Hello and welcome to the Zero to Finals podcast. My name is Tom and in this episode I'm going to be

talking to you about sickle cell anemia. And you can find written notes on this topic at

zero tofinals.com slash sickle cell anemia or in the hematology section of the second edition of the zero to finals medicine book.

So let's get straight into it.

Sickle cell anemia is a genetic condition that causes sickle or crescent shaped red blood cells.

The abnormal shape makes the red blood cells more fragile and easily destroyed,

leading to hemolytic anemia, where the red blood cells break down. Patients with sickle cell

anemia are prone to various sickle cell crises, which we'll talk about in more detail later on.

Let's start with the pathophysiology.

Hemoglobin is the protein in red blood cells that transports oxygen. Oxygen attaches to the hemoglobin molecule and is delivered around the body. During fetal development, around 32 to 36 weeks of pregnancy,

fetal hemoglobin, or HBF, production decreases, and adult hemoglobin or HBA, increases.

So the fetal hemoglobin is gradually replaced with adult hemoglobin.

At birth, around half the hemoglobin is fetal hemoglobin and half is adult hemoglobin.

By six months of age, very little fetal hemoglobin is produced and the red blood cells contain

almost entirely adult hemoglobin is produced and the red blood cells contain almost entirely adult

hemoglobin. Patients with sickle cell disease have an abnormal variant called hemoglobin S or HBS.

Hemoglobin S results in sickle-shaped red blood cells.

Sickle cell anemia is an autosomal recessive condition affecting the gene for beta globin on

chromosome 11.

One abnormal copy of the gene results in sickle cell trait.

Patients with sickle cell trait are usually asymptomatic, meaning they have no symptoms.

Patients with one abnormal copy are defined as carriers of the condition, so they carry the

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