In a client with sickle cell disease, what primarily causes symptoms of pain and swelling?

In sickle cell disease, the primary cause of pain and swelling is the occlusion of blood vessels by sickled cells. These abnormal red blood cells, shaped like a crescent or sickle, can become rigid and sticky, leading to blockages within small blood vessels. When these cells obstruct blood flow, it results in reduced oxygen delivery to tissues and organs, which can cause ischemic pain and subsequent swelling in the affected areas. This phenomenon is often referred to as a vaso-occlusive crisis, a hallmark of sickle cell disease.

The complications of vaso-occlusive crises can lead to significant morbidity, including pain episodes, organ damage, and an increased risk of infections due to reduced blood flow and the potential for tissue ischemia. Understanding this mechanism helps to clarify why managing sickle cell disease often focuses on preventing these occlusions and alleviating the pain associated with them.