This disease is marked by increased extravascular hemolysis, with laboratory findings including increased lactate dehydrogenase and decreased or absent haptoglobin in both warm and cold AIHA, and positive Coombs test. Clinically, jaundice or dark urine present in approximately one-third of the cases, and most of the symptoms are related to anemia.Other less commonly observed causes of hemolysis include:

Hemolysis secondary to drug toxicity
Thalassemia minor
Congenital dyserythropoietic anemiaThe above list is not exhaustive, and rare causes of hemolysis such as Bartonella infection, hemolysis due to transfusion reactions, and microangiopathic hemolytic anemia should be suspected when symptoms specific to those causes manifest. Pathophysiology
Bilirubin overproduction
The mechanisms by which bilirubin is overproduced in hemolytic jaundice can be understood in relation to the two major sites of hemolysis: intravascular and extravascular.During intravascular hemolysis, red blood cells are broken down within the vasculature, allowing hemoglobin from the ruptured red blood cells to form haptoglobin-hemoglobin complexes with haptoglobin, which will be internalized and degraded by hepatocytes and the spleen. If the degree of hemolysis is abnormally high, the unbound hemoglobin is converted to methemoglobin from which the heme moiety is bound to hemopexin or to albumin, and both heme-hemopexin and heme-bound albumin are internalized by hepatocytes and subsequently degraded to bilirubin. During extravascular hemolysis, red blood cells are destroyed by phagocytosis by macrophages in the reticuloendothelial system and digested by phagosomes.
Kernicterus affects mainly the basal ganglia, and its effects can spread to the hippocampus, geniculate nuclei, and cranial nerve nuclei. Symptoms of kernicterus include athetoid cerebral palsy and in severe cases, may lead to death of the patient. Most cases of kernicterus develop in infants following early hospital discharge from phototherapy. == References ==