Low Glucose and pH Levels in Malignant Pleural Effusions: Diagnostic Significance and Prognostic Value in Respect to Pleurodesis

Abstract

In order to determine the diagnostic and prognostic significance of low pleural glucose and pH levels, we executed a prospective study of these parameters and cytologic yield in 77 cases of malignant pleural effusions diagnosed from 116 consecutive thoracoscopies. The extension of the neoplasms detected by thoracoscopy as well as the results of our attempts to carry out pleurodesis by talc were also studied. Pleural glucose levels were less than 60 mg/dl in 16 cases, and the cytologic yield was positive in 14 of these cases (87%). The glucose value rose above this level in 61 cases, and the cytology was positive in 30 cases (49%; p less than 0.006). A pH less than 7.30 was encountered in 18 cases and there were positive cytologic findings in 14 of these cases (78%). The pH was above 7.30 in 46 cases, and cytologic studies were positive in 22 cases (48%; p less than 0.03). There were ten cases in which both the glucose and pH levels were low, and the cytology was positive in 9 cases (90%), while there were 40 cases in which both the glucose and pH levels were high and cytologic yields of 20 of these cases were positive (50%; p less than 0.03). The extension of the lesions observed during thoracoscopy showed important differences as far as this related to the glucose levels (p less than 0.005), but this relationship as it concerned pH levels was even more significant (p less than 0.0002). The differences were also highly significant (p less than 0.003) when the glucose and pH were jointly considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence that mesothelial cells regulate the acute inflammatory response in talc pleurodesis

“…The experimental finding that mesothelial cells may play a major role in the mechanism of pleural inflammation and contribute to an effective sclerosis in talc-induced pleurodesis may help explain why malignant pleural effusions with a high tumour burden and a low pleural fluid pH and glucose concentration may be less responsive to talc-pleurodesis than malignant effusions with less malignant involvement of the pleural space [18][19][20][21][22]. However, this is not absolute because effective pleurodesis can be achieved using talc by thoracoscopy despite the findings of low pleural fluid pH [23].…”

Clinically Important Factors Influencing the Diagnostic Measurement of Pleural Fluid pH and Glucose

“…Near patient testing of pleural fluid pH is an important component of this assessment for the diagnosis of pleural infection (including tuberculosis), rheumatoid pleural effusion, and esophageal rupture (3), and the prognostic assessment of malignant effusion (1,(4)(5)(6)(7). Measurement of pleural fluid pH is advocated in the literature and in management guidelines from professional societies (including the American and British Thoracic Societies [3,[8][9][10][11]) as part of first-line pleural fluid analysis.…”

“…A reduced pH (typically ,7.20 [12]) has been shown to be a robust marker for instituting intercostal tube drainage in patients with suspected pleural infection (13,14), and is used as an entry criterion for clinical studies of pleural infection (15,16). In malignant pleural effusion, low pleural fluid pH correlates with a poor prognosis (7) and predicts pleurodesis failure (6). To maximize diagnostic accuracy in individual patients requires that any measurement inaccuracies that cancel out in larger samples be minimized.…”

Derrame pleural neoplásico

“…(3,6) Baixos níveis de pH e glicose parecem ser marcadores de doença avançada no espaço pleural, podendo estar associados a menor sobrevida e a uma pior resposta à pleurodese. (13)(14) Porém, devido a estudos que não encontraram associação entre sobrevida e baixo pH, a análise destes parâmetros deve ser feita em conjunto com o estado geral do paciente, tipo histológico do tumor e resposta terapêutica à toracocentese. (3,6) Elevados níveis de amilase na ausência de ruptura de esôfago podem indicar a etiologia neoplásica do líquido pleural, (15) principalmente nos derrames pleurais associados ao adenocarcinoma de pulmão e ao adenocarcinoma de ovário.…”