Cor pulmonale – causes, symptoms, diagnosis, treatment, pathology

Learning medicine is hard work! Osmosis makes it easy. It takes your lectures and notes to create
a personalized study plan with exclusive videos, practice questions and flashcards, and so
much more. Try it free today! With cor pulmonale, cor is Latin for heart
and pulmonale is Latin for lungs. Cor pulmonale, then, is a relationship between
the two, it’s when a disorder of the lungs causes dysfunction of the heart. Normally, de-oxygenated venous blood from
the body goes into the right atrium of the heart. From there, it goes into the right ventricle
and gets pumped into the lungs where it is reoxygenated as it goes through the pulmonary
circulation. The pulmonary circulation is a low-resistance
system with pressures ranging between 10 mmHg and 14 mmHg. After going through the lungs, oxygenated
blood goes into the left atrium, and then into the left ventricle, and finally gets
pumped back out to the body. When the heart can’t pump enough blood to
meet the body’s demands, it’s initially called heart dysfunction and can worsen to
the point where it’s called heart failure. This can happen in two ways, either it’s
systolic heart failure, where the ventricles can’t pump blood hard enough during systole,
or diastolic heart failure, where not enough blood fills the ventricles during diastole,
called diastolic heart failure. Heart failure can affect the right ventricle,
the left ventricle, or both ventricles, so someone might have, right-sided heart failure,
left-sided heart failure, or both which is called biventricular heart failure. Cor pulmonale is when a lung disorder causes
right-sided heart dysfunction that can develop into right-sided heart failure. Lung disorders make it harder to oxygenate
the blood, which can lead to hypoxia, or low oxygen levels. In response, this triggers a process called
hypoxic pulmonary vasoconstriction. Let’s say you have a couple pulmonary arterioles
here, meaning they’re in the lungs, and the alveoli of the lungs here, and oxygen
exchange between the two. If one of these alveoli is poorly ventilated,
the corresponding arteriole vasoconstricts to divert blood away from it. This works pretty well, but when lots of alveoli
are poorly ventilated like with a lung disorder, they all start to vasoconstrict and the mechanism
backfires. When lots of arterioles vasoconstrict together,
there’s an increase in resistance and it leads to pulmonary hypertension – with the
pulmonary blood pressure rising above 25 mm Hg. The high pulmonary pressure makes it hard
for the right ventricle to pump blood into the pulmonary circulation.As compared to the
left side, the right side of the heart is thinner walled and used to ejecting against
a low pulmonary vascular resistance. In acute lung disorders, like a pulmonary
embolism, where a blood clot blocks blood flow in a pulmonary artery, the result is
a rapid increase in right ventricular pressure that makes the right ventricle stretch out
like a water balloon. In chronic lung disorders, prolonged high
pressure causes the right ventricle to hypertrophy, or grow, so it can contract with more force. The hypertrophy is concentric, which means
that the new sarcomeres are generated in parallel with existing ones. So as the heart muscle wall enlarges, it crowds
into the ventricular chamber space, resulting in less room for blood to fill the heart,
and that leads to diastolic heart failure. The increase in right ventricular muscle mass
also means that there is a greater demand for oxygen, and, to make matters worse, the
coronaries get squeezed down by the this extra muscle so that even less blood’s delivered
to the right ventricle. More demand and reduced supply leads to right
ventricular ischemia and that leads to weaker contractions and systolic failure. Cor pulmonale results from pulmonary hypertension,
which typically comes from one of three categories of diseases – something that damages the lung
tissue, like chronic obstructive pulmonary disease, something that damages the pulmonary
vessels themselves, like chronic thromboembolisms or recurrent blood clots, something that affects
the spine or ribcage, like kyphoscoliosis, where the spine is curved and the lungs can’t
fully expand. An important distinction is left heart dysfunction
or failure, which can result in pulmonary hypertension, but wouldn’t be considered
cor pulmonale because the initial problem is with the heart itself, not the lungs. Primary right sided heart failure (might happen
after a right ventricular myocardial infarction or as a consequence of pulmonary valve stenosis)
would also not be considered cor pulmonale as the underlying defect is related to the
heart not the lungs. Because cor pulmonale stems from pulmonary
hypertension, the symptoms are all related to the backup of blood in the venous system. Pulmonary hypertension can lead to severe
shortness of breath, fatigue, and fainting and right-sided heart failure can cause blood
to get backed up coming from the body, causing jugular venous distension, hepatomegaly , and
edema. The diagnosis of cor pulmonale is usually
made with an echocardiogram that shows evidence of increased pressure in the pulmonary arteries
and right ventricle. Follow up tests can be done to identify the
underlying cause, for example spirometry can be done to look for chronic lung disease. The gold standard diagnostic test to directly
measure pulmonary pressures and assess for response to vasodilating medications is a
right heart catheterization. Treatment for cor pulmonale targets this underlying
lung condition. Supplemental oxygen can help with hypoxia-induced
vasoconstriction. All right, as a quick recap…Cor pulmonale
is right heart hypertrophy, dysfunction or failure caused by pulmonary hypertension from
a lung condition. This results in systemic fluid congestion
leading to jugular venous distension, hepatomegaly, and edema. After diagnosis with echocardiography, right
heart catheterization and potentially spirometry, treatment includes addressing the underlying
lung condition and administering supplemental oxygen.


Leave a Reply

(*) Required, Your email will not be published