Why does the stasis give microbleeds in the surrounding tissue, when the pulm. hypertension gives edema in the alveoli? I am especially confused because both pathologic conditions cause stasis of blood in the pulm. Arteries.
So, what are the differences and similarities between stasis and pulmonary hypertension? And are they both caused by left heart insufficiency?
Added by: AL
On: October 3rd 2011
They both derive from the same cause. High pressure in the pulmonary system due to most commonly congestive heart failure.
Is it possible to predict which one will appear in a patient?
Pulmonary hypertension = High blood pressure in the pulmonary blood circuit (According to current thinking, pulmonary endothelial cell and/or vascular smooth muscle cell dysfunction is the probable cause of pulmonary hypertension). The hypertension leads to the extravasation of fluid thus causing edema.
Lung stasis = Severely reduced blood flow in the pulmonary blood circuit. Leading to the accumulation of blood cells and mechanical stress of the vessel walls and red blood cells, causing these to break thus leading to bleeding.
AL:
I think that part of the problems in your understanding the concepts of pulmonary hypertension and stasis pertains to the fact that both terms describe pathophysiologic , i.e. dynamic events and we as pathologists see the consequences.Also these two processes are interrelated one to another.
PULMONARY HYPERTENSION= increased blood pressure in the pulmonary circulation.It is expressed as > 30 mmHg systolic and 12 mmHg diastolic pressure. Most common cause left heart failure .
PULMONARY STASIS= stoppage or diminution of outflow of blood from the lungs.Again the most common cause is left heart failure.It can be seen in histology slides as blood vessels full of blood.
NOTE:Both pulmonary hypertension and stasis can be acute (e.g. myocardial infarction) or chronic ( in chronic left heart failure).
PATHOLOGY: Pathologists can recognize changes of chronic pulmonary hypertension because hypertension damages the blood vessels in the lungs.Later you will learn that similar changes can occur in a disease called primary pulmonary hypertension, a deadly disease of uknown etiology.
Chronic stasis due to heart failure is also known as chronic passive congestion of lungs and it causes fibrosis, bleeding into the alveoli etc, i.e. changes that pathologists sometimes call chronic brown induration of the lungs (“brown” from old hemorrhage and accumulation of RBC derived iron rich pigment hemosiderin!)