Increased versus decreased or absent breath sounds -- need clarification please!

[nursegirl333]

Hey everyone,

I'm studying for an upcoming health assessment test that covers the thorax and lungs. I've had some confusion after reading my Jarvis textbook about auscultating increased and decreased breath sounds.

This is what my textbook says:

"Decreased or absent breath sounds occur:

1...

2...

3: When anything obstructs transmission of sound between the lung and your stethoscope, such as pleurisy or pleural thickening, or air (pneumothorax) or fluid (pleural effusion) in the pleural space.

Increased breath sounds mean that sounds are louder than they should be...They sound very close to your stethoscope as if they were right in the tubing close to your ear. They occur when consolidation (e.g. pneumonia) or compression (e.g., fluid in the intrapleural space) yields a dense lung area that enhances the transmission of sound from the bronchi. When the inspired air reaches the alveoli, it hits solid lung tissue that conducts sound more efficiently to the surface."

I just want to clarify..so does this mean that excess fluid in the pleural space can cause either decreased / absent breath sounds OR increased breath sounds? I'm having trouble distinguishing what an obstruction would be versus consolidation or compression...I don't really know what pleural thickening is, but I would imagine that if the pleura was thickened, this could also compress the lung, and create increased density in the lung that would cause increased breath sounds instead of decreased/absent breath sounds as the text states...

Can someone please clarify this?