Infectious and Neuropathic Arthritis

00:01 So in an infectious arthritis, you have destruction of the articular cartilage and the adjacent cortex and this can happen within 24 hours of initial infection.

00:09 You can have adjacent periosteal reaction and you actually have more sensitivity and demonstration of a joint effusion when you are using an MRI.

00:19 So it?s actually hard to see some of these findings radiographically.

00:21 On an MRI you can also see enhancement of the synovium which is very helpful when diagnosing an infectious arthritis.

00:27 Here we have a plain film of a patient with an infectious arthritis and you can see destruction of the boney cortex at the level of the infection.

00:35 And you can also see soft tissue swelling and soft tissue gas adjacent to the site of the infectious arthritis.

00:43 So neuropathic arthritis is also called a charcot joint.

00:47 It?s caused by lack of sensation to the affected joint while the mobility remains maintained so the patient is able to move the joint?s base around but they can?t tell if they?re having any pain to the area.

00:58 This results in the joint being stressed beyond normal which result in multiple asymptomatic or mildly symptomatic microfractures and the most common cause of this is a patient with diabetes.

01:10 So the imaging features include extensive subchondral sclerosis, bony fragmentation which is actually a key feature, periosteal reaction, and bony and joint destruction. You can see in this patient, we have destruction and fragmentation of the first digit and tarsal bones so all of these appear destroyed. You can compare this with the normal bony structures of the rest of the digits. You actually have changes of the distal second digit from a prior amputation here. So these findings which are both acute and chronic, so the chronic finding of the amputation as well as the more acute finding of the destruction and fragmentation are highly suggestive of a diabetic foot and this is very commonly seen again in patients with diabetes.

01:57 So let?s take a look at this case, this patient is presenting with right sided hip pain.

02:02 So what are the different findings that you see here? So you can see that this is the femoral head and you can see the adjacent acetabulum.

02:21 Both of them appear abnormal.

02:23 So this right hip has joint space narrowing, you can almost see obliteration of the joint space here, there?s very little lucency present.

02:30 You have osteophyte formation right here, as well as at the margins up here.

02:38 You have subchondral sclerosis, so you have an increase in density in the surrounding bone here and you have multiple cystic changes which you can see scattered all around this joint.

02:52 So this is an example of osteoarthiritis.

02:54 This patient has hip pain because of degenerative osteoarthiritis, again, one of the most common types of arthritis that we can see.

03:01 So in this lecture we?ve reviewed several different types of arthritis and some of the common imaging findings associated with each one.

03:07 Often times, patients come in with joint pain and they start off by having a radiograph so having a general knowledge of the different types of arthritis and the differences between each one is always helpful to help the clinical physician know which direction to go.