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 ( Figure 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 mental retardation are often associated. As a rule, epilepsy is more common when congenital malformations cause infantile hemiplegia than when the cause is stroke.




FIGURE 11-1


Closed lip schizencephaly with periventricular heterotopias. (A) T 1 coronal MRI; (B) axial MRI.


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 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 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 couple of minutes; migraines tend to manifest their neurologic signs over several minutes. Infants and children who have acute hemiplegia are divisible almost equally 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





  • Alternating hemiplegia



  • Asthmatic amyotrophy (see Chapter 13 )



  • Cerebrovascular disease


    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



  • Trauma



  • Tumor



Differential Diagnosis of Acute Hemiplegia


Alternating Hemiplegia


This is a rare and poorly understood clinical syndrome with hemiplegia as a cardinal feature ( ). Considerations of its nosological identity include migraine, epilepsy, and familial paroxysmal choreoathetosis. Most cases are sporadic, but some families show mutations in a sodium-potassium ATPase gene 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, 8 months). The initial features are mild developmental delay and abnormal eye movements. Motor attacks may be hemiplegia, dystonia, or both. 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 to 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.


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. 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.


Diagnosis


Results of electroencephalography (EEG), cerebral arteriography, and MRI are normal. The diagnosis relies entirely on the clinical features.


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. Other calcium channel blocking agents and anticonvulsant drugs have not been useful.


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 levodopa-carbidopa.


Cerebrovascular Disease


The annual incidence of stroke in children after the newborn period is approximately 2.3 per 100000 ( ). This represents a significant decline over the past 20 years ( ). Half are ischemic and half are nontraumatic intracerebral and subarachnoid hemorrhages ( ). The incidence rate is slightly higher in black than in white children and lowest in Hispanic children. Girls have a lower incidence than boys, but the gender and racial differences are not attributable to head injuries or sickle cell disease. Approximately 25 % of ischemic 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


Cerebrovascular Malformations





  • Arteriovenous malformation



  • Fibromuscular dysplasia



  • Hereditary hemorrhagic telangiectasia



  • Sturge-Weber syndrome



Coagulopathies/Hemoglobinopathies





  • Antiphospholipid antibodies/lupus anticoagulant



  • Congenital coagulation defects


    Denotes the most common conditions and the ones with disease modifying treatments




  • Disseminated intravascular coagulation



  • Drug-induced thrombosis



  • Malignancy



  • Sickle cell anemia/disease



  • Thrombocytopenic purpura



Heart Disease





  • Arrhythmia



  • Atrial myxoma



  • Bacterial endocarditis



  • Cardiac catheterization



  • Cardiomyopathy



  • Cyanotic congenital defects



  • Mitral valve prolapse



  • Prosthetic heart valve



  • Rhabdomyoma



  • Rheumatic heart disease



Trauma





  • Arterial dissection



  • Blunt trauma to neck



  • Intraoral trauma



  • Vertebral manipulation



Vasculitis





  • Carotid infection



  • Drug abuse (amphetamines and cocaine)



  • Hemolytic-uremic syndrome (see Chapter 2 )



  • Hypersensitivity vasculitis



  • Isolated angiitis



  • Kawasaki disease (see Chapter 10 )



  • Meningitis (see Chapter 4 )



  • Mixed connective tissue disease



  • Systemic lupus erythematosus



  • Takayasu arteritis



  • Varicella infection



Vasculopathies





  • Fabry disease



  • Homocystinuria (see Chapter 5 )



  • Mitochondrial encephalopathy, lactic acidosis, and stroke (MELAS)



  • Moyamoya disease



Causes of Stroke


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, vaculitis, 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


Activated Protein C Resistance





  • Factor V Leiden mutation



Deficiencies





  • Antithrombin III



  • Protein C



  • Protein S



Other Genetic Factors





  • 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



Inherited States Promoting Cerebral Infarction


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
Hypercoaguable 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 nonatheromatous 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 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 separate 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.


Management


In children with cervicocephalic arterial dissection (CCAD), use either Unfractionated heparin (UFH) or Low molecular weight heparin (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 to 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 bitemporal 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.


Management


Long-term aspirin prophylaxis is a common recommendation, but not proven effective.


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.


Diabetes Mellitus


Acute but transitory attacks of hemiparesis occur in children with insulin-dependent diabetes mellitus. Complicated migraine is a suggested mechanism, but the pathophysiology remains unknown.


Clinical Features


Attacks frequently occur during sleep in a child with a respiratory illness. Hemiparesis is present on awakening; weakness is greater in the face and arm than in the leg. Sensation is intact, but aphasia is present if the dominant hemisphere is affected. Tendon reflexes may be depressed or brisk in the affected arm, and an extensor plantar response is usually present. Headache is a constant feature and may be unilateral or generalized. Some patients are nauseated. The family does not have a history of migraine. Attacks last for 3 to 24 hours, and recovery is complete. Recurrences are common.


Diagnosis


Stroke is not a complication of juvenile insulin-dependent diabetes, except during episodes of ketoacidosis (see Chapter 2 ). Head CT in children with transitory hemiplegia does not show infarction.


Management


Although some children have further attacks, a method for prevention of recurrences is not established.


Epilepsy


Hemiparetic Seizures


Todd paralysis is a term used to describe hemiparesis that lasts for minutes or hours and follows a focal or generalized seizure. It occurs most often following prolonged seizures, especially those caused by an underlying structural abnormality.


Hemiparesis may be a seizure manifestation as well as a postictal event. Such seizures are hemiparetic or focal inhibitory seizures. Todd paralysis may be difficult to distinguish from hemiparetic seizures because it is not always clear whether a seizure preceded the hemiparesis or whether the hemiparesis is ictal or postictal.


Clinical Features


The initial feature may be a brief focal seizure followed by flaccid hemiparesis or the abrupt onset of flaccid monoparesis or hemiparesis. Consciousness is not impaired, and the child seems well otherwise. The severity and distribution of weakness fluctuate, affecting one limb more than the other and sometimes the face. Tendon reflexes are normal in the hemiparetic limbs, but the plantar response may be extensor.


Diagnosis


EEG shows recurrent spike- and slow-wave discharges over the hemisphere contralateral to the weakness. A radioisotope scan shows increased focal uptake in the affected hemisphere during the ictal phase and decreased uptake between seizures. Results of MRI, CT, and cerebral arteriography may be normal.


Management


The treatment is with the same drugs used for the treatment of partial seizures such as levetiracetam, oxcarbazepine, and lamotrigine (see Chapter 1 ).


Heart Disease


Congenital Heart Disease


Cerebrovascular complications of congenital heart disease are most likely in children with cyanotic heart conditions. The usual complications are venous sinus thrombosis in infants and embolic arterial occlusion in children. Emboli may occur from valvular vegetations or bacterial endocarditis. In either case, the development of cerebral abscess is a major concern. Cerebral abscess of embolic origin is exceedingly uncommon in children younger than 2 years of age with congenital heart disease and occurs only as a complication of meningitis or surgery.


Children with complex congenital heart disease are at risk for cardioembolic stroke, thrombotic stroke, and watershed infarcts from drops in perfusion pressure. The rates of stroke in children with complex congenital heart disease vary with (1) the severity of the malformation; (2) the number of corrective surgeries required; (3) anesthetic techniques during surgery; (4) patient selection; and (5) length of follow-up. The greatest risk for children with congenital heart disease occurs at the time of surgery or cardiac catheterization ( ). Cerebral dysgenesis is an important consideration in children with congenital heart disease. Postmortem studies show a 10–29 % prevalence of associated cerebral malformations. Children with hypoplastic left heart syndrome are especially at risk for associated dysgenetic brain lesions.


Clinical Features


Venous thrombosis occurs most often in infants with cyanotic heart disease who are dehydrated and polycythemic. One or more sinuses may occlude. Failure of venous drainage always increases intracranial pressure. Hemiparesis is a major clinical feature and may occur first on one side and then on the other with sagittal sinus obstruction. Seizures and decreased consciousness are associated features. The mortality rate is high in infants with thrombosis of major venous sinuses, and most survivors have neurological morbidity.


Children with cyanotic heart disease are at risk for arterial embolism when vegetations are present within the heart or because of the right-to-left shunt, which allows peripheral emboli to bypass the lungs and reach the brain. The potential for cerebral abscess formation increases in children with right-to-left shunt because decreased arterial oxygen saturation lowers cerebral resistance to infection.


The initial feature is sudden onset of hemiparesis associated with headache, seizures, and loss of consciousness. Seizures are at first focal and recurrent but later become generalized.


Diagnosis


MRI is the preferred procedure for the detection of venous thrombosis and emboli. A pattern of hemorrhagic infarction occurs adjacent to the site of venous thrombosis, and multiple areas of infarction are associated with embolization.


The CT appearance may be normal during the first 12 to 24 hours following embolization. By the next day, the study shows a low-density lesion. Although the sequence is consistent with a sterile embolus, the possibility of subsequent abscess formation is a consideration. Repeat enhanced CT or MRI studies within 1 week reveal ring enhancement if an abscess developed.


Management


Treatment for congestive heart failure may reduce the possibility of cardiogenic embolism and stroke. Repairing the congenital heart defect reduces the risk of subsequent stroke (this is unknown with patent foramen ovale, PFO). UFH or LMWH is given until warfarin is adjusted for children with a cardiac embolism unrelated to a PFO who are judged to have a high risk for recurrent embolism. Alternatively, it is reasonable to use LMWH initially in this situation and to continue it instead of warfarin. In children with a risk of cardiac embolism, it is reasonable to continue either LMWH or warfarin for at least 1 year or until the lesion responsible for the risk has been corrected. If the risk of recurrent embolism is judged to be high, it is reasonable to continue anticoagulation indefinitely as long as it is well tolerated. For children with a suspected cardiac embolism unrelated to a PFO with a lower or unknown risk of stroke, it is reasonable to begin aspirin and to continue it for at least 1 year. Surgical repair or transcatheter closure is reasonable in individuals with a major atrial septal defect (not for PFO) both to reduce the stroke risk and to prevent long-term cardiac complications. Anticoagulant therapy is not used for individuals with native valve endocarditis ( ). Antibiotics are very important to decrease the possibility of transformation into abscess in cases of endocarditis.


Treatment for venous thrombosis is primarily supportive and directed toward correcting dehydration and controlling increased intracranial pressure. Dexamethasone is useful to decrease cerebral volume, but osmotic diuretics may cause further thrombosis. The infarction is usually hemorrhagic, and anticoagulants are contraindicated. Distinguishing a septic from a sterile thrombosis is impossible, and all infants receive antibiotic treatment.


Mitral Valve Prolapse


Mitral valve prolapse is a familial disorder present in 5 % of children. It is usually asymptomatic but estimated to cause recurrent attacks of cerebral ischemia in 1 in every 6000 cases each year. Sterile emboli from thrombus originating either from the prolapsing leaflet or at its junction with the atrial wall cause the recurrent attacks.


Clinical Features


The initial feature is usually a transitory ischemic attack in the distribution of the carotid circulation producing partial or complete hemiparesis. Weakness usually clears within 24 hours, but recurrent episodes, not necessarily in the same arterial distribution, are the rule. Basilar insufficiency is less common and usually results in visual field defects. The interval between recurrences varies from weeks to years. Permanent neurological deficits occur in less than 20 % of individuals.


Diagnosis


Only 25 % of patients have late systolic murmurs or a midsystolic click. In the remainder, a cardiac examination is normal. Two-dimensional echocardiography is required to establish the diagnosis.


Management


No treatment is needed for asymptomatic children with auscultatory or electrocardiographic (ECG) abnormalities, nor is specific treatment available for a transient ischemic attack. However, once a child has suffered a transitory attack of ischemia, administer daily aspirin to reduce the likelihood of further thrombus formation in the heart.


Rheumatic Heart Disease


The frequency and severity of rheumatic fever and rheumatic heart disease in North America have been decreasing for several decades. Unfortunately, a mini epidemic of acute rheumatic fever recurs every 5–10 years in the United States. Rheumatic heart disease involves the mitral valve in 85 % of patients, the aortic valve in 54 %, and the tricuspid and pulmonary valves in less than 5 %. The source of cerebral emboli is either valvular vegetations or septic emboli due to infective endocarditis.


Clinical Features


The main features of mitral valve disease are cardiac failure and arrhythmia. Aortic valve disease is often asymptomatic. Neurological complications are always due to bacterial endocarditis except in the immediate postoperative period, when embolization is the likely explanation. Symptoms are much the same as in congenital heart disease, except that cerebral abscess is less common.


Diagnosis


Rheumatic heart disease is an established diagnosis long before the first stroke. Multiple blood cultures identify the organism and select the best drug for intravenous antibiotic therapy.


Management


Bacterial endocarditis requires vigorous intravenous antibiotic therapy.


Hypercoagulable States


A prethrombotic condition is present in 20–50 % of children presenting with arterial ischemic stroke and 33–99 % of children with cerebral venous sinus thrombosis ( ).


Abnormalities of blood cells or blood cell concentration may place the child at risk for hemorrhagic or ischemic stroke. Low platelet count due to autoimmune thrombocytopenia or bone marrow suppression may lead to hemorrhage. Anything that increases blood viscosity, such as sickled cells, polycythemia, or chronic hypoxia, may predispose to arterial or venous infarct. Dehydration is associated with arterial strokes and cerebrovascular thrombosis (CVT), possibly because it increases viscosity. Anemia is a risk factor for arterial ischemic infarction and CVT, possibly due to alterations in hemodynamics or imbalances in thrombotic pathways.


Risk factors for a prothrombotic state include recurrent episodes of deep vein thrombosis or pulmonary emboli, especially if they occur at a young age, or a family history of thrombotic events. The likelihood of stroke from most prothrombotic states seems to be relatively low, but the stroke risk increases when other risk factors are present. Thus, it is reasonable to test for the most common prothrombotic states even when another explanation for the stroke is present. Hypercoagulable states include antithrombin III, protein C or protein S deficiencies, activated protein C resistance, factor V Leiden mutation, prothrombin gene mutation ( G20210A ), antiphospholipid antibody syndrome, elevated levels of lipoprotein A and homocysteine. Protein C deficiency and the genetic polymorphisms collectively (factor V Leiden, prothrombin gene mutation, thermolabile form of the MTHFR gene) may be independent risk factors in children for recurrent arterial stroke. Cerebral venous and, less often, cerebral arterial thromboses may occur in patients with paroxysmal nocturnal hemoglobinuria. Polycythemia rubra vera, essential thrombocythemia, and disseminated intravascular coagulation may lead to cerebral infarction or intracranial hemorrhage ( ). Thrombosis also accompanies secondary to transitory hematological abnormalities associated with intercurrent illness. For example, idiopathic nephrotic syndrome is associated with decreased antithrombin and CVT ( ).


Clinical Features


The typical features of venous thrombosis are headache and obtundation caused by increased intracranial pressure, seizures, and successive hemiplegia on either side. Suspect an inherited hypercoaguable state in children with recurrent venous thromboses, a family history of venous thrombosis, or thrombosis at an unusual site (see Table 11-1 ). Arterial thromboses usually cause ischemic stroke in the distribution of a single cerebral artery.


Diagnosis


Suspect venous thrombosis when hemiplegia and increased intracranial pressure develop suddenly. The diagnosis of sagittal sinus thromboses is suggested when parasagittal hemorrhage or infarction is associated with absence of the normal flow void in the sagittal sinus on MRI. Cerebral arteriography is the more definitive procedure. Box 11-4 summarizes laboratory studies.


Mar 3, 2019 | Posted by in NEUROLOGY | Comments Off on Hemiplegia
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