Disorders of the Spinal Cord in Children

Canada

PREFACE

Peter Rosenbaum’s vivid characterization, in his excellent Foreword, of the cord as the marginal and apologetic country cousin to the more prominent and influential brain will have resonance with many clinicians. The spine features less both in undergraduate and postgraduate paediatric training than it might, and less than the devastating impact of a spinal cord lesion might justify.

But the country cousin is not without guile. Examples of the often enigmatic role of the cord in a spectrum of clinical situations might include the unidentified cord lesion in a sick and floppy neonate, or in a ventilated child recovering from severe pneumococcal meningitis, the incipient cord compression underlying a strikingly ‘non-organic’ gait disorder in a teenager, and the increasing awareness of cord involvement in shaken impact syndrome.

The range of subject matter, the complexity of many of the clinical issues, and the variety of expertise engaged in paediatric spinal cord disease were all persuasive reasons for taking up the challenge of editing this book. It was a delight to collaborate with the distinguished and diverse group of clinicians and academics who generously agreed to contribute. Our fascinating, often humorous, and occasionally surreal e-mail traffic over a substantial gestational period could produce a worthy chapter in itself!

I have received kindness, support, and forbearance in equal measure from everyone at Mac Keith Press and am grateful in particular to Peter Baxter, Hilary Hart, Ann-Marie Halligan, Udoka Ohuonu, and Alessy Beaver. Chris Purdon of The Clyvedon Press has been a perceptive and kindly copy-editor, Laurence Errington a precise and rigorous indexer, and Karl Hunt an imaginative cover designer.

Finally, I am most grateful of all to my wife Claire who has been a source of love, support, and perceptive comment throughout the genesis of this book.

Michael Pike

Children’s Hospital, Oxford, UK

May 2013

1

THE NEUROLOGICAL EXAMINATION OF CHILDREN WITH SPINAL CORD DISORDERS

Saleel R Chandratre and Sandeep Jayawant

In this chapter we present an approach to the clinical assessment of children who have symptoms and signs suggestive of spinal cord dysfunction, with a view to formulating a differential diagnosis and management strategy. The spinal cord is involved in many complex neurological disorders, either in isolation or as part of a multisystem disorder. This warrants a thorough clinical history and both a general systems and neurological examination in addition to a focused assessment of the functions of the spinal cord itself.

History of present illness

The history narrows the differential diagnosis and focuses the examination. Spinal cord dysfunction may present with motor, sensory, or a combination of motor and sensory symptoms, sphincter disturbances, autonomic dysfunction, and/or pain. The most common symptoms are gait abnormality (in an ambulant child), paucity of limb movement (in the pre-ambulant infant), sensory disturbance including reduced sensation and dysaesthesia, sphincter disturbance, and neck, back, or truncal pain.

The age at onset of symptoms, the nature of the initial symptoms, and their evolution over time will influence the clinical approach. Preceding events including identifiable triggers, concurrent infection and trauma, and the pace of progression may identify a static, progressive, or episodic process with implications for focused examination and investigation.

The causes of myelopathy are myriad and extensively described in other chapters. To set the background to the clinical approach, Table 1.1 lists selected categories of acute myelopathy and Table 1.2 selected causes of chronic myelopathy. Table 1.3 lists characteristic presenting symptoms and signs of childhood spinal pathology. Table 1.4 highlights some salient features that should be specifically sought when eliciting the history of a suspected myelopathy.

Clinical examination

The identification and localization of cord pathology is dependent on a familiarity with its anatomy and physiology. Figures 1.1–1.4 illustrate the anatomy of the spinal cord in section, the dermatomal distribution of sensory nerves, and the reflex arc.

TABLE 1.1

Selected categories of acute myelopathy

Infections: discitis, epidural abscess, tuberculosis, Herpes simplex virus

Trauma: birth-related trauma, accidental and non-accidental injury, acute disc prolapse

Vascular: thromboembolic events (paediatric intensive care unit) or haemorrhage (spinal epidural haematoma)

Neoplastic: neuroblastoma, lymphoma, intrinsic spinal cord tumours

Toxins: lathyrism (e.g. caused by ingesting legumes of the genus Lathyrus or similar), chemotherapeutic drugs

Demyelinating: acute disseminated encephalomyelitis, neuromyelitis optica, multiple sclerosis

TABLE 1.2

Selected causes of chronic myelopathy

Degenerative/metabolic: bone pathology with compression, chronic disc prolapse, adrenomyeloneuropathy, sub-acute combined degeneration

Neoplastic: indolent tumours, neurofibromas

Genetic: spinocerebellar ataxias, hereditary spastic paraplegia

Salient features in the examination of suspected myelopathy through observation or formal examination are highlighted in the following paragraphs. In addition, depending on the age at presentation, certain aetiologies are more likely; therefore the following section focuses on some specific age and aetiology-based examination findings that need to be actively elicited.

OBSERVATION

An accurate description of pain or sensory impairment is often not obtained. It is therefore vital to observe the child’s reaction to gauge this. Engagement with surroundings, visual attention and exploration, physical interaction with toys, the nature of play, paucity, and symmetry of movement, and response to sensory stimulus may be the primary examination tool in a young or fretful child.

Observation of the following features is particularly important:

Consciousness may be impaired in situations where the cord lesion is accompanied by other pathology. This may occur in traumatic injury, meningitis or demyelinating disorders (acute disseminated encephalomyelitis, neuromyelitis optica)

Interaction with carer or parent

Visual attention and strabismus

Facial expression, weakness, and drooling

Ability to weight bear and ambulate in an independently ambulant child

Gait: paraplegic, spastic, antalgic, high stepping

Ability to rise from the floor or climb stairs

Paucity of use of limbs and antigravity movement especially in a pre-ambulant child

Breathing pattern: pattern of diaphragmatic and intercostal muscle use.

TABLE 1.3

Characteristic presenting symptoms and signs of childhood spinal pathology

Motor symptoms and signs

Hypotonia in the acute stage and at the level of cord involvement

Weakness: may be static or progressive

Ataxia: progressive (Friedreich ataxia, other spinocerebellar ataxias)

Hypertonia

Gait abnormality: toe walking, foot drop, hemiplegic, scissoring (hereditary spastic paraplegia) Frequent falls

Torticollis or scoliosis

Arthrogryposis

Sensory symptoms and signs

Pain or segmental paraesthesiae: localized at the level of cord involvement and/or radiating (cervical, to the arms; thoracic, circumferential to the chest or abdomen; lumbar or sacral, to the legs or saddle area)

Loss of ipsilateral discriminative sensation (position, vibration, discriminative touch, pressure touch, two-point discrimination, stereognosis, and shape and movement awareness).

Loss of contralateral light touch (two or three segments below cord involvement)

Loss of contralateral pain and temperature sensation (two or three segments below cord involvement) Sensory level (alteration of sensation to pinprick at and below a segmental level)

Sensory ataxia

Sphincter disturbance

It is extremely important to take a sphincter history even in the pre-toilet-trained infant including

Change in pattern of voiding and/or defaecation

Is there intermittent wet and/or soiled nappy with a dry one between, or is the nappy always wet and/or dirty suggesting continuing incontinence?

When the nappy is off for a period, is a normal voiding of urine with a good stream seen with full continence before and after?

Does the perianal area remain clean once wiped or is there a continuous faecal leak?

In the previously toilet-trained child:

Bladder (change in pattern and/or urinary urgency, hesitancy, retention or incontinence)

Bowel (change in pattern and/or constipation and/or faecal incontinence)

Other autonomic symptoms and signs

Tachy-/bradycardia

Orthostatic hypotension/labile blood pressure

Sweating or lack thereof

Impaired temperature control and vasomotor instability below the level of the lesion Ipsilateral Horner syndrome (cervico-thoracic cord lesion)

Sexual dysfunction after puberty

Other symptoms that may be associated with cord pathology

Raised intracranial pressure (due to cranio-cervical junction abnormalities)

Eye movement abnormalities (for example in spinocerebellar ataxias)

Respiratory distress (diaphragmatic breathing due to intercostal muscle weakness)

TABLE 1.4

Salient features when eliciting the history of a suspected myelopathy

Presentation history

Time frame of presentation and progression (distinguishing acute from chronic myelopathy)

Sensory, motor, autonomic, or associated symptoms as in Table 1.1

History of trauma

Intercurrent or preceding illness, for example upper respiratory tract infection, cold sores, gastroenteritis (e.g. in acute disseminated encephalomyelitis)

Medication history (see section 6 below)

Systemic disease (other autoimmune conditions if suspecting neuromyelitis optica, systemic lupus erythematosus, other autoimmune disorders)

Contact with infectious adults or children, particularly tuberculosis and herpes simplex virus

Contact with pets or animals, in particular exposure to ticks (Lyme disease)

Foreign travel (infectious pathology)

Diplopia, decreased visual acuity (neuromyelitis optica)

Encephalopathic features (acute disseminated encephalomyelitis, encephalitis)

Recent spinal surgery or period of intensive care including central vascular access (vascular, infectious)

Any risk factors for thromboembolism (ischaemic cord lesion)

Antenatal and birth history

Fetal movements in utero (congenital malformations, e.g. spina bifida)

Pregnancy: diabetes, antenatal bleeds, anomaly scan data, folate supplementation, medication use

Labour and delivery, for example shoulder dystocia, instrumental delivery, traumatic delivery

Arthrogryposis or talipes at birth

Neonatal intensive care including umbilical artery catheter placement

Developmental history and social history

Achievement of motor milestones (to elucidate congenital vs acquired and static vs progressive cord pathology)

Achievement of continence (and history of patterns of voiding in pre-toilet-trained child)

Social history, particularly where medically unexplained neurological symptoms are being considered or where there is a suspicion of non-accidental traumatic injury

Family history

First-degree relatives with demyelinating disorders

First-degree relatives with haemorrhage of the central nervous system (e.g. familial cavernomas)

First-degree relatives with neural tube defects

Genetic conditions, for example spinocerebellar ataxias, hereditary spastic paraparesis, neurofibromatosis

Family history of autoimmune disease

Immunization history (particularly recent vaccination): post vaccination demyelination

Medication and toxin exposure

Bronchodilators and steroids (Hopkin syndrome)

Chemotherapeutic agents, for example vincristine, methotrexate, cytosine

Contaminated dhal (lathyrism) and bitter cassava (konzo)

Out of date tetracyclines and quiniodochlor

Botulism presenting as flaccid paraplegia should be considered in the differential diagnosis of an acute myelopathy in an infant (prodromal constipation, rapidly progressive flaccid quadriparesis, cranial nerve involvement)

Fig. 1.1. Spinal reflex arc.

GENERAL AND SYSTEMIC EXAMINATION

The general examination may reveal clinically relevant information either in terms of aetiology or of associated features requiring appropriate management.

For example neurocutaneous markers such as café au lait patches may suggest an underlying diagnosis of neurofibromatosis type 1 (NF1), or skin or retinal haemangiomas may suggest intracerebral and intraspinal haemangiomas. Spinal cord arteriovenous malformations have been reported in Klippel–Trenaunay–Weber syndrome, Osler–Weber– Rendu syndrome, and in NF1. Hemihypertrophy with or without hemimegalencephaly would suggest Klippel–Trenaunay–Weber syndrome with spinal cavernomas (Maher et al. 2008; Song et al. 2010).

Dysmorphic features may suggest an underlying genetic diagnosis and/or an identifiable syndrome diagnosis (achondroplasia, Down syndrome), which may warrant detailed assessment of other systems. Skeletal abnormalities, corneal clouding, coarse facial features, and organomegaly may suggest mucopolysaccharidoses with or without features of compressive myelopathy secondary to spinal stenosis or odontoid hypoplasia.

Scoliosis, kyphosis, and gibbus formation may indicate vertebral malformations or a bony destructive process with the possibility of underlying cord involvement.

Generalized lymphadenopathy may indicate infections such as tuberculosis or a leukaemia or lymphoma. Skin rashes and joint swelling raise the possibilities of Lyme disease or an autoimmune disorder. Pallor may be seen in lymphoproliferative disorders or vitamin B12 deficiency.

Cardiac examination, electrocardiography, and echocardiography may identify cardiac structural or rhythm disturbances as a source of cardioembolic anterior spinal artery stroke, or the cardiomyopathy of Friedreich ataxia.

Motor nerve (efferent)

Fig. 1.2. Dermatomes: anterior aspect.

Fig. 1.3. Dermatomes: posterior aspect.

Fig. 1.4. Cross-section anatomy of spinal cord showing tracts within spinal cord. A colour version of this figure is available in the plate section at the end of the book.

Abdominal examination may reveal faecal loading due to anal sphincter disturbance. A painful or painless palpable bladder is an important early sign of urinary retention. Abdominal neuroblastoma or lymphoma may be palpated.

NEUROLOGICAL EXAMINATION

Neurological examination of a child with spinal cord dysfunction may be challenging because of the associated sensory symptoms, pain, and possible encephalopathy. Head circumference should be charted as a baseline measure and to monitor velocity of head growth over time using appropriate growth charts (compare with previous measurements if available). Macrocephaly is noted in achondroplasia and in chronic hydrocephalus.

Cranial nerve examination should focus on facial involvement (Guillain–Barré syndrome, neuromuscular disorders), hearing (a presenting feature in paediatric neurofibromatosis type 2 [NF2]), bulbar involvement (botulism, Guillain–Barré syndrome, high cervical pathology), Horner syndrome (may suggest a cervical or thoracic cord lesions) and vision (optic neuritis, multiple sclerosis, neuromyelitis optica), as well as ocular movements (foramen magnum lesions, spinocerebellar disorders).

The back needs to be carefully examined for the cutaneous markers of cord dysraphism and for kyposcoliosis and gibbus formation. The neck should be examined for torticollis.

Particular attention must be given to the assessment of skeletal abnormalities secondary to spinal cord dysfunction (congenital talipes, acquired bony deformities, dislocated hips, limb length discrepancy, scoliosis, and kyphosis)

Motor examination

This should start with a careful observation and characterization of the gait in an ambulant child. Gowers test will confirm proximal weakness if it is suspected on observation. In a non-ambulant child, opportunistic observation of posture, head and trunk control, and antigravity movement is a good guide to muscle strength. Careful assessment of distal power in hand muscles may point to a syrinx or a craniocervical junction anomaly such as a Chiari malformation. Distal weakness in the lower limbs points to a conus medullaris or cauda equina syndrome.

Wherever possible, formal muscle strength charting using the Medical Research Council grade from 0 to 5 or a more detailed grading used by physiotherapists using addition or subtraction signs in addition to whole numbers (e.g. 4− or 4+) helps ascertain the strength at baseline and aids the monitoring of recovery (Table 1.5).

Each muscle group or individual muscle strength needs to be charted depending on the nature (focal or diffuse) of spinal cord involvement to monitor improvement or deterioration. The Modified Ashworth scale (Table 1.6) and other muscle strength assessment scales are in practical usage. In non-organic symptomatology careful preliminary observation may demonstrate the inconsistencies suggestive of non-organic weakness. Mild weakness may be best detected by functional assessment, for example ability to walk on tiptoes and heels, standing on either leg, jumping, hopping, and supporting weight on hands in the wheelbarrow position.

TABLE 1.5

Medical Research Council grading of muscle power

TABLE 1.6

Clinical scale for spastic hypertonia (Modified Ashworth Scale)

Sensory examination

The sensory examination is challenging in an infant or young child and requires careful observation. The cooperative older child may be able to respond accurately to a formal ‘adult’ sensory examination.

Observation may suggest a difference in colour, temperature, perspiration, and the skin may be cooler and dry below the level of a spinal cord lesion.

The Romberg sign is positive in the sensory ataxia of spinal cord or peripheral nerve disorders, often with abnormal joint position sense and impaired vibration. In the upper limbs, sensory ataxia is assessed by asking the child to touch his nose with alternating fingers initially with eyes open and then with eyes closed. There is increased difficulty with eyes closed.

Neck flexion may elicit a sudden ‘electric’ sensation down the back or into the arms (Lhermitte sign), which is secondary to increased mechano-sensitivity of the dorsal columns and is seen in multiple sclerosis, compressive cord lesions, or after cervical cord irradiation.

Pain in spinal cord lesions

There are several types of pain that occur in spinal cord lesions. It is important to recognize this and manage it effectively: central pain, musculoskeletal pain, visceral pain and neuropathic pain.

Central pain is typically a burning, tingling, shooting, stinging, or ‘pins and needles’ sensation. Some individuals also complain of a stabbing, piercing, or lancinating pain. This type of pain usually occurs within days, weeks, or months of the injury and tends to decrease with time in both frequency and intensity. Central pain is diffuse and occurs most often in the legs, back, feet, thighs, and toes although it can also occur in the buttocks, hips, upper back, arms, fingers, abdomen, and neck. Young children may rub or simply scratch an affected area resulting in a mistaken assumption that the problem is dermatological. This type of pain is often exacerbated by noxious stimuli such as bladder and bowel distension, infection, and pressure sores. Management involves identifying triggers as well as addressing the pain itself.

Musculoskeletal pain is a dull aching sensation that occurs as result of muscle tension with increased frequency in the shoulder, hip and hand, although it also occurs in the lower back and buttock. Muscle tension is probably caused by a combination of factors including soft tissue inflammation and limb stretching in the setting of contractures owing to paralysis, spasticity, and disuse. Generally speaking, this pain is usually aggravated by activity and relieved by rest, analgesia, and anti-inflammatory drugs. Therapists involved in rehabilitation need to take account of this in planning mobilization programmes.

Visceral pain is a vague, dull, or diffuse abdominal sensation, or a feeling of discomfort or bloating, or sometimes a referred pain experienced, for example, in the shoulder. Visceral pain is caused by problems such as distension, perforation, inflammation, impaction, or constipation involving organs such as the stomach, kidney, gall bladder, urinary bladder, and intestines; immobility and autonomic dysfunction are often contributory. These problems may also cause associated symptoms such as nausea, fever, and malaise.

In children with an established cervical or high cord transection and a subsequent acute surgical abdomen, it is important to recognize that the expected abdominal and autonomic symptoms and signs, particularly pain and altered perfusion, may be modified by the preexisting cord lesion.

Neuropathic pain, of varying type is a significant problem in some children with spinal cord disease. Nerve root pain is described as having a sharp or electric shock quality in a dermatomal distribution.

Specific spinal cord anatomical syndromes

Based on characteristic patterns of motor and sensory loss, various spinal cord syndromes affecting specific anatomical distributions and tracts within the spinal cord are described.

Figure 1.5 illustrates some common spinal cord syndromes. The signs and symptoms are a result of specific corresponding spinal tract involvement, as described below.

Fig. 1.5. Some common spinal cord syndromes.

Complete transection

After complete spinal cord transection,

All sensory modalities (soft touch, position sense, vibration, temperature, and pain) are impaired below the level of the lesion

Loss of sharp/blunt sensation below a segmental level is most valuable in localizing the lesion. A sensory level may be easily missed unless carefully, and sometimes repeatedly, sought by gradually advancing from an area of normal sensation to where an alteration in sharpness is perceived. Specifically asking to distinguish sharp and dull sensation can also be used as adjunct to sharp/blunt testing

In incomplete lesions, particularly with extra-medullary pathology, the sensory level may be several segments below the level of the lesion as (1) axons of second-order neurons in the dorsal horns decussate over several segments through the ventral white commissure and (2) the lowest segments are represented more superficially in the lateral spinothalamic tract

Band-like radicular pain or segmental paresthesiae may occur at the level of the lesion. If the pain is cervical, it radiates to the arms; if thoracic in origin, it is circumferential to the chest or abdomen; and if lumbar or sacral, it radiates to the legs and/or saddle area

Localized vertebral pain, overlying the spinous process, worse on palpation or percussion may occur with destructive bony lesions e.g. tumours and infections.

Hemisection of the spinal cord (Brown–Séquard syndrome) Features of this syndrome are as follows:

Unilateral interruption of the lateral corticospinal tracts:

Ipsilateral spastic weakness below the level of the lesion

Upgoing plantar ipsilateral to lesion

Abnormal reflexes and Babinski sign may not be present in acute injury. Unilateral interruption of the posterior column:

Ipsilateral loss of tactile discrimination, vibratory and position sensation below the level of the lesion.

Unilateral interruption of lateral spinothalamic tracts:

Contralateral loss of pain and temperature sensation. This usually occurs two or three segments below the level of the lesion.

Where the cord lesion is entirely unilateral, sphincter function tends to be preserved.

Central cord syndrome

Lesions affecting the spinal cord centrally (syringomyelia, hydromyelia, haematomyelia, and intramedullary cord tumours) present with the following:

Dissociation of sensory loss (thermoanaesthesia and analgesia in a circumferential distribution with preservation of soft touch sensation and proprioception) because the decussating fibres of the spinothalamic tract conveying pain and temperature sensation are compromised initially

Often sacral sensory sparing with relatively preserved dull and sharp pain and temperature sensation in the sacral dermatomal distribution because of the lamination of the spinothalamic tract (dorsomedial cervical sensation and ventrolateral sacral sensation)

Syringomyelia may also occasionally result in a neuropathic arthropathy of the shoulder, elbow, and other joints

Segmental neurogenic atrophy, paresis, and areflexia at the level of the lesion due to anterior extension of the disease process with anterior horn cell involvement.

Bladder dysfunction (usually urinary retention) and patchy sensory loss below the level of the lesion with weakness more pronounced in the arms (distal more than proximal) is seen after severe hyperextension injuries of the neck. Strength in the legs may be regained in a matter of minutes or hours after the initial injury to the central grey matter and lateral corticospinal tract at the level of the cervical cord.

Anterior cord syndrome

Complete bilateral motor paralysis (flaccid tetraplegia or paraplegia) below the level of the lesion owing to interruption of the corticospinal tract

Loss of pain and temperature sensation at and below the level of the lesion owing to interruption of the spinothalamic tract

Retained proprioception and vibratory sensation owing to intact dorsal columns

Areflexia, flaccid anal sphincter, urinary retention, and intestinal obstruction may also be present in individuals with anterior cord syndrome.

Conus medullaris and cauda equina (CES) syndromes

Features of these are as follows:

Saddle anaesthesia (in cauda equina syndrome) and perianal anaesthesia (in conus medullaris syndrome)

Urinary retention followed by overflow

Loss of anal tone and sensation; constipation or incontinence

Often low back pain or ‘sciatica’

Proximal and distal lower extremity motor weakness and loss of lower limb reflexes (cauda equina syndrome) or preserved knee jerks with symmetric distal weakness (conus medullaris syndrome). These motor features may be absent in low cord lesions (S2–S4).

REFLEXES

Deep tendon reflexes are reduced or absent during the acute ‘spinal shock’ phase of acute myelopathy. Spinal shock is a temporary physiological disorganization of spinal cord function below a total or near-total spinal cord lesion. This loss of neurological activity includes loss of motor, sensory, reflex, and autonomic function. It can start between 30 and 60 minutes after the onset of spinal cord pathology and can last up to 6 weeks.

Hyper-reflexia gradually sets in below the level of the lesion with associated hypertonia, spastic catch, and reflex spinal muscular spasms after a few days to weeks. In established or chronic myelopathy, hyper-reflexia is present below the level of the spinal cord lesion and hyporeflexia or areflexia at the level of the lesion.

In compressive myelopathy, there may be asymmetry of reflexes, with initial hyperreflexia due to nerve root irritation followed by hypo- or areflexia at the level of the lesion and hyper-reflexia below the level.

Superficial reflexes, including the abdominal reflex (T8–T12), cremasteric reflex in males (L1–L2), and the plantar reflex (L5, S1), may help determine the level of the lesion.

Absence of all abdominal reflexes suggests a level above T8

Absence of abdominal reflexes below but presence above the umbilicus suggests a level at T10

Presence of all abdominal reflexes suggests a level below T12

Asymmetry of abdominal reflexes suggests hemi-spinal-cord syndrome

The plantar reflex is equivocal or flexor during the early stages of acute myelopathy. During the recovery phase or with established myelopathy the plantar response is extensor in lesions at or above the conus medullaris. In cauda equina lesions the plantar reflex is diminished or absent

Absence of the cremasteric reflex in males (gently stroking the superior medial thigh normally leads to immediate contraction of the ipsilateral cremaster muscle lifting the testis) localizes the lesion to L1–L2

Anal sphincter involvement is manifested by a patulous anus, absence of contraction of the anal sphincter when the peri-anal skin is stimulated (anal wink), and by the lack of contraction of the anal sphincter during rectal examination. Faecal incontinence may occur with disorders of the sensory roots, conus, cauda equina, motor roots (S3–S4), or peripheral nerves and occasionally in high spinal lesions (better sphincter control than low spinal lesions).

CEREBELLAR EXAMINATION

Cerebellar signs are present in lesions at the foramen magnum and in the spinocerebellar ataxias. Cerebellar involvement leads to hypotonia, scanning dysarthria, downbeat, or pendular nystagmus, and decreased deep tendon reflexes. Gait ataxia is an early sign of Friedreich ataxia and is secondary to a combination of cerebellar and sensory ataxia.

SPINE EXAMINATION

Torticollis may be muscular but may indicate an underlying abnormality in the cervical vertebrae including craniocervical junction and posterior fossa abnormalities, or abnormalities of the intraspinal structures at the cervical level.

Scoliosis may be present in several spinal cord disorders including Chiari 1 malformation with associated syringomyelia, neural tube defects, Friedreich ataxia, and cord tumours

The skin over the spine may show evidence of an obvious neural tube defect either open (pre-surgical assessment) or repaired or have signs of occult dysraphism (tuft of hair, lipoma, dermal sinus). Kyphosis or scoliosis may suggest an underlying vertebral anomaly or a destructive process of the vertebrae.

Palpation of the spine may reveal tenderness, protective paraspinal muscle spasm in response to pain (neuropathic or musculoskeletal), or a ‘step’ indicative of a vertebral body fracture.

SPHINCTER ASSESSMENT

Sphincter assessment is a critical component of the assessment of spinal cord pathology and should always be performed even in infants. See under history above for a description of the relevant questions to be asked about the pre-toilet-trained child.

The bladder is acontractile during the initial variable period of spinal shock

Reflex detrusor activity returns in days to weeks and various types of bladder dysfunction may be noted.

A hyperreflexic, uninhibited neurogenic bladder also called the spastic or upper motor neuron bladder (due to lesions above the bladder centre S2–S4, and usually above T12) results in urinary frequency, urgency, urge incontinence, and inability to initiate micturition voluntarily

Detrusor-sphincter dyssynergia (reflex neurogenic bladder) sometimes occurs in lesions above the lower thoracic cord in which simultaneous contraction of the sphincter and the detrusor results in obstructed voiding, interrupted urinary stream, incomplete emptying and high intravesical pressures.

An autonomous neurogenic bladder (detrusor areflexia) with loss of bladder sensation and overflow incontinence occurs with complete lesions below the T12 segment involving the conus medullaris and cauda equina including the bladder neurogenic centre at S2–S4 with associated saddle anaesthesia. This is also called a flaccid or lower motor neuron bladder

Bladder muscle tone, residual urine volume, reflex bladder emptying and ureteric reflux are assessed by urodynamic studies.

Anal sphincter control is often similarly affected.

Spinal cord injury above the T12 level results in a reflex bowel. The ability to feel when the rectum is full may be lost. The anal sphincter muscle remains tight, however, and bowel movements will occur on a reflex basis. This means that when the rectum is full, the defaecation reflex will occur, emptying the bowel.

A spinal injury below the T12 level may damage the defaecation reflex and relax the anal sphincter muscle, resulting in a flaccid bowel with persistent faecal incontinence.

Faecal incontinence may also occur with disorders of the sensory roots, conus, or motor roots (S3–S4). The internal anal sphincter tone may be reduced on rectal examination (or more objectively using dynamic pressure studies) and there may be reduced perianal sensation and loss of the anal skin reflex (anal wink).

Important paediatric scenarios with myelopathy

In this section we discuss some specific issues and conditions that are age related and therefore need special mention.

NEONATAL PRESENTATION

The two main conditions that are seen in the newborn period are traumatic spinal cord lesions typically involving the cervical cord and spinal dysraphism (neural tube defects).

Less commonly, and usually in the neonatal intensive care setting, an ischaemic cord event may occur often in association with umbilical artery catheterization or major neonatal cardiac surgery; ischaemic events are usually thoracic or thoraco-lumbar rather than cervical (Ruggieri et al. 1999). The differential diagnosis in the neonatal period may also include neuromuscular disorders such as spinal muscular atrophy type 1.

Characteristic features in neural tube defects include the following:

Spasticity may be predominant in a high lesion whereas a mixed or flaccid picture will be present in a lumbo-sacral lesion; in most cases, asymmetry is present, reflecting the complexity of the malformation which is not a transection

There may be a history of decreased fetal movements and polyhydramnios; arthrogryposis, talipes, or hip dislocation may be evident

The defect may be obvious or there may be markers for an occult dysraphism, but this is not invariably the case

A spastic or flaccid bladder may result depending on the level of the defect. Early formal assessment of bladder function is vital

Constipation may be significant

Sensory level may be assessed using grimace to pinprick; superficial reflexes such as the abdominal, cremasteric, and anal wink reflexes may also help to determine the level of the lesion

Hydrocephalus may be a comorbid feature

Neurocutaneous markers and kyphoscoliosis may indicate an underlying occult dysraphism and a tethered cord (which may produce signs and symptoms as the child grows presenting with secondary disturbances of gait and sphincter dysfunction)

Other systems may be involved such as renal, gastrointestinal, and cardiac as part of a dysmorphic syndrome and often caused by a shared embryological origin of neural and non-neural systems

Small malformed paralysed legs, an abnormal natal cleft, and malformations of the rectum and genitourinary system point to the caudal regression syndrome.

Characteristic features in intra-partum spinal cord injury include the following:

Most injuries involve the cervical cord and are associated with breech presentation (lower cervical and upper thoracic injury) or cephalic presentation (upper cervical segments). There is evidence of motor, sensory, and sphincter involvement

Thoracic and lumbar vascular injury is rare and usually due to vascular embolism from umbilical catheters

Lower cervical and high thoracic trauma presents with flaccid diplegia or quadriplegia and diaphragmatic breathing. There may be some proximal upper limb movement but the legs are flaccid and areflexic in the shock stage, later evolving to an upper motor neuron picture. Spinal reflexes will be evident as a withdrawal response to pinprick after the shock phase has passed. The bladder