by Nicole Evans M.D.

Created on: April 12, 2009

Though sickle cell disease is rarely the topic of mainstream media, it continues to be one of the most common genetically inherited conditions in African-Americans. The inheritance pattern is autosomal-recessive which means that a child must inherit the sickle cell trait from both his or her mother and father in order to develop the disorder.

Some individuals carry only one copy of the sickle cell trait. While these people generally have no manifestations of disease, they may have painless hematuria (blood in the urine) or inability to concentrate their urine.

Newborn screening for sickle cell disease is performed at birth. The symptoms of sickle cell disease occur because of abnormal hemoglobin contained within red blood cells. Under low oxygen conditions within the body the red blood cells assume a sickled shape. This shape can cause the cell to split open when passing through small vessels and may also cause microvascular obstruction.

Signs & Symptoms:

A progressive hemolytic anemia develops after four months of age causing

-pallor

-enlarged spleen

-jaundice (yellowing of the skin)

-heart murmur

-growth retardation

The spleen will quickly become nonfunctional and eventually become a small mass of scarred tissue that must be surgically removed. This functional or anatomical asplenia causes sickle cell patients to be at risk of serious infection caused by encapsulated organisms such as Strep pneumonia, H. influenzae and Salmonella. Common infections caused by these bacteria include sepsis, septic joints and osteomyelitis.

Sickle Cell Crises:

Certain conditions cause high amounts of sickling and red blood cell death in these individuals.
Triggers include hypoxia, acidosis, changes in temperature and dehydration.

The types of crises include

-Aplastic anemia: Reversible, often due to Parvovirus B19.

-Hyperhemolysis: Typically in patients with G6PD (glucose-6-phosphate dehydrogenase) deficiency.

-Splenic sequestration: Red blood cell pooling in the spleen, typically occurs between 6 month and 2 years of age, can cause hypovolemic shock.

-Vaso-occlusive: Infarcts (strokes) within the tiny vessels causing Hand-foot syndrome, priapism, avascular necrosis of the femoral head, brain stroke, acute chest syndrome, and pain crises (usually in bones).

Treatment and Preventative measures:

Sickle cell crises are treated symptomatically. This often means pain control, fluids, oxygen, and antibiotics. Blood transfusion is sometimes required as well.

All individuals with sickle cell disease should receive twice-daily oral pencillin VK at diagnosis and until atleast age 5. They should be on folic acid once daily as well.

Children with a history of stroke are usually placed on chronic exchange transfusion protocols to prevent future events.

All children with sickle cell disease should also be vaccinated against S. pneuo, H. flu, Hep B, and Influenza because of the increased susceptibility to devastating infections by these bugs.

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