Partial 6 - Pulmonary Hypertension Flashcards
Pressure in pulmonary arteries
18-25/6-10
You diagnosis pulmonary hypertension when the pressure is
above 25mmHg at rest
above 30mmHg during exercise
How does pulmonary hypertension lead to cor pulmonale
It increases the afterload in the right heart leading to hypertrophy of the right ventricle and eventually right sided heart failure (cor pulmonale)
How does pulmonary hypertension lead to polycythemia
The bone marrow will produce more red blood cells to compensate for the oxygen loss
How does pulmonary hypertension lead to pulmonary embolism
The extra red blood cells that is made from the compensatory mechanism of the low oxygen will cause the blood to become thicker and stickier, further increasing the load on the heart
Pathophysiology of Pulmonary hypertension
The overall rise in blood pressure in PHT is the end result of a process which begins with changes in the endothelial cells that line the arteries of the lung. Changes causes the formation of extra tissue and blockage in vessels. Scarring and fibrosis usually occurs and arteries become stiff and narrow. These causes increased resistance to blood flow which raises pressure in the pulmonary arteries. Less often, PH is caused by extensive loss of lung tissue from surgery or trauma. Any injury to endothelial cells leads to overproduction of endothelin, and decreased production of NO and prostacyclins.
Functional classification of pulmonary hypertension
Class 1-4
Class 1 (Functional classification of PH)
Class I patients with pulmonary hypertension does not have limitations in physical activity. Ordinary physical activity does not cause dyspnea or fatigue, chest pain, or near syncope
Class 2 (Functional classification of PH)
Class II patients with pulmonary hypertension have slight limitation of physical activity. They are comfortable at rest, but ordinary physical activity causes dyspnea or fatigue, chest pain, or near syncope.
Class 3 (Functional classification of PH)
Class III patients with pulmonary hypertension have marked limitation of physical activity. They are comfortable at rest, but less than ordinary activity causes dyspnea, fatigue, chest pain or near syncope
Class 4 (Functional classification of PH)
Class IV patients with pulmonary hypertension are unable to carry out any physical activity without symptoms. These patient’s manifest signs of right heart failure. Dyspnea and/or fatigue may be present even at rest, and discomfort is increased by any physical activity.
Primary Pulmonary Hypertension
There is no underlying cause for the high blood pressure in the lungs, and is due to spasm of the muscle layer in pulmonary arteries, due to patient being sensitive to substances that cause blood vessels to constrict, such as cocaine and fenfluramine. Patient may also have an inherited predisposition for the disease, and if this is the case PHT is triggered by another medical condition such as; Lupus, AIDS, chronic liver disease, Scleroderma and sickle cell anemia. (LACSS).
Two-Hit hypothesis
According to this hypothesis, vascular abnormalities characteristic of PPH are triggered by accumulation of genetic and/or environmental insults in a susceptible individual. The first hit can be mutation in Bone morphogenic protein receptor 2 (BMPR2) and the second hit can be ingestion of appetite suppressants or another somatic mutation such as TGF-βR2 mutation. BMPR” normally receives and transmits signal that help the cell respond to its environment, by growing and dividing or by undergoing apoptosis, while TGF- βR2 binds TGF- β which is an important interaction for cell proliferation.
Secondary Pulmonary Hypertension
It results from another medical condition. It most probably occurs due to diseases that impede flow of blood through the lungs or that causes periods of low oxygen in blood.
Causes of secondary pulmonary hypertension
Pulmonary embolism COPD Sleep apnea Congenital heart disease Obesity with reduced ability to breath (Pickwickian syndrome) High altitude Neuromuscular diseases involving respiratory muscles Pulmonary fibrosis Connective tissue disorders (Scleroderma) HIV Chronic liver disease Left sided heart failure
Pathophysiology of PH in Scleroderma
(1) In scleroderma, the left ventricle can become stiff or weakened, leading to back pressure into the lungs
(2) In patients with lung involvement (lung scarring), the capillaries can be damaged leading to PHT
(3) The distinctive problem in scleroderma is narrowing of the small lung arteries, which leads to PHT.
Symptoms of PH
Dyspnea, fatigue or near syncope on exertion Syncope Edema of legs and ascites Cyanosis Coughing (sometimes blood) and wheezing Distended neck veins Hepatomegaly Racing pulse or heart palpitations Angina-like chest pain Feeling week (due to hypoxia) Achy joints (often years before the apparent onset of disorder).
Symptoms of PH in childern
The symptoms in children are similar to adults, although children are more likely to experience tiredness, dizziness and breathlessness and for many fainting is common. The child may fail to put on weight, and the growth may be slowed.
Most common misdiagnosis for pulmonary hypertension
Asthma
Diagnosis of PH
A definite diagnosis of PHT usually includes measuring pulmonary wedge pressure. This is done by passing a tube through a vein in an arm or a leg into the right side of the heart to measure the blood pressure in the right ventricle and the pulmonary artery. You should ask the patient about present illnesses, past medical history, family history, and any past or present medication.
Pregnancy and PH
The consensus of medical opinion is that PH and pregnancy is very dangerous. The life of the mum and baby are put at great risk. Pregnancy can really take its toll on a woman’s body. For example, the heart rate speeds up and the immune system doesn’t work quite as well. For a woman whose body already has to deal with a severe illness, pregnancy can actually have catastrophic consequences.
