Delayed onset of right congenital diaphragmatic hernia associated with Group B streptococcal sepsis in a neonate.

A full-term male neonate was initially managed for respiratory distress which developed few hours after birth. His initial chest radiograph was normal, and blood culture revealed Group B streptococcal (GBS) sepsis. He subsequently developed progressive right chest opacification that did not improve with medical management. Imaging done few days later revealed right-sided diaphragmatic hernia. The 12-day-old neonate underwent primary repair of the diaphragmatic defect and had an uneventful recovery. This case report intends to highlight this unique association between early onset GBS sepsis and delayed onset of the right congenital diaphragmatic hernia.

INTRODUCTION

A right-sided congenital diaphragmatic hernia (CDH) may occasionally have a delayed clinical presentation. The initial symptoms may mimic pneumonia or pleural effusion to confuse and delay the diagnosis. Such a unique association can happen between early onset Group B streptococcal (GBS) sepsis and delayed onset of right CDH. Around forty cases have been described till date in the published English literature.[123] This case report describes a neonate with the similar association and makes us aware of necessary precautions and radiological features.

CASE REPORT

A full-term male neonate with a birth weight of 2.8 kg, and born by spontaneous vaginal delivery, developed respiratory distress around 5 h after birth. There was a maternal history of intrauterine fetal death at 32 weeks during the previous pregnancy due to unknown causes. The initial chest radiograph did not reveal any right-sided diaphragmatic hernia but radiograph done on day 3 of life demonstrated right sided pneumonia [Figure 1]. The sepsis workup revealed a white blood cell count of 3400/cubic mm with severe neutropenia (12%), normal C-reactive protein, and a blood culture was sent. The baby was managed with empirical intravenous antibiotics and oxygen by nasal prongs. Because of progressive respiratory symptoms, the baby was administered pulmonary surfactant on day 3 of life and was subsequently maintained on nasal continuous positive airway pressure until day 5 of life and then on oxygen by nasal prongs. In the meanwhile, the blood culture came back positive for Group B streptococci and penicillin G was initiated. Because of persistent symptoms, computed tomogram was done which revealed right-sided diaphragmatic hernia [Figure 2]. A preoperative echocardiogram revealed an ostium secundum atrial septal defect. At surgery done through a right subcostal incision on day 12 of life, the baby was found to have a 6 by 4 cm smooth edged posteromedial diaphragmatic defect through which the right lobe of the liver along with large and small bowel loops had herniated into the right hemithorax. There was the presence of a moderate amount of straw-colored fluid in the right chest cavity, and the right lung was expanding well. The baby underwent a primary repair of the right diaphragmatic hernia and had an uneventful recovery. The baby was asymptomatic during his outpatient clinic visit at the age of 2 months.

Figure 1

Chest radiograph done 3 days after birth demonstrating right sided pneumonia

Figure 2

Coronal image of computed tomography scan demonstrating right-sided diaphragmatic hernia

DISCUSSION

Right sided defects account for around 20% of all CDHs. A delayed clinical presentation may be seen in 5-30% of the right CDH cases. Late onset right CDH can present itself in a variety of ways such as respiratory distress, intestinal obstruction, jaundice, or failure to thrive. The problem is compounded when respiratory distress occurs in a baby with CDH and GBS sepsis. These patients will have clinical and radiological features that are similar to GBS pulmonary inflammatory conditions. The chest radiograph may be incorrectly interpreted as right sided pneumonia, pleural effusion, or even pneumothorax.[4]

This case report intends to highlight the unexplained and unusual association between early onset Group B streptococci and delayed onset of right CDH. This association is usually seen in full-term male neonates who are initially managed for early-onset GBS disease. There is usually no evidence of right diaphragmatic hernia in the initial chest radiographs. Around 88.6% of these neonates receive mechanical ventilation with some initial improvement. As the infection clears and the neonate is weaned from the ventilator, there develops respiratory deterioration due to the occurrence of a diaphragmatic hernia. However, an overall survival rate of 89.5% in these neonates after diaphragmatic hernia repair gives it an excellent prognosis.[3]

Though this association was initially reported around four decades ago, its exact pathophysiology is still not clear. It has been proposed that decreased mobility of the involved right diaphragm predisposes the neonatal lung to infection. This subsequently results in pneumonia by GBS, which is one of the most common causes of neonatal pneumonia.[3] It has been previously described that neutrophils stimulated by GBS cause lipid peroxidation and functional impairment of lung surfactant resulting in significantly lowered lung compliance.[5] This coupled with increased intra-thoracic pressure due to mechanical ventilation results in an inflamed lung that acts such as a splint on the diaphragmatic defect, thus delaying liver and bowel herniation. More than half of these patients have right sided pleural effusion. This is more significant than those seen in isolated GBS pneumonia. This is thought to be due to hepatic venous outflow obstruction resulting in vascular congestion and a transudate exiting through the liver surface.[36] If the liver is the only herniated organ, then there will be no intestinal gas shadow in the right chest to give a clue to the underlying pathology. The pediatric surgeon may be erroneously consulted for chest tube drainage for an apparent pleural effusion that may actually be a right CDH with the liver being the reason for the clinical percussion dullness or radiographic opacification. The only clues in such a situation may be deviation of the esophageal portion of the nasogastric tube to the left side along with the vertical orientation of the intra-abdominal portion of the nasogastric tube, both of which were seen in the current patient.[78] These subtle radiological features along with the typical clinical scenario should serve as a caution against any accidental chest tube insertion into the neonate's liver.[6]

CONCLUSION

Whenever a neonate with right sided GBS pneumonia or pleural effusion transiently recovers after early onset GBS sepsis only to deteriorate later on should be strongly considered to have a delayed onset of the right CDH.

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Conflicts of interest

There are no conflicts of interest.