Airway obstruction by round worm in mechanically ventilated patient: An unusual cause.

Sir,

Respiratory obstruction is a life threatening condition which requires immediate diagnosis and treatment. We have reported an unusual case of airway obstruction in a mechanically ventilated patient in intensive care unit (ICU).

A 28-year-old male, a trauma victim, was presented in the emergency room with signs of respiratory distress. He was conscious and oriented. As per our hospital protocol, a rapid screening was done to find out the extent of injuries by doing computed tomography (CT) head, cervical spine, thorax and abdomen. He was diagnosed to have compressed fracture of dorsal vertebrae (D1-D2), fracture shaft of right femur and fracture of right tibia and fibula. The cause of respiratory distress was found to be multiple rib fractures with flail segment of chest and pneumothorax. The component of head injury and cervical spine injury was excluded. Patient was haemodynamically stable. Other investigations were within the normal range. Bilateral chest tube insertion was done for pneumothorax. Skeletal traction was applied to immobilise the fractured shaft of femur. Due to ongoing difficulty in breathing, patient was electively intubated in the emergency room and shifted to ICU for further management. He was put on pressure support ventilation (10 cm H2O). He was also started on deep vein thrombosis (DVT) prophylaxis regimen. Analgesia was supplemented with morphine 3 mg intravenously. On the second day of ICU stay, he suddenly became restless and started desaturating. Immediately, bilateral air entry was checked, fraction of inspired oxygen (FiO2) was increased to 100% and the position of tube was confirmed under direct laryngoscopy under sedation (inj. midazolam 4 mg, fentanyl 150 μg). The endotracheal tube (ETT) was found to be correctly placed in trachea. The patency of tube was checked by doing thorough ET suction and no obstruction or tube block was found. Since, it was a case of polytrauma with multiple fractures; we had sent the blood samples for D-dimmer estimation to exclude the diagnosis of pulmonary fat embolism. On further examination, it was noticed that the movement of chest wall is asymmetrical and right sided chest movement was less as compared to left side. Again a wide bore suction catheter was inserted into the ETT suspecting some obstruction. As the suction catheter was removed from the ETT, a 15 cm long Ascaris lumbricoides was suctioned out [Figure 1]. As soon as the round worm was removed from the right bronchus, expansion of chest became symmetrical, saturation improved and patient settled down. To rule out presence of more round worms, fibreoptic bronchoscopic (FOB) examination was done and no round worms were found. He was put on anti-helminthic treatment. He was operated for fractured shaft of femur and fracture of tibia and fibula and conservatively managed for fracture of D1-D2 vertebrae. Rest of the course in the hospital was uneventful.

Figure 1

Round worm (15 cm) suctioned from ETT

Ascariasis is the most common helminthic infection with an estimated worldwide prevalence of 26%. In the literature, very few cases of significant airway obstruction have been reported mainly after extubation.[1-4] Only one case of respiratory obstruction was reported in intubated (non cuffed endotracheal tube) paediatric patient who was a known case of ascariasis.[1] Other cases of respiratory obstruction due to round worms were reported in non intubated patients.[2-4] However, in this case, it was not known that the patient has ascariasis infection. In addition, the mode of entry was also different from the previously reported cases. In previously reported case, worm was pushed from nasopharyngeal cavity into the larynx during intubation and patient was on an uncuffed endotracheal tube when this incident occurred.[1] On the other hand, the migration of round worm is due to aspiration during coughing or vomiting in awake non intubated patients.[2-4] In this case, the roundworm migrated from oesophagus to glottis and entered into trachea by moving through the loosely fitted endotracheal cuff over the tracheal wall and partially blocked the distal end of the tube. In conclusion, as the prevalence of ascariasis is very high in developing countries, sudden airway obstruction may occur due to round worm even in intubated patients and deworming of patients may prevent this rare but life threatening condition.