A pregnant women present with 6 week history of right hip pain.On exam she has guarding on passive hip movements.Plain x ray showed osteoporosis of proximal femur.Most likely diagnosis is?
**Core Concept**
The underlying condition is a hip fracture in a pregnant woman, which is a rare but serious complication. Osteoporosis of the proximal femur is a significant risk factor for hip fractures, particularly in pregnant women due to the increased bone resorption.
**Why the Correct Answer is Right**
The patient's symptoms, such as right hip pain and guarding on passive hip movements, are indicative of a hip fracture. The plain X-ray showing osteoporosis of the proximal femur further supports this diagnosis. Pregnancy is associated with increased bone resorption, which can lead to osteoporosis and an increased risk of hip fractures. The proximal femur is a common site for osteoporotic fractures in pregnant women due to the high bone turnover and reduced bone density.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not take into account the patient's osteoporosis and the specific context of pregnancy. A hip fracture is a more likely diagnosis than a simple femoral neck fracture.
* **Option B:** This option is incorrect because it does not consider the patient's osteoporosis and the clinical presentation of hip pain and guarding.
* **Option C:** This option is incorrect because it is not a common diagnosis in pregnant women, and osteoporosis of the proximal femur is a more significant risk factor for hip fractures in this population.
**Clinical Pearl / High-Yield Fact**
Pregnancy is associated with increased bone resorption, which can lead to osteoporosis and an increased risk of hip fractures. This is particularly relevant in women with a history of osteoporosis or those taking corticosteroids, which can further exacerbate bone loss.
**Correct Answer:** C. **Avulsion fracture of the femoral neck**