An unusual case of hypovolemic shock in a neonate

A term baby boy presented at 8 hours of age with tachypnea and grunting. He was born to a primigravida healthy mother with no infectious risk factors by vacuum-assisted delivery. He required brief suctioning below the vocal cords for thick meconium, and administration of continuous positive airway pressure for his first 15 minutes of life. APGAR scores were 6 and 8 at 1 and 5 minutes, and cord gases were unremarkable. The baby was well after resuscitation and was transferred to the postpartum floor. At 8 hours of life, the baby became hypothermic (34.1°C), and developed grunting, tachypnea, pallor and subsequent hypotension (BP 36/15), resulting in admission to the neonatal intensive care unit (NICU). On physical examination, auscultation of lung fields was clear bilaterally, no murmur was heard and he had no evidence of organomegaly or flank mass. He underwent partial septic workup, ampicillin and gentamicin were started, and chest x-ray showed reduced lung volumes, but was otherwise normal. Blood results demonstrated normocytic anemia (hemoglobin 88 g/L), white blood cell count of 34.1 × 109/L with a normal differential, and a platelet count of 142 × 109/L. A venous gas showed pH 6.97, base excess –23 mmol/L and lactate 22 mmol/L. Accordingly, fluid boluses were given, oxygen was administered and the baby was commenced on a packed red blood cell transfusion over 4 hours. At 20 hours of life, the baby remained pale and clinically unwell, with repeat hemoglobin of 66 g/L. He had evidence of continued metabolic lactic acidosis and of end-organ injury: creatinine 188 µmol/L, urea 9.4 mmol/L, aspartate aminotransferase (AST) 372 U/L, alanine aminotransferase (ALT) 121 U/L. He received a second transfusion of packed red blood cells over 4 hours. Workup for acute anemia included a negative direct antiglobulin test, negative Kleihaur-Betke test, no evidence of reticulocytosis (absolute reticulocyte count 89.9 × 109/L), and no evidence of hemolysis (unconjugated bilirubin 42 µmol/L, conjugated bilirubin 10 µmol/L). Arrangements were made for transfer to a tertiary care NICU. On further review of investigations performed during initial NICU admission, an abdominal x-ray obtained for arterial and venous umbilical line placement had given the first clue to the clinical diagnosis. As shown in Figure 1, there was significant widening of the retroperitoneal space on the abdominal film, with forward displacement of the stomach and duodenum, and downward displacement of the intestines. Abdominal ultrasound (Figure 2) and subsequent abdominal magnetic resonance imaging were performed at the tertiary level NICU revealing a diagnosis of right-sided adrenal hemorrhage. It became clear that the baby’s clinical presentation was consistent with adrenal hemorrhage leading to hypovolemic shock in the newborn period. With intravenous fluid and blood product support, the baby improved, and overall sustained a complete recovery from his acute illness. He was discharged home and at 6 months of age is doing clinically and developmentally well. Abdominal x-ray. Anterior-posterior (A) and lateral (B) x-ray images of the abdomen highlight the shifted bowel gas pattern and widening of the retroperitoneal space, with forward displacement of the stomach and duodenum, and downward displacement of the intestines, as seen in right-sided adrenal hemorrhage. Abdominal ultrasound. Ultrasound images of the right kidney and retroperitoneal space show a mass in the region of the right adrenal gland that measured 3.9 × 3.5 × 2.4cm. This mass had heterogeneous echogenicity with a hypoechoic complex fluid collection surrounding it, likely representing a large complex hematoma around the kidney. Further magnetic resonance imaging confirmed that this was consistent with right-sided adrenal hemorrhage. Adrenal hemorrhage is a potentially life-threatening condition that rarely presents in the neonatal period. Severity of illness and clinical presentation can vary quite broadly depending on degree of organ involvement and underlying cause. Incidence of adrenal hemorrhage in the neonatal period is estimated to be 0.2% to 0.55% (1), and is more common in term babies who are more likely to have large birth weight, prolonged labour, birth trauma, and perinatal asphyxia or hypoxia. Intrauterine infection, neonatal sepsis, and hemorrhagic disorders of the newborn are also important risk factors for the development of this condition. In many cases, however, no risk factors can be identified. The adrenal gland is considered to be particularly vulnerable to hemorrhage due to its intricate vascular supply made of many tiny arterioles that feed into a highly vascular plexus in the adrenal cortex. This cortex is then drained by a single central vein that can cause resistance to blood flow, creating a system that is susceptible to increased pressures, leading to hemorrhage (2). Interestingly, adrenal hemorrhage more commonly affects the right side than the left, presumed to be due to compression between the liver and the spine. Bilateral adrenal hemorrhage occurs in 10% to 15% of cases (1). Clinical presentation of adrenal hemorrhage in the neonate can be quite variable. The most common presentations are jaundice from hemolysis-related unconjugated hyperbilirubinemia, and flank mass; it can also be found incidentally by abdominal ultrasound, or may present as calcification on the abdominal x-ray (2). More severe clinical presentations can be a result of hemorrhagic shock or adrenal insufficiency, and can lead to death as a result. Rarely does adrenal hemorrhage cause adrenal insufficiency acute enough to require mineralocorticoid supplementation, though this has been reported in the literature (3). There have also been reports of bluish scrotal discolouration as a presenting symptom of adrenal hemorrhage, thought to be a result of blood from the adrenal bed tracking through the inguinal canal or perhaps intraperitoneal blood descending through a patent processus vaginalus (4). Overall, the range of often subtle clinical symptoms can make neonatal adrenal hemorrhage an arduous diagnostic challenge. Ultrasonography remains the diagnostic modality of choice for identifying adrenal hemorrhage in the neonate. It can also be a useful tool for tracking the progression of hemorrhage over time and can be used to follow a hemorrhage until resolution. Adrenal hemorrhage usually resolves in 1 to 6 months time (1). Differential diagnosis of adrenal hemorrhage as unilateral flank mass should include neuroblastoma, infectious abscess, hemangioma, benign renal cyst, hydronephrosis, renal vein thrombosis or very rarely pheochromocytoma/paraganglioma (2). The utility of urine homovanillic acid and vanillylmandelic acid levels may help to differentiate neuroblastoma from other causes, as well as further imaging such a magnetic resonance imaging to detail the characteristics of the adrenal lesion. Conservative management is the treatment of choice for most presentations of neonatal adrenal hemorrhage and once identified, adrenal hemorrhages should be followed by ultrasound until complete resolution (2). In summary, we report a rare case of neonatal adrenal hemorrhage presenting as hypovolemic shock in a term baby with no identifiable risk factors. This case illustrates the need to promptly resuscitate with blood products in response to acute anemia and that a diagnosis of adrenal hemorrhage should be considered. 1) Prompt resuscitation of a neonate with hypotension, including blood products, should occur in response to acute anemia, even in the absence of clear etiology. 2) Evaluation in a neonate with unexplained normocytic anemia should also include abdominal imaging, with abdominal x-ray and abdominal ultrasound being relatively accessible first line techniques. 3) Though rare, a diagnosis of adrenal hemorrhage should be considered in the setting of neonatal acute anemia and hypovolemic shock. MLD contributed to diagnostic workup, provided interpretation of results, drafted the manuscript and approved of the manuscript as written. SC contributed to diagnostic workup, provided interpretation of results, critically revised the manuscript and approved of the manuscript as written. DC contributed to diagnostic workup, provided interpretation of results, critically revised the manuscript and approved of the manuscript as written. None None declared.

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