Biopsy
A definite and direct approach to diagnose TBP involves identifying
acid-fast bacilli (AFB) in any body site. But the long waiting time
limits its value in clinical decision. A pericardial biopsy may be
helpful for diagnosing TBP. Typical histology with caseous necrosis and
granulomatous inflammation or positive AFB staining can confirm the
Diagnosis. However, when the progression comes to the end-stage, typical
microscopy findings can disappear, and left only fibrotic changes and
chronic inflammation. So the Diagnosis of TBCP should be made early or
the etiology of the disease should be clear at the early stage. Once the
Diagnosis of the restriction has been made, establishing a TB etiology
is less straight forward, for a large proportion of patients present
restriction but have no prior history of
TB[53,54]. So the response to anti-tuberculosis
treatment should be another criterion of the Diagnosis of TBCP.
The most challenging aspect of the Diagnosis of TBCP (Figure.4) remains
to be establishing a tubercle bacilli etiology, especially in countries
in which TB is not endemic. For those patients with TBCP who developed
from TBP, the Diagnosis is relatively simple. Although there are four
stages of TB (dry, effusive, absorptive, and constrictive), TBCP may not
always result from the progression of acute pericarditis from a dry
stage sequentially through an effusive, and absorptive, but may mainly
result from a fibrotic pericardium without previous history of acute
pericarditis. What’s more, the clinical presentation of constriction is
highly variable, which may range from asymptomatic to severe
constriction. When the disease has reached the advanced stage and the
constriction has formed, finding the etiology may be hard, for the
typical caseous necrosis has disappeared. Therefore, whether in the
endemic area and history are vital to the Diagnosis of TBCP.
Pericarditis-related diseases or procedures such as TB, HIV, T2DM,
obesity, chest radiotherapy, SLE, uremia, infecting by viral, and a
history of heart surgery and so on should be mastered, which can help us
make a faster and accurate diagnosis. Also, we should pay attention to
the differences in the Diagnosis of TBCP accompanied by HIV or T2DM and
TBCP caused by MDR-TB or XDR-TB.