Moyamoya disease is characterized by progressive intracranial vascular stenoses of the circle of Willis, resulting in successive ischemic events. We report serial diffusion-weighted imaging studies in a case of moyamoya disease. A 4-year-old right-handed patient presented with multiple infarcts in the right and left hemispheres. Each new infarct was unambiguously recognized as bright on diffusion-weighted imaging. previous infarcts, readily detected on other magnetic resonance imaging sequences, were not bright on diffusion-weighted imaging. The patient subsequently underwent bilateral synangiosis. In this case, the diffusion-weighted images were helpful in assessing the extent of infarcts, determining the age of the lesion, and correlation with new clinical findings. We emphasize the usefulness of diffusion-weighted imaging for following the clinical course of children with moyamoya disease, in whom new focal deficits are highly suspicious of new infarcts.

The incidence of cerebral infarction complicating cardiac surgery has been estimated to be 0.3% to 5.2% in the adult population.’ The incidence in the pediatric population is less well documented. An incidence of 9% to 22% has been reported in neuropathologic series, the majority associated with cyanotic cardiac disease.2,3 The relative complexity of congenital heart lesions in children, as well as more technical difficulties involved in the repair of these lesions, might account for the discrepancy between the incidence of cerebral infarction in children and in adults. In a recent study assessing neurologic outcome in 142 children operated for transposition of great vessels, 14% had focal and multifocal central ner-

Vertebral artery dissection is an uncommon cause of stroke in children. Accuracy of diagnosis by magnetic resonance angiography (MRA) instead of invasive transfemoral angiography (TFA) has been controversial. The need for anticoagulation and duration of such therapy is also arguable. We report 2 boys with vertebral artery dissection: one, aged 7 years, presented with hemiparesis and seizures and the other, aged 4 years, presented with ataxia. Each boy's initial MRA was not interpreted as delineating occlusive lesions to explain the posterior circulation infarcts visualized on computed tomography and magnetic resonance imaging scans. However, subsequent MRAs were suspicious for vertebral artery dissection, which was confirmed by TFA. Both children were treated with anticoagulation therapy. The first patient continued to manifest evidence of new infarcts despite treatment (initially with aspirin alone, followed by anticoagulation with heparin and warfarin), and is now maintained on a combination of high dose warfarin and aspirin. The second patient is now maintained on aspirin alone after initial anticoagulation for 6 months with heparin followed by warfarin. A high index of suspicion for vertebral artery dissection may allow diagnosis on the basis of MRA alone. Previous reports have indicated good outcomes of vertebral artery dissection in children and adults irrespective of anticoagulation treatment. Our experience suggests that anticoagulation may be beneficial in preventing further strokes caused by the dissection.

A female infant who died 2.5 d after birth with hypoglycemia, lactic acidosis, and sudden multisystem failure was studied. Biochemical studies showed complex III and IV deficiency in liver, kidney, and muscle, with muscle most severely affected. Southern blot analysis of the patient's mitochondrial DNA did not reveal any deletions. Denaturing gradient gel analysis, which detects single base changes by differences in melting behavior, showed an extra band that was not seen in mitochondrial DNA from the mother, the mother's identical twin sister, or an unrelated normal subject. This extra band indicated heteroplasmy for a restriction fragment containing the apocytochrome b and transfer RNA(thr) genes. Sequencing revealed an A to G mutation at nucleotide 15923, the last base of the anticodon loop of the transfer RNA(thr) gene. The mutation lengthens the anticodon stem by added pairing and reduces the anticodon loop size from 7 to 5 nucleotides, potentially compromising transfer RNA(thr) function in translation and/or in processing the polycistronic RNA transcript. The patient's mother previously had a male infant who also died at 1.5 d postnatal, and both the mother and her twin have had multiple miscarriages. Amniocentesis for a genetic screen was performed on the mother's twin sister during a recent pregnancy; some of the cultured cells were made available for this study. The mutation was not found in the amniocytes or in umbilical cord blood obtained at birth; the baby was normal at birth and remains healthy. It is concluded that the mutation at nucleotide 15923 was most likely the cause of the fatal disease in the index case.(ABSTRACT TRUNCATED AT 250 WORDS)

1. Harrison HE, Harrison HC. Disorders of calcium and phosphate metabolism in childhood and adolescence. Philadelphia: WB Saunders, 1979:219. 2. Tieder M, Modai D, Samuel R, et al. Hereditary hypophosphatemic rickets with hypercalciuria. N Engl J Med 1985; 312:611. 3. Tieder M, Modai D, Shaked U, et al. Idiopathic hypercalciuria and hereditary hypophosphatemie rickets: two phenotypical expressions of a common genetic defect. N Engl J Med 1987;316:125. 4. Alon U, Costanzo LS, Chan JCM. Additive hypocalciuric effects of amiloride and hydrochlorothiazide in patients treated with calcitriol. Miner Electrolyte Metab 1984; 10:379. 5. Bijvoet OLM. Renal phosphate excretion in man. Folia Med Meer 1972;15:84. 6. Broadus AE. Nephrogenous cyclic AMP. Recent Prog Horm Res 1981;37:667. 7. Dyer BE, Goodman DBP. A single direct spectrophotometric assay for 24,25-dihydroxyvitamin D. Anal Biochem 1981; 114:37. 8. Eisman JA, Hamstra A J, Kream BE, DeLuca HF. A sensitive, precise and convenient method for determination of 1,25-dihydroxyvitamin D in human plasma. Arch Biochem Biophys 1976;176:235, 9. Broadus AE, Insogna KL, Long R, et al. A consideration of the hormonal basis and phosphate leak hypothesis of absorptive hypercalciuria. J Clin Endocrinol Metab 1984;58:161. 10. Mallette LE, Tuma SN, Berger RE, et al. Radioimmunoassay for the middle region of human parathyroid hormone using a homologous antiserum with a carboxy-terminal fragment of bovine parathyroid hormone as radioligand. J Clin Endocrinol Metab 1982;54:1017. 11. Chan JCM, Alon U, Hirschman GM. Renal hypophosphatemic rickets. J PEDIATR 1985;106:533. 12. Harrell RM, Lyles KW, Harrelson JM, Friedman NE, Drezner MK. Healing of bone disease in X-linked hypophosphatemic rickets/osteomalacia: induction and maintainence with phosphorus and calcitriol. J Clin Invest 1985;75:1858. 13. Kim GS, Whyte MP. Interruption in inorganic phosphate therapy can cause hypercalciuria in 1,25(OH)~D3-treated patients with sex-linked hypophosphatemic rickets. J Bone Miner Res 1986;l(suppl):199. 14. Dent CE, Friedman M. Hyperealciuric rickets associated with renal tubular damage. Arch Dis Child 1964;39:240.

An 11-year-old girl had sudden onset of right hemiplegia and dysphasia with fever. Blood cultures grew Kingella kingae. Echocardiography showed a prolapsed mitral valve vegetation, which became larger during a prolonged course of antibiotics. After seven weeks of therapy, when surgery was being planned, the child deteriorated abruptly. A repeat echocardiogram showed that the vegetation had disappeared. Conservative medical management is usually inadequate in treating vegetations associated with bacterial endocarditis; surgery is advised.

This chapter presents the risk factors of subarachnoid hemorrhage in newborns that did not have an intraventricular hemorrhage. Four maternal risk factors are associated with an increased risk of giving birth to an infant who had subarachnoid hemorrhage evident at postmortem examination. Most prominent of these was socioeconomic status, measured by whether the mother was a clinic or private patient. Clinic mothers were at increased risk. Primigravidas and women with a late menarche were also at increased risk. Among women who had been pregnant previously, increased risk was associated with birth of a baby who weighed less than 3 kilograms and a stillbirth after the 20th week. The only delivery variable associated with an increased risk of subarachnoid hemorrhage was spontaneous rupture of membranes. Newborns were at reduced risk of subarachnoid hemorrhage if they had a low heart rate. In addition, infants whose gestational age was 36 to 39 weeks were at lower risk than gestationally older infants. The two variables associated with reduced risk of subarachnoid hemorrhage are vaginal bleeding at any time during pregnancy and pyuria, either prior to or during pregnancy.

This chapter discusses the epidemiology of delayed myelination. Small head size and low brain weight are viewed as correlates of impaired neurologic function. Delayed myelination may also be a correlate of impaired function. In newborns, delayed evoked responses may be the most reliable quantitative indicator of delayed myelination. Preterm newborns, however, have illnesses that may have a more immediate effect on evoked responses than on the tinctorial properties of myelin. Thus, the greater sensitivity of evoked responses to metabolic stresses and the more rapid reversibility of their abnormalities may limit their usefulness in assessing myelination delays. A large body of data supports the hypothesis that the myelinating brain is vulnerable to the same factors that retard the growth of other organs. Growth retardation is best expressed by the combination of low birth weight and full-term gestational age variables. Factors such as maternal cigarette smoking, third-trimester uterine bleeding, and low maternal hematocrit explain and provide information about the setting for growth retardation.