Sarcoidosis: Pathogenesis

00:01 Idiopathic granulomatous multisystem disease, the keypoint there is "multisystem".

00:07 So get away from thinking that sarcoid only affects the lung That is only partly true.

00:13 You can find these noncaseating type of granuloma, What does noncaseating mean? Meaning that you do not have a necrosis within a granuloma.

00:20 What does a granuloma mean? Well from immunology, it's a fact that you have these antigens that are now encased or imprisoned within the structure things that you'll keep in mind when dealing with your granuloma is the fact that you have T-helper1 cells that are conducting your granuloma formation and then you have these multinuclear giant cells which I'll show you pictures of When you say multisystem, it could be well maybe these noncaseating granulomas might be in the liver, could also be in the intestine, It doesn't just have to be in the lung Skin, joint, heart, nervous system, liver, sinuses do not forget that this could be a multisystem, big time importance.

01:02 next, who's your patient? Most likely a female, african american or perhaps from Scandinavian countries So you might be thinking about Sweden, Norway, Finland and such Sarcoidosis-idiopathic.

01:16 We don't really know what causes it.

01:19 But when it does, you'd know that it's the parenchyma of the lung that's being affected.

01:24 What kind of lung disease is this please? Obviously we're still dealing wth restrictive.

01:29 We will be dealing with restrictive for quite some time.

01:32 The differentials are quite large and quite important.

01:37 Lung disease, interstitium.

01:40 Can you consider all in the diffuse lung disease differential? especially Mycobacterium avium intracellulare type of infection Next, well are you gonna have lymphadenopathy with your sarcoidosis? Absolutely, bilateral hilar type of lymphadenopathy.

01:59 and all that means to you is the fact that you have more differentials Need to rule out lymphoma if it's lymphadenopathy Castleman's disorder.

02:08 In other words you're dealing with an interleukin known as 6 (IL-6) and Bartonella infection, and with bartonella of course you're thinking about cat scratch disease or with Bartonella in HIV patient, then you start thinking about things like bacillary angiomatosis systemic disease, what it is? Well depending on the organ system, you need to consider infiltrated diseases such as well, say that it's the heart or the liver, intestine, skin One of those that will be infected, well what kind of differentials might you be thinking? infiltrative, how about amyloid? hemochromatosis.

02:42 For the neuro, well now you start thinking about well things like multiple sclerosis, CNS infections, paraneoplastic, do you see as to how sarcoid in which yes, could be involved with the lung but is it the lung only that they have to give you presentation for? Not at all.

02:59 But you do know that if it does affect the lung at this point, Restricted lung, take a look at your differentials here For all, need biopsy to confirm sarcoid.

03:09 As far as prevention, risk factors - we call this idiopathic, unknown.

03:15 Maybe asymptomatic but incidental finding, take a look hilar adenopathy on chest x-ray.

03:22 Now you start thinking about bilateral type of hilar lymphadenopathy maybe you're thinking also along the lines of things like Berylliosis may present with cough and progressive dyspnea upon exertion, and young males particularly may present with acute onset, fever I'm gonna show you picture of erythema nodosum What that is is a patient that is then going to complain of pain in the shins of the leg polyarthritis, hilar lymphadenopathy, young males.

03:57 Otherwise, you tell me who your patient most likely is.

04:01 Female, african-american, scandinavian..

04:05 But if it's young males particularly acute onset, fever, erythema nodosum Often referred to as Lofgren's Syndrome.

04:14 Do not get Lofgren's Syndrome confused with what's known as Loeffler's Syndrome that we'll take a look at later, okay.

04:21 With Loeffler's, there we will be looking at more or less an issue with eosinophilia Okay, this is sarcoid, be careful.

04:30 Now with sarcoidosis, if you take a look at the shin and where it's been shown here Then you'll find these areas that are reddened, hence erythema.

04:39 Next if it's nodosum, this then means that you have more or less your subcutaneous fat that is going to be affected Sometimes referred to as being your panniculitis, now you'd wanna be careful Find a patient who is complaining of such pain on the front of the legs, the shin or maybe there is a description of erythema nodosum All it does is just give you a list of differentials.

05:04 If you find your patient to be positive for erythema nodosum, and also has hypertension and also has hypervitaminosis D and it has a lung involvement, restrictive lungs disease, then without a doubt, it's sarcoid.

05:16 But if your patient is maybe exposed in California, In California, there might be earthquakes and such and so therefore therefore it was then going to release these endospores into the atmosphere In which the patient is now inhaling these, these are coccidiodes, these are fungal infection So what I'm saying is that erythema nodosum is just a generic differential that is going to be found in many, many, many instances many systemic fungal infection, coccidiodes Maybe it's going to be Cryptococcus neoformans in your pigeons Maybe it's something like your blastomycosis with the rotten wood, so on and so forth.

05:56 Now with sarcoid, hilar lymphadenopathy, take a look at the chest X-ray Now, the medial side of the lung by the mediastinum, You find lot of activity in that region That increased activity that you find in the middle region medially then represents the hilar lymphadenopathy Remember when you find hilar lymphadenopathy, think of those conditions that also affect the lymph nodes such as lymphoma.