Sandbox:Ezici

Classification and Causes

• Hydrops fetalis may be classified according to the involvement of immunity into:
  • Immune hydrops fetalis.
  • Non-immune hydrops fetalis.

Pathophysiology

• It is thought that hydrops fetalis is caused by conditions with an increased rate of fluid transudation from the vascular compartment or decreased lymphatic return to the circulation, chiefly because of the developmental defects in microcirculation and lymphatic system, respectively.
• While these conditions may be both immune and non-immune, they often result in anemia and further hypoxia.
• The sympathetic system becomes activated due to hypoxia, and it causes blood redistribution with decreased blood flow to the liver and kidneys.
• It results in decreased albumin, increased ADH, and increased activity of RAAS.
• Through these changes, the central venous pressure increases, which further results in decreased lymphatic return.
• As a result, severe and progressive edema occurs in a fetus.
• The pathophysiology of non-immune causes also depend on the underlying conditions, include:
  • Decreased ventricular filling during diastole (i.e. tachyarrhythmias)
  • Increased central venous pressure due to the increased right heart pressure (i.e. cardiac tumors and subendocardial fibroelastosis)
  • Obstruction of lymphatic drainage due to a mass (i.e. cystic hygroma)