Answer

Acute Respiratory Distress Syndrome

Introduction

Acute respiratory distress syndrome (ARDS) is an acute inflammatory lung injury defined by fluid buildup in the lungs causing respiratory difficulty (Fan, Brodie, & Slutsky, 2018). The majority of affected patients require intubation for respiratory failure, with low tidal volume ventilation and dry lung strategy as established by the ARDSnet protocol (Chalkias et al., 2018). To successfully wean patients off ventilation, they need to demonstrate improved lung function on spontaneous breathing trials (SBTs) without developing tachypnea, hypoxia or tachycardia. Other factors to be considered include the ability to protect one’s airway and mental status (Chalkias et al., 2018). In this case, a 79-year-old male is presented who was admitted with ARDS and was unable to be weaned off the ventilator and was found to have developed Guillain Barre Syndrome (GBS).

Case Presentation

A 79-year-old male with rheumatoid arthritis and bronchiectasis was presented with progressive dyspnea after failing outpatient treatment for pneumonia. He was hypotensive, tachycardia and hypoxic on admission. Chest X-ray showed bibasilar consolidations. Despite sepsis protocol, he was hypotensive requiring vasopressor support (Laurikkala et al., 2018). Broad spectrum antibiotics with atypical coverage for pneumonia were started and he was intubated for airway protection. He was placed in a RotoProne bed and cycled between prone and supine positioning on low tidal volume ventilation strategy. In the interim, serum Mycoplasma pneumoniaeIgG resulted positive. Pronation was stopped on ICU day 4. Sedation was weaned off and ventilation settings were optimized in anticipation of SBT. On ICU day 9, he developed atrial fibrillation with rapid ventricular response but converted back to normal sinus rhythm with Diltiazem. His alertness improved but physical exam revealed decreased spontaneous movements of his extremities and areflexia prompting neurological evaluation. GBS in the setting of mycoplasma infection was suspected. Treatment was initiated with intravenous immunoglobulin (IVIG). He had marked recovery on strength exam and was eventually discharged to a long term acute care facility with tracheostomy.

Discussion

ARDS management is aimed at correcting inflammatory mechanisms and initiating ventilator support in a timely manner (Howell & Davis, 2018). Despite passing the SBTs our patient was unable to be weaned from ventilation. Discussion shifted toward critical illness myopathy given weakness and areflexia on exam (Obreja, Sequeira, & Girnita, 2018). But with positive Mycoplasma  pneumoniae immunoglobulin G, GBS was suspected. GBS is a post infectious immune-mediated demyelinating disease. M. pneumoniae infection is associated with GBS (Bajantri, Venkatram, & Diaz-Fuentes, 2018). Diagnosis was supported after improvement with IVIG. Furthermore, new onset atrial fibrillation was consistent with autonomic dysfunction also commonly seen in GBS (Yoshino et al., 2019).

Conclusion

In patients with ARDS requiring mechanical ventilation who are difficult to wean off ventilation, GBS must be considered as a differential diagnosis despite appropriate antibiotic coverage for mycoplasma infection.