Neurological Problems

Dr Gillian Small

Consultant Paediatrician

Neurological Problems

• Congenital anomalies

• Cerebral Palsy

• Seizures

• Meningitis/encephalitis

• Encephalopathy

• Neurodegenerative Disorders

• Neuromuscular Disorders

Cerebral palsy

• Disorder of posture and movement due to non progressive damage of developing brain.

• First described 150 years ago

• Prevalence 2-3 per 1000 live births

• Slight increase in recent years due to increase in survival of sick preterms

Aetiology

Preterm babies

Perinatal cause in 90% of these

• Periventricular leukomalacia

• Intraventricular haemorrhage

Prenatal cause in 10%

• Brain malformation

Aetiology

Term babiesIn 75% cause is prenatal• Genetic• Cerebral malformation eg migration defect• Intrauterine infection eg CMV, rubella, toxo• Maternal – placental illness15% perinatal eg birth asphyxia10% postnatal eg meningitis, head injury, cardiac

arrest

Neurophysiology

Approx 40% of children with CP are preterm

Damage to extrapyramidal system causes dyskinetic CP (basal ganglia) or

ataxic CP (cerebellum)

Spastic CP results primarily from damage to

pyramidal system (motor cortex/ internal capsule)

Neurophysiology

Damage to pyramidal system causes• Loss of selective voluntary control• Dependence on primitive patterns of

mobility• Abnormal muscle tone & weakness• Agonist/antagonist imbalance – causes

fixed joint positions & contractures• Preserved primitive reflexes

Classification of CP

• Diplegia (44%)

• Quadriplegia (7%)

• Hemiplegia (34%)

• Dyskinetic (9%)

• Ataxic (6%)

Associated Problems

• Vision

• Hearing

• Epilepsy

• Feeding

• Constipation

Diagnosis

Made on follow up of at risk infants from neonatal unit in about half of cases

Parental concern

Routine surveillance

Acquired from later severe illness in first year

Diagnosis

• History

Obstetric, perinatal history

Lethargic, irritable

Feeding problems, poor weight gain

Diagnosis

• Examination

To identify motor delay/abnormality

Take gestational age into account for first 2yrs

• General

Dysmorphism, head growth, length, wt gain

DIAGNOSIS

• Tone

Hypotonia, hypertonia• Movements• Primitive reflexes

Normally Grasp gone by 4 months, Moro by 6 months

• Abnormal posture/positioning

Persistent thumb adduction, fisting, head lag

Diagnosis

• Asymmetry

If persistent, indicates hemiplegia

• Trunk control

• General developmental delay

Investigations

• MRI

• Chromosomes

• Rubella/toxo/CMV titres

• TFTs, creatine kinase

• Urine metabolic screen

Management

• Multidisciplinary team approach

Physios

Speech and language therapy

Occupational therapy

Preschool support

Dieticians

Doctors

Febrile Fits

• Fits precipitated by fever not due to intracranial infection or other CNS cause and are not preceded by afebrile fits

• Common: 2 – 5% of children under 5 yrs

Aetiology

• Genetic factors important

• Strong family history – 17-31% in first degree relatives

• Polygenic mode of transmission

• Fever usually high > 38.5 C

• Fits usually occur early in course of fever

• Perinatal factors do not play a role

Clinical Features

• Usually between 6 months and 6 years of age

• Onset before 6 months suggestive of meningitis

• Fits usually brief, bilateral, tonic clonic • Complicated febrile fits – if last more than

15 mins, if focal, those followed by Todds paresis. Higher risk of later epilepsy

Clinical Features

• Fits lasting > 30mins – Status epilepticus

• May leave sequelae if untreated eg association with hippocampal sclerosis and consequent mesial temporal epilepsy

• EEGs poorly correlate with later occurrence of epilepsy

Clinical Features

• Differential diagnosis – meningitis

encephalitis

• Consider LP in infants, especially < 6 mnths

• Herpes encephalitis may present in infants with febrile partial seizures

Prognosis

• Favourable• 60 – 70% have only 1 fit• Only 9% have more than 3 episodes• Risk of recurrence greater if family history, aged

under 1 year, had 2 or more episodes, had complex febrile fits.

• Partial epilepsy more common after long lasting focal fits

• Neurodevelopmental outcome usually excellent

Treatment

• Treat underlying illness

• Cooling measures advised but no evidence that antipyretics prevent fits

• Treat prolonged fits

• Regular anticonvulsants are not advised

Prognosis

• Risk of developing afebrile fits – 2-5% (background risk 1%)

• Risk low in simple seizures, increases with younger age, neurological/developmental abnormality, family history of epilepsy, complex febrile fits

EPILEPSY

Definition of epileptic seizure

Paroxysmal discharge of cerebral neurones sufficient to cause a clinically definable event apparent to the observer or subject

Diagnosis

• RequireEye witness accountBackground historyGeneral and neuro examination

• Causes of misdiagnosisLack of eye witnessPresence of clonic jerks/incontinencePositive family history Over interpretation of EEG

Predisposing Factors

• Genetic• Developmental brain abnormalities• Acquired structural abnormalities

- Perinatal insults

- Intracranial infections/trauma

- Prolonged febrile fits

- Cerebral haemorrhage or infarct

- Tumours or AVMs

Recurrence

• Recurrence after first seizure quoted between 71 – 82%

• Chances of remission

81% 15yrs later (Goodridge and Shorvon)

82% achieve 2 year remission after 8 years

(Elwes 1984)

Differential Diagnosis

• Syncope and related disorders

vasovagal episodes

reflex anoxic seizures blue or pallid

long QT

• Behavioural/ psychiatric disorders• Neurological disorders• Sleep related phenomenon

Types of seizure

• Focal (simple or complex)

• GeneralisedAbsenceMyoclonicAtonicTonicTonic clonicSpasms

Absence seizures

• Sudden cessation of activity with blank facial expression & eyelid flickering

• Uncommon < 5yrs• More common in girls• Rarely longer than 30 seconds• No postictal drowsiness• Precipitated by hyperventilation• EEG – 3/second spike and wave• Treat with sodium valproate or ethosuximide

Infantile Spasms

• 3 – 12 months• Aetiology

Cryptogenic (20%) normal development & CTPrenatal–Tuberous sclerosis, cong infectionPerinatal-hypoxia, birth injuryPostnatal-meningitis, encephalitis,trauma

Infantile spasms

• Flexor spasms – of neck, arms & legs on to trunk

• Extensor spasms – extension of trunk and extremities & are least common

• Mixed

• Very brief, occur in clusters, may be preceded by a cry, occur when drowsy or awakening

Infantile spasms

• EEG most commonly associated shows hypsarrythmia

• Treat with vigabatrin or steroids

• Associated with developmental delay

Floppy infant

• Marked hypotonia, lies in frog position, head lag

• CAUSES

Exclude systemic cause eg infection, hypothyroidism, inborn error of metabolism, congenital lax ligaments

Floppy Infant - Causes

• Central

Encephalopathy

Chromosomal abnormalities eg Down’s, Prader Willi

Ataxic CP

Floppy Infant - Causes

• PeripheralSpinal cord; transection, compression .Ant. horn cell; Werdnig Hoffman (acute spinal

muscular atrophy), A.R., lack of fetal movements, floppy at birth, muscle fasciculation esp of tongue. Diagnosed on EMG, muscle biopsy. Death before 18 months from resp failure.Milder forms exist.

Floppy infant - Causes

• Peripheral Nerve

Guillain Barre neuritis

• Neuromuscular Junction

Myasthenia gravis. Transient in baby of myasthenic mother, or persistent

Floppy infant - Causes

• MuscleCongenital myopathyMyotonic dystrophy; A.D., involves face and neck

muscles producing myopathic face, ptosis, open/fish like mouth. Myotonia – difficulty in relaxing grasp. Also cardiac involvement and cataracts.

Many die in newborn period, those surviving show some recovery.

Floppy infant - Causes

Metabolic myopathyGlycogen storage disease type II (Pompe Disease)Muscular Dystrophy; Duchenne MD X linked

recessive. Rarely symptoms in early infancy. Late walkers, hypertrophied calves, onset of weakness aged 2 yrs, Gower’s sign.

Elevated creatine kinaseGenetic counselling, prenatal diagnosisDeath in late adolescence, early adult life