Cerebral Palsy Aetiology and Pathology

Original Editor - Robin Tacchetti based on the course by Krista Eskay
Top Contributors - Robin Tacchetti and Jess Bell

Introduction[edit | edit source]

Cerebral palsy (CP) is a permanent movement and posture disorder that results from issues in the developing foetal and infant brain.[1] CP is the most common childhood disability.[2] The core symptom of cerebral palsy is motor function disorder, but other associated dysfunctions frequently occur, including cognitive, communication, sensation, perceptual, and behavioural conditions, as well as epilepsy.[3] Despite cerebral palsy being non-progressive in nature, secondary conditions often develop over time that affect functional abilities.[4]

Aetiology[edit | edit source]

The incidence of CP is 2-3 per 1,000 live births.[4] Most cases of CP are due to complications in the foetal or neonatal brain, but post-neonatal onset CP can occur. The main pathologic findings for preterm infants are intracerebral hemorrhage and periventricular leukomalacia (i.e. "diffuse injury of deep cerebral white matter, accompanied in its most severe form by focal necrosis"[5]). Injuries that occur after the neonatal period and before 5 years of age are considered post-neonatal CP; these injuries are generally caused by traumatic brain injury, meningitis and near-drowning.[4]

Risk Factors[edit | edit source]

Two important risk factors associated with CP are prematurity (delivery before 37 weeks) and low birth weight (less than 2.5 kg). Other factors can also increase risk such as multiple gestation, maternal and foetal infections, malformation of the brain and genetic causes.[2][4]

Management strategies to help decrease prematurity prevalence include prescribing magnesium sulphate, progesterone and corticosteroids to pregnant women.[2]

Pre-conception Risk Factors[edit | edit source]

  • Substance abuse
  • Maternal undernutrition
  • Swallowing harmful substances
  • Systemic illness in the mother
  • Fertility issues
  • Previous spontaneous termination of pregnancy[2]

Gestation Risk Factors[edit | edit source]

  • Gestational diabetes
  • Maternal abnormalities of the central nervous system
  • Preeclampsia
  • Excessive bleeding per vagina
  • Multiple gestations
  • Genetics
  • Encephalopathy of prematurity[2]

Delivery Risk Factors[edit | edit source]

  • Vacuum-assisted delivery
  • Forceps delivery
  • C-section
  • Labour induction
  • Prolonged labour
  • Asphyxia
  • Delivery after due date[2]

Diagnosis[edit | edit source]

The diagnosis of CP is generally more reliable after 2 years of age. Before the age of 2, signs and symptoms suggestive of CP could also be a developmental lag, which resolves in many infants. Diagnosing CP is largely based on clinical findings. Early diagnosis needs a combination of clinical findings including history, neuromotor assessments and MRI (to determine the extent of the brain lesion or congenital brain malformation). Clinical findings can continue to evolve up to the age of 4-5 years.[4]

Novak et al.[6] report that the most predictive tools for diagnosing CP are as follows:

  • Infants before 5 months corrected age: "term-age magnetic resonance imaging (86%-89% sensitivity), the Prechtl Qualitative Assessment of General Movements (98% sensitivity), and the Hammersmith Infant Neurological Examination (90% sensitivity)"[6]
  • Infants after 5 months corrected age: "magnetic resonance imaging (86%-89% sensitivity) (where safe and feasible), the Hammersmith Infant Neurological Examination (90% sensitivity), and the Developmental Assessment of Young Children (83% C index)"[6]

Signs of Cerebral Palsy[edit | edit source]

Failure to acquire certain key milestones at the expected age first raises suspicion of a CP diagnosis. Key clinical characteristics of CP are the persistence of primitive reflexes or primary motor patterns beyond the expected age. When primitive reflexes do not dissipate, motor development progression and sequential attainment of higher level neuromotor skills can be prevented and delayed.[4]

** Early diagnosis optimises long-term functional outcomes.[4]

The following are common signs of CP by age group:

3-6 months[edit | edit source]

  • Feels stiff
  • Feels floppy
  • Head falls back when being picked up from supine
  • Overextended back and neck when cradled in a caregiver's arm
  • Legs stiff or scissor when being picked up[4]

Older than 6 months[edit | edit source]

  • Unable to roll in either direction
  • Unable to bring hands together
  • Reaches out with one hand with the other fisted
  • Difficulty with hands to mouth[4]

Older than 10 months[edit | edit source]

  • Scoots around on buttocks or hops on knees, but does not crawl on all fours
  • Lopsided crawl[4]

Symptoms[edit | edit source]

The most common symptom seen in individuals with CP is hypertonicity of the muscles secondary to brain injury.[2] Each case of CP presents differently depending on the lesion in the brain. Some children may only have musculoskeletal issues, while others might have a broad range of symptoms that limit daily activities and/or have life-threatening comorbidities. As the nervous systems matures, symptoms may improve.[2]

Paul et al.[2] listed the comorbidities associated with CP and their frequency:

  1. Pain: 75%
  2. Intellectual disability: 50%
  3. Gait disorders: 33%
  4. Hip displacements: 33%
  5. Speech problems 25%
  6. Epilepsy: 25%
  7. Incontinence: 85%
  8. Behavioural disorders: 25%
  9. Sleep disorders: 40%
  10. Hearing impairments: 9%
  11. Vision impairments: 10%
  12. Cognitive impairments: 77%
  13. Thyroid dysfunction: 3%
  14. Gastrointestinal disturbances: 2%[2]

Classification of Cerebral Palsy[edit | edit source]

Cerebral palsy is classified into three categories: spastic, dyskinetic and ataxic.[2]

Spastic Cerebral Palsy[edit | edit source]

The most common type of CP is spastic CP. This type is also the most amenable to treatment.[1] Individuals with spastic CP present with hyperreflexia and hypertonicity. Spastic CP be bilateral or unilateral.[2]

Individuals may present with diplegia, quadriplegia or hemiplegia.

Diplegia[edit | edit source]

In diplegia, the lower extremities are more affected than the upper extremities. This is the most common clinical phenotype of CP. Children with spastic diplegia usually have a good prognosis for independent ambulation and have normal cognitive function.[4]

Quadriplegia[edit | edit source]

In quadriplegia, all four limbs involved, but the hands are more affected than the legs.[2] Children present with:[2]

  • Limited voluntary movements of all extremities
  • Pseudobulbar signs
  • Accidental food entry in the airways
  • Swallowing difficulty
  • Optic atrophy
  • Seizures
  • Severe intellectual abnormality

** Children with spastic quadriplegia have a poor prognosis for independent ambulation.[4]

Hemiplegia[edit | edit source]

In hemiplegia, one side of the body is affected, but hand function is most affected.[2] Children present with:[2]

  • Severely impaired dorsiflexion and eversion of the foot
  • Increased spasticity in the flexor muscles
  • Sensory abnormalities
  • Seizures
  • Visual problems[2]

** Most children with spastic hemiplegia have a high level of functional ability, normal cognitive ability and are able to maintain independent ambulation.[4]

Dyskinetic Cerebral Palsy[edit | edit source]

Dyskinetic CP (also referred to as dystonic or athetoid CP) involves an injury to the basal ganglia.[7] Individuals with dyskinetic CP display abnormal movements and postures. These deviations are due to impaired movement control, muscle tone and coordination.[8] Children with dyskinetic CP waver from hypotonia to hypertonia.[9]

Cerebral Palsy Guide[9] provides the following definitions:

  • Dystonia - Slow, rotational movements of the torso, arm or leg.
  • Chorea - Sudden involuntary movements, especially in the fingers and toes.
  • Athetosis - Sluggish, writhing movements, mainly in the fingers and face.
  • Choreoathetoid - A combination of chorea and athetosis.
  • Dyskinesia - A general term used to describe involuntary movements.[9]

Ataxic Cerebral Palsy[edit | edit source]

Ataxic CP is the rarest form of CP.[10] Individuals with ataxic CP demonstrate incoordination of goal-directed movements, which results in trunk and gait deviations, intention tremor and slurred speech.[11]

The video below by Cerebral Palsy Alliance shows the various types of CP classifications:

Assessment Scales[edit | edit source]

There are four assessment scales used to classify and assess support and therapy needs for individuals with CP:[4]

  1. Gross Motor Function Classification System (GMFCS): used for children aged 2 to 18 years to describe gross motor function, especially the ability to walk.
  2. Manual Ability Classification System (MACS): used for children aged 4 to 18 years to describe how they use their hands and upper extremities.
  3. Communication Function Classification System (CFCS): used to describe a child's ability for routine daily communication, including vocalisations, manual signs, eye gaze, pictures, communication boards or speech generating devices.
  4. Eating and Drinking Ability Classification System (EDACS): used for children aged 3 years or older to describe eating and drinking function, including safety (risk of aspiration / choking) and efficiency (time taken, any food lost).[4]

The following chart by Paulson et al., (2017) [12][4] displays all four tests and what you would observe at each level:

Level GMFCS MACS CFCS EDACS
I Walks without limitation Handles objects easily and successfully Effective sender and receiver Eats and drinks safely and efficiently
II Walks with limitations (no mobility aid by 4 years) Handles most objects with reduced speed/quality Effective but slow-paced sender and receiver Eats and drinks safely but with some limitations to efficiency
III Walks with hand-held mobility device Handles objects with difficulty, help to prepare or modify activity Effective sender and receiver with familiar partners Eats and drinks with some limitations to safely; there may also be limitations to efficiency
IV Self-mobility with limitations, may use power Handles limited number of objects in adapted setting Inconsistent sender and receiver with familiar partners Eats and drinks with significant limitations to safety
V Transported in manual wheelchair Does not handle objects Seldom effective sender and receiver with familiar partners Unable to eat or drink safely; consider feeding tube

Table 1. Assessment Scales for Cerebral Palsy from Paulson et al., (2017) [12][4]

The following video by Cerebral Palsy Foundation discusses early detection tools for diagnosing CP:

Resources[edit | edit source]

References[edit | edit source]

  1. 1.0 1.1 Papavasiliou A, Ben-Pazi H, Mastroyianni S, Ortibus E. Cerebral Palsy: New Developments. Frontiers in Neurology. 2021;12.
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 Paul S, Nahar A, Bhagawati M, Kunwar AJ. A Review on Recent Advances of Cerebral Palsy. Oxidative Medicine and Cellular Longevity. 2022 Jul 30;2022.
  3. Sadowska M, Sarecka-Hujar B, Kopyta I. Cerebral palsy: Current opinions on definition, epidemiology, risk factors, classification and treatment options. Neuropsychiatric disease and treatment. 2020;16:1505.
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 4.15 4.16 Patel DR, Neelakantan M, Pandher K, Merrick J. Cerebral palsy in children: a clinical overview. Translational pediatrics. 2020 Feb;9(Suppl 1):S125.
  5. Folkerth RD. Periventricular leukomalacia: overview and recent findings. Pediatr Dev Pathol. 2006 Jan-Feb;9(1):3-13.
  6. 6.0 6.1 6.2 Novak I, Morgan C, Adde L, Blackman J, Boyd RN, Brunstrom-Hernandez J, et al. Early, accurate diagnosis and early intervention in cerebral palsy: advances in diagnosis and treatment. JAMA pediatrics. 2017 Sep 1;171(9):897-907.
  7. Eskay K. Cerebral Palsy Aetiology and Pathology Course. Plus, 2023.
  8. Li X, Arya K. Athetoid Cerebral Palsy. InStatPearls [Internet] 2021 Sep 28. StatPearls Publishing.
  9. 9.0 9.1 9.2 Cerebral Palsy Guide, 2022. Available from: https://www.cerebralpalsyguide.com/cerebral-palsy/types/athetoid/
  10. Levy JP, Oskoui M, Ng P, Andersen J, Buckley D, Fehlings D, Kirton A, Koclas L, Pigeon N, van Rensburg E, Wood E. Ataxic-hypotonic cerebral palsy in a cerebral palsy registry: Insights into a distinct subtype. Neurology: Clinical Practice. 2020 Apr 1;10(2):131-9.
  11. Eggink HE, Kremer DA, Brouwer OF, Contarino MF, van Egmond ME, Elema AG, Folmer KA, van Hoorn JF, van de Pol LA, Roelfsema VI, Tijssen MA. Spasticity, dyskinesia and ataxia in cerebral palsy: are we sure we can differentiate them?. European Journal of Paediatric Neurology. 2017 Sep 1;21(5):703-6.
  12. 12.0 12.1 Paulson A, Vargus-Adams J. Overview of four functional classification systems commonly used in cerebral palsy. Children. 2017 Apr 24;4(4):30.