What is Hepatopulmonary Syndrome?
Also referred to as HPS is a condition occurring in individuals with an existing liver disease that has progressed to the point that it affects the lungs by causing low blood levels of oxygen known as hypoxemia as well as shortness of breath which is known as dyspnea.
A function of the liver, one of many, is to assist with regulating the tone of blood vessels in the lungs. But in those individuals with already existing liver problems the blood vessels of the lung expand – vasodilate – in number and size, causing the warning sign of hepatopulmonary syndrome.
- Studies show the presence of this syndrome considerably increases death in those with cirrhosis
- This syndrome occurs in fifteen (15) % to twenty (20) % of individuals with liver cirrhosis
- Main treatment for this syndrome is supplemental oxygen
Hepatopulmonary Syndrome Symptoms
In a patient with liver disease that is known, some of the symptoms or signs of hepatopulmonary syndrome include:
- Oxygen in blood is at low levels
- Shortness of breath
- Symptoms worse in upright position
There are no symptoms that occur without the already underlying liver disease and often the internal pathology of HPS is only found when patient is being prepared for liver transplantation.
Hepatopulmonary Syndrome Causes
HPS develops when arterial oxygenation deficiency happens because of intra-pulmonary vascular dilations that are usually associated with hepatic disease that is severe. Recently completed studies support the theory that the presence of HPS considerably escalates the mortality rate in those patients with cirrhosis particularly in those individuals with worsening deterioration of the liver disease.
A characteristic of HPS is intra-pulmonary vascular dilation. This affects severely the pulmonary gas exchange and these lead to hypoxia or low oxygen levels in the blood.
The mechanism of this intra-pulmonary vascular dilation is being studied to further clarify the pathogenesis of HPS.
Hepatopulmonary Syndrome Diagnosis
Most individual who are diagnosed with a known liver disease and present with low blood oxygen levels as well as shortness of breath will be suspected of HPS and the physician will usually test for the marker of HPS – abnormal blood vessels in the lungs. There are two (2) main tests that are currently used:
- Heart echocardiogram using a contrast agent to visualize heart function and exam images for any signs of blood vessel dilation
- Nuclear medicine lung scan using a contrasting agent which is radioactive to focus on blood flow in the lungs as well as the brain to quantify how much of the agent passes thru the dilated blood vessels in the lungs.
The outcome of these two (2) tests can be used to confirm the diagnosis of HPS in the patient.
An echocardiogram uses waves of sound to produce images of the heart. This is a fairly common test that allows the physician to visualize how the patient’s heart is beating as well as the pumping of blood. The physician uses these images from this test to identify various anomalies in the heart valves and muscles.
Dependent on what other information the physician needs, the patient might have one of several other types of echocardiograms. Every type of this test has very few risks involved.
Hepatopulmonary Syndrome Treatment
Most patients who are diagnosed with HPS will need a liver transplant as this is the only cure for this syndrome. But in the meantime, oxygen therapy can help with the low blood oxygen levels making that patient feel more comfortable but it does not affect the syndrome itself.
Alternative treatments such as supplemental oxygen or somatostatin to inhibit vasodilation remain anecdotal.
Therapy with oxygen can help patients with low oxygen blood levels to be more comfortable, but it does not affect the HPS itself. Larger medical centers are testing some experimental drugs to help symptoms of respiratory distress. One ingredient that is currently being tested is garlic powder and it is actually showing good results but it is still not a cure for HPS.
Hepatopulmonary Syndrome Prognosis
Many individuals with HPS are referred to large medical centers for the liver transplant as these clinics and teaching hospitals have extensive experience treating these diseases as well as performing liver transplants
A liver transplant is the only treatment for HPS that is effective in both adults as well as children. The survival rate after this surgery is five (5) years or more.