Hemodynamic Disorders

Hemodynamic disorders Dr. Mehzabin Ahmed

Edema 



 

Accumulation of excess fluid (protein poor transudate, with specific gravity below1.012) in the tissues Normally very little fluid leaks from the vessels to form interstitial fluid This is cleared up by the lymphatics Edema results when the leakage from the vessels is excessive

Causes of edema Inflammatory edema  Alteration of the vascular permeability- in acute inflammation & in allergic reactions

Non inflammatory edema   hydrostatic pressure  plasma oncotic pressure  Lymphatic obstruction  Salt & water retention

Edema Pressure gradients controlling the fluid movement: • Hydrostatic pressure: or the capillary blood pressure (35mmhg) • Osmotic pressure: maintained by the plasma proteins (25mmhg) • Some fluid enters the lymphatic

Non inflammatory edema  

 hydrostatic pressure- increase in the capillary blood pressure Causes include:  Local increase in the pressure:results from impaired venous outflow.  E.g.,deep vein thrombosis of the lower extremities leads to edema of the affected leg  Generalized increase in venous pressure,with resulting systemic venous pressure occurs more commonly with congestive heart

Non inflammatory edema 



plasma oncotic pressure Reduction in plasma albumin concentration results in edema Causes are:  Nephrotic syndrome  Liver failure  Protein malnutrition  Protein losing gastroenteropathy

Non inflammatory edema  



Lymphatic obstruction prevent the normal drainage of fluids into the thoracic duct Causes are;  Inflammatory  Neoplastic  Postsurgical  postirradiation Salt and therefore the water retention are contributory factors for the development of edema. It occurs with any acute reduction of renal function, e.g.,poststreptococcal

Terms • Edema:increased fluid in the interstitial tissue spaces. • Effusion:excess of fluid in the serous or coelomic cavities – Hydrothorax;excess fluid in the pleural cavity – Hydropericardium;excess fluid in the pericardial cavity – Hydroperitoneum(ascites):excess fluid in the peritoneum

• Anasarca:severe & generalized edema with subcutaneous tissue swelling

Examples of edema Type of edema

Condition causing the edema Pulmonary Left edema sided heart failure Subcutane Right ous edema sided heart failure

Tissue  where the hydrostati fluid c pressure collects is in Alveoli of Pulmonar the lung y vascular bed Subcutane ous

Systemic venous system

Pulmonary edema

Elephantiasis (filariasis)

Pink edema fluid in the alveoli

Subcutaneous pitting pedal edema

Hyperemia 

It is the increase in the blood supply (inflow) to the tissues due to arteriolar dilation as during an exercise.

Congestion 

It is the increased pooling of the blood in the capillary bed as a result of a decreased venous return as in cardiac failure.



In long-standing congestion, called chronic passive congestion, the stasis of poorly oxygenated blood also causes

chronic

hypoxia,

which

can

result

in

parenchymal cell degeneration or death, sometimes with microscopic scarring. 

Capillary rupture at these sites of chronic congestion may also cause small foci of hemorrhage; breakdown



Examples of chronic venous ( passive) congestion are seen in 

Liver in cases of chronic right heart failure -there are alternate regions of congestion and fatty change giving the liver alternate dark and light bands - nutmeg liver



Lungs in cases of chronic left heart failure- longstanding congestion causes the alveolar walls to become fibrosed (makes the lung firm /indurated). Damaged capillaries result in the extravasation of RBCs, which are phagocytosed by the alveolar macrophages and the hemoglobin is converted to hemosiderin (makes the lungs brown in color) - brown induration of the lung.

Nutmeg liver- alternate light (area of fatty change) and dark regions (areas of congestion)

Hemorrhage 





It is the extravasation of blood from ruptured blood vessels. The rupture can occur in large arteries due to trauma, atherosclerosis, inflammation or neoplastic infiltration. Capillary bleeding can occur in chronic congestion.

Types of hemorrhage 

Hematoma- the collection of extravasated blood in the tissues after rupture of the blood vessels.



Petechiae- they are pinpoint hemorrhages (1-2mm diameter) in the skin, mucous membranes or serosal surfaces



Purpura-these are larger hemorrhages (>3mm dia) occurring in vascultis, trauma.



Ecchymosis- larger hemorrhages (>1-2 cm dia) occurring in the subcutaneous tissues. They are commonly called bruises.



Hemothorax- the collection of blood in the pleural cavity



Hemoperitoneum- the collection of blood in the

Petechiae Purpura Cerebral hemorrhage

Subarachnoid hemorrhage

 

At the end of this unit, the student should be able to: Define the following terms            

Hemorrhage Hematoma Hemothorax Hemoperitoneum Hemarthrosis Petechiae Purpura Hematemesis Epistaxis Hemoptysis Melena Menorrhagia



Define the following terms     

     

Thrombosis Embolism DIC Shock infarction

Explain the pathogenesis of thrombus formation List the outcomes of a thrombus List some disorders commonly associated with thrombus formation List the types of embolism and give examples of each type List the types of infarcts and give examples of each type