Chapters Transcript The Child With A Limp: When To Call Rheumatology Tarin Bigley, MD, PhD, discusses the differential and features of a rheumatologic cause of limp. Thanks everyone for coming. Um I, I'm gonna go through a pretty common referral or um consult that we get and give you an idea of how uh we as rheumatologists are thinking through this, the um the differential as well as um uh talking a little bit about some of our diseases. So, um I have no financial disclosures. I'm gonna go through a case of uh a patient that I actually saw who came in with a limp. Um and then kind of quickly go through a pneumonic approach to a child with a limp. I usually do not like pneumonic, but you'll see why this one is especially easy to remember. Um And then I'm gonna talk a little bit about the differential and features of a rheumatologic cause of a limb. So we're gonna start with the case. Um This is a 15 year old male who is presenting a clinic with two months of worsening right or left foot and right knee pain, um recently noted swelling along with pain, um that's causing a limp, favoring the left um has also noticed a diffuse rash. So we have a kid coming in with now months long of limp, um, swelling pain and rash. Um It sounds like a pretty kind of classic, uh rheumatologic console. So I'm, I'm gonna, I'm gonna touch on the rash a little bit later, but the first thing I just want to go through was the limp and especially in this case, uh, limp with swelling. So the Pneumonic that I'm gonna kind of go through is um stop limping, which as I said, I usually don't like pneumonic because I can never actually remember them. But this one I feel like is pretty easy um to remember they are differentiating features of each part of the Pneumonic, but also um just thinking about a limp in general. And so these, some of the things that go into my differential diagnosis are things like age history, um vital signs and then obviously exam findings. All right. So we're gonna, we're gonna go through um the Pneumonic, but then talk about some of these specifically. Um So the first part of the pneumonic is septic arthritis. And I think this is a good one to start with because this is one of our uh more emergent causes of a limp. Um We don't usually get a ton of consoles for this, but there are occasions that are a little bit more insidious that we do see. Uh one of the thing that's really helpful for this cause of a limp is there are criteria that really tell you when you need to get the orthopedist involved to first help rule out uh a septic joint. And so those include nonweightbearing on the affected side, which could present as a lip limp, an elevated esr greater than 40. Obviously, we often see AC RP as well, fever and then a white count greater than 12,000. And if a patient has three or more of these, there's a high likelihood for septic arthritis and this um this patient needs um urgent aspiration. They'll likely need drainage, wash out antibiotics. Generally with septic arthritis, we're looking for synovial uh white blood cell count of greater than 50,000. The reason this is more urgent is because of the risk of joint destruction. Um X ray can be done to evaluate joint health and this as opposed to um our adult colleagues, this generally occurs in otherwise healthy Children. The bacteria we associate this are with, this are staph strep. Um Other bacteria that we can see are kella brucella and isa Kinga is really the one when we get a kid to rheumatology clinic. Um that we are still considering and a reason why we might send a cell count and um microbial studies um including King Ella PC R. This one can present a little bit more insidious, you know, patient who's not overly sick but has some elevations and inflammatory markers and a limp and arthrit, you know, monoarticular arthritis. So the tea and stop limping is trauma. Um Obviously more on, you know, kind of the general pediatric side in an infant or toddler. You're considering something like a toddler's fracture in really young kids who have a torque injury from a fall. Um, and in these cases, we're offering often considering non accidental trauma um, in older Children though it, this sometimes becomes difficult to differentiate and we have so many kids now that are doing um, a single sport all year, five or six times a week and developing um sprains strains, tears fractures. Um and um maybe have some history of uh minor trauma or injuries of repetition. Even for us, it can sometimes be difficult to distinguish. Um uh you know, rheumatologic cause from an injury. As you know, we can see traumatic arthritis that can become chronic in the setting of repetition. Um So this is a picture here of uh um a toddler's fracture. You can see the fracture right here. Um The o in stop limping is another more um urgent cause and that's Osteomyelitis. So I think classically we think about this as bacterial. Uh these are usually kids who are less than five years old. So young kids, it is more common in certain populations such as those with sickle cell disease. Um And that's where you think about that association with salmonella, um immunodeficiency or recent sepsis. These kids usually pre present with more pain. Um that isn't necessarily joint related, although it can, depending on where the Osteomyelitis is they may have limp and refusal to bear weight and may or may not have fever. But we often see with elevated white count, elevated cr pe sr um it's not uncommon that by the time we see these patients, they've had a um some pretreat with antibiotics and so blood culture is not always positive. Um but it is something we get when we see these patients, I think all of us know MRI is much more sensitive than X ray, especially early in disease. Um And the bacteria are similar to what we see in septic arthritis that includes staph um and strep. Um we think about Kinga but other bacteria as well. I think there is a question about uh bone scan. Um I'd have to look at the studies in terms of where we are uh with sensitivity. We usually do get MRI rather than uh a bone scan. And I think part of that is um due to the radiation but also the um increased information that the MRI gives us when we have this on our differential. Um especially if the, you know, may be joint related. Uh We might still be considering um arthritis or septic arthritis. Um in the rheumatology field. The other form of Osteomyelitis that we see not uncommonly. And this is another reason we might get MRI um instead of uh a bone scan. Um And in some cases, we get uh a whole body, MRI is chronic, non bacterial osteomyelitis, um which I'm sure some of you also know as chronic recurrent multifocal osteomyelitis or crmo, these are autoinflammatory bone lesions. They're lytic in nature and can look very similar to um to a bacterial osteomyelitis. And in fact, before we make this diagnosis, we really want to rule out a bacterial infection, uh malignancy, uh histiocytosis um or even scurvy. And so it's not uncommon that in these cases, we're requesting uh a biopsy. Um The closer to the diaphysis, this is the more we really want to rule out something like a malignancy. And the challenging part of this is, you know, we used to call this multifocal and we don't anymore because we know that sometimes it, especially early in disease can be a single lesion. Um but also that a lot of these patients have asymptomatic lesions. Um And so you're not finding them unless you're doing something like a whole body MRI or a bone scan. Um The more common places we see CNO are the femur, um the tibia less a little less often the pelvis. Um vertebra is another common spot. We can see these and um these patients with vertebral lesions. Um If you, you might see we have on a biologic very early in disease and really the the concern is that they're gonna develop a pathologic fracture or maybe they already have. And so that's where we're going straight to uh a biologic or something like pomegranate. Uh versus when we just see it, say in the tibia or the femur, the clavicle and sternum are also common spots. And uh an image of that is shown here. This would be later in disease where you can actually see it on X ray. Um But you can see this lesion here on MRI with some surrounding edema, right? The the P is uh Perthes but within this, I really include avascular necrosis. Um you know, I think leg calf Perthes is something on the pediatrics side where we're all familiar with on our differential. This is an avascular necrosis of the hip. Um This occurs generally in young um kids to uh kind of preteen and it presents as insidious onset intelligent gait. Um more likely it's unilateral, although it can be bilateral and more common in males. And so these patients have pain with internal rotation of the hip. Um and MRI shows um decreased femoral head perfusion necrosis. And so this is just showing kind of that antalgic gait um that you can see in a patient who has uh avascular necrosis. Um You can see the MRI of that here or that you see some abnormalities. Um and this is due to the um uh to the decreased blood supply uh to the hip. And in Perthes, we don't always, always really understand completely understand uh why this occurs. But on the rheumatology side, this is also something you want to be aware of in your patients that uh we're treating with steroids. And so there are occasions um you know, this might in say a lupus patient who's on long term steroids uh who develops this. We don't see this as common in the patients, we treat with bisphosphonates, but it should be on the, the differential. And so if this is something that's seen in a clinic um or um you know, in an urgent care and emergency room, uh you know, a kid with an antalgic gait, um and pain with internal rotation, this should be on the differential. So the L is limb limb length discrepancy. And I think this is a really important thing for us to check for when we have a kid who has an unusual gait that might be um uh look like a limp. There's a pretty wide differential for this. We definitely can see this in our rheumatology patients. Um you know, if they have untreated juvenile arthritis, um you can get a bony overgrowth in the short term, but then in the long term, you can get a limb length discrepancy. We don't see this a lot in rheumatology anymore because our treatments are so good. Um But this can be congenital, it can be due to hip dysplasia. Um Skiffy is on the differential um as well as trauma that's impacting the growth plate. But you usually only see this if there's uh a two centimeter or more um differential uh or discrepancy And so we often in the clinic as a shorthand, we'll have them bend their knees at about 90 degrees and line up their ankles. Um But the better way to measure this is um the anterior superior iliac spine to the medial malleolus. Um the eye is inflammatory and some of the things on here include transient citti, post infectious arthritis and rheumatologic. But I'm gonna come back to this uh as a more focused kind of uh differential. So the M is malignancy and I think this is really important in general. Um You know, there, solid tumors I think are much more often caught because of um the swelling you might see. Um you know, the the presentation is, I think a little bit more recognized. Um you know, this includes ewing sarcoma as well as osteosarcoma and metastasis. But leukemia and lymphoma is something that really can present as arthritis. Um you know, they can have joint swelling, they can have some changes in even range of motion um and can have a limp and this is can also be due to uh bone pain. The main thing to take away from this is if a patient appears sick, has some unexplained symptoms um that you wouldn't necessarily expect to see in just arthritis. Um And that includes b symptoms, things like fever, weight loss, night sweats, um get labs in an X ray. You know, when we, when we see arthritis, we usually aren't necessarily getting labs in an X ray to diagnose arthritis, we're doing this to rule out other causes. A really important note is that thrombocytopenia is uncommon for our inflammatory causes like juvenile arthritis, except in the case of lupus. But in the case of lupus, you're gonna expect some other systemic symptoms and you're gonna re really require labs to make that diagnosis. Um but even in a patient that you see with arthritis who has some elevated inflammatory markers and has relative thrombocytopenia. So maybe it's normal. But with the level inflammatory markers, if this was more of our, you know, juvenile arthritis, you would expect to see throm cytosis. If instead you see platelets like kind of right on that low normal range, we're a little bit more concerned about ruling out uh malignancy first. And so this is a, you know, a picture of a solid tumor I think pretty easy to catch. Um but a little bit more difficult is metaphysical bands that you might see in a leukemia. The p includes pyomyositis and other um my acidities. Um pyomyositis, if this is bacterial in nature, they're gonna have pretty severe pain swelling, they might have other causes of bacterial infection, uh like fever and these kids really need source control. So they need to be in the emergency room um and seeing uh um surgeon but viral myositis um can present a little less severe. And so this is might be a kid who had flu or another viral illness. And then um soon after that several days after that onset develops calf pain and swelling. This is opposed to our, our patients with myositis, the juvenile dermatomyositis versus, whereas kids with high myciti even viral myositis, you're gonna see kind of swelling, the shiny skin, more pain and maybe a localized area. Um but not necessarily weakness per se. Our patients with uh dermatomyositis are gonna have proximal weakness but they should also have other findings like um heliotrope rash or even malar rash. Um They're gonna have Goran's papules on some of these extensor surfaces. And um they often will not have, usually will not have significant pain. Um You know, the these patients are, are gonna sometimes have a more insidious onset than you would expect from uh a bacterial or even a viral. Uh my asciis. And the other thing to remember too is it's much less common in pediatrics for us to see polymyositis. So, you know, this myositis, this autoimmune myositis with weakness without skin findings. Um The I I threw in here is Ileos sos abscess. Um I think this is an important thing on the differential to consider an abscess of some of these kind of internal or hip girdle muscles. Um Ileos being one of the more common places to see an abscess, but these patients can develop back pain, flank pain and have a limp with or without a fever. And I think this is an important thing to have on the differential because on average diagnosis takes close to three weeks. Um the presentation can be quite vague. Um pain improves with hip flexion and they have a positive saw a sign uh with hip extension. So the end is neurologic and I'm not gonna go into any depth on this. Um You know, this can include stroke, neuropathy, Guillain, barre, um muscular dystrophy. This isn't so much a weak as a weakness as uh or limp as abnormal gait. Um transverse myelitis is also in there. So, um if they have weakness without any other symptoms or exam findings such as arthritis, rash, oral ulcers, et cetera, um It's less likely to be rheumatologic and you, you should think about a, a more thorough neurologic exam and um a referral to neurology. Um And then the G is gingu um and just remembering um appendicitis at younger ages associated with more atypical presentation. And so they might have that positive soas sign because of that um inflammation coming from the appendicitis, they're also more likely to present with a ruptured appendix which could cause um you know, some irritation of some of those muscles, uh hernia torsion, um and inflammatory bowel disease, generally with inflammatory bowel disease. This is within our rheumatologic diagnosis. They might have uh arthritis associated with inflammatory bowel disease. So, let's come back to our patient and dive a little bit more into uh rheumatology. Um So the differential for our patient coming in with this limp and swelling could include inflammatory like reactive arthritis, juvenile arthritis, lupus, um and ink uh vasculitis. Uh they might have an infection. You know, this patient has uh joint pain and rash. So I didn't include this um in the differential previously, really an infection, but we often put it under the inflammatory causes acute rheumatic fever. Um malignancy still could be on the differential and then something like inflammatory bowel disease or celiac where you can have um extraintestinal manifestations such as a rash. Um The lower extremity swelling is probably related to this limp. Um And then um this patient's rash, which we will come to um in a second. So diving a little deeper into the inflammatory causes of a limp. Uh The first one I'll mention is transient synovitis. This is obviously much more common than lupus or juvenile arthritis. Uh generally in the younger population and occurs usually within several days um of a ur I or maybe uh uh A G I bug. And the really kind of differentiating factor for us is this pat, these patients often present with um hip pain. And so it's really important on exam to isolate that hip from uh the knee. Um and you can try to bend the knee without putting a lot of movement on the hip um which can help, like I said, isolate the hip from the knee. It is not common at this age. For us to see hip arthritis only is a presenting feature of juvenile arthritis. Um So, you know, in these cases, we're starting to think about transient synovitis. These are the patients that are refusing to bear weight and get an NSAID and are then not long after walking around the room, even if the limp isn't completely gone. Uh post infectious is arthritis is another thing we consider. And um you know, these, I think really the um the different differentiation we make with like a post infectious arthritis versus a transient synovitis, which really is post infectious as well. Is we're usually considering like a strep or a G I infection like Campylobacter salmonella shigella um as well as uh potentially um uh like a reactive arthritis like an STD. Um uh These are often acute, they're asymmetric, they're oligoarticular. Um So four or less joints and they often respond to nsaids. Although we do sometimes treat some of the more prolonged cases or more severe cases with steroids. But generally, these resolve within 4 to 6 weeks. And that's really the differentiation differentiating factor uh with juvenile idiopathic arthritis or JA A. So J A is an inflammatory arthritis that's less greater than six weeks in Children, 16 or younger. Um If you have a patient who really looks like they have arthritis, um but it's only been going on two or three weeks, we are unlikely to make the diagnosis of JI A and with our approach will often be to treat with um scheduled nsaids. And so it's not, uh one approach is to, you know, make the referral and say you can schedule 3 to 4 weeks from now, but you can try um scheduled Ibuprofen or Naproxen. And if the arthritis resolves just with that, a, you know, within that kind of six week time range, um they don't necessarily need to come to us right away and they can be monitored if arthritis keeps returning, uh returning, then these patients often will come to our clinic. So there are a couple of different types of June arthritis. There's a articular, um these patients have uh four or less joints, there's polyarticular. Um so these are five or more joints. Um they're systemic and these patients have to have fever greater than two weeks, rash, arthritis, um uh with systemic symp inflammation. It's very common that these patients present with just fever and rash and they don't yet have arthritis. Arthritis can can occur, you know, anywhere up to six months and sometimes because we have such good treatments. Uh once we make this diagnosis, uh we don't actually see a lot of arthritis. Um obviously, with systemic arthritis patients, we're ruling out uh really any other cause because this is a diagnosis of exclusion and then there's psoriatic arthritis, emphasis related arthritis, um which often can involve the axial spine and undifferentiated forms. And so these are just some pictures that kind of we're looking for when we're thinking about arthritis. Um, you know, these patients with arthritis have uh swelling, you can see kind of loss of uh the normal architecture of the ankle here and it's quite clear the swelling in the knee um, in this toddler. Um, but also these patients often have morning stiffness. Um, except for our teenage patients with like more of the spinal arthritis presentation, they're less likely to have kind of that post activity pain. Um And in our little kids, they often don't have a lot of pain, they just have swelling and some stiffness, their gait changes. Um And on exam, you can see decreased range of motion. So the rheumatologic differential for the inflammatory causes of limp include ja a um uh systemic lupus, um chronic, non bacterial osteomyelitis or crmo um arthritis related to vasculitis or monogenic causes. I won't go any into any depth into that because um these patients uh are much more rare, usually have other manifestations. Um and then dermatomyositis. So when, when should you really be s uh suspicious of a rheumatologic cause? So, as I mentioned, arthritis um lasting more than six weeks. Um if they have cytopenias, as I mentioned, uh we think about something like lupus, cytopenias are not um as common in uh they're pretty uncommon in ja A uh the caveat, this is our really sick, systemic ja a kids who might develop macrophage activation syndrome. Um But when you see cytopenias. Again, the reminder is r really, there's a concern also for malignancy and we're ruling this out before we're making the diagnosis. Typically. Um certain types of rash that I'll come back to in a second. Um, if the patient has eye inflammation, so either, you know, an older patient who has juvenile arthritis and will develop symptomatic eye inflammation, uh or in our younger patients. And uh an important thing to remember is in our um oligoarticular juvenile arthritis patients, especially those that are kind of toddler or elementary school age. Their U Vitis is usually asymptomatic and you might not actually identify it unless they've been to an ophthalmologist um until they have some changes in vision or they develop CIA. So, um abnormalities, um uh abnorm eye abnormalities uh in the iris. And then uh other things we think about would be things like serositis. So they have really bad chest or abdominal pain, um kind of that ongoing searing pain. And then uh A positive A N A which I put as a question mark and this has become, uh I think this is always kind of uh an interesting topic. And when do you send in a, an A, uh, when do you refer for an A N A? But one thing that I think has come up recently is um Lab Corp is pres is um reporting an A N A of 1 to 40 as positive. Um And we don't think of an A N A of 1 to 40 in general as positive. That's gen, that's a, a negative uh finding. And so if you have a patient who you get an A N A and they have an A N A of 1 to 40 especially if they don't have some of these other findings. I it's unlikely to be relevant. And, um, we, we also kind of look at A N A uh based on the tighter. And so if it's 1 to 320 or less, that's the titer, that's much more common to be found in the healthy individuals. And so if they have that, they don't have any of these other findings, um you know, it's unlikely to be rheumatologic and they, they wouldn't meet criteria for something like lupus. So let's let's talk a little bit about um rash. And um there's a, a pretty large differential for uh the different rashes we see, but I think it's um it's, it's good to go over. Um And so in, in our patient, uh the differential is pretty wide, um it included se dermatitis. And so, you know, this is an example of that um these are erythematous patches, um they have overlying scaling, we often see these in the scalp but in ears, but you can see this on the face as well. Um And you can see that in some cases, it can be difficult to differentiate from um psoriasis, for example, which I'll come back to uh the same thing can be said with fungal infections where they have these erythema plaques and they can have nail changes. Um at topic dermatitis, um can have a lot of different forms. Um Here's a picture of uh Nomar eczema which can look like some of our rheumatologic um rashes, um scabies is on the differential and, you know, these are usually um sorry, uh pic but in the case of more severe scabies, um one thing we consider in the rheumatology immunology side is a potential immunodeficiency. Um So, the differential within uh a rheumatologic causes include psoriasis. Um These are often more symmetric erythematous plaques with scaling. Uh We can see this in the scalp, behind the ears or in the ears um on extensors, uh you know, knees, um gluteal cleft, um it can be postular sometimes or um gut tape. Um and these patients fairly commonly have nail abnormalities which again, as I mentioned, sometimes can be different uh hard to differentiate from a fungal infection. Um They can have uh Kemner phenomena where they have flares at the site of trauma um and they can have api signs. So as you kind of peel off the scale, uh they can have pinpoint bleeding, I want to touch quick on uh lupus. So lupus can have a lot of different rashes and much more than I have time to go into. But I think one thing for uh kind of thing about this in general is the malar rash because um this is, I think not always the easiest to differentiate a true malar rash um from uh you know, other rashes. Um you know, usually we see the sparing of the nasal labial uh nasolabial folds. Um but there are some other things that can cause a male or rash. So on your differential should be bloom syndrome, um dermatomyositis or niacin deficiency or Poe um And then other things we consider would be like a te cutaneous T cell lymphoma. These are very uncommon and then a vasculitic rash. So these patients have uh you know, a rash that um is non blanching, they might be a little bit more purpuric. Um and we're considering anco but um there are infections that can cause that as well. Um And this is just showing an example of vasculitis. Um the most common vasculitis that is seen um you know, in the community or in the emergency room would be ig vasculitis or henein and pura. So this is our patient. Um as I mentioned, they had um ankle swelling. You can see, you know, this patient has not only ankle swelling but mid foot swelling, complete loss of uh you know, kind of those anatomical uh landmarks we look for like malleolus and uh this is his rash. So an erythema rash, it's on his face. I'm sorry. Um It includes scaling actually, when he was sent to us there's concern about this being a malar rash. Um if you look closely the nasal labial fold here is um not spared. So are are differential for this patient. Um You know, this patient looks like they have arthritis. So their limp and swelling looks like like arthritis and they have this rash with which we would call seria form. Um But as I showed you, there are other rashes that could look like this. And so this is where our work up comes in. And I mentioned, you know, a lot of times when we're doing the work up, we're not necessarily doing this to diagnose our diseases, we're doing this to rule out some other diseases. So he is a normal C MP. Uh Although hi his glucose was high, um he had a CBC that was um mostly fairly benign, which, you know, again, platelets are on the higher side, uh which helps us out and makes us think a little bit less about something like the leukemia um or lupus for that matter. Um Although, you know, the hemoglobin is a little bit lower. And so that then we start thinking about, you know, whether or not this is due to chronic inflammation. Um And in which case, we might be thinking about inflammatory bowel disease. Um And so we did send a fecal calprotectin that was negative um from an immunologic side. Uh I cannot remember for sure if the A N A was sent before we saw him or during the work up. Um but he did have an A N A of 1 to 80. Um And so we did send some additional work up. He had quite a high CRP and ESR um but he had normal complement. Um INCA was negative double strand DNA and extractable nuclear antigens were negative. And just as an aside in lupus, the typical pattern is a normal CRP in an elevated uh ESR when we have a really high CRP. Um and we're considering lupus, uh we, it makes us think we, we might need to dig a little harder. So we end up getting an MRI for our patient um of the ankles with and without contrast. And another point is that uh contrast is really helpful when we're trying to diagnose arthritis. Um It can help us really identify the tennis and novis that can go along with that. And so this patient has severe um bilateral Tennison novis um around the ankle and hind foot, um involvement of the left fourth toe um had apophysitis within uh emphasis throughout the ankle. Um And so the, this really looked like an inflammatory arthritis. Um There was also osteitis um which suggested that this had been ongoing and quite severe um leading to these erosions and degenerative changes. Um So this is a, a picture of this here. Now, when we see a patient who has TARS ITIS, um so uh arthritis uh of this whole mid foot. This really gets us thinking about more of the the arthritis that can cause uh like a spond arthritis type picture. Um And that for us includes emphasis related arthritis or psoriatic arthritis. And so we diagnosed this patient with juvenile idiopathic arthritis, um psoriatic um subtype. So as I mentioned, arthritis is characterized by swelling, stiffness, decreased range of motion, uh warmth, uh with or without pain and tenderness of the joint. Last greater than six weeks. Um This is a picture of a, a patient with arthritis including uh multiple MC PS as well as their wrist. Um you can see kind of this deviation of the wrist uh due to the inflammation. And then I mentioned this term emphasis, which um is something we're really thinking about. This is inflammation of the anthesis. So where the tendon or ligament connect and this is just a picture showing uh the portions uh are the areas of the body that we will palpate to try to identify emphasis on exam. I kind of went over the different types of arthritis. Um just a couple of points about this. Um oligoarticular arthritis is general. Generally we see in our younger patients. So this might be the toddler who's presenting with arthritis and we diagnosed with JA A. Once we start to see it in kids older than six years old, we're really starting to think about citi related arthritis, uh which may or may not initially present with um spondyloarthritis. Um just looking at a pie chart in pediatrics. The majority of kids are oligoarticular J A or rheumatoid factor negative JA A, the rheumatoid factor positive JA A. These are patients that really look much more like rheumatoid arthritis and they're gonna have a chronic course, but there is an overlap of um our different j um subtypes um in terms of how they present likelihood to have say axial um involvement versus peripheral involvement. Um which I think can sometimes make it a little challenging to understand. Uh again, this is onset at less than age uh 16. Um You know, some of the exclusion that we think of um uh for arthritis, as I mentioned, can include diagnosis of something else, but we also have exclusions within our different arthritis. So I'm gonna talk a little bit about psoriatic arthritis just because I think it has features of all the different types of arthritis. But for example, with psoriatic arthritis, um some very common findings we see are dactylitis and you know, this might include the second digit of either the toe um or the finger uh which is fairly patho mnemonic. But we rule this out if they have something like inflammatory bowel disease or um rheumatoid factor. Um So the psoriasis can be variable in young Children. Um you know, and by a psoriasis, I mean, the actual skin manifestations, it can be subtle. Um it can be uh more atypical and sometimes can be difficult to differentiate from eczema because it can be more subtle or mild in in general pediatrics. This only occurs in uh 0.5 to 1% of Children. Uh Children in adults, most have psoriasis uh within several years of developing joint disease. But in kids, they may present initially just with joint disease. And so we often make the diagnosis because they have a first degree relative with psoriasis. Um It's estimated to only be about 7% of our ja a patients. But it has this interesting bimodal distribution, either early onset in kind of the preschool years. Um and can look similar to um ji A. Um but when we see these patients, they're a little bit more likely to have dactylitis or tars itis or involvement of um small joints of the hands and feet. Um more likely to be female. And again, they have a family history of psoriasis. And then there's the more classic psoriatic arthritis, which is the middle of the late childhood or adulthood where they have psoriasis uh within uh either a year or two before or several years before or um after disease. And these patients are more likely to have axial involvement. As I mentioned, the more like the um the extra articular inflammation um such as dactylitis is more common. Um and they can have kind of the soft tissue edema uh around their joints um really quick in kind of the pathology and pathogenesis in general of um arthritis. I'm gonna touch on psoriatic arthritis here. But um greater than 50% of childhood arthritis has a family history. It's much less with some of the other types of arthritis. But there is some family predisposition. I think a really interesting um finding is that even in twin studies, the concordance is often less than 50% um which suggests there are major environmental factors. Um there are some um some polymorphisms that are associated with genes that we've since found are really important for not only mechanism disease but in targeting for treatment. And so some of these include things like TNF um uh il 17, for example, and these are things we use uh to treat. Um We're learning more about the microbiota um in the intestine as well as the skin. And as I mentioned, environmental factors clearly are important. Um And we see this in some of the twin studies. Um I mentioned um these patients often initially have oligo arthritis um but it can involve the small joints which we don't typically see in some of our other like uh oligo arthritis. Um they can have sacro itis about a third of the time. Uh 10 to uh 30% of the time. And then as in the second toe or finger dactylitis um is kind of patho pneumonic. Uh for us, we talked a little bit about the nail changes. Um And that overt psoriasis um you know, is something that we see only in around 50% of our kids um early on. Um I mentioned uh emphasis. So just for the sake of time, um I'm gonna keep moving. Um we, we have really good treatments for all of our arthritides. I think an important point is that, you know, we recognize this diagnosis. Um there is some evidence that's emerging that early treatment, especially uh with TNF inhibitors uh may impact overall disease course. And, um, I think one thing that we always tell our patients, but also that's important for uh, their primaries to know and be able to communicate is that, um, that we have really good medications, clinical remission on medication is 60% or more long term. Um, in psoriatic arthritis, it's less likely that they're gonna achieve long term remission off of medication. Um, but that really is different depending on the type of arthritis. And so, um, in our oligoarticular, um, J A patients over 80% are going to develop are gonna have long term remission off of medication over time. The other thing to point out, um, is really with almost all of our types of, uh, ja a, there's a fairly high percentage that within five years, uh, we'll be able to discontinue treatment and most of our patients are gonna, with the medications we have, even if they don't maintain durable remission off of medication are gonna be able to do, you know, marching band or athletics or whatever they wanna do, um, that our medications are really gonna reduce the burden of the arthritis. Um, so this is just showing, uh, you know, another study that, um, the percentage of patients in remission off medication well, is not super high in some of these, um, on medication. We do really well and in our systemic or oligoarticular ga a, um, greater than 50% are gonna be coming off of medication long term at some point. So to come back to our patient, he is on methotrexate and uh Remicade uh which is a TNF inhibitor. Um This was his psoriasis, actually not long after starting treatment. Um And now, as long as he stays on his medication, he has very little psoriasis and um his arthritis is largely resolved with just um some remaining um uh some remaining uh hypertrophy of the surrounding tissue. Um So just to summarize what we went over the differential for a child with a limp is large. It's important to recognize emergencies like septic arthritis, infection, trauma or cancer. Um juvenile arthritis is much more slow moving. So it's important to rule out other diseases first and that includes uh getting labs and imaging. Um J is generally not diagnosed until after six weeks of arthritis uh which involves swelling, stiffness and decreased range of motion in early arthritis. Um you know, within the first couple weeks. Um There's no problem with trying scheduled nsaids Um As long as there are no uh contraindications to that, um A positive A N A is generally not pathogenic. Um And if lab core tells you the A N A of 1 to 40 is positive, um that is not how rheumatologists look at it. Uh We have really great treatments so we are always happy to see um kids where there is that question of arthritis, so we can start treatment early and get them back to doing all their normal activities. And so I'll leave it at that and take any questions. Created by Presenters Tarin Bigley, MD, PhD Pediatric Rheumatology & Immunology View full profile
