Kernicterus with abnormal high-signal changes bilaterally in the globus pallidus: A case report

Kernicterus is a relatively rare consequence of hyperbilirubinemia. There is an important role for MRI imaging for this entity in the appropriate clinical context as there are distinct signal changes in the globus pallidus. A case report and image findings are presented

Kernicterus in an Adult Dog

A 7-year-old, spayed female, Wheaton terrier dog was icteric, lethargic, and anorexic with increased activity of hepatocellular and cholestatic liver enzymes and an extreme hyperbilirubinemia level of 609 μmol/L (reference interval: 1.0–4.0 μmol/L). Necropsy findings included profound icterus and red and yellow mottling of the liver. Yellow discoloration of the thalamic and subthalamic nuclei was detected on subgross examination of the formalin-fixed brain. Histologic examination of the brain revealed neuronal necrosis within the discolored nuclei, necrosis of Purkinje cells, and Alzheimer type II astrocytes in the cerebrocortical gray matter and in the nuclei, with gross discoloration. Histologic examination of the liver revealed extensive necrosis in a periacinar-to-bridging pattern and often extending to portal triads. A case of naturally occurring kernicterus in an adult dog secondary to extreme hyperbilirubinemia resulting from fulminant hepatic failure is reported. The few reports of this disease in domestic species involved neonates, namely 1 foal and 1 kitten.

Kernicterus in a Neonatal Foal

A 5-day-old Thoroughbred foal was submitted to the necropsy service at the University of Kentucky Livestock Disease Diagnostic Center. The foal had a clinical history of seizure activity and severe icterus. A complete blood count and serum chemistry analysis indicated that the foal was anemic (hematocrit, 16%), hyperbilirubinemic (45 mg/dl), and hypoglycemic. At necropsy, all tissues were discolored various shades of yellow. Microscopically, there was degeneration and necrosis of cerebral neurons and cerebellar Purkinje cells; severe hepatocellular degeneration and necrosis; and deposition of amorphous golden-yellow material in the cerebellar granular cell layer, pulmonary alveoli, renal tubular epithelium, splenic trabecula, and the lamina propria of the small and large intestine. The golden-yellow material in the brain, lung, spleen, and small intestine was identified as bilirubin by histochemistry. Based on the macroscopic and microscopic findings, a diagnosis of kernicterus (bilirubin encephalopathy) was made. This report describes a rare case of equine neonatal kernicterus.

A novel newborn rat kernicterus model created by injecting a bilirubin solution into the cisterna magna

BACKGROUND

Kernicterus still occurs around the world; however, the mechanism of bilirubin neurotoxicity remains unclear, and effective treatment strategies are lacking. To solve these problems, several kernicterus (or acute bilirubin encephalopathy) animal models have been established, but these models are difficult and expensive. Therefore, the present study was performed to establish a novel kernicterus model that is simple and affordable by injecting unconjugated bilirubin solution into the cisterna magna (CM) of ordinary newborn Sprague-Dawley (SD) rats.

METHODS

On postnatal day 5, SD rat pups were randomly divided into bilirubin and control groups. Then, either bilirubin solution or ddH2O (pH = 8.5) was injected into the CM at 10 µg/g (bodyweight). For model characterization, neurobehavioral outcomes were observed, mortality was calculated, and bodyweight was recorded after bilirubin injection and weaning. Apoptosis in the hippocampus was detected by H&E staining, TUNEL, flow cytometry and Western blotting. When the rats were 28 days old, learning and memory ability were evaluated using the Morris water maze test.

RESULTS

The bilirubin-treated rats showed apparently abnormal neurological manifestations, such as clenched fists, opisthotonos and torsion spasms. Bodyweight gain in the bilirubin-treated rats was significantly lower than that in the controls (P<0.001). The early and late mortality of the bilirubin-treated rats were both dramatically higher than those of the controls (P = 0.004 and 0.017, respectively). Apoptosis and necrosis in the hippocampal nerve cells in the bilirubin-treated rats were observed. The bilirubin-treated rats performed worse than the controls on the Morris water maze test.

CONCLUSION

By injecting bilirubin into the CM, we successfully created a new kernicterus model using ordinary SD rats; the model mimics both the acute clinical manifestations and the chronic sequelae. In particular, CM injection is easy to perform; thus, more stable models for follow-up study are available.

[Differentiation of hypoxic-ischemic encephalopathy and acute bilirubin encephalopathy with magnetic resonance imaging in neonates]

OBJECTIVE

To investigate the value of conventional magnetic resonance imaging (MRI) and diffusion weighed imaging (DWI) in the differentiation of hypoxic-ischemic encephalopathy (HIE) and acute bilirubin encephalopathy in neonates.

METHODS

The MRI findings along with DWI characteristics in 15 neonates with HIE involving basal ganglia and in 18 neonates with acute bilirubin encephalopathy between November 2006 and June 2008 were retrospectively reviewed.

RESULTS

On T1WI, only 5 patients presented hyperintensity in the globus pallidus in the HIE group, but 16 in the acute bilirubin encephalopathy group (p<0.01). Nine patients in the HIE group showed hyperintensity in the putamen, but the hyperintensity in the putamen was not found in the acute bilirubin encephalopathy group. The frequency of hyperintensity in the subthalamus in the acute bilirubin encephalopathy group (55.6%) was significantly higher than that in the HIE group (13.3%) (p<0.05). Eight patients in the HIE group showed abnormal signals in the other regions on T1WI, but only two patients in the acute bilirubin encephalopathy group (p<0.05). On DWI, 7 out of 11 patients with HIE presented hyperintensity in the basal ganglia, while all 10 patients of the acute bilirubin encephalopathy group presented normal in the basal ganglia.

CONCLUSIONS

Conventional MRI along with DWI is useful in differentiating HIE from acute bilirubin encephalopathy in neonates.

Single photon emission computed tomography and serial MRI in preterm infants with kernicterus

Single photon emission computed tomography was performed in three preterm infants with athetoid cerebral palsy due to kernicterus. No clinical signs and symptoms of kernicterus, or ultrasonographic abnormalities were seen during the neonatal period in any patients. Although MRI during infancy revealed high intensity areas in bilateral globi pallidi in all of them, MRI abnormalities were mild in two of them. On later MRI, subtle high intensity areas in the globi pallidi were recognized in only one of them. Single photon emission computed tomography demonstrated hypoperfusion in the basal ganglia regions in all patients. Regions of interest analyses showed decreased blood flow in the basal ganglia related to the cortical areas. Single photon emission computed tomography will be useful for the diagnosis of kernicterus, whereas MRI abnormalities become less clear beyond infancy.

Kernicterus and the Molecular Mechanisms of Bilirubin-Induced CNS Injury in Newborns

Kernicterus is a devastating, chronic disabling neurological disorder whose central nervous system (CNS) sequelae reflect both a predilection of bilirubin toxicity for neurons (rather than glial cells) and the regional topography of bilirubin-induced neuronal injury that is characterized by prominent basal ganglia, cochlear, and oculomotor nuclei involvement. The molecular pathogenesis of bilirubin-induced neuronal cell injury, although incompletely understood, likely reflects the untoward effects of hazardous unconjugated bilirubin concentrations on plasma, mitochondrial, and/or endoplasmic reticulum (ER) membranes. These membrane perturbations, in turn, might lead to the genesis of neuronal excitotoxicity, mitochondrial energy failure, or increased intracellular calcium concentration [Ca2+]i. These three phenomena are likely to be linked spatially and temporally in the pathogenesis of bilirubin-induced neuronal injury. Downstream events triggered by increased [Ca2+]i may include, among others, the activation of proteolytic enzymes, apoptotic pathways, and/or necrosis, the individual occurrence of which is likely a function of the degree and duration of bilirubin exposure. A recent study demonstrates the activation of mitogen-activated protein kinase signal transduction pathways by bilirubin heralding a degree of complexity regarding the molecular mechanism(s) of bilirubin-induced neurotoxicity not previously appreciated. There remains, however, a paucity of data regarding specific effects of bilirubin on intracellular signaling and cell death pathways, particularly in vivo. An enhanced understanding of the molecular pathogenesis of bilirubin-induced neuronal injury will lead to the identification of potential novel interventional strategies to protect the CNS against kernicterus.

Bilirubin-induced inflammatory response, glutamate release, and cell death in rat cortical astrocytes are enhanced in younger cells

Unconjugated bilirubin (UCB) encephalopathy is a predominantly early life condition resulting from the impairment of several cellular functions in the brain of severely jaundiced infants. However, only few data exist on the age-dependent effects of UCB and their association with increased vulnerability of premature newborns, particularly in a sepsis condition. We investigated cell death, glutamate efflux, and inflammatory cytokine dynamics after exposure of astrocytes at different stages of differentiation to clinically relevant concentrations of UCB and/or lipopolysaccharide (LPS). Younger astrocytes were more prone to UCB-induced cell death, glutamate efflux, and inflammatory response than older ones. Furthermore, in immature cells, LPS exacerbated UCB effects, such as cell death by necrosis. These findings provide a basis for the increased susceptibility of premature newborns to UCB deleterious effects, namely when associated with sepsis, and underline how crucial the course of cell maturation can be to UCB encephalopathy during moderate to severe neonatal jaundice.

Clinical (video) findings and cerebrospinal fluid neurotransmitters in 2 children with severe chronic bilirubin encephalopathy, including a former preterm infant without marked hyperbilirubinemia VIDEO

Chronic bilirubin encephalopathy, characterized clinically by extrapyramidal movement abnormalities, vertical gaze abnormalities, and hearing loss, results from neuronal injury after marked hyperbilirubinemia in term and preterm infants. In premature infants, bilirubin staining of specific brain structures has been described at autopsy after only moderate hyperbilirubinemia, but classic chronic bilirubin encephalopathy without marked hyperbilirubinemia has been reported only rarely. We report a case of a 7-year-old, former 29-weeks' gestation, gravely ill premature infant with a peak bilirubin level of 13.3 mg/dL in the neonatal period. We compare this case with a 12-year-old, former term infant with a peak bilirubin level of 49.4 mg/dL on day 10 of life. Both children have dystonia, athetosis, upward gaze palsy, and sensorineural hearing loss, with MRIs showing characteristic abnormal signal in the globus pallidus. We add previously unreported cerebrospinal fluid neurotransmitter levels that show a mild decrease in the dopamine metabolite homovanillic acid in the former premature infant only.

Bronze baby syndrome and the risk of kernicterus

AIM

The problem of kernicterus in infants with bronze baby syndrome (BBS) has been reviewed on the basis of cases reported in the literature. In addition, a new case concerning an infant with severe Rh haemolytic disease, who presented with BBS and who has developed neurological manifestations of kernicterus with magnetic resonance images showing basal ganglia abnormalities, is presented. In this patient, the total serum bilirubin (TSB) concentration ranged from 18.0 to 22.8 mg/dl (306 to 388 micromol/l) and the bilirubin/albumin (B/A) ratio was 6.0 (mg/g) (6.8 is the value at which an exchange transfusion should be considered). The case presented is important due to the fact that kernicterus appeared after an exchange transfusion was performed when the TSB level reached 22.8 mg/dl (388 micromol/l) on 6th day of life while the haematocrit was 30%. From this case and from other cases reported in the literature, we must stress that, even if the level at which hyperbilirubinemia poses a threat remains undefined, BBS may constitute an additional risk of developing kernicterus.

CONCLUSION

The possible strategies for implementing an approach to the management of hyperbilirubinemia (especially the haemolytic kind) in the presence of BBS may include an exchange transfusion carried out at lower TSB concentration than previously recommended or an early administration of Sn-mesoporphyrin.

Molecular basis of bilirubin-induced neurotoxicity

Unconjugated bilirubin (UCB), at slightly elevated unbound concentrations, is toxic to astrocytes and neurons, damaging mitochondria (causing impaired energy metabolism and apoptosis) and plasma membranes (causing oxidative damage and disrupting transport of neurotransmitters). Accumulation of UCB in the CSF and CNS is limited by its active export, probably mediated by MRP1/Mrp1 present in choroid plexus epithelia, capillary endothelia, astrocytes and neurons. Upregulation of MRP1/Mrp1 protein levels by UCB might represent an important adaptive mechanism that protects the CNS from UCB toxicity. These concepts could explain the varied susceptibility of newborns to bilirubin neurotoxicity and the occurrence of neurological damage at plasma UCB concentrations well below therapeutic guidelines, and are relevant to the increasing prevalence of bilirubin encephalopathy in newborns.

Kernicterus in sick and preterm infants (1999-2002): a need for an effective preventive approach

Kernicterus in sick and preterm infants is a rarity. Universal availability of phototherapy and concerted clinical efforts to identify, effectively manage and establish clinical guidelines have been instrumental in preventing kernicterus in US intensive care nurseries. However, in sick and preterm infants the absence of precise data on prevalence of bilirubin induced neurologic injury, the lack of proven predictive indices and the absence of evidence-based studies that clearly demonstrate the actual risk of kernicterus. These leave questions regarding the basis for clinical strategies and recommendations for the management of neonatal jaundice in this select population. This article reviews 6 preterm infants selected from the Pilot Kernicterus Registry who had recovered from life-threatening neonatal illnesses, briefly discusses current indices used to ascertain risk, and offers an initial bilirubin level based identification of infants while future directions and studies are conducted to supplement our presently incomplete knowledge for safer clinical practice.

Bilateral Mesial Temporal Sclerosis and Kernicterus

Two children with mental retardation, choreoathetosis, dystonia, and muscle rigidity are reported. They had a history of severe hyperbilirubinemia after birth as a result of Rh isoimmunization. The history and clinical picture suggested the diagnosis of kernicterus. The magnetic resonance imaging examination showed a bilateral signal intensity increase in the globus pallidus on T2-weighted images. Additionally, our patients showed symmetric bilateral hyperintensity and volume loss in the hippocampus, which is known to be another characteristic area of bilirubin deposition in kernicterus.

Changes in globus pallidus with (pre)term kernicterus

OBJECTIVE

We report serial magnetic resonance (MR) and sonographic behavior of globus pallidus in 5 preterm and 3 term infants with kernicterus and describe the clinical context in very low birth weight preterm infants. On the basis of this information, we suggest means of diagnosis and prevention.

METHODS

Charts and MR and ultrasound images of 5 preterm infants and 3 term infants with suspected bilirubin-associated brain damage were reviewed. Included were preterm infants with severe hearing loss, quadriplegic hypertonia, and abnormal hypersignal of globus pallidus on T2-weighted MR imaging (MRI). In 1 infant who died on day 150, the diagnosis was confirmed during the neonatal period. The others were picked up as outpatients and scanned at 12 or 22 months' corrected age. Three instances of term kernicterus were included for comparison of serial MRI in the neonatal period and early infancy: they were caused by glucose-6-phosphate dehydrogenase deficiency, urosepsis, and dehydration plus fructose 1-6 biphosphatase deficiency.

RESULTS

Five preterm infants of 25 to 29 weeks' gestational age presented with total serum bilirubin (TSB) levels below exchange transfusion thresholds commonly advised. Mixed acidosis was present in 3 infants around the TSB peak. The bilirubin/albumin molar ratio was >0.5 in all, in the absence of displacing drugs. All failed to pass bedside hearing screen tests and had severe hearing loss on auditory brain response testing. Symmetrical homogeneous hyperechogenicity of globus pallidus was the alerting feature in 1 infant. Globus pallidus was hyperintense on T1-weighted MR images in this child. The other infants presented with severe developmental delay as a result of dyskinetic quadriplegia and hearing loss. Globus pallidus was normal on T1- but hyperintense on T2-weighted MR images at 12 or 22 months' corrected age. Subthalamic involvement was documented in coronal fluid attenuated inversion recovery MRI in 2 infants. The term infants with classical clinical presentation in the neonatal period had MR behavior similar to the preterms, but pallidal injury was not recognized with targeted sonographic examination. Their neonatal MR images demonstrated pallidal T1 hyperintensity and mild T2 hyperintensity.

CONCLUSION

Acidotic very low birth weight preterm infants with low serum albumin levels develop MR-confirmed pallidal injury and hearing loss facing "accepted" TSB levels. Serial MRI documents a shift from acute mainly T1 hypersignal to permanent T2 hypersignal in globus pallidus within the late neonatal period. Subthalamic and not thalamic involvement helps to differentiate from ischemic or metabolic disorder. As newborns, these infants are rigid and have severe apnea, before developing hypertonic quadriplegia in infancy.

Thalamic involvement in a patient with kernicterus

We report the MR imaging findings of a 16-month-old boy with dyskinetic cerebral palsy resulting from kernicterus. T2-weighted images showed symmetric bilateral hyperintensity in the thalamus in addition to the globus pallidus.

Chronic hemolytic anemia associated with glucose 6-phosphate dehydrogenase (Guadalajara)1 159 C --> T (387 Arg --> Cys) deficiency associated with Gilbert syndrome in a Turkish patient

The case of an 8-year-old male child with severe kernicterus sequelae is presented in this paper. The child's hemoglobin value varied between 6.0 and 10.8 g/dL and his reticulocyte count ranged between 3.4 and 46.0% during the steady-state condition and hyperhemolytic crisis, respectively. A chronic hemolytic type of red cell G6PD deficiency was diagnosed. DNA studies indicate that the mutation was G6PD Guadalajara 1159 C --> T (387 Arg --> Cys) that is situated at the NADP binding site. Additionally, extra nucleotides of (TA) in the A(TA)n TAA motif of the promoter region of the uridine diphosphate-glucuronosyltransferase gene (UGT-1 A) were found to be homozygous in the patient. The coexistence of Gilbert syndrome with a chronic type of G6PD deficiency was suggested as a cause of neonatal hyperbilirubinemia leading to kernicterus.

Magnetic resonance imaging in three children with kernicterus

The incidence of kernicterus has been greatly reduced by effective monitoring and treatment for hyperbilirubinemia. Findings on magnetic resonance imaging (MRI) in patients with kernicterus are characteristic. This study presents three cases of possible kernicterus without typical symptoms but with MRI features consistent with kernicterus. These cases suggest that kernicterus can develop, especially in preterm infants, in the presence of relatively low levels of bilirubin and the absence of obvious acute symptoms. Therefore assessing the risk of kernicterus may be difficult in the neonatal period. In addition, MRI findings at the posteromedial border of the globus pallidus in patients with athetotic cerebral palsy are strong evidence of brain damage caused by kernicterus.

Role of glutamate receptor-mediated excitotoxicity in bilirubin-induced brain injury in the Gunn rat model

Severe hyperbilirubinemia in neonates with prematurity and/or systemic illnesses such as hemolytic disease, acidosis, and hypoxemia enhances their risk for developing cerebral palsy, paralysis of ocular upgaze, and deafness. This neurologic syndrome has been associated with selective neuronal vulnerability in the basal ganglia, certain brainstem nuclei, and Purkinje cells. However, the mechanism by which bilirubin damages neurons remains unclear. In these studies, we found that intracerebral injection of N-methyl-D-aspartate (NMDA), an excitotoxic analogue of glutamate, caused greater injury in jaundiced 7-day-old Gunn (jj) rat pups than in nonjaundiced heterozygous (Nj) littermate controls. NMDA injection caused even greater injury when protein-bound bilirubin was displaced with the sulfonamide drug sulfadimethoxine in jaundiced homozygous pups. In additional experiments, the acute signs of bilirubin-mediated neuronal injury, induced in homozygous (jj) Gunn rats by treatment with sulfonamide, were reduced by concurrent treatment with the NMDA-type glutamate channel antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohept-5,10-imine (MK-801, dizocilpine). The results suggest that bilirubin may cause encephalopathy and neuronal injury, at least in part, through an NMDA receptor-mediated excitotoxic mechanism. This conclusion is consistent with clinical observations that bilirubin encephalopathy is synergistically worsened by hypoxemia, which also shares an excitotoxic mechanism of neuronal injury.

Morphological changes in the cochlear nucleus and nucleus of the trapezoid body in Gunn rat pups

Mechanisms underlying bilirubin encephalopathy and hearing loss remain poorly understood, including the way bilirubin enters the nervous system and how bilirubin accumulates in circumscribed regions of the brain. The present experiments examined the auditory brainstem in heterozygous (Nj) and homozygous (jj) Gunn rats at an age when serum bilirubin levels were highest, and after brain bilirubin concentration was artificially raised by sulfadimethoxine administration. In four litters of 11-12 days old Gunn rats, Nj and jj littermates received a single intraperitoneal injection of sulfadimethoxine (100 mg/kg) or a comparable volume of saline. At 16-17 days of age, brainstem auditory evoked potentials were recorded to assess the severity of bilirubin toxicity in the Nj and jj animals. Following the recordings, each animal was perfusion-fixed and frozen sections of the brainstem were cut in the transverse plane from medullary through mesencephalic levels. Sections were mounted on slides, stained with thionin and coded to avoid observer bias. Quantitative analysis revealed no differences between saline and sulfa-treated Nj rats for cochlear nucleus volume, or for cell size in the cochlear nucleus or superior olive. In the sulfa-treated jj rats, cochlear nucleus volume, and cross-sectional areas of spherical cells in the anteroventral cochlear nucleus and principal cells in the nucleus of the trapezoid body, were all significantly smaller than in the combined groups of Nj animals. The affected areas in the cochlear nucleus and superior olive are innervated by large axosomatic end-bulbs of Held or calyceal endings, and were associated with bilirubin staining of glia in the most severely jaundiced jj sulfa-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Brainstem auditory evoked potentials correlate with morphological changes in Gunn rat pups

The relationship of brainstem structure and function in bilirubin encephalopathy is incompletely understood. The present experiments compare quantitative measures of brainstem structures with brainstem auditory evoked potentials (BAEPs) in infant jaundiced (jj) and nonjaundiced (Nj) Gunn rats. Ten jj's from 4 litters were injected with sulfadimethoxine at 11-12 days of age to raise their brain bilirubin concentration. Littermate controls were jj's given saline, and Nj's given sulfadimethoxine or saline. At 15-17 days of age BAEPs were recorded, and rats were prepared for histological examination, as was reported in the previous paper (Conlee and Shapiro, 1991). Significant differences between groups were seen for BAEP wave I latency (P = 0.002). I-II interwave interval (P = 0.001), and amplitudes of waves I, II, III, and IV (each P less than 0.0005) due to increased latencies and decreased amplitudes in the jj-sulfa group. Animals with the most severe BAEP abnormalities had the most severe histological abnormalities. Cochlear nucleus volume had a positive linear correlation with the amplitude of BAEP waves I, II, and IV, and an inverse correlation with wave I latency and I-II interwave interval (P less than or equal to 0.001). The highest correlations were BAEP I-II interwave interval and amplitude of waves I and II with cochlear nucleus volume (r = -0.78, 0.71 and 0.70, respectively, P less than 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Autopsy findings associated with neonatal hyperbilirubinemia

Hyperbilirubinemia is associated with bilirubin deposition in tissue in the newborn including the liver, kidney, heart, adrenal, lung, and brain. High levels of serum bilirubin will stain the skin and sclera and be called "jaundice" clinically, and similarly high levels of bilirubin will stain tissues internally, preferentially in areas of tissue damage. Whether the bilirubin causes the damage or marks the damage because of other insults or both remains controversial.

Clinical features of bilirubin encephalopathy

Clinical features of bilirubin encephalopathy vary depending on the age of the infant and the degree of hyperbilirubinemia. In term infants with hyperbilirubinemia, three distinct clinical phases are apparent in the first weeks of life, and long-term consequences include extrapyramidal disturbances (particularly athetosis), hearing loss, gaze abnormalities (particularly limitation of upward gaze), and, in a minority, intellectual deficits. In term infants with moderate hyperbilirubinemia, minor delay in motor development during the first year has been demonstrated, but with longer follow-up this delay is not apparent. Associated conditions such as sepsis, anoxia, and acidosis may increase the likelihood of neurotoxicity of bilirubin in these infants. The clinical consequences of moderate hyperbilirubinemia in premature infants are unclear. No acute clinical syndrome is recognizable during the first weeks. The results of follow-up studies are variable. Hearing loss is the commonest consequence. Follow-up through age 2 years in one large study suggests that static encephalopathy may be a sequel. Longer follow-up is needed to understand the clinical consequences of moderate hyperbilirubinemia in this important group of infants.

Bilirubin and the laboratory. Advances in the 1980s, considerations for the 1990s

The limitations of current methods of measuring bilirubin are well established and relate to the broad dynamic range and inability of the technique to determine different but structurally similar bilirubin species. New instrumentation and methodology circumvent these limitations, and clinical studies are beginning to reveal their increased diagnostic usefulness. Nevertheless, in several clinical situations, for example, the prediction of kernicterus, better bilirubin determinations may not eliminate the controversy surrounding appropriate therapeutic interventions.

Effects of rokitamycin on young rats with hyperbilirubinemia--determination of unbound and brain bilirubin levels and examination for localized yellow discoloration of brain tissue

The effects of rokitamycin (RKM), a macrolide antibiotic, on young rats with hyperbilirubinemia were investigated. RKM at a dose of 1,000 mg/kg was orally administered to 14-day-old rats with hereditary, non-hemolytic hyperbilirubinemia (homozygous Gunn rats, total plasma bilirubin concentration: about 7 mg/dl). Animals given 10 ml/kg of 0.5% carboxymethyl cellulose (CMC) were used as control. Plasma total bilirubin concentration, plasma unbound bilirubin concentration and cerebellar bilirubin level did not significantly change during 1, 3, 6 and 24 hours after administration of RKM or CMC. There was no significant difference in plasma total bilirubin concentration, plasma unbound bilirubin concentration and cerebellar bilirubin level between RKM-treated and control animals at 1, 3, 6 and 24 hours after the administration. No localized yellow discoloration of the brain tissue (non-cerebellar parts) was noted at 1, 3, 6 and 24 hours after administration of either RKM or CMC.

Astrocyte response to perinatal liver disease, hyperammonemia, and hyperbilirubinemia: an immunohistochemical study

Astrocytic reaction to perinatal brain damage, which is caused by hyperammonemia, liver disease, hyperbilirubinemia, and a few other conditions, was studied using immunohistochemical methods for the demonstration of glial fibrillary acidic protein (GFAP). We found no increase in GFAP expression in those areas where Alzheimer II astrocytes usually proliferate. Diffuse astrocytic proliferation in the white matter and focal reaction in gray matter, which we ascribe to complicating factors, the foremost of which is anoxia, was found in many of the cases.

Patterns of bilirubin staining in nonhemolytic kernicterus

Patterns of bilirubin staining were studied in nine infants with kernicterus related to nonhemolytic hyperbilirubinemia, all weighing less than 1200 g, and nine matched controls. Three staining patterns were disclosed: a localized pattern in the central nervous system of kernicteric infants, with only the thalamus staining significantly often; staining, in extraneural tissues (adrenal, myocardial, renal, and colonic mucosa) only in kernicteric infants, despite similar bilirubin levels in both groups; and yellow staining of the alveolar hyaline membranes as a function of survival duration in both groups. Bilirubin staining of tissue is apparently a generalized phenomenon, most recognized in the central nervous system as kernicterus. Failure to maintain the impermeability of the cell membrane coupled with regional differences in blood flow would best explain bilirubin distribution. In contrast, the degree of bilirubin staining of alveolar hyaline membranes is time related in kernicteric and control infants.

Kernicterus in an adult

A 43-year-old woman was initially seen because of icterus. Clinical investigations revealed severe hepatic damage probably due to non-A, non-B hepatitis. She was treated with extracorporeal charcoal-column perfusion but died two weeks later in a hepatic coma. At autopsy, the brain showed kernicterus with typical discoloration of the hippocampus, the subthalamic nuclei, and the cerebellar dentate nuclei. Kernicterus in an adult is very rare. In this case, extracorporeal charcoal-column perfusion treatment led repeatedly to severe depletion of fibrinogen, with extensive hemorrhages. Overload of the already reduced hepatic glucuronyl-transferase capacity resulted in high serum levels of unconjugated bilirubin, an apparent prerequisite for the development of bilirubin encephalopathy.

The neuropathology of kernicterus in the premature neonate: diagnostic problems

Yellow staining of central nervous system (CNS) nuclei occurs in the brains of some neonates, despite low levels of serum bilirubin. Two conditions appear to be important in the evolution of this form of kernicterus: prematurity and asphyxia. In a seven year retrospective study of a large neonatal autopsy population, 102 cases had kernicterus as indicated by selective macroscopic yellow staining and microscopic damage within specific CNS nuclei. Neuropathological study disclosed minor variations and numerous similarities in the manifestations of kernicterus in the asphyctic premature neonate with low levels of serum bilirubin, as compared to kernicterus in the full-term neonate with high levels of serum bilirubin. Acidosis, hypoxia, hyperoxia, hypothermia and sepsis have been considered significant risk factors, but recent comparative clinical studies have not defined predictive indices. Analysis of this disorder is difficult because of the concurrence of other complications of asphyxia and its pathological correlates in premature infants. Diagnostic difficulties are also compounded by variations in the definitions of kernicterus as used by different investigators.

Bilirubin encephalopathy

In babies of low birth weight dying in the first week of life, bilirubin encephalopathy involving the thalamus only or the thalamus and one or two other areas occurred in nineteen of 376 cases examined over a 10 year period. Although coexistent germinal layer haemorrhage was present in sixteen, this was not thought to be an aetiological factor. Bile stained hyaline membranes in nine of the nineteen were considered to indicate the possibility of protein-bound bilirubin traversing a vascular barrier in these cases. This pattern of predominant lateral thalamic involvement may indicate selective vulnerability of this area in this group. It contrasts sharply with the localization in classical kernicterus (three cases) and in a disparate group where yellow discolouration of future white matter areas was observed (thirteen cases).

Increased nervous system-specific enolases in rat plasma and cerebrospinal fluid in bilirubin encephalopathy detected by an enzyme immunoassay

Three forms of enolase isozymes (alpha alpha, alpha gamma, gamma gamma), including nervous system-specific forms, were measured in the cerebrospinal fluid and the blood plasma of jaundiced or nonjaundiced infant rats by means of enzyme immunoassay systems capable of detecting each form of enolase at the 1 amol (10(-18) mol) level. Average enolase levels in cerebrospinal fluid in normal rat were 2.0, 0.2 and 0.1 pmol/ml for alpha alpha, alpha gamma, gamma gamma forms, respectively. Levels of alpha gamma and gamma gamma forms (nervous system-specific enolases; NSE) in jaundiced rats, which suffer Purkinje cell degeneration due to the inborn hyperbilirubinemia, were three to four times as high as the normal values. When kernicterus was induced in jaundiced rats by an injection of bucolome, the NSE level in cerebrospinal fluid was elevated up to more than 30-fold the control, together with a significantly higher level of alpha gamma form in blood plasma are helpful in detecting neuronal damage in the central nervous system.

Ultrastructural aspects of bilirubin encephalopathy in cochlear nuclei of the Gunn rat

The cochlear nuclei of homozygous Gunn rats aged 2 days to 7 months were examined. Ultrastructural abnormalities were observed in all age groups studied, including 2 and 4 days old animals. Mitochondrial alterations are amont the earliest manifestations of bilirubin encephalopathy (2 days). In mitochondria of large neurons, vacuoles were found which contained increasing (with age) collections of alpha and beta glycogen particles. Some of the larger 'ex-mitochondrial sacs' appear to have been caught at the point of disruption, with glycogen-filled vacuoles in close proximity. Dilated profiles of rough ER also contained glycogen particles. In the cytoplasm of the same large neurons, elaborate myelin figures surrounded tongues of cytoplasm, vacuoles and degenerative elements. Reconsideration of previous morphological and biochemical observations in the light of the present findings makes it appear very likely that bilirubin primarily affects membrane function, especially in mitochondria.

[Kernicterus. Anatomo clinical correlation in 64 newborn infants]

The case histories and autopsy reports of 64 neonates who died from kernicterus were reviewed. The most outstanding findings were: high incidence of kernicterus with serum indirect bilirubin less than 15 mg.; different clinical picture of the premature in comparison with term neonate; predisposing factors such as respiratory distress and intrauterine malnutrition were often associated in the premature. Preventive, educational and therapeutic measures were discussed at the end.

The "bronze baby" syndrome: postmortem data

The case history and autopsy findings of an infant with the "bronze baby" syndrome are presented. These findings substantiate that kernicterus occurs in term infants receiving phototherapy for concentrations of serum indirect bilirubin below 20 mg/dl. The findings at autopsy suggest that the photodecomposed pigmented products of bilirubin are unable to pass the blood-brain barrier. The need for establishing the cause of jaundice prior to initiation of phototherapy is stressed.

The use of critical levels of birth weight and "free bilirubin" as an approach for prevention of kernicterus

Free bilirubin (FB) and total bilirubin (TB) were determined in 154 samples of blood taken from 112 jaundiced newborns: 51 prematures without hemolysis (19 of these with RDS); 26 full terms presenting ABO incompatibility; 35 newborns (both prematures and full terms) presenting rhesus incompatibility. Kernicterus was observed in seven cases and only three occurred in the TB group above 20 mg/100 ml; 57 cases had FB equal to or above 0.1 mg/100 ml and all kernicterus fell into this category. In the other 55 cases in which FB was less than 0.1 mg/100 ml no kernicterus was observed. In the group of healthy full-term newborns presenting ABO incompatibility, 15 had FB above or equal to 0.1 mg/100 ml ranging between 0.1 and 0.4 mg/100 ml; however no kernicterus was observed during the neonatal period. On the contrary, in the group of prematures a little more than half of the cases had a FB ranging from 0.1 to 0.4 mg/100 ml whereas four macroscopic kernicterus cases were observed. The difference between the two groups compels us to consider other factors than those acting on the albumin-bilirubin binding especially those acting on the blood-brain barrier and on the fixation of the pigment by the neurons. A second series of 605 consecutive autopsies, on a period of 10 years, on prematures excluding light-for-dates and cases of hemolysis, evaluates the distribution of 40 kernicterus as a function of birth weight. On this second series kernicterus appears with maximal frequency for birth weight between 1,000 and 1,250 g, with a nonnegligible frequency at 1,500 to 2,000 g and was absent between 2,000 and 2,500 g. 13 kernicterus were observed for a peak TB below 12 mg/100 ml. These results seem to justify a systematic determination of FB in the premature weighing less than 2,000 g from the 24th hour of life whether he has jaundice or not.

Neuropathological observations in a patient with carbamylphosphate-synthetase deficiency and in two sibs

Neuropathological findings are described in a child who suffered from carbamylphosphate-synthetase deficiency and died at the age of 7 months. The brain showed ulegyria of the cerebral and cerebellar cortex and hypomyelination of the centrum semiovale and the central part of the brainstem. Two sibs, who had died at the age of 4 weeks after a comparable illness, showed brain damage that seemed to represent an earlier stage of that observed in the first patient. These two children also showed bilateral symmetrical necrotizing lesions in certain brainstem areas (in one, kernicterus was observed macroscopically). The absence of further neuropathological observations in this disease makes it as yet impossible to reach any definite conclusion as to the aetiology of the brain lesions.