Systemic Lupus Erythematosus (SLE) Diagnostic Criteria (4-Skin-RASHNIA)

00:01 So let's take a detour just to talk about systemic lupus erythematosus diagnostic criteria.

00:06 As we know, lupus is a disease of unknown origin and it can affect nearly every organ but there are some very specific agreed-upon criteria that we use to try and tease apart whether somebody does or does not have lupus or has something similar to lupus.

00:20 I like to use this acronym which has been fairly well-established called 4-Skin-RASHNIA and basically we're gonna look at four different types of skin manifestations.

00:29 We're gonna look through each of the letters in RASHNIA which highlighted a different organ system for which you may see some manifestations of lupus.

00:37 First stop, the classic malar rash. It's also called a butterfly rash.

00:42 Specific terminology for it is the acute cutaneous lupus erythema rash.

00:47 It's paranasal -- nasolabial folds classical and it maybe brought on by sun exposure.

00:52 Of course, we got an old world picture of it here on the right.

00:55 Next up is the discoid rash. This is more inflammatory in nature.

01:00 It has the potential to leave some scarring behind particularly if you see it on the scalp where you can have what's called cicatricial alopecia which means scarring.

01:08 You're not gonna have hair grow back into that area afterwards.

01:12 The third type is mucosal ulcers where -- these are also called aphthous ulcers and a variety of different autoimmune conditions can cause this.

01:20 They don't like any particularly different in lupus.

01:23 The one caveat is that for lupus, they tend to be more painless.

01:26 They can occur on the oral or the nasal mucosa.

01:30 The fourth issue which I sort of alluded to already with the malar rash is a photosensitivity.

01:35 Patients who have lupus are just prone to having eruptions on their skin whenever they're exposed to too much sun.

01:42 In fact, I had a patient who simply because when she was driving in her car sitting in the sun on the left side of her body was more likely to have eruptions happening on the left side of her body.

01:52 Next stop, let's talk about the specific organ systems other than the skin.

01:57 Number one, renal. This is one of the biggest concerns with lupus, is how it can affect the kidneys and cause a focal or potentially a diffuse proliferative glomerulonephritis.

02:06 Depending upon the extent of the glomerulonephritis, it may dictate what kind of treatment you're gonna use to approach lupus patients.

02:14 Next stop is arthritis. In contrast to things like psoriasis or rheumatoid arthritis, the distinguishing feature of arthritis in lupus is that when you do x-ray imaging, it tends to be non-errosive.

02:27 You're not gonna see those erosions in the joints that you might see with some other autoimmune conditions.

02:32 That being said, 90% of patients with lupus will have some joint pain.

02:37 Next stop, serositis. This just refers to inflammation of the visceral or parietal pleura or the pericardium and what you can see here in this picture on the left lung field is evidence of a pleural effusion developing in the setting of somebody having a serositis involving the lungs.

02:56 Next stop is hematologic manifestations and shown here on the bottom right corner is just somebody showing conjunctival pallor just reminding us that folks with lupus almost always have some degree of anemia, leukopenia, or thrombocytopenia or all three.

03:11 Next stop, neuropsychiatric. There's actually a lot of different potential neuropsychiatric manifestations of lupus and anytime somebody presents with seizures, cognitive dysfunction, delirium or psychosis or simply a peripheral neuropathy, lupus is on the differential which can make it complicated.

03:30 Nonetheless, neuropsychiatric manifestations are part of our diagnostic criteria.

03:35 Next stop is the immunologic manifestations. This is basically the serologic testing that we can preform.

03:41 There is a barrage or antibodies as you can see on this list. The most sensitive but least specific is really our ANA testing.

03:49 After that, the more specific test that we often perform are the anti-double stranded DNA, the anti-Smith.

03:54 There's other ones as well that you may see.

03:56 For example, you'll note the anti-Ro and anti-La down there in the bottom.

04:00 Those are ones that we often thing of also with Sjogren's disease but can often be positive in lupus as well.

04:05 And lastly, the ANA. This one is set apart from the other ones because it's such an important serologic marker for lupus.

04:14 Shown here on the right side of the screen is antinuclear antibodies being lit up on immunofluorescence and the antinuclear antibodies that are depicted here could a variety of different proteins but this basic test just tells us there are some inflammatory process happening that's been picked up on immunofluorescence microscopy.

04:33 Okay, so any four of those 11 criteria would meet the criteria for lupus.

04:39 So, let's take a look back at our patient and see how many of those criteria our patient meets.

04:45 So, right off the bat, pleuritic chest pain. That basically is a marker of sirositis so she's already got one point.

04:52 Let's move on to the next one.

04:55 Down at the bottom we saw that she has painful hand and knee arthralgias and we saw on physical exam that she had some swelling around her MCPs, PIPs, etc. So, she's also got arthralgias.

05:05 That's two points. Next stop, let's look at that lesion in her mouth.

05:10 It seems that she had a shallow ulcer in the right upper buccal mucosa, suggesting an aphthous ulcer so that's three points.

05:17 She has a mucosal ulcer. Next stop, this rash that she was describing with a subtle macular erythema over the bilateral malar regions.

05:25 That's the malar rash. Four points. Next stop, her blood counts.

05:29 You remember she's got leukopenia, anemia, and thrombocytopenia so she gets another point for that.

05:35 Her urinalysis tells us that she definitely has renal involvement and of course, her ANA at 1:640 really solidifies our diagnosis.

05:43 At this point, we know she has enough criteria met to call this systemic lupus erythematosus but we still want to exclude some of the other items on our differential diagnosis so let's just get a few more tests before we move back to our differential diagnosis.