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Hemiplegia
The approach to children with hemiplegia must distinguish between acute hemiplegia, in which weakness develops within a few hours, and chronic progressive hemiplegia, in which weakness evolves over days, weeks, or months. The distinction between an acute and an insidious onset should be easy but can be problematic. In children with a slowly evolving hemiplegia, missing early weakness is possible until an obvious level of functional disability is attained, by which time the hemiplegia seems new and acute.
An additional presentation of hemiplegia found in infants who come to medical attention because of developmental delay is slowness in meeting motor milestones and early establishment of hand preference. Children should not establish a hand preference until the second year. Such children may have a static structural problem from birth ( hemiplegic cerebral palsy ), but the clinical features are not apparent until the child is old enough to use the affected limbs.
Magnetic resonance imaging (MRI) is the diagnostic modality of choice for investigating all forms of hemiplegia. It is especially informative to show migrational defects in hemiplegic cerebral palsy associated with seizures. Magnetic resonance arteriography (MRA) is sufficiently informative in visualizing the vascular structures to obviate the need for arteriography in most children.
Hemiplegic cerebral palsy
The term hemiplegic cerebral palsy comprises several pathological entities that result in limb weakness on one side of the body. In premature infants, the most common cause is periventricular hemorrhagic infarction (see Chapter 4 ). In term infants, the underlying causes are often cerebral malformations, cerebral infarction, and intracerebral hemorrhage. Imaging studies of the brain are useful to provide the family with a definitive diagnosis.
The usual concern that brings infants with hemiplegia from birth for a neurological evaluation is delayed crawling or walking. Abnormalities of the legs are the focus of attention. Unilateral facial weakness is never associated, probably because bilateral corticobulbar innervation of the lower face persists until birth. Epilepsy occurs in half of children with hemiplegic cerebral palsy.
Infants with injury to the dominant hemisphere can develop normal speech in the nondominant hemisphere, but it is at the expense of visuoperceptual and spatial skills. Infants with hemiplegia and early-onset seizures are an exception; they show cognitive disturbances of verbal and nonverbal skills.
Congenital Malformations
Migrational defects comprise the majority of congenital malformations causing infantile hemiplegia ( Fig. 11.1 ). The affected hemisphere is often small and may show a unilateral perisylvian syndrome in which the sylvian fossa is widened. Chapter 17 describes a bilateral perisylvian syndrome with speech disturbances. Seizures and intellectual disability are often associated. As a rule, epilepsy is more common when congenital malformations cause infantile hemiplegia than when the cause is stroke.
Neonatal Infarction
Cerebral infarction from arterial occlusion occurs more often in full-term newborns than in premature newborns. MRI shows three patterns of infarction: (1) arterial border zone (watershed) infarction is associated with resuscitation and caused by hypotension; (2) multiartery infarction is not often associated with perinatal distress and may be caused by congenital heart disease, disseminated intravascular coagulation, and polycythemia; and (3) single-artery infarction can result from injury to the cervical portion of the carotid artery during a difficult delivery owing to either misapplication of obstetric forceps or hyperextension and rotation of the neck with stretching of the artery over the lateral portion of the upper cervical vertebrae. However, trauma is a rare associated event, and the cause of most single-artery infarctions, especially large infarctions in the frontal or parietal lobes, is often unexplained.
Clinical features
Some newborns with large, single-artery infarcts appear normal at birth but develop repetitive focal seizures during the first 4 days postpartum. Ten percent of neonatal seizures are caused by stroke. Most of these will later show a hemiparesis that spares the face. When neonatal seizures do not occur, hemiparesis, including early handedness during infancy, brings the child to neurological attention. Many such children develop epilepsy during childhood and some have cognitive impairment.
Diagnosis
MRI with or without MRA and MRV (magnetic resonance venography) is the preferred modality for diagnosis of stroke. Diffusion-weighted images are the best sequence for visualization of ischemic areas. Ultrasound is satisfactory to detect large infarcts in the complete distribution of the middle cerebral artery. The size of the defect on MRI correlates directly with the probability of later hemiplegia. Follow-up imaging studies may show either unilateral enlargement of the lateral ventricle or porencephaly in the distribution of the middle cerebral artery contralateral to the hemiparesis. Hemiatrophy of the pons contralateral to the abnormal hemisphere may be an associated feature.
Maternal use of cocaine during pregnancy can cause cerebral infarction and hemorrhage in the fetus. Cocaine is detectable in the newborn’s urine during the first week postpartum.
Management
Provide supportive care for all type of strokes. Correct dehydration and anemia when present. Neonates with prothrombotic states or tendency for cardiogenic emboli may benefit from the use of unfractionated heparin (UFH) or low molecular weight heparin (LMWH). Give vitamin B and folate to neonates with methylenetetrahydrofolate reductase (MTHFR) mutation in an effort to normalize homocysteine levels. The use of LMWH may have a place in cerebral venous sinus thrombosis when the clot is expanding or multiple sinuses are involved. Thrombolytic agents are not recommended as the safety and efficacy in newborns is unknown. Antiepileptic drugs are often needed for seizure control (see Chapter 1 ). Rehabilitative measures may help improve the level of function when sequelae occur.
Neonatal Hemorrhage
Intracranial hemorrhage affects 1% of full-term neonates. Small, unilateral, parietal or temporal hemorrhages occur almost exclusively in term newborns and are not associated with either trauma or asphyxia. Larger hemorrhages into the temporal lobe sometimes result when obstetric forceps apply excessive force to the lateral skull, but more often they are idiopathic. Intraventricular hemorrhage may be an associated feature.
Clinical features
Newborns with small hemorrhages are normal at birth and seem well until seizures begin any time during the first week. The symptoms of larger hemorrhages may be apnea, seizures, or both. Seizures are usually focal, and hemiplegia or hypotonia is present on examination. Some infants recover completely, whereas others show residual hemiplegia and cognitive deficits.
Diagnosis
Seizures and apnea usually prompt lumbar puncture to exclude the possibility of sepsis. The cerebrospinal fluid is grossly bloody. Computed tomography (CT) shows hemorrhage, and follow-up studies show focal encephalomalacia.
Management
Correction of significant thrombocytopenia, replacement of coagulation factors when applicable, vitamin K for all neonates and higher doses for certain factor deficiencies (maternal use of warfarin, phenobarbital, or phenytoin), and ventricular drain sometimes followed by ventriculoperitoneal (VP) shunt is needed for intraventricular bleeds with hydrocephalus. Correct anemia and dehydration when present, and treat seizures when they coexist.
Acute hemiplegia
The sudden onset of an acute, focal neurological deficit suggests either a vascular, epileptic, or migraine mechanism ( Box 11.1 ). Strokes manifest as abrupt onset of the weakness within seconds, seizures within a couple of minutes, and migraines tend to manifest their neurological signs over several minutes. Infants and children who have acute hemiplegia are divisible into two groups according to whether or not epilepsia partialis continua precedes the hemiplegia. Both groups may have seizures on the paretic side after hemiplegia is established. Cerebral infarction, usually in the distribution of the middle cerebral artery, accounts for one-quarter of cases in which seizures precede the hemiplegia and more than half of cases in which hemiplegia is the initial feature. Whatever the cause, the probability of a permanent motor deficit is almost 100% when the initial feature is epilepsia partialis continua and about 50% when it is not.
Box 11.1
Differential Diagnosis of Acute Hemiplegia
-
Alternating hemiplegia
-
Asthmatic amyotrophy (see Chapter 13 )
-
Cerebrovascular disease a
a Denotes the most common conditions and the ones with disease modifying treatments
-
Diabetes mellitus
-
Epilepsy
-
Hypoglycemia (see Chapter 2 )
-
Kawasaki disease (see Chapter 10 )
-
Migraine a
-
Trauma
-
Tumor a
Alternating Hemiplegia
This is a rare and poorly understood clinical syndrome with hemiplegia as a cardinal feature. The majority of cases are caused by a mutation of the ATP1A3 gene, although a minority may be caused by ATP1A2, CACNA1A, or SLC1A3 mutations. The ATP1A3 gene regulates the sodium-potassium ATPase protein complex. Mutations of this complex are also implicated in familial hemiplegic migraine type 2. The clinical spectrum of both disorders, expanded by mutation analysis, now overlaps.
Clinical features
Onset is from birth to 18 months (mean is 8 months). The initial features are mild developmental delay and abnormal eye movements. Motor attacks may be hemiplegia, dystonia, or choreoathetosis. Some children become dyspneic during episodes if the tongue is involved. Autonomic dysregulation is rare but potentially serious. Some individuals identify triggers associated with the attacks; common triggers include heat, illness, sleep deprivation, and stress. As a rule, young infants have more dystonic features and older children are more likely to have flaccid hemiplegia. Brief episodes of monocular or binocular nystagmus, lasting for 1–3 minutes, are often associated with both dystonic and hemiplegic attacks. Because the attack onset is abrupt, dystonia is often mistaken for a seizure and hemiplegia for a stroke. Most reports of epileptic seizures in infants with this syndrome are probably dystonic attacks. However, up to 50% of affected individuals develop epilepsy later in life.
The duration of hemiplegia varies from minutes to days, and intensity waxes and wanes during a single episode. During long attacks, hemiplegia may shift from side to side or both sides may be affected. If both sides are affected, one side may recover more quickly than the other. The arm is usually weaker than the leg, and walking may not be impaired. Hemiplegia disappears during sleep and reappears on awakening but not immediately.
Dystonic episodes may primarily affect the limbs on one side, causing hemidystonia, or affect the trunk, causing opisthotonic posturing. Some children scream during attacks as if in pain. Headache may occur at the onset of an attack but not afterward. Writhing movements that suggest choreoathetosis may be associated. Mental slowing occurs early in the course and mental regression follows later. Stepwise neurological impairment occurs as well, as if recovery from individual attacks is incomplete, and mild to severe cognitive impairment is the norm.
Diagnosis
Results of electroencephalography (EEG), cerebral arteriography, and MRI are normal. The diagnosis relies mainly on the clinical features. Molecular genetic testing is available.
Management
Treatment focuses on avoidance of triggers and symptom management. Anticonvulsant and antimigraine medications have consistently failed to prevent attacks or prevent progression. However, topiramate prophylaxis prevented recurrent attacks in a single case report. Flunarizine, a calcium channel blocking agent, reduces the frequency of attacks, but its efficacy is not established and it is not available in the United States. Other calcium channel blocking agents and anticonvulsant drugs have not been useful for prophylaxis. Benzodiazepines reduce discomfort and assist with sleep during dystonic attacks.
Alternating hemiplegia and dopa-responsive dystonia (see Chapter 14 ) share the feature of episodic dystonia with diurnal variation, and infants with attacks of dystonia should receive a trial of carbidopa-levodopa.
Cerebrovascular Disease
The annual incidence of stroke in children after the newborn period is approximately 2.3 per 100,000. This represents a significant decline over the past 20 years. Ischemic strokes are more common than hemorrhagic, and strokes of all types are slightly more common in boys than in girls and occur most frequently at less than 4 years of age or in adolescence. The most common risk factors for pediatric stroke include congenital heart disease, meningitis/encephalitis, sepsis, and sickle cell disease. Cardiac arrhythmias and hypertension are less common causes. As a rule, adult risk factors for stroke such as obesity or diabetes are not relevant in children. Only 30% of ischemic and hemorrhagic strokes in children are associated with a known risk factor ( Box 11.2 ). The coexistence of multiple risk factors predicts a poor outcome.
Box 11.2
Causes of Stroke
Cerebrovascular Malformations
-
Arteriovenous malformation
-
Fibromuscular dysplasia
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Hereditary hemorrhagic telangiectasia
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Sturge-Weber syndrome
Coagulopathies/Hemoglobinopathies
Heart Disease
Trauma
-
Arterial dissection a
-
Blunt trauma to neck
-
Intraoral trauma
-
Vertebral manipulation
Vasculitis
-
Carotid infection
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Drug abuse (amphetamines and cocaine)
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Hemolytic-uremic syndrome (see Chapter 2 )
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Hypersensitivity vasculitis
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Isolated angiitis
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Kawasaki disease (see Chapter 10 )
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Mixed connective tissue disease
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Systemic lupus erythematosus
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Takayasu arteritis
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Varicella infection
Vasculopathies
Stroke is always a consideration when a previously healthy child suddenly becomes hemiparetic or develops any focal neurological disturbance. MRI (diffusion-weighted images) with or without MRA and MRV is the preferred diagnostic modality. Clinical features vary with the age of the child and the location of the stroke. Hemiparesis, either immediately or as a late sequela, is one of the more common features.
CT scan may show decreased density, effacement of sulci, and loss of differentiation between gray and white matter and may enhance with contrast material. These changes may be subtle or absent in the first 24 hours after stroke. Cerebral infarction is often superficial, affecting both gray and white matter, and is in the distribution of a single artery. Multiple infarcts suggest either embolism or vasculitis. Small, deep lesions of the internal capsule are rare but can occur in infants.
Box 11.3 lists inherited states promoting cerebral infarction and Table 11.1 summarizes the evaluation of a child with cerebral infarction. The usual line of investigation includes tests for coagulopathies, vasculitis, and vasculopathies, a search for cardiac sources of emboli, and cerebral arteriography. The basic evaluation for prothrombotic disorders may include prothrombin time and activated partial thromboplastin time and a complete blood cell count, including platelets, protein C, protein S, and antithrombin III levels, activated protein C resistance, plasminogen, fibrinogen, homocysteine, antiphospholipid antibody screen, lipoprotein(a), and a cholesterol panel. Genetic testing may include screening for the factor V Leiden mutation, the prothrombin 20210A gene, and the MTHFR mutation.
Box 11.3
Inherited States Promoting Cerebral Infarction
- 1.
Activated Protein C Resistance
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Factor V Leiden mutation
-
- 2.
Deficiencies
-
Antithrombin III
-
Protein C
-
Protein S
-
- 3.
Other Genetic Factors
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Elevated antiphospholipid antibodies and lupus anticoagulant
-
Elevated factor VIII levels, and low plasminogen or high fibrinogen
-
Elevated lipoprotein(a)
-
Plasminogen activator inhibitor promoter polymorphism (PAI 1)
-
Prothrombin gene 20210 mutation
-
MTHFR gene defect
-
Table 11.1
Evaluation of Cerebral Infarction
| Blood | |
| Activated protein C resistance, antiphosphospholipid antibodies, apolipoproteins, cholesterol (high and low density lipoproteins), complete blood count, culture, erythrocyte sedimentation rate, factor V, free protein S, lactic acid, Leiden mutation, lupus anticoagulant, plasminogen, protein C, serum homocystine, triglycerides | Bacterial endocarditis, homocystinuria, hypercoagulable state, hyperlipidemia, leukemia, lupus erythematosus, MELAS, polycythemia, sickle cell anemia, vasculitis |
| Urine | |
| Cocaine, urinalysis | Cocaine abuse, homocystinuria, nephritis, nephrosis |
| Heart | |
| Echocardiography, electrocardiography | Bacterial endocarditis, congenital heart disease, mitral valve prolapse, rheumatic heart disease |
| Brain | |
| Arteriography, magnetic resonance imaging | Arterial dissection, arterial thrombosis, arteriovenous malformation, fibromuscular hypoplasia, moyamoya disease, vasculitis |
An area of increased density on a noncontrast-enhanced CT identifies intracerebral hemorrhage. Edema frequently surrounds the area of increased density and may produce a mass effect with shift of midline structures.
Arteriovenous Malformations
Supratentorial malformations may cause acute or chronic progressive hemiplegia. Intraparenchymal hemorrhage causes acute hemiplegia. The major clinical features of hemorrhage into a hemisphere are loss of consciousness, seizures, and hemiplegia. Large hematomas cause midline structures to shift and increase intracranial pressure. Chapter 4 contains the discussion of arteriovenous malformations. MRA, CT angiogram, or direct angiogram are the best techniques to visualize the malformation.
Brain Tumors
The usual cause of acute hemiplegia from brain tumor is hemorrhage into or around the tumor. Hemorrhage may hide the underlying tumor on CT and MRI is more informative (see Chapter 4 ). Tumors may also cause a slowly progressive hemiparesis with or without increased intracranial pressure, disk edema, or seizures.
Carotid and Vertebral Artery Disorders
Cervical infections
Unilateral and bilateral occlusions of the cervical portion of the internal carotid arteries may occur in children with a history of chronic tonsillitis and cervical lymphadenopathy. Whether this is cause and effect or coincidence is uncertain. Tonsillitis may cause carotid arteritis.
Unilateral cerebral infarction may occur in the course of cat-scratch disease (see Chapter 2 ) and mycoplasma pneumonia. In both diseases, the presence of submandibular lymph node involvement is associated with arteritis of the adjacent carotid artery. Necrotizing fasciitis is a serious cause of inflammatory arteritis with subsequent occlusion of one or both carotid arteries. The source of parapharyngeal space infection is usually chronic dental infection. Mixed aerobic and anaerobic organisms are isolated on culture.
Clinical features
The usual sequence in cervical arteritis is fever and neck tenderness followed by sudden hemiplegia. Bilateral hemiplegia may occur when both sides are infected.
Diagnosis
Culture of the throat or lymph node specimens is required to identify the offending organism or organisms. Arteriography, CT angiogram, or MRA identifies the site and extent of carotid occlusion.
Management
An aggressive course of antibiotic therapy, especially for necrotizing fasciitis, is mandatory. The outcome is variable, and recovery may be partial or complete.
Fibromuscular dysplasia
Fibromuscular dysplasia is an idiopathic, segmental, non-atheromatous disorder of the renal arteries and the extracranial segment of the internal carotid artery within 4 cm of its bifurcation. Seven percent of patients also have intracerebral aneurysms.
Clinical features
Transitory ischemic attacks and stroke are the only clinical features of fibromuscular dysplasia. Fibromuscular dysplasia is primarily a disease of women over 50 years of age but can occur in children.
Diagnosis
Arteriography shows an irregular contour of the internal carotid artery in the neck resembling a string of beads. Suspect concomitant fibromuscular dysplasia of the renal arteries if hypertension is present.
Management
Either operative transluminal balloon angioplasty or carotid endarterectomy are options to treat the stenosis. The long-term prognosis in children is unknown.
Trauma to the carotid artery
Children may experience carotid thrombosis and dissection from seemingly trivial injuries, such as during exercise and sports, and these can also occur without known cause in otherwise normal children. They also occur in child abuse (grabbing and shaking the neck) or from injuries to the carotid artery during a fall, when the child has a blunt object (e.g., pencil, lollipop) in the mouth. Other risk factors for carotid dissection include fibromuscular dysplasia, Ehlers-Danlos syndrome type IV, Marfan syndrome, coarctation of the aorta, cystic medial necrosis, autosomal dominant polycystic kidney disease, osteogenesis imperfecta, atherosclerosis, extreme arterial tortuosity, moyamoya syndrome, and pharyngeal infections.
Clinical features
Usually, a delay of several hours and sometimes days separates the injury from the onset of symptoms. The delay probably represents the time needed for thrombus to form within the artery. Clinical features usually include hemiparesis, hemianesthesia, hemianopia, and aphasia when the dominant hemisphere is affected. Deficits may be transitory or permanent, but some recovery always occurs. Seizures are rare.
Diagnosis
MRA safely visualizes carotid dissection and occlusion. Formal angiography should be considered if clinical suspicion is high and MRA is negative.
Management
In children with cervicocephalic arterial dissection (CCAD), use either UFH or LMWH as a bridge to oral anticoagulation with warfarin. It is common and reasonable to treat a child with CCAD with either subcutaneous LMWH or warfarin for 3–6 months. Alternatively, an antiplatelet agent may be used. Continue therapy beyond 6 months when symptoms recur or when there is radiographic evidence of a residual abnormality of the dissected artery. Surgery such as bypass or extracranial to intracranial shunts may be considered in patients who continue to have symptoms from a CCAD while on medical therapy. Do not give anticoagulation medication to children with an intracranial dissection or with subarachnoid hemorrhage from CCAD.
Trauma to the vertebral artery
Vertebral artery thrombosis or dissection may follow minor neck trauma, especially rapid neck rotation. The site of occlusion is usually at the C1–C2 level. Boys are more often affected than are girls.
Clinical features
The usual features of vertebral artery injury are headache and brainstem dysfunction. Repeated episodes of hemiparesis associated with bi-temporal throbbing headache and vomiting may occur and are readily misdiagnosed as basilar artery migraine. The outcome is relatively good, survival is the rule, and chronic neurological disability is unusual.
Diagnosis
The clue to diagnosis is the presence of one or more areas of infarction on CT or MRI. The possibility of stroke leads to an arteriographic study, which reveals the vertebral artery occlusion. If a clear history of trauma is lacking, then further evaluation of the cervical vertebrae is required to rule out bony abnormalities predisposing to injuries of the posterior circulation. Note any unusual joint flexibility or skin laxity, as this may indicate an underlying connective tissue disorder.
Management
Treatment is not well established and varies among institutions. UFH or LMWH are used as a bridge to oral anticoagulation, which is typically continued for 3–6 months. Long-term aspirin prophylaxis is a common recommendation. Repeat imaging after 3–6 months is recommended.
Cocaine Use
Cocaine is a potent vasoconstrictor that causes infarction in several organs. Stroke occurs mainly in young adults and may follow any route of administration. The interval from administration to stroke is usually unknown but may be minutes to hours. Intracerebral hemorrhage and subarachnoid hemorrhage are more common than cerebral infarction and often occur in people with underlying aneurysms or arteriovenous malformations. Vasospasm or vasculitis is the probable cause of infarction.
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