Post COVID Interstitial Lung Abnormalities-Incidence and Management

Purpose of Review

This review aims to summarize the available literature to identify the incidence and risk factors for persistent interstitial lung abnormalities (ILAs) following hospitalization for COVID-19. The current and prospective treatment options are reviewed in an effort to help pulmonary practitioners care for this burgeoning patient population.

Recent Findings

Statistical modeling suggests that 11.7% of all patients hospitalized with COVID-19 have irreversible fibrotic features on long-term follow-up imaging.

Summary

The available evidence suggests that up to 30% of patients have ILAs following COVID-19 hospitalization. The radiographic abnormalities improve or resolve in a majority of these patients. However, estimates suggest that up to one-third of these patients have irreversible fibrotic features. Clinical trials of the impact of anti-fibrotic agents are ongoing. As there continue to be thousands of COVID-19 hospitalizations in the USA each week, the management of post-COVID ILAs will become a common problem for the pulmonary practitioner.

Characteristics of a diagnostic bronchoscopy in hypersensitivity pneumonitis

BACKGROUND

Bronchoalveolar lavage and transbronchial biopsy can increase diagnostic confidence in the diagnosis of hypersensitivity pneumonitis (HP). Improving the yield of bronchoscopy may help to improve diagnostic confidence while decreasing the risk of potential adverse outcomes associated with more invasive procedures such as surgical lung biopsy. The purpose of this study is to identify factors that were associated with a diagnostic BAL or TBBx in HP.

METHODS

We conducted a retrospective cohort study of HP patients at a single center who underwent bronchoscopy during the diagnostic evaluation. Imaging characteristics, clinical characteristics including use of immunosuppressive medications and presence of active antigen exposure at the time of bronchoscopy, and procedural characteristics were collected. Univariable and multivariable analysis was performed.

RESULTS

88 patients were included in the study. 75 patients underwent BAL and 79 patients underwent TBBx. Patients who had an active fibrogenic exposure at the time of bronchoscopy had a higher BAL yield than those who were out of exposure at the time of bronchoscopy. TBBx yield was higher when more than 1 lobe was biopsied, with a trend toward higher yield of TBBx when nonfibrotic lung was biopsied compared to fibrotic lung.

DISCUSSION

Our study suggests characteristics that may improve yield of BAL and TBBx in patients with HP. We suggest that bronchoscopy be performed when patients are in the antigen exposure and that TBBx samples are taken from more than 1 lobe in order to improve diagnostic yield of the procedure.

Defining natural history: assessment of the ability of college students to aid in characterizing clinical progression of Niemann-Pick disease, type C

Niemann-Pick Disease, type C (NPC) is a fatal, neurodegenerative, lysosomal storage disorder. It is a rare disease with broad phenotypic spectrum and variable age of onset. These issues make it difficult to develop a universally accepted clinical outcome measure to assess urgently needed therapies. To this end, clinical investigators have defined emerging, disease severity scales. The average time from initial symptom to diagnosis is approximately 4 years. Further, some patients may not travel to specialized clinical centers even after diagnosis. We were therefore interested in investigating whether appropriately trained, community-based assessment of patient records could assist in defining disease progression using clinical severity scores. In this study we evolved a secure, step wise process to show that pre-existing medical records may be correctly assessed by non-clinical practitioners trained to quantify disease progression. Sixty-four undergraduate students at the University of Notre Dame were expertly trained in clinical disease assessment and recognition of major and minor symptoms of NPC. Seven clinical records, randomly selected from a total of thirty seven used to establish a leading clinical severity scale, were correctly assessed to show expected characteristics of linear disease progression. Student assessment of two new records donated by NPC families to our study also revealed linear progression of disease, but both showed accelerated disease progression, relative to the current severity scale, especially at the later stages. Together, these data suggest that college students may be trained in assessment of patient records, and thus provide insight into the natural history of a disease.

Biochemical changes after a 100 km hill walk

Biochemical changes after a 100 km hill walk were studied in 16 subjects (nine male and seven female). Plasma concentrations of potassium, albumin and total protein were lower, and the concentrations of phosphate, urea, alanine transaminase (ALT) and bilirubin were higher after the walk than before. Activities of creatine kinase (CK), lactate dehydrogenase (LD) and their isoenzymes CKMB and LD1 increased several fold after the walk. Although CKMB increased, the relative amount of CKMB was less than that seen in myocardial infarction. We conclude that after a 100 km hill walk there is evidence of plasma volume expansion, muscle damage, and increased protein breakdown.

Protein excretion after prolonged exercise

Random urine samples were obtained from 16 healthy subjects (nine men and seven women) before and after a 100 Km hill walk for the estimation of total protein, albumin, N-acetyl-beta-glucosaminidase (NAG), retinol binding protein (RBP) and creatinine. The excretion of total protein, albumin and NAG (expressed in relation to creatinine excretion) increased significantly after the walk. The relative clearance of protein and albumin also increased. In four subjects serial measurements were made for 4 days and the excretion of albumin and NAG on the fourth day were similar to the pre-walk values. We conclude that proteinuria of prolonged exercise is at least partly due to reduced tubular reabsorption.

Prediction of creatinine clearance from plasma creatinine: comparison of five formulae

1. Glomerular filtration rate is commonly assessed by measurement of endogenous creatinine clearance (CLcr). Several formulae have been described to calculate CLcr from plasma creatinine and we have evaluated the effectiveness of five formulae in 95 healthy subjects (17 F and 78 M, 20-25 years) and in 72 patients attending a renal clinic (48F and 24 M, 14-69 years). Endogenous CLcr was measured and the CLcr was also estimated by five formulae. 2. In healthy subjects CLcr calculated by the formulae of Cockcroft & Gault (1976) and Mawer et al. (1972) gave higher correlation coefficients than the other three formulae. 3. When all of the subjects with a wide range of CLcr (3.1-164) were considered all formulae gave good correlations, but the formula of Cockcroft & Gault (1976) gave the best estimate.