Attention-Deficit/Hyperactivity Disorder (ADHD) Clinical Overview
I. The "On-Call" Snapshot
Clinical Significance in Malaysia
ADHD is the most common neurobehavioural disorder in Malaysian children. You will be managing its comorbidities and medication side effects in clinics and, occasionally, in the Emergency Department (ED). Early identification and management are crucial to prevent long-term academic and psychosocial impairment.
High-Yield Definition
ADHD is a neurodevelopmental disorder characterised by a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development, as defined by DSM-5 criteria.
(Source: Malaysian CPG on Management of ADHD, 2nd Ed., 2018)
Clinical One-Liner
A child (usually <12 years) who cannot sit still, constantly interrupts, and is failing in school despite adequate intelligence, with symptoms present both at home and in school.
II. Etiology & Risk Factors
Etiology
A highly heritable neurobiological disorder. The exact cause is multifactorial, involving a complex interplay of genetic factors (high heritability, ~70-80%) and neurobiological factors (e.g., dysregulation of dopaminergic and noradrenergic pathways, particularly in the prefrontal cortex).
Risk Factors
Genetic: Strong family history of ADHD.
Perinatal: Very low birth weight (<1500g), prematurity, significant antenatal alcohol/smoking exposure.
Environmental: Severe early life psychosocial adversity, head trauma.
Note: Poor parenting or "sugar rush" are not primary causes.
III. Quick Pathophysiology
This is not a "naughty child" problem; it's a brain problem. Think of it as a failure of the brain's executive "braking" system. There is dysfunction in the prefrontal cortex and its connections to the basal ganglia and cerebellum, leading to:
Dopamine/Norepinephrine Imbalance: Insufficient neurotransmitters for signal transmission in circuits responsible for attention, reward, and impulse control.
Impaired Executive Function: This is the core issue. It leads directly to the clinical signs:
Inattention: Failure to sustain focus (dorsolateral prefrontal cortex dysfunction).
Impulsivity: Failure to inhibit prepotent responses (orbitofrontal cortex dysfunction).
Hyperactivity: Failure to regulate motor output (prefrontal motor cortex dysfunction).
IV. Classification
Based on DSM-5 criteria, symptoms must be present before age 12, occur in $\geq$2 settings (e.g., home, school), and cause functional impairment.
Predominantly Inattentive Presentation (ADHD-I)
$\geq$6 inattentive symptoms (e.g., easily distracted, forgetful, "daydreaming").
Often missed; may present as "lazy" or "unmotivated" rather than disruptive.
Predominantly Hyperactive-Impulsive Presentation (ADHD-HI)
$\geq$6 hyperactive/impulsive symptoms (e.g., fidgeting, leaving seat, interrupting).
This is the "classic" disruptive child.
Combined Presentation (ADHD-C)
Meets criteria for both inattention and hyperactivity-impulsivity ($\geq$6 symptoms from each category).
Most common presentation in clinical settings.
V. Clinical Assessment
🚩 Red Flags & Immediate Actions
ADHD itself is not a medical emergency, but you must screen for urgent comorbidities.
Sudden onset of severe aggression/agitation: Action: Rule out substance misuse, acute psychosis, or an underlying medical condition (e.g., encephalitis, delirium). Requires immediate medical and psychiatric assessment.
Suicidal ideation or self-harm: Action: Immediate psychiatric referral and safety planning. This is common in adolescents with comorbid depression.
Signs of stimulant overdose (if on treatment): Tachycardia, hypertension, hyperthermia, seizures. Action: Stop medication, manage ABCs, and refer to ED.
History
Key Diagnostic Clues (Pathognomonc Presentations)
The "engine is always on" description from parents.
School reports consistently mention "does not listen," "disrupts class," "careless mistakes," "bright but doesn't apply himself."
Symptoms are persistent (since early childhood) and pervasive (seen everywhere).
Symptom Breakdown (based on DSM-5)
Inattention (Common):
Makes careless mistakes in schoolwork.
Difficulty sustaining attention in tasks or play.
Seems not to listen when spoken to directly.
Fails to follow through on instructions or finish chores.
Difficulty organising tasks and activities.
Avoids tasks requiring sustained mental effort (like homework).
Loses things necessary for tasks (e.g., school books, pencils).
Easily distracted by extraneous stimuli.
Forgetful in daily activities.
Hyperactivity/Impulsivity (Common):
Fidgets with or taps hands/feet, squirms in seat.
Leaves seat when remaining seated is expected.
Runs about or climbs in inappropriate situations.
Unable to play or engage in leisure activities quietly.
Is "on the go," acting as if "driven by a motor."
Talks excessively.
Blurts out an answer before a question has been completed.
Difficulty waiting their turn.
Interrupts or intrudes on others (e.g., butts into conversations).
Pertinent Negatives
No symptoms in one setting: If the child is only problematic at home but a "perfect angel" at school (or vice-versa), reconsider the diagnosis. This may be a parenting/environmental issue.
Acute onset of symptoms: ADHD is chronic. Sudden onset suggests another cause (e.g., new stressor, anxiety, medical issue).
No functional impairment: If the child is inattentive but still scoring "A"s and has friends, they do not meet diagnostic criteria. Impairment is mandatory.
Physical Examination (OSCE Approach)
A full physical and neurological exam is mandatory to rule out organic causes.
General Inspection: Look for dysmorphic features (suggesting genetic syndromes like Fragile X), signs of self-injury, or stigmata of neurocutaneous disorders (e.g., cafe-au-lait spots in NF1).
Vitals:
Baseline: Record height, weight (plot on growth chart), BP, and heart rate. This is crucial before starting stimulants.
Disease-Specific Examination (Neurology & Development):
Vision & Hearing: Perform basic screening. Impaired hearing can mimic inattention.
Neurological Exam: Check for focal deficits, cerebellar signs, or tics (high comorbidity with Tourette's).
"Soft" Signs: Look for minor neurological abnormalities (e.g., poor coordination, difficulty with rapid alternating movements), which are common but not diagnostic.
Examination for Differentials:
Thyroid: Check for goitre, proptosis, tremor (to rule out hyperthyroidism).
Anaemia: Check for pallor (can cause fatigue and poor concentration).
Differentiating Disease Stage
We grade severity based on functional impairment (not just symptom count):
Mild: Few, if any, symptoms in excess of those required for diagnosis. Minor functional impairment in social or academic settings.
Moderate: Symptoms or functional impairment are between "mild" and "severe."
Severe: Many symptoms in excess of diagnostic requirements. Significant and pervasive impairment at home, school, and with peers.
Clinical Pearl
Always, always get collateral information. Use the SNAP-IV or Conners' Rating Scales and give forms to both parents and the school teacher. The child's teacher is often your most objective observer.
VI. Diagnostic Workflow
Differential Diagnosis
This is primarily a clinical diagnosis. Your job is to rule out mimics and identify comorbidities.
Oppositional Defiant Disorder (ODD) / Conduct Disorder (CD)
Points For: Disruptive, argumentative, breaks rules. High comorbidity.
Points Against: In ADHD, the child breaks rules impulsively (e.g., runs across the road without thinking). In ODD/CD, the child breaks rules defiantly (e.g., looks you in the eye and says "no").
How to Differentiate: Assess intent. Is it impulsivity or malice?
Specific Learning Disorder (e.g., Dyslexia)
Points For: Poor school performance, inattention during class, avoids homework.
Points Against: The inattention is task-specific (e.g., only during reading/writing). Global attention is intact.
How to Differentiate: Full psycho-educational assessment. If they can pay attention during math but not English, suspect a learning disorder.
Anxiety Disorder / Depression
Points For: Fidgeting (anxiety), poor concentration (depression), irritability.
Points Against: In anxiety, worry is the core theme. In depression, anhedonia/low-mood is. In ADHD, inattention/impulsivity is the primary driver.
How to Differentiate: Ask why they can't focus. "I'm too worried about my exam" = Anxiety. "My brain just... drifted away" = ADHD.
Organic Causes (Rarer)
Hyperthyroidism: Mimics hyperactivity. Differentiate with TFTs.
Absence Seizures: Mimics inattention ("daydreaming"). Differentiate with EEG (will show 3Hz spike-and-wave).
Sleep-Disordered Breathing (e.g., OSA): Causes daytime inattention and hyperactivity due to poor sleep. Differentiate with sleep history (snoring, apnoeic episodes) and ENT referral.
Investigations Plan
Investigations are primarily to rule out organic causes and establish a baseline before treatment. There is no blood test or scan to "diagnose" ADHD.
Bedside / Initial (First 15 Mins):
Vitals: BP, HR, Height, Weight (MUST be documented).
Vision/Hearing: Snellen chart, whisper test (or formal audiology).
First-Line Labs & Imaging (if clinically indicated):
Full Blood Count (FBC): Rule out anaemia.
Thyroid Function Test (TFT): Rule out hyperthyroidism, especially if tachycardic, weight loss.
ECG: Mandatory baseline before starting stimulants, as per Malaysian CPG. Look for long QT, arrhythmias, or structural heart disease signs.
Confirmatory / Gold Standard:
The "gold standard" is a comprehensive clinical and developmental history from multiple informants (parents, teachers) and direct observation, confirming DSM-5 criteria.
Formal psycho-educational assessment may be needed to rule out learning disorders or assess cognitive level (IQ test).
VII. Staging & Severity Assessment
We use the Malaysian CPG (2018) approach, which aligns with DSM-5:
Severity (Mild, Moderate, Severe): Based on symptom count and, more importantly, the degree of functional impairment in academic, social, and family domains.
Impact on Management:
Mild (in pre-schoolers): Behavioural therapy ONLY.
Mild (school-aged): Behavioural therapy first.
Moderate-Severe (school-aged): Requires combination therapy (pharmacological + behavioural) from the start.
VIII. Management Plan
A. Principle of Management
A multimodal approach is standard of care. "Pills do not teach skills."
Educate the family and child (psychoeducation).
Treat the core symptoms (medication).
Train new skills (behavioural therapy).
Support the child in their environment (school/home interventions).
B. Immediate Stabilisation (The ABCDE Plan)
Not applicable. ADHD is a chronic condition. Immediate stabilisation is only relevant for acute complications (e.g., medication overdose, acute psychosis, or severe self-harm), which should be managed as per their respective protocols.
C. Definitive Treatment (The Ward Round Plan)
1. Non-Pharmacological (First-line for all, sole treatment for mild/pre-school)
Psychoeducation: Essential. Explain the biological basis to remove stigma.
Behavioural Therapy:
Parent Management Training (PMT): Teach parents positive reinforcement, clear commands, and structured routines. This is the most evidence-based intervention.
Classroom Intervention: Daily report cards, seating the child at the front, breaking tasks into smaller chunks.
Diet/Lifestyle: Advise a balanced diet, good sleep hygiene, and regular exercise. Evidence for specific food (e.g., sugar, additives) as a primary cause is weak.
2. Pharmacological (First-line for moderate-severe school-aged children)
(Source: Malaysian CPG on Management of ADHD, 2nd Ed., 2018)
First-Line: Stimulants
Drug: Methylphenidate (Ritalin). Comes in short-acting (IR) and long-acting (LA/SR) forms.
Mechanism: Blocks dopamine and norepinephrine reuptake.
Dosing (as per CPG):
Start: 5mg OD-BD (IR) or 10mg OM (LA) for children >6 years.
Titration: Titrate slowly every 1-2 weeks based on response and side effects.
Max Dose: 60mg/day.
Key Point: Dose is based on symptom response, not weight. "Start low, go slow."
Monitoring (MANDATORY):
Pre-treatment: Baseline ECG, Height, Weight, BP, HR.
Follow-up: Monitor Height, Weight (every 3-6 months on growth chart), BP, HR (at every dose change, then 3-6 monthly).
Side Effects: Loss of appetite (most common), insomnia, headaches, irritability, tics.
Second-Line: Non-Stimulants
Indication: Failed/intolerant to stimulants, active tics, severe anxiety, or parental refusal.
Drug: Atomoxetine (Strattera).
Mechanism: Selective norepinephrine reuptake inhibitor (SNRI).
Dosing: Start 0.5mg/kg/day, titrate to 1.2mg/kg/day.
Key Points: Not a controlled drug (no 'buku pink'). Takes 4-6 weeks for full effect (unlike stimulants, which work in 30 mins). Less effective for hyperactivity but good for inattention.
Side Effects: Somnolence, nausea, abdominal pain. Small risk of hepatotoxicity (monitor LFT if symptomatic) and suicidal ideation (black box warning).
D. Long-Term & Discharge Plan
Follow-up:
Medication: Monthly follow-up during titration, then 3-6 monthly once stable.
Comorbidities: Regular screening for learning disorders, anxiety, depression, and ODD.
Medications: This is often long-term. Discuss "drug holidays" (e.g., weekends/school holidays) only if the child is stable and impairment is minimal off-medication.
Lifestyle: Emphasise structured routines, sleep hygiene, and a "homework-friendly" environment (e.g., quiet desk, no distractions).
IX. Complications
Short-Term:
Academic: Underachievement, failing grades. Action: Liaise with school for IEP.
Social: Peer rejection, poor social skills. Action: Refer for social skills training.
Accidents: Higher risk of injuries due to impulsivity. Action: Psychoeducation on safety.
Long-Term (if untreated):
Psychiatric: Higher risk of ODD/CD, anxiety, depression, and substance use disorder (SUD). Action: Regular screening.
Functional: School dropout, unemployment, relationship difficulties. Action: Emphasise long-term treatment adherence.
X. Prognosis
With treatment, functional outcomes are good.
Without treatment, prognosis is poor for academic and social functioning.
Symptom Persistence: ~60-80% continue to have symptoms into adolescence; ~30-60% continue into adulthood.
Key point: Hyperactivity tends to decrease with age, but inattention and impulsivity persist.
Malaysian Data: Local studies show high rates of comorbidity (e.g., ~40% with ODD) which worsens prognosis if not co-managed.
XI. How to Present to Your Senior
Use the SBAR format.
(Situation): "Dr. [Senior], I am reviewing [Child's Name], a [Age]-year-old boy in the PAC, referred by the school for poor academic performance and disruptive behaviour."
(Background): "He has a 3-year history of inattention and hyperactivity, present both at home and school, causing significant impairment. He is not on any treatment. Baseline vitals and ECG are normal."
(Assessment): "My primary diagnosis is ADHD, Combined Presentation, severe. The Conners' scales from both parent and teacher are highly positive. I have ruled out immediate organic causes; TFTs and FBC are pending."
(Recommendation): "I plan to complete the diagnostic workup. I would like to psychoeducate the parents today and schedule him for our Parent Management Training program. Given his age and severe impairment, I am also counselling them to start a trial of methylphenidate (Ritalin LA) 10mg OM. Is this plan agreeable?"
XII. Summary & Further Reading
Top 3 Takeaways
ADHD is a real, biological neurodevelopmental disorder, not just a "naughty child."
Diagnosis is clinical (via DSM-5) and requires collateral from school; investigations are to rule out mimics and get a baseline.
Management is multimodal. "Pills don't teach skills." For moderate-severe cases, stimulants (Methylphenidate) are first-line, and you must monitor ECG, growth, and vitals.
Key Resources
Malaysian CPG: Malaysian CPG on Management of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents, 2nd Ed., 2018
UpToDate: "Attention deficit hyperactivity disorder in children and adolescents: Clinical features and diagnosis"
Amboss: "Attention-Deficit/Hyperactivity Disorder"
