Haemorrhagic pulmonary oedema ("massive pulmonary haemorrhage") in the newborn

Understanding the Full Spectrum of Organ Injury Following Intrapartum Asphyxia

Birth asphyxia is a significant global health problem, responsible for ~1.2 million neonatal deaths each year worldwide. Those who survive often suffer from a range of health issues including brain damage-manifesting as cerebral palsy (CP)-respiratory insufficiency, cardiovascular collapse, and renal dysfunction, to name a few. Although the majority of research is directed toward reducing the brain injury that results from intrapartum birth asphyxia, the multi-organ injury observed in surviving neonates is of equal importance. Despite the advent of hypothermia therapy for the treatment of hypoxic-ischemic encephalopathy (HIE), treatment options following asphyxia at birth remain limited, particularly in low-resource settings where the incidence of birth asphyxia is highest. Furthermore, although cooling of the neonate results in improved neurological outcomes for a small proportion of treated infants, it does not provide any benefit to the other organ systems affected by asphyxia at birth. The aim of this review is to summarize the current knowledge of the multi-organ effects of intrapartum asphyxia, with particular reference to the findings from our laboratory using the precocial spiny mouse to model birth asphyxia. Furthermore, we reviewed the current treatments available for neonates who have undergone intrapartum asphyxia, and highlight the emergence of maternal dietary creatine supplementation as a preventative therapy, which has been shown to provide multi-organ protection from birth asphyxia-induced injury in our preclinical studies. This cheap and effective nutritional supplement may be the key to reducing birth asphyxia-induced death and disability, particularly in low-resource settings where current treatments are unavailable.

Pulmonary hypertension and the asphyxiated newborn

Persistent pulmonary hypertension of the newborn may occur with perinatal asphyxia, either because of direct effects of hypoxia/ischemia on pulmonary arterial function or indirectly because both are associated with meconium aspiration syndrome or perinatal sepsis/pneumonia. Therapies for persistent pulmonary hypertension of the newborn have the potential to affect cerebral function and cerebral perfusion in infants with hypoxic ischemic encephalopathy. Our literature review concludes that hyperventilation should be avoided, bicarbonate therapy is unproven, and hypoxia and hyperoxia should both be avoided. Nitric oxide improves pulmonary artery pressure and systemic perfusion. The effects of inotropic agents on cerebral perfusion or outcomes are uncertain.

Sudden oronasal bleeding in a young child

Sudden severe upper-airway obstruction occurring in a hospital setting can sometimes precipitate an episode of acute haemorrhagic pulmonary oedema. A review of 197 published case reports shows that the presenting feature is almost always the sudden appearance of blood stained fluid coming up through the larynx or out through the mouth and nose of an adult or child in obvious respiratory distress. Such overt features are seen in 10-15% of cases of sudden severe, but sub-lethal, upper-airway obstruction. Signs normally appear within minutes once the obstruction is relieved but are occasionally only recognized after 1-4 h. All signs and symptoms usually resolve within 12-24 h. Other causes of acute pulmonary haemorrhage are rare in young children.

CONCLUSION

If what looks like blood is seen in, or coming from, the mouth or nose of a previously healthy young child who has suddenly become distressed and started to struggle for breath, that child has most probably suffered an episode of acute pulmonary oedema, and the commonest precipitating cause is sudden upper-airway obstruction.

Acquired Nonneoplastic Neonatal and Pediatric Diseases

The lung biopsy is an established procedure to procure a pathologic diagnosis in a child with a suspected pneumonic process of undetermined etiology. Improvements in pediatric anesthesia and surgery have reduced the operative complications to a minimum. A biopsy can usually be taken through a small intercostal incision when localization is not especially important in a patient with diffuse changes (see Chapter 1). The alternative method for tissue sampling is the endoscopic transbronchial biopsy. There is less risk to the patient, but the specimen is smaller and crush artifacts from the instrument are more common.

Patent Ductus Arteriosus as a Natural Cause of Pulmonary Hemorrhage in Infants

Patent ductus arteriosus (PDA) is a recognized risk factor for massive pulmonary hemorrhage (MPH) in the newborn and is generally seen in association with other MPH risk factors such as prematurity. We report 6 cases of sudden and unexpected death of infants older than 4 days with MPH and PDA at autopsy. The cases were reviewed for other factors that could contribute to MPH to ascertain whether PDA is directly linked to MPH. Histology samples were examined for distribution of hemorrhage in the lungs and iron stained for hemosiderin evaluation. All of the cases had clinical histories and scene examinations which raised the differential diagnosis of mechanical asphyxia in the form of so-called overlayings. The diagnostic dilemma of attributing the MPH to the PDA as the sole cause, dual cause, or incidental finding is discussed. These cases illustrate the medicolegal dilemma faced by the pathologist, as well as the need for further research into the potential association of PDA with MPH.

Multiple organ involvement in perinatal asphyxia

OBJECTIVES

(1) To evaluate the frequency and spectrum of severity of multisystem dysfunction after perinatal asphyxia and (2) to analyze the relationship between the clinical and biochemical markers of perinatal asphyxia and multiorgan involvement.

STUDY DESIGN

Seventy-two consecutive term newborn infants with perinatal asphyxia were studied prospectively. Systematic neurologic, renal, pulmonary, cardiac, and gastrointestinal evaluations were performed. Involvement of each organ was classified as moderate or severe.

RESULTS

Involvement of one or more organs occurred in 82% of the infants; the central nervous system (CNS) was most frequently involved (72%). Severe CNS injury (7 infants) always occurred with involvement of other organs, although moderate CNS involvement was isolated in 14 infants. Renal involvement occurred in 42%, pulmonary in 26%, cardiac in 29%, and gastrointestinal in 29% of the infants; 15% neonates had renal failure and 19% had respiratory failure. The Apgar scores at 1 and 5 minutes were the only perinatal factors related to the number of organs involved and the severity of involvement; the Apgar score at 5 minutes had the stronger independent association. No relationship or organ dysfunction was found with the umbilical cord arterial blood pH, meconium-stained amniotic fluid, umbilical cord abnormalities, presentation, or type of delivery.

CONCLUSIONS

Our findings indicate that the Apgar score at 5 minutes, in infants who have other criteria for asphyxia, is the perinatal marker that may best identify infants at risk of organ dysfunction.

Coagulation failure in babies with rhesus isoimmunization

Serial prospective studies of coagulation status have been undertaken on 73 babies with a positive Coombs test. No abnormalities were detected in the babies with mild haemolytic disease, but seven of the 36 babies with severe haemolytic disease (cord Hb less than 11 g/dl or cord bilirubin greater than 85 mumol/1) showed evidence of transient defibrination 1 d after birth and another six had evidence of coagulation failure at birth with a platelet count of less than 150 x 10(9)/1 and a severe deficiency of multiple coagulation factors. The level of factor II and factor X was less than a fifth of the normal cord blood level in these six babies and the level of I, VII and IX was severely reduced; the factor VIII level was normal or high. Exchange transfusion started within 1 h of birth corrected the immediate factor deficiency in these six babies, but evidence of defibrination then became apparent with afibrinogenaemia, a marked fall in factors II and V, less constant falls in factors VII, IX and X, and a raised fibrin:fibrinogen degradation product level. One of these six babies died with severe pulmonary hypoplasia within an hour of birth; the other five died from haemorrhage into the lung or brain 1 1/2--6 d after birth. The very low vitamin-K dependent factor levels in the cord blood of the babies who died are presumably the result of liver damage in utero, but the subsequent changes are those of a comsumption coagulopathy. Simple screening tests at birth served to indicate which babies were at risk and it is concluded that death due to haemorrhage might be reduced by more intensive factor replacement before there is overt evidence of haemorrhage in these babies.

Fatal intra-alveolar pulmonary bleeding complicating pulmonary embolectomy

Two patients are reported in whom fatal alveolar pulmonary haemorrhage occurred after pulmonary embolectomy. Possible causes and methods of prevention are discussed.

Hyaline membrane disease. II. Lung lecithin

The lecithin content of lung, together with its surface tension properties, were determined in 34 stillbirths, and 61 neonatal deaths. Lecithin content ranged widely from 1·5 to 18·6% of dry lung tissue. In 24 cases the `palmitic-lecithin' was also measured; it formed 44-79% of the total lecithins. Since the two were related linearly, changes in palmitic-lecithin could be adequately studied by measuring total lecithins. Lecithin content was negatively correlated with minimum surface tension of lung extract in both fresh stillbirths and neonatal deaths. Cases with hyaline membranes had lung lecithin in the lower range (< 8% dry tissue). Lung lecithin content may be a measure of surfactant reserve. After 29 weeks' gestation, fresh stillbirths and neonatal deaths, other than those with hyaline membranes, had normal lung surfactant. The exception was a small group of infants having immature lungs lacking surfactant, and who survived less than 2½ hours; some of these, it is surmised, would have developed hyaline membranes had they survived longer. This was consistent with the fact that well-formed hyaline membranes were only found in infants that had survived for at least 3 hours. Surfactant deficiency probably develops only after birth (except in very immature infants), and as a consequence of an initial rapid consumption of surfactant to form a lining layer covering the alveolar surface, when a gas-liquid interface is created by aeration of lung. Surfactant deficiency, by promoting interstitial pulmonary oedema, is thought to be the immediate cause of hyaline membrane disease. A scheme for the pathogenesis of hyaline membrane disease is set out. It provides a possible mechanism for the different ways in which surfactant deficiency may arise in immature and mature infants. Cases where hyaline membranes occur with normal surfactant fall into three groups: (1) Cases with hyaline membrane disease that have survived several days, the lungs being in the stage of repair. (2) Cases with massive lung haemorrhage, with severe anaemia from haemolytic disease, or with heart failure; extravasation of oedema fluid or blood may be the common factor in this group. (3) Infants of diabetic mothers.

Effect of asphyxia due to umbilical cord occlusion in the foetal lamb on leakage of liquid from the circulation and on permeability of lung capillaries to albumin

1. Experiments were performed on foetal lambs, exteriorized at Caesarean section, to determine the effects of asphyxia on the leakage of liquid from the circulation and on the permeability of lung capillaries to albumin. Following a period of control observation (30-120 min) the foetus was asphyxiated by occlusion of the umbilical cord for 5-10 min and then allowed to recover while observations were continued for a further 20-80 min.2. Measurements were made of the lymph flow from the lungs, that had drained via the thoracic duct; of protein concentration in lymph and plasma; of arterial blood haematocrit, pH, P(O2) and P(CO2); and of arterial and left atrial pressures and heart rate. Human serum albumin labelled with (125)I was infused intravenously during the control period and (125)I count rates were followed in plasma and lymph throughout the experiment. Values for the transfer coefficient of albumin (E/V min(-1), i.e. interstitial fluid clearance of albumin per unit of lung interstitial fluid volume) were determined during control, cord-occlusion and post-occlusion periods.3. During cord occlusion arterial and left atrial pressure, haematocrit and plasma protein concentration all rose, returning to the control value by 20 min after release of cord occlusion. The haematocrit values indicated that about 9% of the blood volume was temporarily lost from the circulation. Lung lymph flow also increased, reaching a maximum in the 5 min period after release of occlusion and returning to the control level 15 min later. Values for E/V of albumin were at no time significantly different from those during the control period.4. It was concluded that acute foetal asphyxia produced by umbilical cord occlusion caused an increased leakage of liquid from the circulation in general. This effect was temporary and was probably due to an increase in capillary pressure during cord occlusion. The asphyxia had no persistent effect on the permeability of lung capillaries to albumin.