Congenital right hemidiaphragmatic agenesis.

Congenital diaphragmatic hernia is a congenital defect of the diaphragm through which intestine and other viscera herniate into the chest. In extreme form of diaphragmatic maldevelopment, there might be a complete agenesis of diaphragm. A 45-day old male infant was presented with fever, cough and respiratory distress for a week. Chest radiograph showed right-sided congenital diaphragmatic hernia. The patient underwent surgical exploration and found to have an unusual and large defect of right hemidiaphragm. The diaphragm was absent on anterior and lateral aspects of the chest wall and only a small rim of diaphragm was present on posterior aspect. The defect was identified as agenesis of right hemidiaphragm and successfully managed by suturing the posterior rim of diaphragm to the intercostal muscles and ribs. This report describes successful management of hemidiaphragmatic agenesis without incorporating a prosthetic material.

INTRODUCTION

Congenital diaphragmatic hernia (CDH) is a congenital malformation of diaphragm, characterized by a defect in the diaphragm along with herniation of gastro-intestinal loops and other abdominal viscera into the thoracic cavity. In case of extreme maldevelopment of diaphragm, there might be a complete agenesis of diaphragm, usually involving one side, but, sometimes both sides.[12]

To repair a defect like that is a management dilemma. Various techniques have been put forward for repairing such defects including use of prosthetic material, abdominal or intercostals muscle flaps and so on. The prosthetic incorporation has its own advantages and drawbacks. We are reporting the index case on the basis of extreme rarity of the congenital hemidiaphragmatic agenesis (CHDA) and its successful repair without the need of a prosthetic material.

CASE REPORT

A 45-day old male infant was referred to the surgical emergency of our institution with complaints of fever, cough and respiratory distress for 1 week. The baby was born to a primigravida 22-year old mother in a village setting, as spontaneous vaginal delivery. The baby was alright for more than a month when he developed respiratory distress associated with fever and few episodes of non-bilious and non-projectile emesis. The parents took the baby to local hospital where the baby was given steam nebulization and intra-muscular antibiotics along with oxygen therapy. The baby did not improve, and was thus referred to our hospital.

During the admission, the weight of the baby was 3.2 kg and a general physical examination revealed mild pyrexia (100F) and tachypnea (respiratory rate >50/min). Pulse was 120/min and blood pressure within normal age range. On respiratory system examination there were overt signs of respiratory distress including nasal flaring, intercostal and subcostal retractions and tachypnea. On auscultation the air entry was absent on lower right chest and reduced on the upper right chest. Air entry was normal on left chest auscultation. Abdomen was soft and not much scaphoid. A chest radiograph was requested that revealed intestinal gas shadows in the right hemi-thorax. A diagnosis of right-sided CDH was made and patient optimized for elective surgical intervention.

His preoperative laboratory parameters were normal except for the WBC count which was in upper normal limits. Patient was started on parenteral antibiotics, nebulization and chest physiotherapy. The fever was settled in two days and an elective operation was planned on the 10th day of admission. Parents were counseled about the surgical procedure and its postoperative complications. Patient was operated by a right subcostal incision. The entire liver and most of small and large intestine were found herniating into the right hemi-thorax. The contents were reduced back to the abdominal cavity. The diaphragm was absent on anterior and lateral aspects of the right hemi-thorax and only a small rim of diaphragm was present on posterior aspects [Figure 1].

Figure 1

Operative view of the right hemidiaphragmatic agenesis. The diaphragm was absent on anterior and lateral aspects whereas a small rim of diaphragm can be appreciated posteriorly and lifted up by taking stay sutures

The lung was looking hypoplastic. There was no hernial sac found during the operation. The part of diaphragm present on posterior aspects was mobilized and sutured to the intercostal muscles (an incision was given on inferior aspects of the intercostal space to get some mobilization) and ribs using interrupted stitches of silk 0 sutures [Figure 2]. The abdominal wound was closed by only skin closure, as we were not able to oppose the abdominal wall muscles.

Figure 2

Diaphragmatic defect was repaired by apposing the residual diaphragm with the intercostal muscles and ribs using a “0” silk suture

The postoperative recovery was uneventful. We were anticipating a need of ventilator assistance but the patient did not require mechanical ventilation postoperatively. The nasogastric tube was removed on the fourth postoperative day; and started orally on the next day and discharged on the ninth postoperative day. Patient has a symptom-free follow up of three months and we advised a definitive closure of the ventral hernia after one year of age.

DISCUSSION

Classical CDH is characterized by a left-sided postero-lateral defect in the diaphragm, and named after Bochdalek who was the first to identify the defect in 1848. The right-sided Bochdalek's CDH are very rare and reported to be 8–15%. Left-sided CDH has better prognosis as compared to right-sided CDH.[1]

CHDA is considered as one of the rare congenital malformations of diaphragm and reported to be in 6% of all CDH. Unilateral diaphragmatic agenesis is common on left side as compared to the right side.[2-4] However, in our case the hemidiaphragmatic agenesis was on right side showing rare side of occurrence of a very rare lesion. Some cases of bilateral CHDA have been reported with extremely high mortality. The etiology of CHDA is largely based on assumptions and speculation, and not well defined to date. A failure of pleuroperitoneal membrane to close the pleuroperitoneal canal on the involved side is considered the probable etiology; however, others proposed a failure of all the precursors components of diaphragm to develop. Environmental factors and various drugs have been proposed to play a key role in development of the CDH in animal modules.[2-4]

The classical presentation of CDH is within first 24 hours of life with clinical features dependent upon the severity of pulmonary hypoplasia and pulmonary hypertension. More severe the lung hypoplasia and pulmonary hypertension, early will be the presentation and worse will be the outcome, and vice versa. The clinical features are usually respiratory distress, cyanosis and vomiting. About 10% of patients with mild to modest lung hypoplasia and pulmonary hypertension may escape the early presentation, as happened in our case.[1] In our case the patient escaped the early newborn-period-presentation, thus, reflecting a less severe grade of pulmonary hypoplasia and pulmonary hypertension. The patients with CDH may present in infantile age or thereafter; nascent presentation of CDH in adults and even senile persons have frequently been reported in literature. The presentation of CHDA is somewhat similar to the CDH and is considered, by many authors, as an extreme variety of Bochdalek CDH. Similarly as for CDH, CHDA may also appear in adults but the overall incidence is very low.[1-4]

Chest radiograph cannot specifically diagnose the CHDA but is a modality of choice in case of CDH. CT scan and MRI are important diagnostic modalities for the delineation of the diaphragm and its abnormalities.[2-3] In our case our diagnosis of CDH was straight-forward as depicted by the chest radiograph, thus, precluding us to opt for the sophisticated diagnostic modalities.

The configuration of the defect, in a case of a Bochdalek's CDH, is a well-defined anterior part of diaphragm followed by a postero-lateral defect through which gastro-intestinal loops and other viscera herniated into the thoracic cavity, and a retroperitoneal-buried posterior rim of diaphragm on the affected side.[1] In our case the defect was absent on anterior and lateral sides of right chest cavity and a small rim of diaphragm was present posteriorly. CHDA may be differentiated into partial and complete agenesis with regard to the defect. In case of partial diaphragmatic agenesis a small rim of diaphragm may be present especially on posterior aspects, whereas, in case of complete hemidiaphragmatic agenesis, no diaphragmatic remnant is present.[125] The findings of remnant of diaphragm on posterior aspect led us to place our case in partial variety of CHDA.

The surgical repair of the lesion is very difficult owing to completely absent diaphragmatic tissue or if present not suffice to accomplish the repair. Various authors used different treatment options including, prosthesis, abdominal wall and chest wall muscle flaps, suturing the chest margins with liver, use of pre-renal fascia and some advocated no repair at all. About 30–50% of cases with CDH, treated with mesh incorporation in the defect, showed prosthesis related complications and even recurrence of the herniation.[124-5] In our case, we had a small rim of diaphragm that became sufficient after mobilization from retroperitoneum; and suturing it with the intercostal muscles (an incision was given on the inferior aspect of intercostal space to get mobilization of intercostal muscles) and ribs served the purpose well. After reduction of entire liver and most of small and large intestine from the chest cavity to the abdominal cavity, it was not possible to close the surgical wound primarily. There was a risk of abdominal compartment syndrome if a repair would have been done under tension. Thus, only skin closure was performed that did well in our patient.

It is inferred that congenital right hemidiaphragmatic agenesis is a rare malformation of the diaphragm. It may remain asymptomatic for decades; however, in case of symptomatic presentation, an early surgical intervention may prove boon for the patient. Partial variety of CHDA can be repaired by mobilizing and suturing diaphragmatic remnant with intercostal muscles and ribs.