A crisis in a patient with sickle cell disease is most likely to be caused by
**Core Concept**
Sickle cell disease is a genetic disorder characterized by abnormal hemoglobin production, leading to deoxygenated red blood cells adopting a sickle shape. This abnormal shape causes vaso-occlusion, ischemia, and tissue damage. Crisis episodes are a major complication of this disease.
**Why the Correct Answer is Right**
Dehydration is a common cause of sickle cell crisis. When a patient with sickle cell disease becomes dehydrated, their red blood cells become more concentrated, increasing the likelihood of sickling. This can occur due to inadequate fluid intake, excessive fluid loss from diarrhea or vomiting, or other causes of dehydration. As a result, the patient may experience severe pain, fever, and other symptoms of a crisis.
**Why Each Wrong Option is Incorrect**
**Option A:** Infection is a common trigger for sickle cell crisis, but it is not the most likely cause. Infections, especially those involving the lungs or urinary tract, can cause inflammation and increase the risk of sickling, but dehydration is a more direct precipitant.
**Option B:** Cold stress is another factor that can contribute to sickle cell crisis, but it is not the most likely cause. Exposure to cold temperatures can cause vasoconstriction, which can lead to ischemia and increase the risk of sickling.
**Option C:** While some medications can precipitate sickle cell crisis, they are not the most likely cause. Certain medications, such as narcotics and anesthetics, can cause vasodilation and increase the risk of sickling.
**Clinical Pearl / High-Yield Fact**
To prevent sickle cell crisis, patients should maintain adequate hydration by drinking plenty of fluids, especially during episodes of fever or diarrhea.
**Correct Answer: D. Dehydration. Dehydration is a common cause of sickle cell crisis.**