Paediatric Development, Sleep, and Forensic Medicine

Child Development and Milestone Monitoring

• Development is a neurologically based progression from the total dependence of a newborn to the competency of an adult.

• While every child has an individual rate of development, the sequence typically remains the same across all children. Development involves periods of rapid increase followed by plateaus; however, development is never expected to regress.

• Developmental disability is defined as a sufficient difference in neurologically based development that results in problems affecting a person’s ability to manage daily life. This process is influenced by the interaction of the nervous system with environmental, social, cultural, and ethnic factors, as well as genetic predispositions for personality and temperament.

Domains of Development

• Gross Motor: Evaluates major physical movements, such as the age at which a child begins to walk, run, or jump.

  • Correction for prematurity is necessary for children under $2$ years of age. For example, if a child was born $3$ months premature, the chronological age is reduced by $3$ months for assessment purposes.

  • The milestone for independent walking is typically expected by $18$ months of age.

• Fine Motor: Presumes that vision is intact. Milestones include the pincer grip (at approximately $9$ months), holding crayons or pens, and using a spoon for self-feeding.

• Language Skills: Hearing is a prerequisite for language development after $9$ months of age.

  • Expressive Language: The ability to speak. Milestones include single words by $12$ months, two-word sentences by $2$ years ($24$ months), and complex sentences by $3$ years.

  • Receptive Language: The understanding of language. A failure to turn when a name is called indicates poor receptive language. In some conditions, like autism, receptive language may be significantly worse than expressive language.

• Social Interaction: Begins with social smiling and progresses to to-and-fro conversation, playing with peers, and making social initiations.

• Executive Functioning: Relevant as children reach school age; includes organization, planning, and academic learning.

Clinical Red Flags

• Developmental Regression: Any loss of previously acquired skills (e.g., a child who used to wave or speak words but can no longer do so). Regression is abnormal and requires urgent escalation to a paediatrician.

• Head Circumference: Large or small heads (macrocephaly/microcephaly) or head circumferences that cross $2$ or more centiles require urgent review to check for issues like intracranial bleeding, craniosynostosis, or small brain development.

• Focal Neurology: New neurological symptoms or the development of seizures are marks of potential pathology.

Fetal Alcohol Spectrum Disorder (FASD)

• FASD is an acquired brain injury caused by alcohol exposure prior to birth. The alcohol molecule crosses the placenta easily and acts as a teratogen, damaging the developing central nervous system (CNS), other body organs, and causing distinctive facial features and growth delays.

• The CNS has critical developmental periods for most of the pregnancy, meaning there is no safe time, no safe amount, and no safe type of alcohol to consume during pregnancy or while breastfeeding.

Prevalence and History

• FASD was first described by William Sullivan in $1899$ and further defined by Jones and Smith in the mid-$1970s$.

• In Australia, prevalence is under-researched due to under-diagnosis and reluctance to discuss alcohol use, but specific populations, such as Fitzroy Crossing, have shown rates as high as $120$ per $1000$ (roughly $12$ in every $100$ children).

• In the United States, conservative estimates place FASD prevalence at $1\text{--}5\%$. It is considered the most common cause of developmental disability in several countries.

Diagnostic Criteria (Australian 2016 Guidelines)

• A diagnosis is made based on three components:

  1. Confirmed Prenatal Alcohol Exposure: High-risk exposure must be documented. Assessment involves nonjudgmental history-taking regarding the amount, frequency, and timing of alcohol intake.

  2. Severe Neurodevelopmental Impairment: Requires impairment in at least $3$ of $10$ domains, defined as a score of at least $2$ standard deviations below the mean ($30^{th}$ centile). Domains include motor skills, executive function, memory, attention, language, academic achievement, adaptive function, cognition, and affect regulation.

  3. Sentinel Facial Features: Three specific features are assessed:

     • Smooth Philtrum: The groove between the nose and upper lip is flattened.

     • Thin Upper Lip: Measured using a specific grading system.

     • Short Palpebral Fissures: Short eye spaces measured between the inner and outer corners of the eye ($\text{endocanthion}$ to $\text{exocanthion}$).

• Diagnostic Categories:

  • FASD with $3$ sentinel facial features.

  • FASD with less than $3$ sentinel facial features (requires more extensive neurodevelopmental evidence).

Sleep Physiology and Disorders in Children

• Sleep is regulated by a two-process model:

  • Homeostatic Model: Sleep pressure increases the longer one is awake and dissipates during sleep.

  • Circadian Model: An endogenous rhythm (approximately $23\text{--}25$ hours) modulated by light entering the retina and signalling the suprachiasmatic nucleus in the hypothalamus.

Genetics of Circadian Rhythms

• The $2017$ Nobel Prize was awarded for the discovery of the genetic mechanisms of the circadian rhythm.

• Key proteins include the PER (period) protein and TIM (timeless) protein. In the cytoplasm, PER and TIM unite to cross into the nucleus and block further PER production, creating an oscillatory cycle that dictates the internal clock.

Sleep Architecture and Development

• Non-Rapid Eye Movement (Non-REM): Divided into stage $1$ (light), stage $2$, and stage $3$ (deep/slow-wave sleep). Deep sleep typically occurs in the first third of the night.

• Rapid Eye Movement (REM): Associated with dreaming and occurs primarily in the second half of the night.

• Age-Based Changes:

  • Newborns (full term) spend $50\%$ of sleep in REM and $50\%$ in Non-REM.

  • By $3\text{--}6$ months, an adult-like pattern (Non-REM stages $1\text{--}3$) develops.

  • By $12$ months, children usually have a two-nap pattern, moving to a one-nap pattern by $18$ months. By $5$ years, children should stop napping if they receive sufficient night sleep.

  • Total sleep duration decreases with age, from an average of $11\text{--}14$ hours in toddlers to $9$ hours in teens.

Common Sleep Problems

• Obstructive Sleep Apnoea (OSA): Upper airway obstruction involving snoring, gasping, and paradoxical chest movement. Peak age is $2\text{--}7$ years due to adenotonsillar hypertrophy. Complications include neurocognitive deficits, failure to thrive, and, rarely, pulmonary hypertension.

• Parasomnias (Disorders of Arousal):

  • Night Terrors/Sleepwalking: Partial arousals from deep (Non-REM stage $3$) sleep, usually occurring in the first third of the night. Children have no memory of the event.

  • Nightmares: Occur during REM sleep in the second half of the night; children are lucid and can recall the dream.

• Narcolepsy: A disorder of dream sleep presenting with excessive daytime sleepiness, cataplexy (sudden loss of muscle tone triggered by laughter), hypnagogic hallucinations, and sleep paralysis. It is caused by the autoimmune destruction of hypocretin (orexin) cells in the anterior hypothalamus.

• Rhythmic Movement Disorder: Common in infants and toddlers; involves soothing behaviors like body rocking or head banging at sleep onset. Usually resolves spontaneously by age $5$.

Forensic Paediatrics and Child Maltreatment

• The World Health Organization (WHO) reports that globally:

  • $\frac{1}{4}$ of children have been physically abused in the last $12$ months.

  • $\frac{1}{3}$ have been emotionally abused.

  • Smaller proportions suffer from neglect and sexual abuse.

• Child abuse is defined as an act of commission (deliberate act) or omission (failure to provide care) by a parent or caregiver that endangers a child's health, development, or dignity.

Forensic Assessment Principles

• Clinicians must differentiate between inflicted injuries and accidental ones or "mimics" (e.g., rashes, allergies, or bone diseases).

• Bruising Patterns: Bruises on protected areas like the buttocks, genitals, ears, neck, or soft parts of the cheek are highly suspicious.

• TEN-4 Rule: Consider inflicted injury for any bruise on the Torso, Ears, or Neck in children under $4$ years, and any bruise on an immobile infant under $4$ months.

• Patterned Injuries: "Tram track" bruising (two parallel linear bruises with a central area of sparing) indicates impact from a straight-edged implement like a ruler or cord.

• Abusive Head Trauma (Shaking): Involves a triad of subdural haemorrhage, retinal haemorrhage, and encephalopathy. The "Purple Period" of crying (peaking at $8\text{--}12$ weeks) often triggers these events. Retinal haemorrhages in abusive trauma are often too numerous to count and extend to the periphery.

Investigations in Maltreatment

• Skeletal Survey: Identification of fractures (rib, femoral, humeral). Rib fractures at the posterior near the transverse process are highly suggestive of a squeezing mechanism.

• Bone Scan: Used in conjunction with X-ray to detect acute fractures that may not yet show callous formation.

• Coagulation Studies: Necessary to exclude bleeding disorders like Von Willebrand disease or Leukemia that may mimic bruising.

• Mandatory Reporting: In Victoria, doctors are legally required to report suspected physical or sexual abuse to Child Protection Services. This law was significantly influenced by the death of Daniel Valerio in the $1990s$.

Adolescent Medicine and Psychosocial Health

• Adolescence is the period from age $10$ to $24$. It is marked by a developmental mismatch: the limbic system (emotional center) is mature by age $18$, but the prefrontal cortex (higher executive function/judgment) does not fully develop until age $25\text{--}35$.

Puberty and Physical Changes

• Tanner Stages ($1\text{--}5$): Standardized measurement of pubertal development.

• Girls: Onset at $9\text{--}11$ years. Growth spurt occurs early (Tanner stages $2\text{--}3$). Menarche typically occurs at $12\text{--}13$ years, and $90\%$ have periods by age $15$.

• Boys: Onset at $10\text{--}12$ years. Growth spurt occurs later (Tanner stage $4$). Sperm production starts at approximately $50,000$ per minute.

• Mortality: Leading causes of death are suicide and road traffic accidents. Three-quarters of adolescent deaths are considered avoidable.

Eating Disorders

• Anorexia Nervosa: Characterized by restrictive eating and body dysmorphia. Mortality rate is $12$ times higher than the general population.

• Bulimia Nervosa: Involves binging and purging. Average time for clinical presentation is $7$ years because weight often appears normal.

• Refeeding Syndrome: A life-threatening metabolic complication during nutritional rehabilitation. Involves rapid shifts in electrolytes including low phosphate ($PO_4$), potassium ($K^+$), and magnesium ($Mg^{2+}$), leading to respiratory failure, seizures, or cardiac arrest.

Communication Tools: HEEADSSS and The Hand Model

• HEEADSSS Screen: Evaluates Home, Education/Employment, Eating, Activities/Social Media, Drugs, Sexuality, Suicide/Depression, and Safety.

• Consent: To be valid, it must be informed, voluntary, and the patient must have the capacity to consent. Confidentiality should be established early but with clear "harm to self or others" exceptions.

• The Hand Model of the Brain:

  • Fist/Cortex: The "thinking brain" should be in charge.

  • Thumb/Limbic System: The "emotional brain."

  • When stressed or anxious, an adolescent may "flip their lid," letting the emotional brain take control. Calming techniques (breathing, distraction) help re-engage the prefrontal cortex.

Questions & Discussion

• Question: What are the mimics of child abuse?

  • Response: Rashes, allergies, and specific bone disorders can mimic skin and skeletal injuries. Investigations like blood counts and coagulation studies are used to rule out medical causes.

• Scenario: A toddler with trains (Hayden Case)

  • Details: Hayden is a $3$-year-old who lines up blocks for hours, has poor eye contact, and does not exhibit shared attention or pointing. He tantrums with changes in activities.

  • Assessment: This is a classic presentation of Autism Spectrum Disorder (ASD). Features include deficits in social communication and the presence of repetitive, restricted behaviors.

• Scenario: A child with regression (Chloe Case)

  • Details: Chloe is $22$ months old; she previously had two-word sentences but now only uses single words. She lost purposeful hand skills and exhibits stereotypic hand-wringing. Her head growth has slowed from the $50^{th}$ to the $10^{th}$ centile.

  • Assessment: This suggests a neurodegenerative condition, specifically Rett Syndrome (associated with the MECP2 gene mutation), requiring urgent referral.

• Scenario: A teen in the ER (Alice Case)

  • Details: Alice presented as hostile with multiple piercings and tattoos. She wouldn't engage until the clinician noticed a lump under her sheet—a tattered teddy bear.

  • Outcome: Engaging with the object of comfort (the bear) allowed Alice to reveal a history of domestic violence, sexual assault, and home instability. This emphasizes looking past aggressive exteriors for underlying trauma.

• Scenario: Burn evaluation (4-month-old)

  • Details: A baby has a small burn on the foot while being held by an uncle.

  • Interpretation: This is considered a neglectful burn because it was highly preventable. In contrast, "doughnut" sparing on the buttocks or "sock and glove" distributions on limbs suggest deliberate immersion in hot water.