Medical-Care-of-neonatal-jaundice - Medical Care of Medical...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Medical Care of Medical neonatal jaundice neonatal Dr.SAMER JENIDI Dr.SAMER Medical Care Medical Phototherapy Exchange transfusion Drugs Drugs Diet Phototherapy Phototherapy Phototherapy Phototherapy Is the primary treatment . primary Was discovered serendipitously in England in the 1950s . England Why Phototherapy is effective? effective? Three reactions can occur when bilirubin is exposed to light : 1- photooxidation 12- Configurational isomerization 3- Structural isomerization 3- Phototherapy effect Phototherapy photooxidation photooxidation Was believed to be responsible for the beneficial effect of phototherapy. beneficial Although bilirubin is bleached through the bleached action of light, the process is slow and is now slow believed to contribute only minimally contribute to the therapeutic effect of phototherapy. phototherapy. Phototherapy effect Phototherapy Configurational isomerization Configurational Is a very rapid process that changes very some of the predominant bilirubin isomer to water-soluble isomers . water-soluble The isomer constitutes 20% of circulating 20% bilirubin after a few hours of few phototherapy. phototherapy. This proportion is not influenced significantly by the intensity of light. intensity Phototherapy effect Phototherapy Structural isomerization Structural Consists of intramolecular cyclization, resulting in the formation of lumirubin. lumirubin This process is enhanced by increasing This the intensity of light. intensity During phototherapy, lumirubin may constitute 2-6% of the total serum bilirubin 2-6% concentration concentration Phototherapy effect Phototherapy Bear in mind Bear when initiating phototherapy : when lowering of the total serum bilirubin lowering concentration is only part of the only therapeutic benefit. therapeutic 75-80% of the total bilirubin is 75-80% present in a form that can enter the brain. So …… So So…… So…… Phototherapy reduces the risk of bilirubin-induced neurotoxicity as soon as neurotoxicity as the lights are turned on. the Factors That Affect the Dose and Efficacy of Phototherapy and Wavelength Wavelength Irradiation level Distance Distance Bilirubin concentration Nature and character of the light source Factors That Affect the Dose and Efficacy of Phototherapy and Wavelength Wavelength Irradiation level Distance Distance Bilirubin concentration Nature and character of the light source Nature Wavelength Wavelength - Bilirubin absorbs light primarily around 450 nm. typically 425 to 475 nm 450 typically 425 - In practice, light used in wavelengths : In white, blue, and green Factors That Affect the Dose and Efficacy of Phototherapy and Wavelength Wavelength Irradiation level Irradiation Distance Distance Bilirubin concentration Nature and character of the light source Nature Irradiation level Irradiation A dose-response relationship exists exists 30-40 mW/cm2/nm. 6 mW/cm2/nm mW/cm2/nm Factors That Affect the Dose and Efficacy of Phototherapy and Wavelength Wavelength Irradiation level Distance Distance Bilirubin concentration Nature and character of the light source Nature Distance Distance Distance should not be greater than Distance 50 cm (20 in) 50 and can be less if the infant's can temperature is monitored. temperature Energy delivered decreases with increasing distance . Factors That Affect the Dose and Efficacy of Phototherapy and Wavelength Irradiation level Distance Distance Bilirubin concentration Bilirubin concentration Nature and character of the light source Nature Bilirubin concentration Bilirubin concentration The efficiency of phototherapy The increases with : with - serum bilirubin concentration. serum - skin surface skin Factors That Affect the Dose and Efficacy of Phototherapy and Wavelength Wavelength Irradiation level Distance Distance Bilirubin Nature and character of the light source Nature and character of the light source light - Quartz halide spotlights Quartz - Green light - Blue fluorescent tubes Narrow-spectrum Narrow-spectrum Ordinary Ordinary - White (daylight) fluorescent tubes White - White quartz lamps - Fiberoptic light The purpose of phototherapy The is to avoid neurotoxicity. to Historical data Historical derived from infants with hemolytic jaundice suggest that : suggest total serum bilirubin levels greater than (20 mg/dL) were associated with than were increased risk of neurotoxicity, at least in full-term infants. least Autopsy findings Autopsy suggested that : suggested Immature infants were at risk of bilirubin encephalopathy at lower total serum bilirubin levels than mature infants. mature But ………. But Unfortunately, because the endpoint of bilirubin neurotoxicity is permanent brain damage, damage, a randomized study to reassess the guidelines is ethically unthinkable. ethically Indications for phototherapy Indications In most neonatal wards, In total serum bilirubin levels are used as the primary bilirubin measure of risk for bilirubin encephalopathy. encephalopathy. Test for serum albumin have failed to serum gain widespread acceptance. gain Indications for phototherapy Indications A number of number guidelines for the guidelines management of neonatal jaundice have been published with significant disparity . disparity This disparity illustrates how difficult to how translate clinical data into sensible treatment guidelines. Indications for phototherapy Indications The 2004 AAP guidelines represent a significant change from the 1994 guidelines. guidelines The emphasis on preventive action and preventive risk evaluation risk is much stronger. is Indications for phototherapy Indications Physicians in different ethnic or geographic Physicians regions must consider factors that are regions unique to their medical practice settings. settings Such factors may include : factors - racial characteristics racial - prevalence of congenital hemolytic disorders congenital - environmental concerns environmental Key points in the practice Key - Maximizing energy delivery - Maximizing the available Maximizing surface area. surface Key points in the practice Key 1 - Maximizing energy delivery : Maximizing - Distance should be no greater than 50 cm and 50 may be reduced down to 10-20 cm if temperature 10-20 homeostasis is monitored to reduce the risk of overheating. - Cover the inside of the bassinet with reflecting Cover material; white linen works well. - Hang a white curtain around the phototherapy unit and bassinet. and These simple expedients can multiply energy delivery by several fold. Key points in the practice Key 2- Maximizing the available surface area . The infant should be naked except naked for diapers and the eyes should be covered for eyes to reduce risk of retinal damage. to Intermittent Versus Continuous Phototherapy ? Phototherapy Clinical studies have produced conflicting Clinical results. results. Individual judgment should be exercised. Individual If the infant’s bilirubin level is approaching If the exchange transfusion zone , phototherapy should be administered continuously until a satisfactory decline in the serum bilirubin level occurs or exchange transfusion is initiated. What about insensible water loss? What New data suggest that if temperature homeostasis is maintained, fluid loss is not increased significantly by phototherapy. increased In infants who are fed orally, the preferred fluid In is milk, since milk serves as a vehicle to milk transport bilirubin out of the gut. Timing of follow-up Timing serum bilirubin ? - In infants admitted with extreme serum bilirubin values ( 30 mg/dL): serum monitoring should occur every hour or every other hour.--------- Reductions in serum other Reductions bilirubin values (5 mg/dL/h). (5 - In infants with more moderate elevations of serum bilirubin : elevations monitoring every 6-12 hours . Expectations regarding Expectations efficacy of phototherapy ? - Bilirubin concentrations are still rising- ---- Bilirubin a significant reduction of the rate of increase . significant - Bilirubin concentrations are close to their peak----- phototherapy should result in measurable peakreductions in serum bilirubin levels within a few hours. reductions In general, the higher the starting serum bilirubin In concentration, the more dramatic the initial rate of decline. of When discontinuation of phototherapy? phototherapy? When serum bilirubin levels fall When (1.5-3 mg/dL) (1.5-3 below the level that triggered the initiation of phototherapy. of Serum bilirubin levels often rebound , rebound and follow-up tests should be obtained within 6-12 hours after discontinuation. 6-12 What about What prophylactic Phototherapy ? No purpose No In general, the lower the serum bilirubin level, bilirubin the less efficient the phototherapy. Phototherapy complications Phototherapy Phototherapy is very safe, Phototherapy and and it may have no serious long-term effects in neonates . effects Phototherapy complications Phototherapy Insensible water loss is not as important as previously believed. as Loose stools. Loose Retinal damage Effects on cellular genetic material in vitro and animal data have not been shown any implication for treatment of human neonates. human However, most hospitals use cut-down diapers during phototherapy . diapers Phototherapy complications Phototherapy Skin blood flow is increased-- redistribution of blood flow may occur in small premature infants-- premature Increased incidence of patent ductus arteriosus (PDA) has been reported arteriosus But this effect is less pronounced in modern servocontrolled incubators. Phototherapy complications Phototherapy Hypocalcemia in premature infants . It has been suggested that this is mediated by altered melatonin metabolism. Deteriorationof certain amino acids in total parenteral nutrition (TPN) solutions total Shield TPN solutions from light as much as possible. Accidents have been reported, including burns resulting from failure to replace UV filters. Exchange transfusion transfusion What are indications of Exchange transfusion? Exchange Avoiding bilirubin neurotoxicity Avoiding when other therapeutic modalities have failed. have In addition, even in the absence of high serum bilirubin levels, the procedure may be indicated in infants with erythroblastosis . Exchange transfusion has been performed because of : has - Cord hemoglobin <11 g/dL - Cord bilirubin Cord > 4.5 mg/dL - Rapid rate of increase in bilirubin Rapid >1 mg/dL/h - More moderate rate of increase in bilirubin > 0.5 in the presence of moderate anemia Hb=11-13 - Hemolytic jaundice with bilirubin > 20 or a rate of increase that predicted this level (fear of 20) . . Why Exchange transfusion become a rare procedure ?? become Immunotherapy in Rh-negative women So Immunotherapy ,ABO incompatibility has become the most ABO frequent cause of hemolytic disease in industrialized frequent countries. countries. Effective phototherapy Recently, immunotherapy has been introduced as treatment in the few remaining sensitized infants. treatment Results are promising So... When exchange transfusion So . should be performed ? should When phototherapy does not significantly lower serum bilirubin levels bilirubin Intensive phototherapy is strongly recommended in preparation for an exchange transfusion. do not await laboratory transfusion test results in these cases . Does nonhemolytic jaundice cause Neurotoxicity ? cause Many physicians believe that hemolytic jaundice represents a greater risk for neurotoxicity than nonhemolytic jaundice, although the reasons for this belief are not obvious . In animal studies, bilirubin entry into the brain In was not affected by the presence of hemolytic not anemia.. DRUGS What about Phenobarbital ? an inducer of hepatic bilirubin metabolism Several studies have shown that phenobarbital is effective . Phenobarbital may be administered : Phenobarbital - pre-natally in the mother or pre-natally - post-natally in the infant. post-natally However, concerns exist regarding the long-term effects of phenobarbital on long-term these children. What about IV immunoglobulin IV (500 mg/kg) ? (500 Significantly reduce the need for Significantly exchange transfusions in infants with isoimmune hemolytic disease. with The mechanism is unknown . mechanism Experience is somewhat limited, but it Experience does not appear risky . does risky New therapy : New Mesoporphyrins and Protoporphyrins Mesoporphyrins Currently under development under Inhibition of bilirubin production through blockage of heme oxygenase. heme Apparently, heme can be excreted directly through the bile . This approach may virtually eliminate This neonatal jaundice as a clinical problem. neonatal But … But Important questions Important before the treatment can be applied before - Long-term safety ?. Long-term - Complete understanding of putative role for bilirubin in light of data role suggesting that bilirubin may play an important role as a free radical quencher ( anti-oxidant ) ?. quencher DIETE DIETE Temporary interruption of breastfeeding… breastfeeding… is it recommended ? It is not recommended It unless serum bilirubin levels reach 20 mg/dL unless Supplementation with dextrose solution Supplementation is it recommended ? is It is not recommended It because - it may decrease caloric intake - it may decrease milk production - it may accelerate entero_hepatic it circulation and consequently delay the drop in serum bilirubin concentration bilirubin So .. What is So the recommendation ? Increase breastfeeding to 8-12 times per day to Breastfeeding can also be supported with manual or electric pumps and the manual pumped milk given as a supplement to the baby. Some questions ??? Some When infants can be discharged ? discharged When they are : When - feeding adequately feeding and - demonstrating a trend towards lower values. lower Auditory function tests prior is advisable in Auditory infants who have had severe jaundice. severe How to manage infants released within the first 48 hours of life ? within In the era of early discharge in recent years, a In early number of infants have developed kernicterus --- kernicterus Infants need to be reassessed for jaundice within 1-2 days. jaundice Use of hour-specific bilirubin hour-specific may assist in selecting infants . may nomogram TABLE 4. Risk Zone.htm Are infants need follow-up obsevation after Bilirubin falls? obsevation hemolytic jaundice require hemolytic follow-up observation for several weeks several because hemoglobin levels may fall hemoglobin Infants with Infants lower than seen in physiologic anemia. lower Erythrocyte transfusions may be required if Erythrocyte infants develop symptomatic anemia. symptomatic Finally…What about Finally…What Prognosis ? Prognosis is excellent if the patient Prognosis receives treatment according to accepted guidelines. guidelines. The increased incidence of kernicterus The in recent years may be due to the misconception that jaundice in the healthy full-term infant is not dangerous healthy and can be disregarded. and thanks thanks ...
View Full Document

Ask a homework question - tutors are online