest position, oxygen, morphine, IV fluids.
2. Community & Developmental
Autism Spectrum Disorder
Prevalence is commonly reported around ~1–2% (varies by definition/ascertainment), M>F. Typically detected before school entry. Intellectual disability is a possible comorbidity.
Source: AIHW (Autism in Australia) / DSM-5-TR.
Social Interaction:
- Poor eye contact
- No sharing of enjoyment
- No response to name
Communication:
- No pointing by 12 months
- No single words by 18 months
- No 2-word combinations by 2 years
- Echolalia
Restricted Behaviours:
- Spinning, twirling, flapping
- Fixation on detail
- Hypersensitivity to sound/textures
Absolute indicators for referral:
- No babbling by 12 months
- No single words by 18 months
- No 2-word phrases by 2 years
- Any regression in language
Diagnosis (DSM-5):
- Persistent deficits in social communication across multiple contexts
- Restricted repetitive patterns of behaviour
- Symptoms present early and cause impairment
The key distinguishing feature of autism vs intellectual disability is social communication deficits.
Management:
- Early intervention, speech therapy
- Visual strategies (PECS)
- Medications for comorbidities (not core symptoms):
- Stimulants for ADHD (Attention-Deficit/Hyperactivity Disorder) symptoms
- Risperidone for aggression
- SSRIs (Selective Serotonin Reuptake Inhibitor) for anxiety
- Melatonin for sleep
Attention Deficit Hyperactivity Disorder (ADHD (Attention-Deficit/Hyperactivity Disorder))
Prevalence is commonly reported around ~5% in school-age children; M>F. Typically detected after school entry. Highly heritable.
Source: DSM-5-TR / Australian child mental health epidemiology sources.
Risk Factors:
- Family history (biggest risk factor)
- Low birthweight
- Maternal smoking in pregnancy
- Epilepsy (25-40% have ADHD)
DSM-5 Diagnosis: 5+ inattentive AND/OR hyperactive-impulsive symptoms, present >6 months, before age 12, in 2+ settings.
| Inattention | Hyperactivity-Impulsivity |
|---|---|
| Poor attention to detail | Fidgets and squirms |
| Can't sustain attention | Often out of seat |
| Doesn't listen | Runs/climbs excessively |
| Poor organisation | Can't play quietly |
| Loses things | Excessive talk, interrupts |
Comorbidity is common in ADHD (Attention-Deficit/Hyperactivity Disorder) (e.g., learning disorders, disruptive behaviour disorders, anxiety/mood disorders, autism).
Source: DSM-5-TR.
Treatment:
MTA Trial finding: Medication alone is superior for core ADHD (Attention-Deficit/Hyperactivity Disorder) symptoms. Medication + behaviour management for non-core symptoms (anxiety, aggression).
| Medication | Formulation |
|---|---|
| Methylphenidate (Ritalin) | Short: 10mg (3-4h), Long: Ritalin LA (7-8h), Concerta (12h) |
| Dexamphetamine | Short: 5mg (3-4h), Long: Lisdexamphetamine/Vyvanse (10-12h) |
Side Effects:
- Common: Loss of appetite (especially lunch)
- Less common: Difficulty sleeping, emotional lability
- Rare: Mood lability, psychotic symptoms, growth delay
Stimulant medication requires 6-monthly monitoring of height, weight, HR (Heart Rate), and BP (Blood Pressure).
3. Dermatology
Birthmarks
| Type | Description | Association |
|---|---|---|
| Cafe au lait spots | Increased melanocyte activity | Neurofibromatosis if >6 |
| Ash leaf macules | Hypopigmented | Tuberous sclerosis |
| Naevus flammeus | Dilated capillaries | Port wine stain |
Infantile Haemangioma
Most common benign soft tissue tumour of childhood. Not usually present at birth. 3 phases: proliferative (3-6 months), plateau, involution (50% by 5 years, 90% by 9 years).
Most haemangiomas don't need treatment. Ulceration is the most distressing complication. Bad locations: ophthalmic (amblyopia), nasal tip.
Treatment (if needed): Oral propranolol, oral corticosteroids
- P - Posterior fossa anomalies (Dandy-Walker)
- H - Haemangioma (large facial/cervical)
- A - Arterial anomalies (coarctation)
- C - Cardiac anomalies
- E - Eye anomalies (coloboma, glaucoma)
- S - Sternal defects
Atopic Dermatitis (Eczema)
Prevalence: 10-20% of children. 45% begin in first 6 months, 85% by 5 years. Most children grow out of it (only 1-3% of adults affected).
Atopic associations: Asthma 50%, allergic rhinitis 50-80%, food allergy 30%
Clinical Features:
- Dry skin, fine scale, poorly demarcated margins
- Affects flexures
- Babies: Cheeks ("Headlight Sign" - prominence of cheeks, sparing folds)
- Napkin area typically spared
No response to treatment? Think secondary infection with Staph aureus or Strep pyogenes. Colonisation managed with bleach baths.
Management:
- Avoid environmental triggers (soap, wool, heat)
- Regular emollients (continue even when skin looks good)
- Topical steroids are gold standard
- Face: Sigmacort (1% hydrocortisone)
- Trunk: Aristocort (moderate)
- Limbs: Diprosone (potent)
Do not be afraid to treat intensively with potent topical steroids! Steroid phobia is real but steroids are safe when used appropriately.
Psoriasis
Immune-mediated disorder. Guttate psoriasis = sudden scaly lesions 2-3 weeks post-streptococcal infection.
Classic features: Erythematous, well-demarcated plaques, thick silvery-white scale, symmetrical, extensor surfaces
Paediatric presentations: Guttate, facial, flexural, scalp
Skin Infections
Impetigo
School sores. Caused by Staph aureus and Strep pyogenes. Remember: impetigo is itchy (herpes hurts)!
| Non-bullous (70%) | Bullous |
|---|---|
| Broken skin, face/extremities | Staph toxin causes blistering of intact skin |
| Pustules with honey-coloured crust | Large thin-roofed bullae, trunk/buttocks |
Complications: Sepsis, guttate psoriasis, scarlet fever, PSGN
Staphylococcal Scalded Skin Syndrome
Typically child <5 years with haematogenous spread of staph toxin. Extremely painful. Unlike SJS, no mucosal involvement.
Fungal Infections - Tinea
Annular lesions are tinea until proven otherwise. Diagnose with skin scraping. Beware tinea incognito - clinical appearance altered by inappropriate use of topical steroids.
Molluscum Contagiosum
- Skin-coloured papules with umbilicated centres
- Highly contagious, spread by close contact/warm water
- Treatment: cryotherapy, deroof lesion, or wait for spontaneous resolution
4. Endocrinology
Puberty
Typical duration: 2-5 years. Delayed and precocious puberty are defined by gonadarche (activation of gonads by FSH/LH).
- Adrenarche (6-8y): Adrenal androgen production
- Pubarche (8-13y): Pubic/axillary hair, acne, body odour
- Gonadarche: Ovarian/testicular enlargement
- Thelarche (girls, 10.5y): Breast bud formation
- Menarche (girls, 12.25y) / Spermarche (boys, 13.5y): Last events
| Feature | Girls | Boys |
|---|---|---|
| First physical sign | Thelarche | Testicular enlargement (4mL) |
| Peak growth spurt | 11.5y (early, before menses) | 13.5y (late) |
| Peak velocity | 6-10 cm/year | 7-12 cm/year |
| Total growth | +20cm, +20kg | +30cm, +30kg |
Bone age (hand/wrist X-ray) can assess puberty stage. Tanner staging: genitalia/breasts from Stage 1-5.
Short Stature
Height <3rd centile for age and gender. Most common causes: constitutional growth delay and familial short stature.
Constitutional Delay of Growth and Puberty (CDGP):
- Absent breast development in girls >13 years
- Testicular volume <4mL in boys >14 years
- Delayed bone age, normal gonadotrophins for bone age
- Usually resolves spontaneously; may trial low-dose sex steroids if distressed
Turner Syndrome (45,XO): Consider in any female with short stature or delayed/arrested puberty. May respond to GH therapy.
Delayed Puberty
| Cause | Level | Labs |
|---|---|---|
| Gonadal (Turner, Klinefelter, radiation) | Primary | High LH/FSH, low sex steroids |
| Pituitary (tumours, trauma) | Secondary | Low LH/FSH, no response to GnRH |
| Hypothalamic (constitutional, Kallmann) | Tertiary | Low LH/FSH, rises after GnRH |
Kallmann syndrome = delayed puberty + anosmia (GnRH neurone migration defect).
Precocious Puberty
Central Precocious Puberty: Normal pubertal sequence but much earlier. Usually idiopathic in girls (>90%), but CNS (Central Nervous System) lesion in boys (75%).
Morbidity: Short adult stature (early epiphyseal closure), psychosocial distress
Premature adrenarche (pubic hair, acne before 8-9y) is NOT precocious puberty, but excess weight gain can drive early puberty.
Pubertal Gynaecomastia
80% of normal males in Tanner Stage 3-4 have gynaecomastia. Usually resolves spontaneously; surgery in 10%.
Pathological causes: Drugs (marijuana), sex-steroid tumours, Klinefelter syndrome
Diabetes in Children
Type 1 DM is the most common form in children. Autoimmune destruction of beta cells. Presentation: polyuria, polydipsia, weight loss, fatigue.
Diabetic Ketoacidosis (Diabetic Ketoacidosis): Life-threatening. pH <7.3, HCO3 <15, ketonuria/ketonaemia. Cerebral oedema is the most feared complication in paediatric DKA (Diabetic Ketoacidosis).
DKA (Diabetic Ketoacidosis) Management:
- Fluid resuscitation (10mL/kg boluses, avoid over-resuscitation)
- Insulin infusion (0.1 units/kg/hr, start AFTER first hour of fluids)
- Potassium replacement
- Monitor for cerebral oedema (headache, altered LOC, bradycardia, HTN)
Type 2 diabetes in children is rising with obesity. More common in Aboriginal and Torres Strait Islander youth, Pacific Islander and South Asian populations. Acanthosis nigricans is a key clinical sign of insulin resistance.
Thyroid Disease in Children
Congenital hypothyroidism is the most common preventable cause of intellectual disability. Detected on newborn screening (elevated TSH). Incidence: 1 in 3000-4000 live births.
Acquired hypothyroidism:
- Most common cause in children: Hashimoto's thyroiditis (autoimmune)
- Presents with growth deceleration, weight gain, fatigue, constipation, delayed puberty
- Bone age is delayed
- Treatment: levothyroxine
Graves disease is the most common cause of hyperthyroidism in children. Presents with weight loss, tremor, exophthalmos, tachycardia, and goitre. Treatment: carbimazole or propylthiouracil, with beta-blockers for symptomatic control.
Practice Questions
What is the most appropriate immediate management?
What is the most appropriate first-line treatment?
What is the most appropriate treatment?