Case Study—Acute & Specialty Care
Hepatopulmonary Syndrome in the Presence of Abernethy Malformation: A Pediatric Case Report Kimberly Saulters, MSN, RN, CPNP AC/PC, CCRN, & Kristin Hittle, MSN, RN, CPNP-AC, CCRN
Section Editors Karin Reuter-Rice, PhD, CPNP-AC, FCCM Corresponding Editor Duke University Durham, North Carolina Terea Giannetta, DNP, RN, CPNP California State University ChildrenÕs Hospital Central California Fresno, California Maureen A. Madden, MSN, RN, CPNP-AC, CCRN, FCCM Rutgers Robert Wood Johnson Medical School New Brunswick, New Jersey Bristol Myers Squibb Children’s Hospital New Brunswick, New Jersey Kimberly Saulters, Pediatric Nurse Practitioner, Pediatric Intensive Care Unit, Children’s Medical Center Dallas, Dallas, TX. Kristin Hittle, Pediatric Nurse Practitioner, Pediatric Intensive Care Unit, Children’s Medical Center Dallas, Dallas, TX. Conflicts of interest: None to report. Correspondence: Kimberly Saulters, MSN, RN, CPNP AC/PC, CCRN, Pediatric Intensive Care Unit, Children’s Medical Center Dallas, 1935 Medical District Dr, Dallas, TX 75235; e-mail: [email protected]
J Pediatr Health Care. (2015) 29, 104-107. 0891-5245/$36.00 Copyright Q 2015 by the National Association of Pediatric Nurse Practitioners. Published by Elsevier Inc. All rights reserved. Published online June 28, 2014. http://dx.doi.org/10.1016/j.pedhc.2014.05.005
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KEY WORDS Abernethy malformation, portosystemic shunt, hepatopulmonary syndrome
Abernethy malformation (AM) is a rare, congenital, extrahepatic, portosystemic shunt that allows the intestinal and splenic venous blood to bypass the liver and drain into the systemic venous circulation. Diagnosis of AM The hepatic anomalies often involves a associated with AM considerable result in serious complications, including workup, and early hepatopulmonary syninclusion as a drome (HPS), which differential can lead to significant clinical findings of diagnosis in hypoxia and hypoxpatients with emia. Several physiounexplained logic mechanisms associated with HPS hypoxia and are known to induce hypoxemia may hypoxemia, including facilitate diagnosis. diffusion defects, shunts, and ventilation-perfusion (V/Q) mismatch (Kinane & Westra, 2004). Diagnosis of AM often involves a considerable workup, and early inclusion as a differential diagnosis in patients with unexplained hypoxia and hypoxemia may facilitate diagnosis. CASE REPORT An 11-year-old girl presented to the emergency department (ED) with acute onset of chest pain, increased work of breathing, exercise intolerance, headache, Journal of Pediatric Health Care
and fever. These symptoms developed while she was at school, along with hypoxia with an oxygen saturation of 70% on room air. Prior to this presentation, she had upper respiratory symptoms, including cough, for 1 week. She had been seen by her primary care provider and treated with amoxicillin/clavulanic acid (Augmentin) for streptococcal pharyngitis. She reported a 7-month history of intermittent perioral and peripheral cyanosis, as well as shortness of breath with physical activity. The patient’s medical history was significant for premature birth at 34 weeks with no neonatal complications, pulmonary valve stenosis, and polycythemia. She was followed up by a cardiologist until 9 years of age, at which time an echocardiogram demonstrated resolution of the pulmonary valve stenosis without surgical intervention. She was followed up briefly by a hematologist for polycythemia but was lost to follow-up. Upon initial examination in the ED, the patient was hypoxic with oxygen saturations ranging from 79% to 83% on room air. She required oxygen therapy via a Venturi mask (Ventimask) to maintain oxygen saturation as measured by pulse oximetry (SpO2) greater than 90%. Her physical examination was significant for slightly coarse breath sounds throughout, digital clubbing, peripheral cyanosis without perioral cyanosis, and no abnormal abdominal examination findings. Her evaluation in the ED included a chest radiograph, an electrocardiogram, and an echocardiogram, all of which were normal. Her laboratory tests were significant for polycythemia, with a hemoglobin level of 19 g/dl, and a hematocrit of 54%. She was admitted to the pediatric intensive care unit for further evaluation because of the unexplained hypoxia. Differential diagnoses for hypoxemia include pulmonary embolism, intrinsic pulmonary disease, pulmonary hypertension, portal vein thrombosis, hereditary hemorrhagic telangiectasia, and hepatopulmonary syndrome. Initially, the patient underwent an extensive pulmonary evaluation. A pulmonary embolism was ruled out when results of her d-dimer test and computed tomography of the chest were normal. A V/ Q scan was suggestive of intrapulmonary right-to-left shunting and pulmonary arteriovenous malformations (AVMs). As a result, a magnetic resonance angiogram of the chest was performed, and no pulmonary AVMs were identified. With no identified pulmonary physiology to explain her hypoxemia, the workup continued in an attempt to find other possible causes. Findings of a hepatic and renal ultrasound with Doppler were normal, with no indication of vascular malformation. Subsequently, a computed tomography scan of the abdomen and pelvis with contrast was completed, which showed cirrhosis and portal hypertension, raising concern for portal vein thrombosis, along with extensive collateral vessels consistent with a www.jpedhc.org
chronic process. The hepato-renal team was consulted. A liver biopsy with venogram was performed, which showed normal hepatic pressures and no abnormalities according to the biopsy results. Next, a magnetic resonance venogram of the liver was obtained, which showed no thrombosis but small varices in the distal para-esophageal region and along the stomach. A repeat echocardiogram with a bubble study was completed, which confirmed the intrapulmonary shunting that was demonstrated on her prior V/Q scan. Successively, a cardiac catheterization was performed that confirmed bilateral micropulmonary AVMs. Given these findings and concern for hepatopulmonary syndrome, a mesenteric angiogram was performed. This test revealed a congenital extrahepatic portosystemic shunt without hypoplasia of the portal vein. With this finding, along with the presence of hypoxia and micropulmonary AVMs, AM variation type II with HPS was diagnosed. DISCUSSION Abernethy malformation is a congenital extrahepatic porto-systemic shunt whereby the intestinal and splenic venous blood bypasses the liver and drains into systemic veins, most commonly the inferior vena cava (Alonso-Gammara et al., 2011). John Abernethy first diagnosed this condition in 1793, when he described a portocaval shunt bypassing the liver in a 10-month old girl (Osorio et al., 2011; Witjes, Ijzermans, Noodegraaf, & Tran, 2012). Since that time, only 80 cases of AM have been reported in the literature (Witjes et al., 2012). Type I AM consists of a complete diversion of portal blood into the vena cava with an absence of the portal vein. In comparison, type II AM consists of a hypoplastic portal vein with portal blood diverted into the vena cava through a side-to-side extrahepatic communication, which allows for partial portal blood flow (Alonso-Gamarra et al., 2011; Witjes et al., 2012). Although rare, AM can result in HPS. To date, there have been only six case reports of HPS in the presence of AM (Osorio et al., 2011). The classic triad of symptoms associated with HPS includes arterial oxygenation defect, intrapulmonary vasodilation, and liver disease (Grace & Angus, 2012; Kinane & Westra, 2004; Osorio et al., 2011; Rodriguez-Roisin & Krowka, 2008). The exact mechanism that causes HPS is unknown; however, it is thought to involve several different processes that lead to the up-regulation of nitric oxide production, causing vasodilation of the pulmonary bed. As mesenteric, renal, and splenic blood flow completely or partially bypasses the liver via shunts, as seen with AM, hepatic metabolism is decreased, sending unfiltered blood to the right side of the heart and subsequently into the lungs. The unfiltered blood contains vasoactive mediators, namely nitric oxide, that causes January/February 2015
vasodilation in pulmonary vessels, resulting in V/Q mismatch, diffusion limitation, and shunting (AlonsoGamarra et al., 2011; Kinane & Westra, 2004; Witters et al., 2008). When intrapulmonary vasodilation is present, the distance oxygen must travel to saturate red blood cells in the center of the capillary increases, which is known as diffusion limitation and leads to hypoxia. Pulmonary vasodilation also causes V/Q mismatch, leading to overperfusion of the alveolar capillary bed, resulting in hypoxemia. The third mechanism is shunting of blood through the pulmonary AVMs. This shunting causes deoxygenated blood to bypass the alveoli and mix with oxygenated blood, returning to the pulmonary veins and back into systemic circulation, leading to hypoxia (Grace & Angus, 2012; Kinane & Westra, 2004; Morikawa et al., 2008). Clinical findings indicative of AM with HPS include cyanosis, digital clubbing, dyspnea on exertion, hypoxemia, hypoxia, and even hepatic encephalopathy (Alonso-Gamarra et al., 2011; Rodriguez-Roisin & Krowka, 2008; Witters et al., 2008). It is uncommon to see hepatic encephalopathy in children unless the shunt ratio becomes greater than 60% (AlonsoGamarra et al., 2011). AM has also been associated with other congenital anomalies. Most commonly these patients may have congenital heart disease, biliary atresia, polysplenia, sinus inversus, and malrotation (Alonso-Gamarra et al., 2011; Witters, et al., 2008). According to published case reports, management for patients diagnosed with AM range from shunt ligation to liver transplantation (Alonso-Gamarra et al., 2011; Osorio et al., 2011; Witjes et al., 2012). For type I AM, the only For type II AM, the treatment option is liver transplantation treatment of choice because of the is shunt ligation; absence of the portal however, if no vein. For type II AM, the treatment of improvement in choice is shunt symptoms occurs ligation; however, if after ligation, then no improvement in symptoms occurs transplantation is after ligation, then considered. transplantation is considered. Timing of surgical treatment or transplantation is related to clinical symptoms. Progression to transplantation is often delayed until the patient experiences symptoms of hepatic encephalopathy or, in the case of type II, has a shunt ratio of greater than 60%, because this ratio places the patient at greater risk of developing encephalopathy. In a literature review case report by Osorio and colleagues (2011), six patients were found to have HPS in the presence of AM. Of these six patients, two underwent ligation, two underwent transplanta106
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tion, and two did not undergo surgical treatment. HPS resolved in all four patients who underwent surgical intervention. Elisa, Scirica, and Herlt (2008) reported the successful resolution of HPS secondary to AM in a 4-year-old boy 4 months after he received a liver transplant. In this instance, our patient underwent a shunt ligation. Immediately after ligation she continued to have hypoxia, especially with exertion. Her postoperative course was uncomplicated, and she was discharged home on postoperative day 8 with oxygen being delivered by a nasal cannula, 2 to 4 L per minute. A repeat magnetic resonance angiogram 2 months after surgery showed no residual portosystemic shunt; however, at 1 year after shunt ligation, she still exhibits hypoxia and requires oxygen supplementation with 2 to 4 L via a nasal cannula. She has become wheelchair bound as a result of activity intolerance and severe hypoxia with exertion. Her most recent liver biopsy shows mildly dilated portal and central veins because of her extrahepatic vascular abnormalities. Given her persistent HPS despite shunt ligation without improvement in hypoxia or activity intolerance, she was evaluated for a liver and lung transplant and is awaiting transplantation at this time. CONCLUSION Although AM is a very rare congenital anomaly, the clinical manifestations can be serious, including HPS, which can lead to significant hypoxia and hypoxemia from V/Q mismatch. If left untreated, AM can result in hepatic encephalopathy. The initial presentation of these patients can often lead to a variety of differential diagnoses and an extensive workup, as seen with our patient. AM should be considered as a diagnosis in patients with HPS when no liver disease is initially present. REFERENCES Alonso-Gamarra, E., Parron, M., Perez, A., Prieto, C., Hierro, L., & Lopez-Santamaria, M. (2011). Clinical and radiologic manifestations of congenital extrahepatic portosystemic shunts: A comprehensive review. Radiographics, 31(3), 707-722. Elisa, N., Scirica, C. V., & Hertl, M. (2008). Liver transplantation for the Abernathy malformation. New England Journal of Medicine, 358(8), 585. Grace, J. A., & Angus, P. W. (2012). Hepatopulmonary syndrome: Update on recent advances in pathophysiology, investigation, and treatment. Journal of Gastroenterology and Hepatology, 28(2), 213-219. Kinane, T. B., & Westra, M. D. (2004). Case 31-2004: A four-year-old boy with hypoxemia. New England Journal of Medicine, 351(16), 1667-1675. Morikawa, N., Honna, T., Kuroda, T., Kitano, Y., Fuchimoto, Y., Kawashima, N., & Kawasaki, K. (2008). Resolution of hepatopulmonary syndrome after ligation of a portosystemic shunt in a pediatric patient with an Abernethy malformation. Journal of Pediatric Surgery, 43(2), E35-E38.
Journal of Pediatric Health Care
Osorio, M. J., Bonow, A., Bond, G. J., Rivera, M. R., Vaughan, K. G., Shah, A., & Shneider, B. L. (2011). Abernethy malformation complicated by hepatopulmonary syndrome and a liver mass successfully treated by a liver transplantation. Pediatric Transplantation, 15(7), E149-E151. Rodriguez-Roisin, R., & Krowka, M. J. (2008). Hepatopulmonary syndrome—a liver induced lung vascular disorder. New England Journal of Medicine, 358(22), 2378-2387.
Witjes, C. D., Ijzermans, J. N., Noodegraaf, A. V., & Tran, T. C. (2012). Management strategy after diagnosis of Abernethy malformation: A case report. Journal of Medical Case Reports, 6(1), 167. Witters, P., Maleux, G., George, C., Delcroix, M., Hoffman, I., Gewillig, M., . Cassiman, D. (2008). Congenital veno-venous malformations of the liver: Widely variable clinical presentations. Journal of Gastroenterology and Hepatology, 22(8 pt 2), E390-E394.
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