History Is the Key to Diagnosis: A Case of Nitrofurantoin-Induced Interstitial Lung Disease.

We present the case of a 74-year-old woman with a past medical history (PMH) significant for anxiety, depression, and hypertension who presented to the pulmonary clinic for consultation regarding progressive shortness of breath, which started five months ago after developing COVID-19. Further history-taking revealed that she had been started on nitrofurantoin two months ago for recurrent urinary tract infections (UTIs). Her pulmonary function tests (PFTs) demonstrated a moderately restrictive disease. A CT chest was obtained, showing pleural thickening with bilateral pleural-based ground glass opacities. Nitrofurantoin was then discontinued, and she was started on a prednisone taper for suspected nitrofurantoin-induced interstitial lung disease (ILD). At a follow-up clinic visit six months later, she showed great improvement in her shortness of breath, marked improvement in forced vital capacity (FVC) on PFTs, and near resolution of pleural-based lesions and basal ground glass opacities on CT chest. This case emphasizes the importance of keeping the diagnosis of nitrofurantoin-induced ILD in mind, as well as the need to implement guidelines for the monitoring of this potential pulmonary adverse effect.

Secondary Spontaneous Pneumothorax in a Patient With Interstitial Lung Disease Undergoing Routine Outpatient Pulmonary Function Tests.

We present the case of a 64-year-old female with a past medical history significant for unclassified interstitial lung disease (ILD) from suspected hypersensitivity pneumonitis secondary to chronic mold exposure with steroid responsiveness and prior pneumothorax. The patient developed shortness of breath and pleuritic chest pain after undergoing routine outpatient pulmonary function tests (PFTs). She was immediately transferred to the emergency department and found to have a moderate left basilar pneumothorax. She underwent emergent surgical chest tube placement followed by doxycycline pleurodesis. Repeat chest imaging showed inadvertent retraction of the chest tube and extensive subcutaneous emphysema. The surgical chest tube was replaced by a pigtail catheter with an improvement of subcutaneous emphysema. This case demonstrates the development of a rare but serious complication of pneumothorax that could occur in patients who have ILD undergoing routine PFTs. Clinicians should be aware of this risk when patients who have ILD present for PFTs and counsel them to seek immediate medical attention if they develop signs of acute onset dyspnea after performing PFTs.