American Board of Internal Medicine (ABIM) Certification Practice Exam

What medical condition can lead to secondary infection with Staphylococcus aureus when associated with repeated trauma?

1. Prepatellar bursitis

2. Patellar tendonitis

3. Pes anserine bursitis

4. Patellofemoral syndrome

The correct answer is: Prepatellar bursitis

Prepatellar bursitis is a condition characterized by inflammation of the bursa located in front of the kneecap (patella). It typically arises from repetitive trauma or pressure, which is often seen in individuals who kneel frequently, such as carpet layers or miners. The repeated trauma can compromise the skin and underlying tissues, making them more susceptible to infections. When the bursa becomes inflamed, it creates an environment that can facilitate the growth of bacteria, particularly Staphylococcus aureus, which is a common skin flora but can cause secondary infections when there is a break in the skin or surrounding tissues. This risk of secondary infection is exacerbated in prepatellar bursitis due to the location of the bursa and the frequent trauma that can lead to abrasions or the formation of an open wound. In contrast, conditions like patellar tendonitis, pes anserine bursitis, and patellofemoral syndrome do not typically involve the same level of trauma that results in open wounds or significant inflammation of the bursae that could lead to secondary infections. Instead, these conditions primarily involve pain due to muscle or tendon strains and do not generally predispose individuals to infectious complications associated with trauma.