Bronchogenic cyst in a child presenting with chronic cough and wheezing: a case report

¹Pediatric Intensive Care Unit, Muhimbili National Hospital, Dar es Salaam, Tanzania, ²Department of Radiology and Diagnostic Imaging, Muhimbili National Hospital, Dar es Salaam, Tanzania, ³Department of Surgery, Muhimbili National Hospital, Dar es Salaam, Tanzania

^&Corresponding author
Evance Godfrey, Pediatric Intensive Care Unit, Muhimbili National Hospital, Dar es Salaam, Tanzania

Introduction    

Respiratory symptoms are common pediatric problems encountered by physicians. They can vary from cough, and wheezing to severe symptoms like labored breathing with cynosis. Wheezing in children is one of the most common symptoms before six years of age, can be due to asthma, allergies, infections especially viral or even gastroesophageal reflux disease, and less commonly due to foreign body aspiration, congenital lung anomalies like mediastinal mass and congenital vascular anomalies including double aortic arch [1,2]. Mediastinal mass though rarely can cause recurrent respiratory symptoms and can be life-threatening, a bronchogenic cyst is among congenital malformations of the lung accounting for 10% to 15% of benign mediastinal tumors and 10% to 15% of bronchopulmonary malformation [3-5]. The bronchogenic cyst is a developmental anomaly that occurs during embryogenesis, whereby there is abnormal budding of the ventral diverticulum of the foregut or the tracheobronchial tree. The cyst arises from the mediastinum, pulmonary parenchyma, or less frequently below the diaphragm or on the neck [6,7]. Prevalence of bronchogenic cyst varies from 1 per 42,000 to 1 per 68,000 live births with an incidence of 13% to 15% of congenital cystic lung disease, and 6% of mediastinal mass with male predominance [2,5]. This case report presents a case of a nine-month-old infant who has experienced recurrent coughing and wheezing since four months of age. He was initially diagnosed with recurrent pneumonia with a differential of asthma but did not show any improvement with treatment.

Patient and observation     

Patient information: a 9-month-old African male infant presented with a history of recurrent cough accompanied by difficulty in breathing since 4 months of age, characterized by fast breathing, wheezing, interrupted breastfeeding, and poor weight gain. His birth weight was 3kg, and at nine months he weighed 5kg. No history of fever or seizures. He had multiple outpatient visits and was treated as a case of pneumonia with a differential diagnosis of bronchiolitis or asthma. He was treated with several antibiotics, oral prednisolone, and nebulized with salbutamol with no clinical improvements and the condition kept on recurring. The index is the third born in a family of three children, with no family history of atopy, open TB contact, or prolonged fever.

Clinical findings: upon admission, he was lethargic, malnourished, and in severe respiratory distress. Physical examination revealed perioral cyanosis, tachypnea (respiratory rate of 60 breaths per minute) with oxygen saturation below 85% on room air, audible wheezes, intercostal retraction, on auscultation had bronchial breath sounds with bilateral wheezes with crackles more pronounced on the left lower lobe. Had normal heart sounds and the rest of the systemic examination was normal.

Timeline of the current episode: initial blood gas revealed chronic respiratory acidosis with PH of 7.21, PaCO₂ of 100mmHg, and HCO₃ of 40 mmol/L. He was mechanically ventilated and nebulized with salbutamol with ipratropium bromide and intravenous dexamethasone-treated as a case of status asthmaticus with severe pneumonia. Other blood investigations, including complete blood count and inflammatory markers such as C-reactive protein, were within normal ranges.

Diagnostic assessment: on the 15^th day post-admission, there was no clinical improvement in mechanical ventilation. Serial arterial blood gases (ABG) done each day as shown in Table 1, showed chronic respiratory acidosis with no change despite the treatment given. Hence, chest X-ray was done and revealed a subcarinal density, left lower lobe collapse, and hyperinflated right lung as shown in Figure 1.

Diagnosis: a CT scan of the chest with contrast revealed a large subcarinal cyst compressing both main bronchi, collapse with consolidation in the right upper lobe, left lingula segment, and lower lobe. The hyperinflated right lung was explained by overinflation of the right middle lobe herniating across the midline to the contralateral side along with the shift of cardio mediastinal structures as shown in Figure 2, Figure 3.

Therapeutic intervention: following the imaging results, a complete resection of the solitary bronchogenic cyst was performed by thoracotomy, it contained clear fluid which was sent for histology.

Follow-up and outcome of intervention: post operation he had a persistent air leak and developed a right-sided pneumothorax, on the second day, and a chest tube was inserted. Later he was clinically discharged from the hospital and during follow-up visits has been doing well with improved nutrition status.

Parent perspective: "am happy my baby got cured as he suffered a lot.”

Informed consent: written informed consent for the publication and associated images were obtained from the parents of the child.

Discussion     

A bronchogenic cyst is a rare congenital non-vascular anomaly of the lungs which present as round solitary or rarely multiple cysts not communicating with the tracheal bronchial tree. To the best of our knowledge, no case presentation has ever been published from our region. Due to its rarity, attending pediatricians are least included in the diagnosis. Our patient was treated in several hospitals, including in our hospital as a case of pneumonia with bronchospasm/acute asthma exacerbation. Delays in diagnosis occur due to similar symptoms with other common conditions like bronchiolitis or asthma. Symptoms are due to airway obstruction caused by mass effect, which can occur as early as the neonatal period to as late as adulthood. Diagnosis can be reached after multi-imaging modalities and confirmed with histology. Several case reports have reported delays in reaching the diagnosis, for example, in a case report from the Republic of Congo, an infant was treated twice as bronchiolitis, another case report from the United Kingdom was misdiagnosed as croup and a case report from India initial diagnosis was bronchiolitis [3,4,8].

The first surgical resection of the bronchogenic cyst was performed in 1948 by Maier, histologically it contained a thin wall lined with columnar epithelial cells filled with protein-rich mucoid [6,8]. After surgical resection, our patient developed a right-sided pneumothorax due to an air leak as a postoperative sequela. This is among rare complications but has been reported from 1985 to 2002. Sarper et al. reported of 22 patients operated on at Akdeniz University one developed an air leak and in another study from India from 2001 to 2011 of 14 patients, one developed an air leak [7,9]. So this stresses the importance of putting in a chest tube after the surgery and close monitoring for any clinical deterioration. Other complication that can occur if no surgical excision is performed, includes infection, the rapture of the cyst, pericarditis, and malignant transformation [3,10].

Conclusion     

Bronchiogenic cyst is a rare disease entity, high index of suspicion is important, and imaging modality should be done in a coughing and wheezing infant not responding to medical treatment. Surgical resection of the cyst is recommended and it has minimal morbidity.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Patient management: Aika Shoo, Evance Godfrey, Deogratius Mally, Karim Bembe, Frederick Lyimo, Charles Komba and Namala Mkopi. Manuscript drafting: Evance Godfrey Aika Shoo, Deogratius Mally, Karim Bembe. Manuscript revision: Charles Komba, Aika Shoo, Namala Mkopi and Frederick Lyimo. All authors have read and approved the final version of the manuscript.

Acknowledgement     

The authors acknowledge support from the Muhimbili National Hospital. Furthermore, we thank parents and the child for their participation in this study.

Table and figures     

Table 1: serial arterial blood gases (ABG) result

Figure 1: chest X-ray showing a subcarinal density, left lower lobe collapse, and hyperinflated right lung

Figure 2: chest CT with IV contrast, coronal reformatted showing a subcarinal cystic lesion and collapsed right upper lobe

Figure 3: chest CT IV contrasted axial view showing a subcarinal cystic lesion, collapsed left lower lobe hyperinflated right lower lobe herniating to the contralateral side of the thorax

References