Diffuse alveolar haemorrhage secondary to haemophilus influenzae in a vaping patient

Background

Various mechanisms of lung injury have been connected to diffuse alveolar haemorrhage (DAH). Community-acquired infections are identified in some cases and frequently thought to be the sole aetiology. However, given the rarity of DAH in patients with community-acquired pneumonia, other factors are thought to contribute, such as an immunocompromised state. The infectious aetiologies differ between the immunocompetent and immunocompromised populations, with the latter being prone to a wider spectrum of organisms including fungal and parasitic pathogens. On the other hand, an evolving epidemic concern for acute lung diseases, including DAH, is vaping. We present a case where a patient developed DAH and Haemophilus influenzae pneumonia with no other apparent risk factors except vaping. Linking vaping to DAH is of clinical importance to help educate patients regarding the emerging complications of vaping.

Case presentation

Our patient is a 67-year-old man with a history of undifferentiated lung cancer of the right upper lobe. His only home medication was statin therapy for hyperlipidaemia. He has significant history of vaping for the preceding 10 years (nicotine used 6 mg/mL; 0.6% on daily basis) but has been asymptomatic from a respiratory standpoint. He vaped until the night prior to surgery and underwent elective right upper lobectomy with no surgical complications. On the following day, he developed rapidly progressive shortness of breath associated with haemoptysis. At the time, he was receiving only 5000 mg of heparin subcutaneously three times a day for deep venous thrombosis (DVT) prophylaxis.

Investigations

On physical examination, he was tachypneic with a respiratory rate of 28, but otherwise, his vital signs, including body temperature, were within the normal limits. Oxygen saturation was 90% despite 100% oxygen at a rate of 55 liters per minute (LPM) using high flow nasal cannula. He had reduced air entry bilaterally with biphasic crepitations and wheezing. Examination of other systems was otherwise unremarkable.

Figure 1 shows X-ray of the chest of the patient while being transferred to the intensive care unit. Arterial blood gas analysis showed pH 7.23, PaCO₂ 52 mm Hg, PaO₂ 65 mm Hg and bicarbonate level of 23 meq/dL.

Treatment

Given these findings and worsening clinical picture, he was intubated and placed under mechanical ventilation. Laboratory tests showed within normal range prothrombin time (PT), partial thromboplastin time (PTT) and platelet count at 283×10⁹/L. Haemoglobin was chronically reduced at 120 g/L. Given suspicion of DAH, bronchoscopy was performed after intubation, and airway examination displayed normal anatomy with no blood or blood clots. Serial bronchial lavage (BAL) of the right middle lobe with normal saline showed progressive increase in blood-tinged return, confirming DAH diagnosis. Gram stain of the BAL sample showed few Gram-positive cocci; however, the final culture report showed heavy growth of H. influenzae. Other infections were considered, namely, fungal and TB studies performed on the BAL and did not grow at 4 weeks’ time. Two blood cultures also showed no growth after 5 days. COVID-19 PCR nasal swab was also negative on admission (prior to surgery). No respiratory viral panel (RVP) panel was performed. Given the amount of alveolar haemorrhage radiologically, prophylactic heparin was discontinued. Pulse dose steroids, at 60 mg of methylprednisolone, was administered intravenously every 6 hours to cover for any underlying pulmonary vasculitis. Empirical antibiotics with cefepime were also initiated. Nebulised tranexamic acid at 500 mg three times a day was administered as well. As daily haemoglobin levels were stable at 11–12 g/dL, no blood transfusion was administered. Three days later and based on the results of BAL cultures, antibiotic regimen was changed to ceftriaxone. Clinical improvement was not noticed until the fourth day of intubation, and he was subsequently extubated to high flow nasal cannula.

Outcome and follow-up

Clinical improvement marked with decrease in oxygen requirements and extubation followed a temporal relationship with antibiotic therapy. Images of CT of the chest at the time of symptom onset and 1 week after supportive therapy and antibiotics are demonstrated in figures 2 and 3. It was decided to continue H. influenzae coverage with antibiotics for total of 10 days, and he continued to have reduction in oxygen requirements. Initial 3-days course of methylprednisolone did not seem to be helpful as during that time, his oxygen requirements increased along with worsening serial chest radiographs. He then improved the following week, with gradual decrease in oxygen requirements and subsequently discharged home on 2 L/min 14 days later.