Amyloid vs FDG-PET in the differential diagnosis of AD and FTLD.

OBJECTIVE: To compare the diagnostic performance of PET with the amyloid ligand Pittsburgh compound B (PiB-PET) to fluorodeoxyglucose (FDG-PET) in discriminating between Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD). METHODS: Patients meeting clinical criteria for AD (n = 62) and FTLD (n = 45) underwent PiB and FDG-PET. PiB scans were classified as positive or negative by 2 visual raters blinded to clinical diagnosis, and using a quantitative threshold derived from controls (n = 25). FDG scans were visually rated as consistent with AD or FTLD, and quantitatively classified based on the region of lowest metabolism relative to controls. RESULTS: PiB visual reads had a higher sensitivity for AD (89.5% average between raters) than FDG visual reads (77.5%) with similar specificity (PiB 83%, FDG 84%). When scans were classified quantitatively, PiB had higher sensitivity (89% vs 73%) while FDG had higher specificity (83% vs 98%). On receiver operating characteristic analysis, areas under the curve for PiB (0.888) and FDG (0.910) were similar. Interrater agreement was higher for PiB (κ = 0.96) than FDG (κ = 0.72), as was agreement between visual and quantitative classification (PiB κ = 0.88-0.92; FDG κ = 0.64-0.68). In patients with known histopathology, overall classification accuracy (2 visual and 1 quantitative classification per patient) was 97% for PiB (n = 12 patients) and 87% for FDG (n = 10). CONCLUSIONS: PiB and FDG showed similar accuracy in discriminating AD and FTLD. PiB was more sensitive when interpreted qualitatively or quantitatively. FDG was more specific, but only when scans were classified quantitatively. PiB slightly outperformed FDG in patients with known histopathology.

Distinct clinical and metabolic deficits in PCA and AD are not related to amyloid distribution.

BACKGROUND/OBJECTIVE: Patients with posterior cortical atrophy (PCA) often have Alzheimer disease (AD) at autopsy, yet are cognitively and anatomically distinct from patients with clinical AD. We sought to compare the distribution of ß-amyloid and glucose metabolism in PCA and AD in vivo using Pittsburgh compound B (PiB) and FDG-PET. METHODS: Patients with PCA (n = 12, age 57.5 ± 7.4, Mini-Mental State Examination [MMSE] 22.2 ± 5.1), AD (n = 14, age 58.8 ± 9.6, MMSE 23.8 ± 6.7), and cognitively normal controls (NC, n = 30, age 73.6 ± 6.4) underwent PiB and FDG-PET. Group differences in PiB distribution volume ratios (DVR, cerebellar reference) and FDG uptake (pons-averaged) were assessed on a voxel-wise basis and by comparing binding in regions of interest (ROIs). RESULTS: Compared to NC, both patients with AD and patients with PCA showed diffuse PiB uptake throughout frontal, temporoparietal, and occipital cortex (p < 0.0001). There were no regional differences in PiB binding between PCA and AD even after correcting for atrophy. FDG patterns in PCA and AD were distinct: while both groups showed hypometabolism compared to NC in temporoparietal cortex and precuneus/posterior cingulate, patients with PCA further showed hypometabolism in inferior occipitotemporal cortex compared to both NC and patients with AD (p < 0.05). Patients with AD did not show areas of relative hypometabolism compared to PCA. CONCLUSIONS: Fibrillar amyloid deposition in PCA is diffuse and similar to AD, while glucose hypometabolism extends more posteriorly into occipital cortex. Further studies are needed to determine the mechanisms of selective network degeneration in focal variants of AD.

Evaluation of neonates born with intrauterine growth retardation: review and practice guidelines.

Intrauterine growth retardation affects approximately 10% of live-born infants. Causes of intrauterine growth retardation are heterogeneous, and frequently the care of these infants poses a diagnostic and therapeutic challenge. Diagnosis of impaired fetal growth is an area in which close collaboration among the obstetrician, pediatrician, and dysmorphologist is essential for proper care of these newborns. It is axiomatic that the best way to care for these infants is to establish an accurate diagnosis prenatally or soon after birth and to manage on that basis. An algorithm for evaluation and management of intrauterine growth retardation that is based on available empiric data is presented. These guidelines are intended to guide medical practice and not to replace clinical judgment.

Evaluation of hypothalamic-pituitary-adrenal axis in premature infants treated with dexamethasone.

Results of a national survey of the current use of steroids in newborns in 1993 showed that 95% of the neonatologists in the United States have used dexamethasone for neonates at risk for chronic lung disease. Dexamethasone therapy for a period of a week or longer is associated with suppression of the hypothalamic-pituitary-adrenal axis (HPAA) in a substantial number of premature infants. A review of our current understanding of the biochemical tests evaluating HPAA function in premature infants and suggested guidelines for HPAA evaluation and management following dexamethasone therapy are presented.

Management of neonates born to mothers with group B streptococcus colonization.

Approximately 20% of pregnant women harbor group B streptococcus (GBS) in the lower genital tract at the time of delivery. Intrapartum chemoprophylaxis of mothers with GBS colonization who have risk factors for neonatal GBS at delivery improves the outcome of the neonates. The recommendations for treating newborn infants of mothers who receive intrapartum chemoprophylaxis for GBS colonization and the recommendations for those who do not remain empiric, because clinical studies to support such recommendations are not available. An algorithm for treatment of neonates born to mothers with GBS colonization that is based on available data and empiric recommendations is presented. These guidelines are intended to guide medical practice and not to replace clinical judgment.

Management of premature infants with extensive bowel resection with high volume enteral infusates.

To avoid long-term parenteral nutrition (PN), three premature infants with extensive bowel resections were fed high volume enteral infusates (HVEI). Following surgery an elemental hypo-osmolar gastric infusate was initiated. The infants were weaned of PN and were subsequently maintained on HVEI feeding. Rather than using the volume of the ileostomy outputs or the presence of reducing substances as guides for adjustment of enteral intake, we tolerated large ileostomy output and focused instead on the patients' hydration, serum electrolytes and acid base status. During HVEI feeding, the patients had sustained weight gain, while the mean +/- SD enteral intakes were 373 +/- 67, 689 +/- 132, and 415 +/- 108 ml/kg per day; osmolarity of enteral infusates were 250 +/- 25, 225 +/- 40 and 228 +/- 27 mosmol/l; caloric intakes were 163 +/- 29, 258 +/- 54, and 153 +/- 44 Kcal/kg per day; and ileostomy outputs were 113 +/- 47, 228 +/- 59, and 175 +/- 69 ml/kg per day, respectively. Gut adaptation lasted 122, 141, and 205 days, respectively. Re-anastomoses of the intestines were performed at the ages of 8, 78, and 36 months. At 18, 108, and 58 months, infants' weights were in the 50th, 20th, and 5th percentiles, respectively. No infant developed cirrhosis. High volume enteral infusate feeding in infants with extensive bowel resection may help achieve gut adaptation and may serve as an alternative nutrition modality to prolonged PN.

Central venous line thrombosis in premature infants: a case management and literature review.

Increased risk of central venous line thrombosis in tiny premature infants occurs because the size of the catheter relative to the cross-sectional area of the vessel is large, decreased plasma levels of plasminogen and antithrombin III, and relative low flow of the infusate through the catheter, in comparison with larger infants. A potentially fatal complication of central venous catheters is an intracardiac thrombus. The yield of detecting right atrial thrombi by routine echocardiographic monitoring is very low. Persistent positive blood cultures in infants with central venous lines, in spite of appropriate antibiotic therapy, or signs of catheter occlusion, may increase the yield of echocardiographic detection of intracardiac thrombi. Surgical removal of intracardiac thrombi in infants weighing less than 1500 gm carries a high mortality rate because of the need to use cardiopulmonary bypass with total circulatory arrest and profound hypothermia during surgery. It is in these infants that thrombolysis with urokinase should be considered. A successful therapy with urokinase of a complete occlusion of the right pulmonary artery by an embolus originating from the right atrium is described in a premature infant. For thrombolysis, a loading dose of urokinase of 4400 U/kg followed by 4400 to 8800 U/kg/hr for a few days was used. The thrombolytic effect was manifested by decreased thrombus echogenicity followed by its disappearance, by increased fibrinogen split products, and by decreased plasma fibrinogen. Urokinase therapy may cause massive bleeding, dislodge an intracardiac thrombus causing obstruction of cardiac valves or main vessels or causing embolization to the pulmonary or systemic circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

The clinical utility of serum creatinine measurement vs calculated glomerular filtration rate in the assessment of renal function in the premature infant.

The ability to assess the glomerular filtration rate (GFR) without the necessity of collecting urine in premature infants would be of significant clinical benefit. In 1986, the modified Schwartz formula (MSF = 0.33 x length (cm)/plasma creatinine (mg/dL)) was developed. In the MSF, GFR was estimated in premature infants during the first post-natal year. The goal of the present study was to test the applicability of the MSF in premature infants during the neonatal period and to evaluate the clinical use of serum creatinine (Cr) as a predictor of GFR. In 42 premature infants of mean (+/-SD) birthweight 1506.6 (+/-388.8) g, gestational age 31.3 (+/-1.7) wks and post-natal age 14.7 (+/-8.3) d, the correlation between GFR, estimated by endogenous creatinine clearance (ECrC), was compared with the serum Cr and with GFR estimated by the MSF. The correlation coefficient between ECrC and serum Cr was 0.6789 and between estimated GFR derived from ECrC and MSF, 0.4657. In premature infants during the neonatal period, serum Cr has a better correlation with GFR than with MSF. When serum Cr is less than 0.9 mg/dL, the 95% confidence interval suggests that at least 89% of the infants can be expected to have an ECrC within the normal range.

Noninvasive medical management of fungus ball uropathy in a premature infant.

Unilateral renal obstruction secondary to fungus balls is described in a premature infant. Noninvasive medical management, which included amphotericin B and 5-flucytosine therapy and forced diuresis, resulted in disappearance of fungus balls and resolution of the obstruction.

Hypothalamic-pituitary-adrenal axis function in very low birth weight infants treated with dexamethasone.

The effect of dexamethasone therapy on hypothalamic-pituitary-adrenal axis function was prospectively investigated in very low birth weight infants with bronchopulmonary dysplasia. Ten infants (mean +/- SD birth weight 825 +/- 265 g, gestation 25.8 +/- 1.9 weeks, postnatal age 33.1 +/- 17.7 days) initially received intravenous dexamethasone, 0.5 mg/kg per day for 3 days, and then were weaned over a period of 45 +/- 19.0 days to a replacement dose, followed by a metyrapone test. Morning plasma cortisol and 11-deoxycortisol levels were measured before and after an oral metyrapone dose given at midnight. Five infants (group A: birth weight 876 +/- 313 g, gestation 26.2 +/- 1.3 weeks, age of entry 31.8 +/- 22.8 days) had normal metyrapone test results, and five infants (group B: 778 +/- 234 g, 25.4 +/- 2.5 weeks, 34.4 +/- 13.4 days) had suppressed test results. Group A infants, in comparison with group B infants, had higher basal cortisol plasma levels (14.52 +/- 12.53 and 3.00 +/- 1.38 micrograms/dL, P = .047), higher postmetyrapone 11-deoxycortisol plasma levels (3.11 +/- 3.93 and 0.55 +/- 0.51 micrograms/dL, P = .028), larger differences between basal and postmetyrapone cortisol levels (7.10 +/- 4.67 and 2.12 +/- 1.31 micrograms/dL, P = .047), and larger differences between basal and postmetyrapone 11-deoxycortisol levels (2.99 +/- 3.93 and 0.29 +/- 0.25 micrograms/dL, P = .009). The hypothalamic-pituitary-adrenal axis function in group B infants eventually returned to normal when they continued to receive low-dose dexamethasone therapy after a period of 36.8 +/- 16.6 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Critical tricuspid insufficiency due to papillary muscle rupture. A result of prenatal hypoxic insult.

Fatal tricuspid insufficiency secondary to papillary muscle rupture due to prenatal hypoxic insult occurred in a full-term newborn. The diagnosis of flail tricuspid valve should be considered when fetal distress is encountered in a newborn with persistent hypoxemia. Prenatal diagnosis of this condition combined with prompt delivery, prostaglandin E1 therapy, and possible surgical repair of the tricuspid valve may improve chances of survival.

Spontaneous regression of cardiac rhabdomyoma in tuberous sclerosis.

Life-threatening cardiac rhabdomyoma in a newborn infant regressed spontaneously within a 5 month period. Since cardiac surgery for rhabdomyoma is dangerous in infancy, medical management should be considered if symptomatology is not severe. When a fetal arrhythmia is diagnosed, antenatal ultrasound examination for presence of cardiac tumors is warranted.

Neonatal hypoglycemia associated with umbilical artery catheter positioned at the eighth to ninth thoracic vertebrae.

Previous reports of neonatal hypoglycemia have been associated with malpositioned umbilical cord artery catheters. Neonatal hypoglycemia in association with normally positioned umbilical artery catheter and responsive to catheter repositioning is reported for the first time.