pathoma Pulm Hypertension

Question 1

Pulm Hypertension Deffinition

Answer 1

mean arterial pressure in pulm circuit is greater than 25 mmHg (normal is 10)

Question 2

what is pulm hypertension characterized by

Answer 2

• atheroclerosis of the pulm trunk
• smooth muscle hypertorphy of pulm arts
• intimal fibrosis
• plexiform lesions (tufts of capilaries that arise from long standing disease) are seen with severe, long-standing disease
• presnts with exertional dyspnea or right sided heart failure

Question 3

what is primary pulm HTN

Answer 3

• classically seen in young adult females
• etiology is unknown
• familial forms are related to inactivating mutations of BMPR2 - when these gene is deleted they have proliferation of vascular smooth muscle = HTN

Question 4

what is secondary pulm HTN

Answer 4

• due to hypoxemia (COPD and interstitial lung disease) cuases all parts of the lung to clamp down and raises pressure, can also be cuased by increased volume in the pulm circuit (congenetal heart disease)
• may also arise with recurrent pulm embolism

Question 5

Acute Respiratory Distress Syndrome

Answer 5

• Diffuse damage to alveolar-capillary interface (diffuse alveolar damage) - this damage cuases leakage
• leakage of protein rich fulid leads to edema and formation of hyaline membranes in alveoli
• histologically you can see this hyaline membrane = pink stuff on the edges of the alveoli
  
  • thicker diffusion barrier = no good gas exchange
    
    • develop hypoxemia and cyanosis
  • membranes are sticky and increase Surface tension = collapse of airsacs
• on CXR you will see diffuse white out

Question 6

what is the etiology and treatment of ARDS

Answer 6

• sepsis, infeciton, shock, trauma, aspiration, pancreatitis, DIC, hypersensitivity reactions, and drugs
• activation of neurtrophils induce pretase mediated and Free radical damage of type 1 and 2 pneumocytes
• treatment
  
  • address underlying cuase - this is what is cuasing it in the first place
  • ventilation with positive end-expiratory pressure (PEEP) - this holds airsacs open
  • recovery may be complicated by interstitial fibrosis - if you knock out type 2 pneumocytes (stem cells of lungs) you get fibrosis instead of full healing

Question 7

Neonatal Respiratory distress syndrome

Answer 7

• respiratory distress due to inadequate surfactant levels
• Clinical features
  
  • increasing respiratory effort after birth, tachypnea with use of accessory muscles and grunting
  • hypoxemia with cyanosis
  • diffuse granularity of lung on X-ray
• Associated with
  
  • prematurity, screen with L:S ratio (should be greater than 2) (L=lethecin = phosphatidylcholine = major part)
  • C section delivery
  • maternal diabetes - the mother will have high blood sugar which will enter fetal circulation - kid has a good pancrease so they will produce a lot of insulin (insulin inhibits surfactant production)

Question 8

complications

Answer 8

• hypoxemia increases the risk for persistence of patient ductus arteriosus (PDA normally closes when there is good oxygenation of the blood) and necrotizing enterocolitis (becuase there is decreased O2 going to gut)
• supplemental oxygen increases risk for free radical injury
  
  • if free radicals get into blood they can injure the retina and cause blindness
  • when lungs are premature and hit with a ton of O2 they generate radicals which damage the lung = bronchopulmonary dysplasia