Cerebral Palsy

Cerebral palsy (CP) is the commonest cause of physical disability in childhood and a perennial NEET PG favourite from Paediatrics — Growth & Development. The cardinal exam idea: it is a non-progressive (static) disorder of movement and posture due to a lesion in the developing brain, even though the clinical picture and musculoskeletal consequences evolve with growth.

Definition

High-yield: Cerebral palsy = a group of permanent disorders of movement and posture causing activity limitation, attributed to non-progressive disturbances in the developing fetal or infant brain. The brain lesion is static; the clinical manifestations change over time.

Key qualifiers tested repeatedly:

• Non-progressive — the underlying brain insult does not worsen. If a child shows neuro-regression or loss of acquired milestones, think of a neurodegenerative/metabolic disorder, NOT CP.
• Developing brain — by convention the insult occurs before the brain is mature, generally taken as < 2-3 years of age (some texts: up to 5 years). An identical motor picture after a mature-brain insult (e.g. trauma in an older child) is not labelled CP.
• The motor disorder is the core, but it is frequently accompanied by disturbances of sensation, perception, cognition, communication, behaviour, epilepsy and secondary musculoskeletal problems.

Classification

Two axes are examined: physiological/clinical type (tone & movement pattern) and topographical distribution (limbs involved). A functional severity scale (GMFCS) is increasingly the most-asked.

A. Physiological (by motor type)

Type	Lesion site	Tone / movement	Notes
Spastic	Pyramidal (motor cortex / corticospinal tract)	Hypertonia, clasp-knife, brisk reflexes, clonus, extensor plantar	Commonest type (~70-80%)
Dyskinetic (choreoathetoid / dystonic)	Extrapyramidal — basal ganglia	Involuntary movements, fluctuating tone, athetosis, dystonia	Classic with kernicterus and birth asphyxia
Ataxic	Cerebellum	Hypotonia, intention tremor, dysmetria, wide-based gait	Rarest; consider genetic/cerebellar malformation
Hypotonic	Often transitional	Pure hypotonia	Frequently evolves into spastic or dyskinetic
Mixed	Multiple	Combination (often spastic + dyskinetic)	Common in severe HIE

High-yield: Spastic is the commonest type overall. Dyskinetic/athetoid CP is the classic sequela of kernicterus (bilirubin-induced basal ganglia injury) — look for athetosis + sensorineural hearing loss + upward gaze palsy + dental enamel dysplasia.

B. Topographical (spastic CP subtypes)

Pattern	Limbs involved	Typical cause	Association
Spastic diplegia	Both legs >> arms	Prematurity / PVL	Scissoring gait, commando crawl, relatively preserved intellect
Spastic hemiplegia	One side (arm > leg)	Antenatal stroke, MCA infarct, porencephaly	Early hand preference (<1 yr is abnormal), focal seizures
Spastic quadriplegia	All four (arms ≥ legs)	Severe HIE, malformation	Worst prognosis; severe intellectual disability, epilepsy, microcephaly, pseudobulbar palsy

High-yield: Spastic diplegia ↔ premature baby ↔ periventricular leukomalacia (PVL) ↔ scissoring gait. This single chain is one of the most repeated CP links.

C. GMFCS — Gross Motor Function Classification System

A five-level functional scale based on self-initiated movement, especially sitting and walking, age-banded (most validated for 2-12 years). It is the international standard for describing severity and prognosis.

Level	Functional ability (gist)
I	Walks without limitation; difficulty only with advanced skills (running, stairs)
II	Walks with limitations; difficulty on uneven ground, may need rail for stairs
III	Walks using a hand-held mobility device (walker); wheelchair for long distances
IV	Self-mobility limited; powered mobility or transported in manual wheelchair
V	Transported in a manual wheelchair; no independent mobility, poor head/trunk control

High-yield: GMFCS Levels I-III are essentially ambulatory; Levels IV-V are non-ambulatory. The level is stable over time in older children, making it a robust prognostic tool. Related scales: MACS (Manual Ability), CFCS (Communication Function), EDACS (Eating and Drinking Ability).

Etiology & Risk Factors

CP is the end-result of many insults, not a single disease. The timing matters for the exam:

• Prematurity / low birth weight — the single most important risk factor. Risk rises steeply below 32 weeks / 1500 g. Mechanism: periventricular leukomalacia (ischaemic white-matter injury) and germinal matrix–intraventricular haemorrhage (IVH grade III-IV).
• Hypoxic-ischaemic encephalopathy (HIE) / birth asphyxia — important but accounts for a minority (~10-15%) of cases; pattern depends on severity (acute profound → basal ganglia/thalamus → dyskinetic; partial prolonged → watershed/cortex).
• Antenatal causes (the majority) — congenital brain malformations, intrauterine infections (TORCH), placental insufficiency, multiple gestation, chorioamnionitis/maternal infection (inflammatory pathway).
• Postnatal (early) — kernicterus (severe neonatal hyperbilirubinaemia), neonatal meningitis/encephalitis, hypoglycaemia, head trauma, stroke.

High-yield: Most CP is NOT due to intrapartum asphyxia. The largest share is antenatal/prenatal. Prematurity is the leading identifiable risk factor.

Pathophysiology in one flow

Insult to developing brain → injury to motor pathways (pyramidal / extrapyramidal / cerebellar) → loss of descending inhibition and disordered tone → spasticity / dyskinesia / ataxia → over years, secondary musculoskeletal changes (muscle contractures, hip subluxation, scoliosis, bony torsion) → progressive functional consequences despite a static brain lesion.

The crucial nuance: the neurological lesion is fixed, but orthopaedic deformity is progressive because abnormal tone acts on a growing skeleton — this is why CP "looks" progressive clinically and why surgery is often deferred until deformity stabilises.

Clinical Features

CP usually presents in infancy with delayed motor milestones and abnormal tone/posture rather than a dramatic single event.

Early red flags (motor):

• Delayed milestones (not sitting by 9 months, not walking by 18 months).
• Persistent primitive reflexes beyond expected age (Moro > 6 mo, ATNR > 6 mo).
• Delayed/absent protective reflexes (parachute should appear ~8-9 months; its absence is concerning).
• Hand preference before 12 months — a strong clue to hemiplegia (the affected hand is "neglected").
• Abnormal tone: early hypotonia that later evolves to hypertonia/spasticity; "feels stiff" on handling, scissoring of legs, fisting.
• Spontaneous fidgety movements absent at 3-4 months on General Movements Assessment (Prechtl) — earliest predictor.

Established signs: spasticity, hyperreflexia, clonus, extensor plantar response, persistent toe-walking, equinus / scissoring gait, contractures.

Associated disabilities (the "comorbidity quartet" and more)

High-yield: Always remember CP is more than motor. Frequently tested associations:

• Epilepsy — in ~30-50%; highest in spastic quadriplegia and hemiplegia, lower in diplegia.
• Intellectual disability / learning difficulty — risk parallels motor severity (worst in quadriplegia); diplegics often have normal/near-normal intellect.
• Visual impairment — strabismus is very common; PVL → posterior visual pathway / cortical visual impairment and visual field defects; refractive errors.
• Hearing impairment — especially sensorineural in kernicterus and post-meningitic CP.
• Feeding/swallowing difficulty, GERD, aspiration, drooling, malnutrition, failure to thrive.
• Speech and communication disorders (dysarthria, anarthria).
• Orthopaedic: hip subluxation/dislocation (surveillance needed), scoliosis, contractures.
• Behavioural/emotional problems, sleep disturbance, constipation, osteopenia.

High-yield: Hip surveillance (serial X-ray with migration percentage) is mandatory in non-ambulatory CP (GMFCS IV-V) — a silent dislocating hip is a classic preventable complication. A migration percentage > 30-33% warrants orthopaedic referral.

Diagnosis & Investigation of Choice

CP is a clinical diagnosis — based on history, persistent abnormal motor exam, delayed milestones, and crucially demonstrating that the disorder is non-progressive. Imaging supports etiology but does not "make" the diagnosis.

Diagnostic approach (stepwise):

1. History — antenatal/perinatal risk factors, milestone trajectory; confirm no regression of acquired skills.
2. Examination — tone, reflexes (deep, primitive, protective), posture, gait, hand preference; classify type and topography; assign GMFCS level.
3. Confirm non-progression — serial assessment; loss of milestones → re-investigate for neurometabolic/degenerative disease.
4. Neuroimaging — MRI brain is the investigation of choice.
5. Screen for comorbidities — vision, hearing (BERA), EEG if seizures, swallow assessment, cognition.

High-yield: MRI brain is the imaging investigation of choice in CP (abnormal in ~80-90%). Typical findings: PVL (premature), basal ganglia/thalamic injury (term asphyxia, kernicterus), MCA infarct/porencephaly (hemiplegia), or malformations.

When to look beyond CP / metabolic-genetic workup: normal MRI + family history, regression, episodic deterioration, or no identifiable risk factor → exclude inborn errors of metabolism, hereditary spastic paraplegia, dopa-responsive dystonia (a key mimic), or arginase deficiency.

High-yield: Dopa-responsive dystonia (Segawa disease) is a classic treatable mimic of (often diplegic) CP — diurnal variation of symptoms, dramatic response to low-dose levodopa. Always consider a levodopa trial in atypical "diplegic CP".

Management

There is no cure; management is supportive, multidisciplinary, and goal-directed, aiming to maximise function, prevent secondary deformity, and support participation. Physiotherapy and early intervention are the backbone.

Core multidisciplinary team

Paediatrician/neurologist, physiotherapist, occupational therapist, speech-language therapist, orthopaedic surgeon, ophthalmologist, audiologist, dietician, special educator, orthotist, and social/psychological support.

Spasticity management — a tiered ("ladder") approach

Focal spasticity → Botulinum toxin (chemodenervation) / phenol nerve block. Generalised spasticity → oral agents → intrathecal baclofen. Fixed deformity → orthopaedic surgery.

Modality	Indication	Notes
Physiotherapy, stretching, orthoses (AFOs)	All children	First-line, continuous; prevents contractures
Botulinum toxin A	Focal/dynamic spasticity (e.g. equinus, adductors)	Reversible, ~3-6 month effect; enables therapy & delays surgery
Oral agents: baclofen, diazepam, tizanidine, dantrolene	Generalised spasticity	Sedation limits use; dantrolene acts on muscle
Intrathecal baclofen pump	Severe generalised spasticity	Pump implanted; for non-ambulatory severe cases
Selective dorsal rhizotomy (SDR)	Selected spastic diplegia, good strength	Neurosurgical; improves gait in carefully chosen children
Orthopaedic surgery	Fixed contractures, hip subluxation, scoliosis	Tendon lengthening, osteotomy; timed to skeletal maturity

High-yield: Botulinum toxin type A is the drug of choice for focal/dynamic spasticity in CP — it blocks acetylcholine release at the neuromuscular junction, is reversible, and is used adjunctively with physiotherapy and serial casting. For generalised spasticity, oral baclofen (GABA-B agonist) or intrathecal baclofen is used.

Management of comorbidities & supportive care

• Seizures — standard anti-epileptic drugs.
• Drooling — anticholinergics (glycopyrrolate), botulinum toxin to salivary glands.
• Nutrition/feeding — dietary fortification; gastrostomy (PEG) for unsafe swallow / failure to thrive.
• Spasticity-related pain, constipation, GERD, osteopenia — addressed actively (osteopenia: calcium, vitamin D, weight-bearing).
• Assistive devices — AFOs, walkers, wheelchairs, communication aids (AAC).

Early intervention

High-yield: Early intervention programmes — structured, family-centred therapy begun as soon as CP is suspected — leverage neuroplasticity of the developing brain for best functional outcomes. The trend is toward early diagnosis (even before 6 months using MRI + Prechtl General Movements + HINE) so intervention starts early. Do not "wait and watch".

Complications

• Orthopaedic: progressive contractures, hip subluxation/dislocation, scoliosis, bony torsion, patella alta.
• Respiratory: recurrent aspiration pneumonia (leading cause of death), chronic lung disease.
• Nutritional: failure to thrive, malnutrition, osteopenia → fragility fractures.
• Neurological: intractable epilepsy.
• GI: GERD, constipation, dysphagia.
• Pressure sores, pain, sleep disorders, dental problems.
• Psychosocial: social exclusion, caregiver burden.

High-yield: Aspiration pneumonia is the commonest cause of mortality in severe CP.

Key Differentials

Condition	Distinguishing feature from CP
Neurodegenerative / metabolic disorders (leukodystrophies, mitochondrial)	Regression / loss of milestones; CP is non-progressive
Dopa-responsive dystonia (Segawa)	Diurnal variation; levodopa-responsive — treatable mimic
Hereditary spastic paraplegia	Family history, slowly progressive, often pure leg spasticity
Spinal cord lesion / tethered cord	Sensory level, bladder/bowel signs, back/midline cutaneous markers
Muscular dystrophy / SMA	Weakness with hypotonia & areflexia, raised CK (DMD), no UMN signs
Congenital hypothyroidism	Coarse facies, hypotonia, treatable; newborn screening
Global developmental delay / autism	Delay without the characteristic tone/posture motor disorder
Ataxia-telangiectasia, brain tumour	Progressive ataxia, additional signs

High-yield: The pivotal differentiating principle: CP does NOT regress. Any child losing previously acquired skills must be investigated for a progressive (metabolic/degenerative) disorder.

Recently asked / exam angle

• Commonest type of CP → Spastic (and spastic diplegia link with prematurity / PVL and scissoring gait).
• Dyskinetic/athetoid CP ↔ kernicterus ↔ basal ganglia injury (plus SNHL, upgaze palsy).
• Investigation of choice → MRI brain.
• GMFCS — recognise it as a 5-level functional classification of gross motor function; ambulatory (I-III) vs non-ambulatory (IV-V).
• Drug for focal spasticity → Botulinum toxin A; mechanism = inhibits acetylcholine release at NMJ.
• Most important risk factor → prematurity / low birth weight.
• CP is non-progressive — single best distinguishing point from neurodegenerative disease; regression rules out CP.
• Treatable mimic → dopa-responsive dystonia (levodopa trial).
• Backbone of management → physiotherapy / multidisciplinary early intervention (no cure).
• Commonest cause of death in severe CP → aspiration pneumonia.
• Hip surveillance (migration percentage) mandatory in GMFCS IV-V.
• Persistent primitive reflexes + early hand preference (<1 yr) = classic early clues.

Rapid revision

1. CP = non-progressive disorder of movement & posture from a lesion of the developing brain; motor picture evolves, brain lesion does not.
2. Spastic type is commonest (~70-80%); pyramidal lesion, hypertonia, brisk reflexes, extensor plantar.
3. Spastic diplegia ↔ premature baby ↔ periventricular leukomalacia ↔ scissoring gait, usually normal intellect.
4. Spastic quadriplegia = worst prognosis (severe ID, epilepsy, microcephaly); hemiplegia shows early hand preference.
5. Dyskinetic/athetoid CP = basal ganglia injury, classically kernicterus (+ SNHL, upgaze palsy).
6. Ataxic CP = cerebellar, hypotonia + intention tremor; rarest type.
7. GMFCS = 5-level gross-motor functional scale; I-III ambulatory, IV-V non-ambulatory; prognostic and stable.
8. Prematurity/LBW is the leading risk factor; most CP is antenatal, NOT intrapartum asphyxia.
9. MRI brain = investigation of choice; CP itself is a clinical diagnosis.
10. Botulinum toxin A = focal spasticity (inhibits ACh at NMJ); baclofen for generalised; physiotherapy/early intervention is the cornerstone — no cure.
11. Associated disabilities: epilepsy, intellectual disability, visual & hearing impairment, feeding/speech problems, hip dislocation.
12. Regression of milestones rules OUT CP — investigate for neurodegenerative/metabolic disease; remember dopa-responsive dystonia as a treatable mimic.