The adrenal glands in newborns are relatively large in size (10-20 times larger than in adults relative to body weight) and exhibits increase in vascularity (50-60 arterial branches from 3 suprarenal arteries). Incidence of adrenal hemorrhage most commonly (~70%) occur on the right side because anatomically, the right adrenal gland is located between the liver and spine and thus, can result to its compression. Moreover, the right adrenal vein drains into the inferior vena cava and its compression can induce venous pressure changes.
The cause of adrenal hemorrhage usually is multifactorial, with mechanical compression as well as changes in venous pressure during delivery thought to be the most likely cause. In hypoxia, hemorrhage occurs from congestion and endothelial damage that occurs when blood is redistributed (increase in pressure) to the central nervous system, heart and adrenal glands. Clinical symptoms of poor feeding, vomiting, persistent jaundice, anemia, and abdominal mass are usually noted with jaundice as the most frequent. Hemolysis from enclosed hemorrhage in this case results to jaundice. Adrenal hemorrhage may occur also from asphyxia, shock, septicemia and preexisting hematologic disorders.
Sonographically, its appearance varies depending on its stage. From solid and echogenic in its early phase to mixed echogenicity with central hypoechogenicity as liquefaction occurs. The presence of calcifications can be seen as early as 1-2 weeks after the onset. Neonatal adrenal hemorrhage is usually self-limited with resolution. It becomes anechoic at approximately 2 to 3 months after onset and on rare instances extends to a maximum of 9 months. Addisonian crisis rarely occurs in neonatal adrenal hemorrhage because hemorrhage is usually subcapsular and adrenal insufficiency does not occur until at least 90% of adrenal tissue is destroyed. Surgery should only be considered mostly in cases where high suspicion of a mass (e.g. neuroblastoma) with positive tumor markers, elevation of the urinary catecholamine metabolites, nuclear scintigraphic findings of increased uptake in the suprarenal region, evidence of metastasis, progression in size and non-resolution / unusual clinical course under conservative treatment.
In this case the patient was noted to be anemic on blood exams as well as with persistence of jaundice despite adequate phototherapy. In cases of hyperbilirubinemia of unknown etiology, adrenal hemorrhage must be considered. Ultrasonography remains the modality of choice for evaluation of the adrenal glands in neonates.