Meconium Peritonitis Presenting with Nonimmune Hydrops and Mirror Syndrome.

Meconium peritonitis (MP) presenting as hydrops is a rare entity. A 34-week hydropic infant was born to mother diagnosed with a case of nonimmune hydrops. Postnatally, the neonate was diagnosed as a case of MP based on clinical examination and investigations. The neonate underwent exploratory laparotomy which revealed diffuse MP with ileal perforation. She underwent resection of ileal perforation with ileocolic anastomosis. The index case highlights the importance of thorough clinical examination and abdominal X-ray in the diagnosis of MP. Copyright:

INTRODUCTION

The incidence of meconium peritonitis (MP) is one in 30,000 births.[1] In about 5% of cases, it is associated with hydrops.[2] Unlike other causes of nonimmune hydrops which may require fetal echocardiography and invasive testing for diagnosis, MP can be easily diagnosed with antenatal ultrasound (USG) and postnatal X-ray. Timely surgical intervention results in a favorable outcome in cases with MP. We hereby describe a preterm neonate who presented with nonimmune hydrops antenatally and was diagnosed with MP postnatally and was successfully managed with mechanical ventilation, total parenteral nutrition, and surgical intervention.

CASE REPORT

The index case was born at 34 + 2 weeks gestation to a 22-year primigravida without any history of consanguinity. She was diagnosed with hydrops and gestational hypertension outside and referred to our facility at 31 weeks of gestation. Ultrasonography done in our facility revealed single live intrauterine fetus with amniotic fluid index of 32.1 cm suggestive of polyhydramnios. Features of hydrops in form of fetal ascites and subcutaneous scalp edema were present. Her hemoglobin was 8.4 g/dl, aspartate transaminase was 102U/L, alanine transaminase was 37U/L, serum albumin was 1.9 g/dl, and serum uric acid was 6.4 mg/dl. Blood pressure at admission was 146/87 mmHg and urine microscopy showed proteinuria with 1+ positivity on the dipstick. Possibility of mirror syndrome (MS) was kept. Antenatal investigations as part of hydrops workup (MCA peak systolic velocity, TORCH profile, parvovirus serology, high-performance liquid chromatography, and fetal echocardiography) were normal. As fetal monitoring tests were reassuring and her blood pressure was stable, she was planned for weekly follow-up. She presented at 34 weeks with established preterm labor. For fetal bradycardia, baby was delivered by emergency cesarean section. Baby had moderate birth asphyxia (1 min and 5 min Apgar score was 2 and 4, respectively) and required resuscitation, administration of early rescue surfactant and mechanical ventilation for 24 h. On clinical examination at admission, baby had gross ascites without any dysmorphic features or limb anomalies. Investigations showed baby's blood group to be B +ve and there were no features suggestive of hemolysis in peripheral smear. The admission renal function test, liver function test parameters were within the normal limits. Chest X-ray was not suggestive of pleural or pericardial effusion. Abdominal X-ray showed a distended fluid-filled abdomen with small bowel localized to the central abdomen. Diffuse coarse calcifications were seen bilaterally in the upper abdomen, more appreciated on the right side [Figure 1]. Paracentesis revealed hemorrhagic fluid. The possibility of MP was kept. Noncontrast computed tomography (CT) abdomen showed calcifications both in the abdominal wall and in the peritoneum. There was no evidence of bowel obstruction [Figure 2]. Cystic fibrosis being one of the causes of MP, CFTR gene mutation analysis for delta F 508 as well as intron 19 was sent which turned out to be negative. Baby was kept nil per oral and total parenteral nutrition was initiated. Exploratory laparotomy was done on day 7 of life. Peroperative findings showed hemorrhagic fluid with small bowel enclosed in a thin flimsy sac. Meconium calcifications were present in the inter-bowel region, liver surface, paracolic gutter, and a small perforation was seen in ileum on antimesenteric side, 2 cm proximal to ileocecal junction [Figure 3]. Small bowel adhesiolysis was done with resection of distal 2.5 cm ileum, cecum, and appendix followed by ileocolic anastomosis. No intussusception or atretic segment was found on examination. Oral feeds were started on a postoperative day (POD) 5 and baby was on full feeds by POD 8. Since the mother was found to have ascites in the immediate postoperative period, she was investigated accordingly. USG and CT abdomen showed features of chronic liver disease with borderline splenomegaly with esophageal varices on endoscopy. At the time of discharge, her ascites had resolved.

Figure 1

Abdominal X-ray

Figure 2

Contrast computed tomography

Figure 3

Peroperative finding

Baby was discharged on day 19 of life. On follow-up at 3-months baby was on exclusive breastfeeding with normal weight gain and neurodevelopment.

DISCUSSION

MP is a sterile chemical peritonitis due to small bowel perforation in utero secondary to vascular accident, intussusception, intestinal atresia, meconium ileus, congenital bands, or unknown causes. Leakage of meconium in the peritoneal cavity results in an intense inflammatory reaction with the accumulation of peritoneal macrophages and secretion of cytokines like tumor necrosis factor-alpha.[3] These exudates can completely seal off the perforation or form a large cyst if the perforation is not sealed. Index case had the fibro-adhesive type with dense intestinal adhesions. Calcifications, the pathognomonic feature of MP occur as a result of the precipitation of calcium salts by intestinal enzymes with the fatty meconium compounds. Diagnosis is usually made after 20 weeks when peristalsis appears leading to extrusion of meconium into the peritoneal cavity. Cystic fibrosis with meconium ileus accounts for 25%–40% cases of MP.[4] Calcifications are rarely seen in cystic fibrosis due to the lack of pancreatic enzymes. In the index case, mutational analysis for commonly prevalent cystic fibrosis gene was negative.

Antenatal USG an important diagnostic tool in hydrops is used to look for structural anomalies. The presence of anemia points toward hematological disorders such as thalassemia, TORCH, or parvovirus infection. Findings such as ascites, calcifications, dilated bowel loops, and the presence of pseudocysts provide clues for the diagnosis of MP. In a study by Wang et al., fetal ascites was the most common finding followed by intra-abdominal calcification.[5] Postnatal diagnosis is made radiographically by the presence of calcifications. Other causes of intra-abdominal calcifications-hepatic calcification, tumors such as hemangioma, neuroblastoma, teratomas, and intrauterine infections such as cytomegalovirus were ruled out by clinical and radiological findings. Imaging studies such as CT can detect associated anomalies such as stenosis, congenital bands.

Mechanisms of hydrops in MP are not well defined. The presence of a giant cyst can lead to venous outflow obstruction or massive ascites can cause circulatory failure causing hydrops.[4] Studies have shown increased inflammatory markers such as C-reactive protein and CA-125 in cord blood and hypoalbuminemia as contributory factors in disease pathogenesis.

Treatment of MP can be conservative or surgical. Antenatal USG findings such as the presence of pseudocysts, dilated bowel loops, ascites, and polyhydramnios are important determinants of surgery. Some of the cases with isolated calcifications can be managed conservatively. The risk of surgery increases with increase in the number of associated findings.[6] Prognosis in nonimmune hydrops depends on underlying etiology and age of onset of hydrops, earlier the diagnosis poorer is than the outcome. Cases with chylothorax and MP have the best survival rates of 92%–100% as compared to 41% in cases diagnosed with cystic hygroma or cardiogenic anomalies.[7]

MS is defined as the development of maternal edema in association with fetal hydrops. Our index case had edema, hypertension, proteinuria, and anemia as presenting features. Preeclampsia commonly presents with hemoconcentration, a feature used to distinguish from MS which presents with hemodilution.[8] Hyperuricemia present in 25% of MS cases was also present in our case. Although the mother was coincidentally found to have features of liver disease on investigations, disappearance of edema and proteinuria a few days after delivery with a normal liver function test favors the diagnosis of MS in the index case.

Thus, antenatally if ascites is the predominant manifestation, other findings suggestive of MP such as dilated bowel loops or calcifications should be looked for and treated promptly as it results in a good outcome.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.