Cerebral Palsy, Hydrocephalus & Spina Bifida

Cerebral palsy: definition and subtypes

Definition. Cerebral palsy (CP) is a group of permanent disorders of movement and posture caused by a nonprogressive injury to the developing brain, from fetal life to about 2 years of age. It affects roughly 2–3 per 1,000 births and is the most common cause of physical disability in childhood. The lesion is static, but the picture evolves: a hypotonic infant may later develop spasticity, contractures, and an abnormal gait.

Risk factors. Prematurity is the leading risk factor; intrapartum asphyxia explains only a minority of cases.

Classification. Spastic forms (hypertonia, hyperreflexia, clonus, upgoing toes) make up about three quarters of cases. The site of injury predicts the pattern.

PVL spares the arms because corticospinal fibers to the legs run closest to the lateral ventricles and are injured first.

Recognizing CP and its comorbidities

Red flags. Delayed motor milestones plus Moro or asymmetric tonic neck reflexes persisting beyond about 6 months, a consistent hand preference before 12 months (the neglected hand is weak), toe walking with hypertonia or sustained clonus, persistent fisting, or early truncal hypotonia that evolves into limb spasticity.

Diagnosis. CP is a clinical diagnosis. Brain MRI is the imaging study of choice to identify the lesion and is abnormal in most children; CT is less sensitive, and by the second year the fontanelle is usually too small for ultrasound. Loss of acquired skills is never CP and demands evaluation for a neurodegenerative, metabolic, or spinal cord disorder.

Comorbidities. Severity is graded by the Gross Motor Function Classification System (GMFCS, level I walks without limitation to level V wheelchair-transported); higher levels carry more comorbidity:

• Epilepsy; intellectual disability (most frequent in quadriplegia)
• Strabismus, visual impairment, hearing loss
• Dysphagia with aspiration and poor growth, drooling, GERD, constipation
• Hip displacement, scoliosis, osteopenia with low-trauma fractures

Managing cerebral palsy

Care is multidisciplinary: physical and occupational therapy, stretching, ankle-foot orthoses, and speech and feeding therapy. Spasticity treatment is matched to its distribution:

Hip surveillance. Adductor and hip-flexor spasticity pulls the femoral head out of the acetabulum, and risk climbs with GMFCS level. Nonambulatory children get serial AP pelvis radiographs so surgery can precede painful dislocation.

Abrupt interruption of intrathecal baclofen (empty pump, kinked catheter) causes high fever, itching, rebound spasticity, altered mental status, seizures, and rhabdomyolysis, and can be fatal.

Hydrocephalus and shunt failure

Presentation. With open sutures the infant skull expands: head circumference crosses percentiles, the fontanelle bulges, sutures split, scalp veins distend, and the baby is irritable and vomits. The setting-sun sign (forced downgaze) reflects dorsal midbrain pressure. Older children have morning headache, vomiting, papilledema, and abducens palsy.

Causes and imaging. Obstructive causes include aqueductal stenosis, Chiari II, Dandy-Walker malformation, and posterior fossa tumors; communicating hydrocephalus follows intraventricular hemorrhage or meningitis. With an open fontanelle, cranial ultrasound is the fast, radiation-free first study; MRI defines the cause. Treatment is a ventriculoperitoneal (VP) shunt or, for some obstructive lesions, endoscopic third ventriculostomy. A large head tracking parallel to a high percentile, with normal development and a large-headed parent, is benign familial macrocephaly.

Shunt malfunction. Obstruction is most common, then disconnection or fracture; all cause headache, vomiting, lethargy, irritability, a bulging fontanelle, or an enlarging head. Infection occurs mostly within 6 months of surgery, from coagulase-negative staphylococci or S. aureus, with fever or erythema along the tubing.

Unchanged ventricles do not exclude malfunction, because stiff "slit" ventricles may not dilate. Lumbar puncture is not the test: it is unsafe with obstruction and does not sample shunt fluid.

Myelomeningocele

Spectrum. The posterior neuropore closes around day 28. Spina bifida occulta is a vertebral arch defect under intact skin; a lumbosacral dimple above the gluteal cleft, hair tuft, or lipoma can mark an occult tethered cord (spinal ultrasound in early infancy). A myelomeningocele contains cord and meninges, usually lumbosacral, with weakness, sensory loss, and bladder and bowel dysfunction below the lesion.

Screening and prevention. Maternal serum AFP is elevated at 15–20 weeks; ultrasound shows the lemon and banana signs, and amniotic fluid shows ↑AFP with acetylcholinesterase. Risk factors include a prior affected pregnancy, valproate or carbamazepine, pregestational diabetes, and obesity.

At birth. Cover the sac with a sterile, saline-moistened nonadherent dressing, keep the infant prone, use latex-free equipment, and close within about 72 hours.

Chiari II. Nearly all affected children have downward displacement of the vermis, fourth ventricle, and medulla through the foramen magnum; most develop obstructive hydrocephalus, often after the back is closed. Brainstem compression causes stridor from vocal-cord paralysis, apnea, and dysphagia and is a leading cause of early death.

Bladder, bowel, latex. Detrusor-sphincter dyssynergia creates high pressures that cause reflux, hydronephrosis, UTIs, and chronic kidney disease. Clean intermittent catheterization from infancy plus oxybutynin, guided by renal ultrasound and urodynamics, protects the kidneys; bethanechol would raise pressures. Neurogenic bowel needs a scheduled bowel program. Repeated surgery and catheterization cause latex allergy, so care is latex-free from birth.

Tethered cord. Growth stretches a cord scarred to the repair: back or leg pain, worsening gait or spasticity, new bladder or bowel changes, progressive scoliosis, cavus foot. Exclude shunt malfunction, then obtain spine MRI; treatment is surgical untethering.

Abnormal head shape

Positional plagiocephaly. One-sided occipital flattening from supine lying or torticollis. From above the head is a parallelogram, with the ipsilateral ear and forehead pushed forward, no ridge, and open sutures; the diagnosis is clinical. Treat with counter-positioning (the infant still sleeps supine), supervised tummy time, and neck stretching or PT; a helmet is reserved for severe or persistent deformity.

Craniosynostosis. Premature fusion blocks growth perpendicular to the suture. A palpable ridge and fixed shape suggest it; 3-D CT confirms it. Surgery in infancy (endoscopic strip craniectomy or cranial vault remodeling) prevents raised intracranial pressure and deformity.

Ear forward with a parallelogram = positional; ear back with a trapezoid = lambdoid synostosis.