Sequential pulmonary functions in survivors of leptospirosis pulmonary haemorrhage syndrome: a prospective cohort study

Abstract

Background: Leptospirosis, a spirochaete infection, can lead to Leptospirosis Pulmonary Haemorrhage Syndrome (LPHS), which requires intensive care admission and has a high mortality. Although data on short-term outcomes are available, the long-term respiratory sequelae of LPHS survivors are not known. We aimed to identify the post-discharge pulmonary functions and functional limitations in survivors of LPHS.

Methods: We conducted a prospective cohort study from January to December 2022 at the Medical Intensive Care Unit (ICU) of the National Hospital of Sri Lanka to assess the sequential changes in the spirometry parameters in patients who survived LPHS. The Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1 s (FEV1) were measured on the day of discharge from the ICU (D0), 7th day after discharge (D7) and 28th day after discharge (D28). The predicted lung volume was calculated using the gender, age and height as per standard protocol. Physical and functional role limitations were assessed on D28 using the modified Medical Outcomes Study Questionnaire Short Form 36 Health Survey (SF-36).

Results: Twenty-one patients with a mean age of 44 years (SD 16.07) were enrolled for the study. The majority were male patients (n = 19, 90.5%). Leptospirosis was serologically confirmed in all individuals. Seventeen (81%) patients had reduced FEV1 and FVC on D0, indicating a restrictive lung abnormality. FVC and FEV1 improved during the first 7 days (p < 0.01) but did not change significantly afterwards. Only seven individuals (33.3%) achieved a normal FVC (exceeding 80% of the predicted volume) at D28. However, 19 (90.5%) individuals achieved a normal FEV1 (exceeding 80% of predicted volume) by D28. In our study, administering corticosteroids during ICU stay did not impact lung recovery in FVC (p = 0.521) or FEV1 (p = 0.798). The participants did not have significant physical, functional, and role limitations at D28.

Conclusions: The spirometry measurements of individuals diagnosed with LPHS significantly improved during the first 7 days. Most survivors did not have a functional impairment despite the FVC not recovering to normal by D28.

Keywords: FEV1; FVC; Leptospirosis; Lung function; Pulmonary haemorrhage.

Fig. 1

Sequential changes in spirometry parameters in the study population. Pulmonary function was assessed in survivors of leptospirosis pulmonary haemorrhage syndrome on discharge from the ICU (D0), on the 7th day (D7) and 28th day from discharge (D28). The figure demonstrates forced vital capacity (FVC), forced expiratory volume in the 1st second (FEV1), and FEV1/FVC ratio in each patient as a percentage of the predicted value. The horizontal red line indicates 80% and 70% are the lower cut off of the normal range for FVC, FEV1 and FEV1/FVC ratio, respectively

Fig. 2

Sequential changes of pulmonary function in patients grouped according to treatment with steroids (A–C) and invasive ventilation (D, E). (A & D) FVC, (B & E) FEV1 and (C & F) FEV1/FVC ratio are given as a percentage of the predicted value for age, sex and height. D0; day of discharge from the ICU; D7; 7th day after discharge; D28; 28th day after discharge. Methyl-prednisolone was given intravenously with a dose ranging from 0.5 g to 1g per day for 1–3 days