Biological and cytological-morphological assessment of tuberculous pleural effusions

Abstract

Aim: Tuberculosis (TB) came back in the top of causes for infectious disease-related deaths and its pleural involvement is still in the top two extrapulmonary sites. The authors continued their studies on TB pleural effusions (Pl-Effs) with the assessment of biological and cytological variable of pleural fluid (PF), introducing in the investigation algorithm and testing a new tool, the computer-assisted evaluation of cell populations on PF smears.

Patients, materials and methods: A series of 85 patients with TB pleurisy (PLTB) were selected from a larger group of 322 patients with different types of Pl-Effs. The algorithm of investigation included. clinical variables, biological assays of PF, gross aspects including imagistic variables and PF cytology on May-Grünwald-Giemsa (MGG)-stained smears. All the data obtained were entered into and processed using Microsoft Excel module of the 2019 Microsoft Office Professional software along with the 2014 XLSTAT add-in program for MS Excel. The PF cellularity was assessed qualitatively by a cytologist and quantitatively with in-house software. Continuous variables were compared using Pearson's correlation test, while categorical variables were compared using χ² (chi-squared) test.

Results: Our analysis showed that patients were usually males, aged between 25 and 44 years with Pl-Eff discovered at clinical imagistic examination, almost always one-sided and free in the pleural cavity. Its extension was either moderate or reduced. The PF had a serous citrine appearance in most of the cases, and biological characteristics pleaded for an exudate [high levels of proteins and lactate dehydrogenase (LDH)], with elevated adenosine deaminase (ADA) values and rich in lymphocytes (Ly). The attempt to identify the pathogen in PF was not of much help. Apart from Ly, neutrophils [polymorphonuclear neutrophils (PMNs)] were a rare presence and their amount had only a trend of direct correlation with Ly. The same situation was encountered in the case of mesothelial cells (MCs). The comparison between the qualitative and the quantitative, computer-assisted evaluations of cytological smears showed that the results of the two methods overlapped in less than one third of the cases, although the sensitivity and specificity values as well as the two calculated predictive values of the qualitative method were encouraging.

Conclusions: The assessment of biological variables and cell populations of the PF are basic tools in the diagnosis of pleural TB. The assessment of PF cell population could be improved by the use of computer-assisted quantitative analysis of the PF smears, which is simple to design, easy to introduce and handle and reliable.

Keywords: biology; cytology; pleura; pleural fluid; tuberculosis.

Figure 1

Glucose amount: (Left) PF’s glucose values; (Right) Patients’ PF’s glucose distributions. PF: Pleural fluid.

Figure 2

Proteins’ amount: (Left) PF’s proteins values; (Right) Patients’ PF’s proteins distributions. PF: Pleural fluid

Figure 3

LDH’s amount: (Left) PF’s LDH values; (Right) Patients’ PF’s LDH distributions. LDH: Lactate dehydrogenase; PF: Pleural fluid

Figure 4

ADA’s amount: (Left) PF’s ADA values; (Right) Patients’ PF’s ADA distributions. ADA: Adenosine deaminase; PF: Pleural fluid

Figure 5

Results of PF cultures

Figure 6

Sides of PF: (a) Right pleural cavity; (b) Bilateral involvement; (c) Left pleural cavity

Figure 7

Distribution of PF in pleural cavities. B: Bilateral; L: Left; R; Right

Figure 8

Types of PF extension: (a) Minimal extension; (b) Moderate extension; (c) Massive extension; (d) Hemithorax extension; (e) Loculated; (f) Locked up

Figure 9

Assessment of PF extension on Rx

Figure 10

PF’s amount: (Left) PF’s extracted amounts values; (Right) Patients’ PF’s extracted amounts distributions

Figure 11

The amount of PF evacuated: (a) Reduced; (b) Moderate; (c) Massive

Figure 12

Different gross aspects of PF evacuated: (a) Serous–citrine; (b) Hemorrhagic; (c) Serous–hemorrhagic; (d) Purulent.

Figure 13

Distribution of PF gross aspects. H: Hemorrhagic; P: Purulent; Se-Ci: Serous-citrine; Se-H: Serous-hemorrhagic

Figure 14

Qualitative assessment of PF cell population

Figure 15

Qualitative assessment of PF smears: (a) Cellularly very rich; (b) Cellularly poor; (c) Frequent cells; (d) Cellularly rich. MGG staining: (a, c and d) ×40; (b) ×20. MGG: May-Grünwald–Giemsa; PF: Pleural fluid

Figure 16

Distribution of cytological diagnosis types

Figure 17

Cytological diagnoses of PF smears: (a) Normal smear; (b) Chronic inflammation + mesothelial reaction; (c) “Warmed-up” chronic inflammation; (d) Hemorrhagic smear + chronic inflammation. MGG staining: (a–d) ×40

Figure 18

PF smears cellularity: (Left) Cells/×40 field values; (Right) Distribution depending on cell density/×40 field.

Figure 19

Qualitative assessment of PF smears: (a) Normal smear; (b) Cellular smear; (c) Hypercellular smear; (d) Hypocellular smear. MGG staining: (a–d) ×40

Figure 20

PF smears Ly population: (Left) Absolute lymphocytes count; (Center) Distribution depending on Ly percentage from nucleated cells/×40 field; (Right) Percentage of Ly from nucleated cells. I: ≥90%; II: ≥50%; III: <50%. Ly: Lymphocytes; PF: Pleural fluid

Figure 21

Lymphocytes’ density in patients with pathological smears: (a) >90%; (b) <50%. MGG staining: (a and b) ×40.

Figure 22

PMNs in patients with pathological smears: (a) Minimum number of PMNs; (b) Maximum number of PMNs. MGG staining: (a and b) ×40

Figure 23

PF smears PMN population: (Left) Absolute PMNs count/×40 field; (Center) Distribution depending on PMNs percentage from nucleated cells; (Right) Number of PMNs from WBCs/×40 field. I: >50%; II: >20%; III: >2%; IV: >0%; V: 0%

Figure 24

Mesothelial cells density in patients with pathological smears: (a) No MCs on the ×40 field; (b) 47 MCs/×40 field. MGG staining: (a and b) ×40

Figure 25

Mesothelial cells density in patients with pathological smears: (Left) Absolute MCs count/×40 field; (Center) Distribution depending on MCs percentage from nucleated cells; (Right) Number of MCs from nucleated cells/×40 field. I: >80%; II: >5% – <40%; III: >1% – <5%; IV: >0% – <1%

Figure 26

RBCs’ density in patients with pathological smears: (Left) Absolute RBCs count/×40 field; (Center) Distribution depending on RBCs percentage from nucleated cells; (Right) Number of RBCs from all cells/×40 field. I: >50%; II: >10% – <50%; III: <10%

Figure 27

RBCs’ density in patients with pathological smears: (a) No RBCs on the ×40 field; (b) 496 RBCs/×40 field