An unusual cause of neonatal shock: a case report

Introduction

Birth injury causing damage to visceral organs (such as the liver) is an uncommon clinical diagnosis in newborn babies, but when such serious birth injuries occur, they are often diagnosed at the time of autopsy [1], [2], [3], [4]. Most commonly, the liver and adrenal glands are the primary victims of infant organ damage due to birth trauma [5]. Intraabdominal and intracranial bleeding should be in the differential diagnosis when very low birth weight (VLBW) neonates present with unexplained shock. The authors present an unusual case of subcapsular hematoma of the liver (SHL) caused by traumatic delivery in a VLBW neonate.

Case presentation

A premature male infant was born at 28 2/7 weeks of gestation to a 23-year-old African-American primi-gravid mother. The pregnancy was complicated by migraine, chronic hypertension, short cervix, pre-eclampsia, unknown group B streptococcus status and preterm labor. The infant was delivered by cesarean section due to footling breech presentation. The delivery of the baby was difficult because the foot was struck in the introitus. Apgar scores were 7 and 10 at 1 and 5 min, respectively, and the birth weight was 970 g. Following delivery, the infant was placed in a pre-warmed isolette and was resuscitated by providing positive pressure ventilation with bag and mask due to lack of respiratory efforts. The infant was eventually intubated and was placed on a mechanical ventilator in the delivery room. A physical exam in the delivery room was significant for diffuse bruising. No other significant clinical findings were noted. Initial labs done at the first 6 h of life were significant for severe anemia with hematocrit of 22% and a normal platelet count of 209 × 10⁹/L. The authors did not find any source of active bleeding or any reason for having low hematocrit. The infant was transfused with packed red blood cells (pRBC) per protocol.

On day 1 of life, the infant was successfully extubated to continuous positive airway pressure. Despite receiving pRBC transfusion, the infant’s hematocrit dropped from 22% to 13%, and platelet counts decreased from 209 × 10⁹/L to 40 × 10⁹/L. He also started showing signs of acute deterioration with increasing tachypnea, tachycardia and declining systemic blood pressure levels. The infant was in significant distress with diffuse pallor, poor perfusion and decreased activity.

An abdominal exam was significant for dusky appearance as well as a distended, firm and tender abdomen. A pediatric surgery team was consulted immediately. In addition to subcapsular liver hematoma, the differential diagnosis included hemoperitoneum due to liver and/or splenic laceration, spontaneous intestinal perforation giving rise to pneumoperitoneum, intrahepatic hematoma presented with hepatic mass, necrotizing enterocolitis giving rise to disseminated intravascular coagulation (DIC) or DIC secondary to sepsis. After thorough consideration of differential diagnosis, all the appropriate labs were ordered.

Labs and imaging included but were not limited to arterial blood gas, complete blood count, blood culture, c-reactive protein, coagulopathy panel (prothrombin time/international normalized ratio (PT/INR)), abdominal imaging such as abdominal X-ray (two views) and abdominal sonogram at the bedside.

The lab results showed hematocrit 13% (lowest), platelet count 40 × 10⁹/L (lowest), prolonged prothrombin time (PT) 17.5 s (normal range: 12.2–15.3 s), activated partial thromboplastin time 34.5 s (normal range: 23–36 s) and PT/INR 1.4 (normal range: 0.9–1.1), suggestive of DIC. An arterial blood gas showed metabolic acidosis (pH 7.19, base deficit of negative 14). A series of abdominal ultrasound scans was performed; the first (Figure 1) showed a large, ill-defined area mostly consisting of increased echogenicity and some anechoic areas (fluid) just underneath the skin bruising, which represented a liver hematoma. Anechoic areas in the scans represent fresh blood or old areas within the hemorrhage where the blood products were already breaking down. Second and third ultrasound scans (Figure 2 and Figure 3) showed the well-defined and diffusely hypoechoic lesion with an evolving hematoma decreasing in size. A cranial sonogram was negative for bleeding. Pediatric surgery and pediatric hematology teams were consulted. The infant was provided volume replacement, including pRBC, fresh frozen plasma and cryoprecipitate transfusions. He was monitored closely with serial blood work and abdominal exams. He was maintained nil per os to provide gut rest during this acute illness. The infant was hemodynamically stabilized, and feeds were started successfully on day 3 of life. From the above-mentioned differential diagnosis list, all the other diagnoses were ruled out by obtaining pertinent labs and/or imaging, and the authors’ diagnosis was narrowed down to SHL. Given the concomitant physical findings of diffuse bruising and a history of emergent cesarean section required for footling breech presentation, the contributing factor for SHL was likely to be birth injury along with prematurity.

Figure 1:

Subcapsular hematoma right lobe of the liver as circled by white dots. The large area of hypo-vascular heterogeneous echogenicity in the right lobe of the liver and a large skin bruise overlying this lesion indicates that traumatic delivery was the cause of hematoma.

Figure 2:

Evolving liver hematoma which is liquefying

Figure 3:

Hematoma which is gradually decreasing in size.

The rest of the course in the hospital was uneventful, and the authors discharged the infant home at 36 weeks of corrected gestational age (2 months of chronological age). The ultrasound scan of the liver (Figure 3) at 5 months of age showed signs of resolution of hematoma, and the repeat scan at 1 year showed a small well-circumscribed lesion which is consistently becoming smaller. The patient’s hematocrit was 28% at 5 weeks of age, and reticulocyte count was 8%. His liver functions were followed closely. During his neonatal intensive care (NICU) stay, the infant’s alanine amino transferase (ALT) and aspartate aminotransferase (AST) were normal, but his gamma glutamyl transferase was mildly elevated to 175 IU/L (normal up to 150 IU/L); this number was normalized in a week. The patient’s direct bilirubin was elevated (1.7 mg/dL) due to parenteral nutrition (TPN) cholestasis and has normalized before the infant was discharged. His liver functions remained normal during the follow-up visits in the pediatric clinic. At his first birthday, the infant’s hematocrit was 36% and his reticulocyte count was 4% while he was on multivitamin and iron therapy. His growth and development were appropriate for the age.

Discussion

Liver hematoma happens in approximately 10–15% of neonates and is associated with prematurity, low birth weight infants, relatively large size for gestational age infants, breech delivery and difficult or traumatic delivery [6]. Sepsis, pneumothorax, congenital bleeding diathesis, prematurity, DIC, maternal preeclampsia, maternal DIC, perinatal hypoxia and umbilical venous catheterization are shown to increase the risk of liver hematomas [7], [8]. Several theories have previously been proposed on the subject of the various etiologies that cause SHL; some of them include abnormal presentation of the fetus, compression of the fetal liver during delivery (which is relevant mainly in premature infants due to weaker abdominal musculature) and configuration (which exposes a larger hepatic surface below the rib cage and whose liver holds considerable amounts of extramedullary hematopoiesis giving rise to a more friable organ) [1], [2], [8], [9]. An additional commonly mentioned element is deficiency of vitamin K-dependent clotting factors in newborns, primarily in preterm neonates [2]. Anoxic brain injury and/or hypoxia-induced injury is also reported to be associated with SHL [2]. Excessive manipulation, physical stress and/or intubation is also found to be a known risk factor for SHL. SHL must be differentiated from intraparenchymal, adrenal or intraperitoneal hemorrhage of the liver. An intraparenchymal hemorrhage in the liver is usually less severe than SHL [8]. An abdominal sonogram is the principle investigative modality in diagnosing liver hematoma [10] and would assist in differentiating intraabdominal bleeding [11].

Throughout the medical literature of the 1980s and 1990s, many case studies on VLBW infants were diagnosed with SHL at the time of autopsy [2], [3], [4], [12]. French noticed that out of 783 neonatal deaths, 15% of the neonates had extensive liver hematomas or intra-abdominal hemorrhages [2]. Advances in therapy have contributed to the better survival of VLBW infants [13]. In recent years, there have been a few case reports of atypical presentations of SHL [5], [14]. Risk factors for a liver hematoma present in the current case included prematurity, traumatic delivery, excessive stress and intubation, DIC and umbilical venous catheterization [14]. Some other risk factors not present in the current case included sepsis, pneumothorax and congenital bleeding diathesis [14]. A massive hemorrhage may present with signs of hypovolemic shock (pallor, hypotension and metabolic acidosis) associated with abdominal fullness. When the bleeding is slow, clinical features may be subtler with the gradual onset of pallor and abdominal distention. Occasionally in SHL, blue discoloration of the skin over the liver may extend to the scrotum [15]. Bleeding diathesis, including DIC and hemophilia, need to be excluded as a cause of bleeding [16].

French and Waldstein found in their study that SHL incidence is seen more in neonates born at less than 28 weeks of gestational age; it was also found that SHL is discovered mostly during the autopsy. Management of SHL mainly includes supportive therapy and treating the underlying etiology, as was also seen in the current case. Ryan and Finer [6] have shown that the majority of the infants with SHL have succumbed to death due to shock or other comorbidities. The literature shows most of the SHL are discovered after death [2], [6]. In survivors, the consequences of SHL are acute and chronic. The acute consequences include hypovolemic shock, DIC, abdominal distention, unexplained anemia and jaundice. The chronic consequences of SHL include iron deficiency anemia, growth and developmental delay especially in preterm infants. Pathologically, the SHL resolves completely over a period of time without causing hepatic derangements in survivors.

In the current case, the infant was in DIC as a result of the traumatic delivery, causing a liver hematoma and eventually resulting in hypovolemic shock. The infant was treated conservatively with administration of fresh frozen plasma, cryoprecipitate, pRBC and platelets. The bleeding stopped after correction of DIC, and the infant went home without any major concerns.

Conclusion

The current case highlights the importance of considering intraabdominal hemorrhage when managing unexplained shock and hypovolemia in VLBW neonates. High index of suspicion and use of appropriate investigative modalities and timely interventions were paramount in managing this infant.