Talc slurry pleurodesis. Pleural fluid and histologic analysis

Our plain-English summary of Talc slurry pleurodesis. Pleural fluid and histologic analysis, by L. Kennedy, R.A. Harley, S.A. Sahn, et al (Chest, 1995).

The study

• Authors: L. Kennedy, R.A. Harley, S.A. Sahn, C. Strange
• Journal: Chest
• Published: 1995;107(6):1707-12
• Cited by: 88 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Although talc slurry pleurodesis is effective for control of malignant pleural effusions and recurrent pneumothorax, the mechanisms of pleurodesis remain incompletely defined. We instilled 70 mg/kg of sterile asbestos-free talc slurry into the pleural space of New Zealand white rabbits and studied the inflammatory response at 1, 2, 3, 7, 15, 30, 60, 90, and 120 days by observing pleural fluid and histologic characteristics. Talc slurry caused mesothelial denudement and an exudative neurotrophilic pleural effusion that resolved after 48 h. A transient mononuclear vasculitis was seen within the lung at 1, 2, and 3 days after instillation. Pleural adhesions were minimal and did not increase in number over time. Talc was found outside of the pleural space in mediastinal lymph nodes (4 of 23 animals examined), kidney (1 of 6), and spleen (4 of 10). The predominant cause of pleurodesis with talc slurry instillation is an acute pleural injury similar to the tetracycline class agents.

In plain English

This was an animal experiment on how talc works in pleurodesis, a treatment that seals the space between the lung and the chest wall. The researchers injected 70 mg/kg of sterilized, asbestos-free talc in salt water into the right chest cavity of 28 New Zealand white rabbits. They examined the animals at nine time points from 1 to 120 days afterward. The study did not test asbestos. A small amount of pleural fluid formed at 24 and 48 hours (2.9 mL and 1.7 mL). Neutrophils, a type of white blood cell, predominated at 24 hours (56%). By 24 hours the cells lining the pleura had been stripped away, and pleural thickening peaked between 3 and 7 days. Patchy inflammation around lung blood vessels appeared on day 1 and had cleared by day 7. Adhesions were thin, never fully sealed the space, and did not increase over time. Talc was found in mediastinal lymph nodes in 4 of 23 animals examined, kidney in 1 of 6, spleen in 4 of 10, and liver in 0 of 12. The authors concluded that talc slurry works mainly through an acute injury to the pleura, similar to tetracycline-type drugs.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: animal experiment (rabbit model, examined at set times after talc slurry instillation)
• Who was studied: 28 New Zealand white rabbits weighing 2 to 3 kg, studied by researchers at the Medical University of South Carolina, Charleston; killed at 1, 2, 3, 7, 15, 30, 60, 90 and 120 days (number of animals per time point not stated; pleural fluid data from 4 animals at 24 h and 5 at 48 h)
• Exposure: a single injection into the right pleural space of 70 mg/kg USP asbestos-free talc, dry heat sterilized, in 3 mL 0.9% NaCl (extrapolated from the usual human dose of 5 g in a 70-kg person); no asbestos exposure was studied
• Main results:
  • Small volumes of pleural fluid were present at 24 h (2.9 mL) and 48 h (1.7 mL); less than 0.2 mL at all other time points
  • Neutrophils were the main cell in pleural fluid at 24 h (56%); monocytes and macrophages predominated by 48 h
  • Pleural fluid was exudative, with lactate dehydrogenase levels of 484 IU/L at 24 h and 528 IU/L at 48 h
  • The mesothelium (pleural lining cells) was denuded by 24 h
  • Patchy pleural thickening was seen in every animal and peaked between 3 and 7 days after instillation
  • A patchy inflammatory reaction around small lung blood vessels appeared on day 1; no talc particles were detected in the lung, and the lesions regressed completely by day 7
  • Pleural adhesions were thin; complete pleural symphysis (fusion) was never observed
  • Pleural adhesions formed early and did not increase over time
  • Talc was found in mediastinal lymph nodes in 4 of 23 (17%), kidney in 1 of 6 (17%), liver in 0 of 12 (0%), and spleen in 4 of 10 (40%)
  • A tissue reaction to talc particles was noted in all of the organ sections where talc was found
• The authors' conclusion: The authors concluded that the predominant cause of pleurodesis with talc slurry is an acute pleural injury similar to that caused by tetracycline-class agents.
• Limitations the authors state:
  • The authors could not exclude that talc causes pleurodesis by altering pleural fluid and solute exchange in some unknown way. They suggested that differences in adhesion numbers between their study and others were more likely related to particle size, dose, or pleural abrasion used in some animal models.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Talc, Pleurodesis, Pleural Effusion, Pneumothorax, Asbestos-Free Talc, Mediastinal Lymph Nodes.

Related studies

• Sterilization of talc for pleurodesis. Available techniques, efficacy, and cost analysis — L. Kennedy, L.M. Vaughan, et al. (1995)
• Pleural granuloma mimicking malignancy 42 years after slurry talc injection for primary spontaneous pneumothorax — S. Tenconi, L. Luzzi, et al. (2010)
• CT appearances of talc pleurodesis — S. Narayanaswamy, S. Kamath, et al. (2007)
• Disruption of iron homeostasis in mesothelial cells after talc pleurodesis — A.J. Ghio, J.M. Soukup, et al. (2012)
• Medical thoracoscopic talc pleurodesis for chylothorax due to lymphoma: a case series — D.C. Mares, P.N. Mathur (1998)
• A randomized controlled trial of the efficacy of cosmetic talc compared with iodopovidone for chemical pleurodesis — R. Agarwal, A.S. Paul, et al. (2011)

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