Photo Credit: Dr Microbe

Assessing internal mammary lymph node involvement is beneficial in determining the pre-test probability of tuberculous pleurisy.

Assessment of internal mammary lymph nodes (IMLNs) involvement is key in determining the pre-test probability of tuberculous pleurisy (TP), according to results published in Pulmonology Journal.

Researchers noted that diagnosing TP can be difficult and often requires a pleural biopsy. Further, a strategy for improving the pre-test probability of TP may be beneficial in the diagnostic work-up, and previous research has indicated that the enlargement of IMLNs has been suggested to play a potential role.

The study team aimed to determine the role of IMLN involvement in TP in a multicentric case-control study. They compared its prevalence and test performance to those seen in patients with infectious non-tuberculous pleurisy (NTIP) and control subjects with no respiratory diseases (CP).

Ipsilateral IMLN Involvement Higher in Patients With TP

The analysis included 419 patients: 127 with TP, 163 with NTIP, and 129 with CP. The mean age of patients with TP was significantly lower than both control groups (P<0.001); there was no significant difference regarding sex or laterality of pleural effusion.

Researchers found that the prevalence of ipsilateral IMLN involvement in TP was significantly higher (77.2%) than that seen in patients with NTIP (39.3%) and patients in the CP group (14.7%).

Results on test performance, as stratified by age, indicated a high positive predictive value in patients aged 50 and younger, while a high negative predictive value was seen in patients aged older than 50.

For the NTIP group, ipsilateral IMLN involvement had values of 76.4% sensitivity, 78.5% specificity, 77.6% accuracy, 73.5% positive predictive value, and 81.0% negative predictive value. For patients in the CP group, researchers reported 76.4% sensitivity, 98.4% specificity, 87.5% accuracy, 98.0% positive predictive value, and 80.9% negative predictive value for IMLN involvement.

The comparison between CT scan and ultrasound demonstrated moderate agreement (Kappa=0.502), according to the study results.

Incorporating IMLN Involvement in Clinical Settings

According to investigators, the study indicates that the assessment of IMLN involvement “plays a relevant role in assessing the pre-test probability of TP.”

“Considering the increasing global prevalence of mycobacterial infections, a tool able to guide diagnostic work-up of suspected TP is crucial, especially where local sources are limited,” they wrote.