Definition

Cerebral palsy (CP) is a neurodevelopmental condition caused by a nonprogressive lesion of the brain. Whereas CP is typically diagnosed early in life and brain lesions are not progressive, it continues to bear effects that may worsen throughout the life span.

Many definitions of CP have been proposed. The most recent was agreed on in 2006 after review of the proposed definition by the International Workshop on Definition and Classification of CP. Through this review, it was decided that CP would be used as a clinically descriptive term instead of an etiologic diagnosis, defined as follows:

Prevalence

The prevalence of CP has been reported to range from 1 to 3 per 1000 live births [2–4]. Yeargin-Allsopp and coworkers [3] reported a higher incidence of CP in boys compared with girls, with a ratio of 1.4 to 1. The same study found a higher prevalence of CP in black compared with white children or those of Hispanic descent [3]. Subsequent studies confirmed this finding [5–8]. Maenner and colleagues [8] also evaluated mobility. In this study, the majority of children were ambulatory, followed by those who were nonambulatory or had limited mobility, with the smallest number walking with an assistive device.

Mobility difficulties have been associated with increased mortality of children with CP. In a study by Strauss and coworkers [9], those who were categorized as having poor mobility (defined by the inability to lift the head while in a prone position) had twice the mortality rate as those with high mobility (defined by the ability to roll or to sit). However, the same study found that the overall mortality rate of children with severe disabilities is declining by an estimated 3.4% per year.

Etiology

Risk factors for CP can be divided into pre-pregnancy risk factors, maternal disease, and pregnancy related. Pre-pregnancy risk factors, which have been associated with thrombosis and perinatal stroke, include advanced maternal age and primiparity, respectively. Maternal diseases such as diabetes, anemia, hypertension, epilepsy, thyroid dysfunction, and chronic renal disease have also been associated with CP. Associations have been found with multiple gestation (twins, triplets) and delivery factors such as assisted fertilization, plurality, placental disease, bleeding during pregnancy, preeclampsia or eclampsia, intrauterine exposure to infection (urinary tract infections, sexually transmitted diseases, and rubella, among others) or maternal fever in labor, restricted or excessive growth for gestational age, abnormal presentation at time of delivery, rupture of membranes longer than 24 hours before delivery, and induced labor [10,11]. Apgar score of less than 7 at 5 minutes, low birth weight, and gestational age of less than 37 weeks are also risk factors for CP.

Although many risk factors for CP exist, the actual cause is a cerebral abnormality. CP may be caused by neonatal encephalopathy from hypoxic-ischemic events, ischemic stroke, or congenital malformations [12].

Classification

CP has been classified on the basis of the dominant presentation of tone or movement into spastic, dyskinetic (dystonic or choreoathetotic), and ataxic [1]. It has been further divided on the basis of limb involvement into unilateral (or hemiplegia) or bilateral (either diplegia or quadriplegia) [1,13]. It is also recommended to account for accompanying impairments and anatomic findings in classifying CP [1].

Neuroimaging findings have been associated with specific CP subtypes. Bilateral spastic CP has most frequently been found to have periventricular white matter changes on imaging. On the other hand, unilateral spastic CP has been associated with periventricular white matter lesions, periventricular gliosis, focal cortical dysplasia, and unilateral schizencephaly. Athetoid CP has been associated with cortical or deep gray matter lesions. In ataxic CP, lesion patterns are less common, but imaging may demonstrate cerebellar malformations [14].

Symptoms

Whereas CP has a profound effect on the musculoskeletal system, it can be accompanied by myriad symptoms affecting other body systems. Symptoms vary by disease severity and may include intellectual disability, seizures, learning disorders, skeletal deformities, pain, abnormal tone, weakness, developmental delay, poor dental health, difficulties with bowel and bladder management, difficulties with oral-motor control, tremors, difficulties with sleep, and difficulties with mood. Here we discuss the body systems most commonly affected by CP.

Head, Eyes, Ears, Nose, and Throat

CP may be accompanied by visual deficits, sensorineural hearing loss, poor oral-motor control, and poor dentition. Vision may be hindered by strabismus (esotropia) or nystagmus. Depending on etiology, there may also be concern for retinopathy of prematurity. Difficulty with oral-motor control may lead to excessive drooling, dysphagia, dysarthria, or aphasia [15,16].

Cardiovascular

Cardiovascular disease may be of concern as those with CP age. Increased circulatory system disease in adult CP cases compared with age-matched peers has been reported [17].

Pulmonary

Many CP-associated symptoms can lead to deterioration of the pulmonary system. Dysphagia may lead to aspiration, which in turn can lead to pneumonia. Changes in tone and development of scoliosis can lead to decreased vital capacity and restricted airway disease. As patients age with CP, there may be an increase in respiratory illnesses, including pneumonia, influenza, and chronic obstructive pulmonary disease [16,17].

Gastrointestinal and Genitourinary

Along with oral-motor impairment, feeding may be affected by swallowing dysfunction. A high incidence of gastroesophageal reflux disease has also been reported [16]. This may be due to associated hiatal hernias, scoliosis, increased intra-abdominal pressure from spasticity, seizures, or neuromuscular incoordination. Regardless of cause, chronic gastroesophageal reflux may lead to esophagitis. This may be manifested with dystonic posturing of the head and neck, hematemesis or vomiting, anemia, or chronic irritability. Chronic peptic esophagitis may potentially cause esophageal mucosal ulceration and stricture formation. Constipation may also arise because of low-fiber or liquid diet, use of medications (including opioids, antispasmodics, antihistamines, and anticonvulsants), immobility, decreased bowel motility, hypotonia, or skeletal abnormalities. Chronic constipation may in turn lead to megarectum, anal fissures, or soiling [16,17].

Musculoskeletal

Musculoskeletal disease is the hallmark of CP. Its impact is lifelong and causes arthritic changes, deformity or contracture, and joint dislocation. This can lead to decreased mobility, osteoporosis, fracture, skin breakdown, and pain [15,17].

Pain is reported in both children and adults with CP and may be caused by muscle imbalance or spasticity. Back pain is commonly reported, followed by pain in weight-bearing joints. The presentation of CP can influence the location of pain. Foot pain is commonly reported in those with diplegic CP, whereas knee pain is more frequent in quadriplegic CP. Neck pain, shoulder pain, and headaches are reported in those with dyskinesia [17]. Pain can affect socialization and education as well as lead to fatigue and decreased mobility [18,19].

Pain affects not only mobility but also strength, endurance, balance, and spasticity. A study looking at aging with CP found that 39% of 20-year-old CP patients could ambulate 20 feet without an assistive device. This declined progressively to 37% by 40 years and 25% by 60 years of age. Subtype also played a role; spastic diplegic patients most commonly showed this progressive decline in mobility [17].

Decreased mobility can lead to osteoporosis. A study in 2008 reported that adults and children with spastic quadriplegia who are nonambulatory have decreased bone density of the lower spine across their life span [17]. Decreased mobility may also influence scoliosis progression over time. It was reported that curves of more than 4 degrees by the age of 15 years led to progressive worsening of spine curvature with age. Curvature of the spine, whether scoliosis, kyphosis, or lordosis, can affect sitting balance, increase pain, and cause difficulties with bowel and bladder management [17].

Sitting may also be influenced by hip subluxation due to muscle imbalance, especially in spastic CP [20]. Hip subluxation can lead to difficulties with wheelchair seating and fit, which may result in skin breakdown and pain, as persistent hip dislocations have been reported to increase pelvic obliquity [20].

Other joints commonly affected in CP include the knee, foot, and ankle. The most common disorders of the foot are equinus deformity, equinoplanovalgus deformity, and equinocavovarus deformity (Fig. 124.1). Equinus deformity is a disorder of the hindfoot characterized by excessive plantar flexion of the hindfoot in reference to the ankle. It is seen with hypertonicity of the gastrocnemius or soleus muscles. Equinoplanovalgus deformity is seen with pronation of the forefoot and midfoot and is typically accompanied by hallux valgus and valgus deformity at the ankle. This is commonly seen with increased tone to the gastrocnemius and the peroneals. Equinovarus deformity is seen with supination of the midfoot and involves the gastrocnemius and posterior tibialis muscles [21]. Increased tone at the gastrocnemius can also produce toe walking, which is a common occurrence in CP.

Excessive knee flexion due to increased tone in the hamstrings may be seen. However, increased tone alone does not lead to the crouched gait pattern commonly seen in CP. This pattern may be due to a combination of skeletal deformity, weakness, spasticity, and poor motor control [22,23]. It is characterized by flexion at the hips, due in part to increased tone of the iliopsoas, and flexion at the knees. Increased tone of the hip adductors may lead to further gait abnormality, producing a scissoring gait pattern.

Neurologic