A 58-Year-Old Woman With An Unusual Cause Of Respiratory Failure

摘要

A 58-year-old woman presented to the emergency department (ED) after she was found unresponsive for an unknown period of time. Upon paramedics’ arrival she had a respiratory rate of 4 breaths/min, an O2 saturation of 71% and a Glasgow Coma Score of 3. Her home medications included ibuprofen, fentanyl and lorazepam. The patient’s mental status deteriorated and she ultimately required intubation and mechanical ventilation. She was managed in the intensive care unit (ICU) for what appeared to be a drug overdose and on the following day, after successful extubation, was transferred to the medicine wards. We report an unexpected twist in the pathogenesis of this case. Case Report A 58-year-old woman presented to the emergency department (ED) after she was found unresponsive for an unknown period of time. Upon paramedics’ arrival she had a respiratory rate of 4 breaths/min, an O2 saturation of 71% and a Glasgow Coma Score of 3. The paramedics administered 0.8 mg of intravenous naloxone while transporting her to the hospital in addition to supplemental oxygen via a non-rebreather mask. Her mental status and respiratory rate slightly improved. Upon admission to the ED her mental status made it difficult to obtain a thorough history. She denied any shortness of breath or any other recent generalized symptoms, but she admitted to ingesting an unknown quantity of diphenhydramine. She recently required casting for a broken right wrist and was wearing several 75 mcg/hr fentanyl patches, which were removed in the ED. She eventually admitted to ingesting 8 tablets of diazepam, dosage unknown. Her past medical history was significant for alcoholism, bipolar disorder, tobacco abuse and intravenous drug abuse. Her home medications included ibuprofen, fentanyl and lorazepam. The patient’s mental status deteriorated and she ultimately required intubation and mechanical ventilation. She was managed in the intensive care unit (ICU) for what appeared to be a drug overdose and on the following day, after successful extubation, was transferred to the medicine wards. Physical Examination On admission to the ICU, her vital signs revealed sinus tachycardia at 100 beats/min and her blood pressure was 153/91 mmHg. She was intubated and sedated with a set respiratory rate of 20 breaths/min and an oxygen saturation of 100 percent while receiving an FiO2 of 50%. Her pulmonary, cardiac, abdominal and extremity exams were unremarkable other than the cast on her right arm. Laboratory Findings Initial complete blood count and differential showed no signs of infection. Her blood chemistry was otherwise normal. Urine toxicology was negative for opiates but positive for methadone. Lab tests showed no evidence of salicylate or acetaminophen ingestion. An initial chest x-ray showed no signs of acute cardiopulmonary abnormality. Due to mental status changes, a computed tomography scan of the head was obtained and showed no acute pathology. Three days into her hospital course the patient developed a leukocytosis of 12,800 cells per cubic millimeter along with a cough, tachypnea and generalized weakness. Her left lung developed diminished breath sounds with dullness to percussion appreciated throughout her left hemithorax. A subsequent chest x-ray revealed opacification of the entire left lung (figure 1), while the right lung appeared normal. She was started on piperacillin - tazobactam and levofloxacin for empiric coverage of a presumed hospital acquired pneumonia. The decision was then made to proceed with bronchoscopy.