March 22, 2023

The clinical manifestations, diagnosis, differential, and treatment or IgG4-related disease.

Foreign hello everyone i’m eric from strong medicine and today in this ongoing series on underappreciated diseases i’m discussing igg4 related disease igg4 rd is an immune-mediated fibro-inflammatory condition which results in the development of tumor-like masses and or fibrosis of involved organs although the many individual manifestations of igg4 rd have been

Known for a long time the recognition of a probable shared underlying pathology didn’t happen until about 20 years ago and a broader recognition of this as a unified clinical entity has come even more recently than this adding to the relative lack of awareness of the disease is the confusion caused by the long list of other terms that have been used in the past for the

Disease or for individual manifestations every single term here refers to some aspect of igg 4 rd regarding the clinical presentation as already implied there are many different ways in which igg4 rd can present the most common manifestation is autoimmune pancreatitis other common clinical features include sclerosing cholangitis salivary gland enlargement orbital

Pseudotumor which can lead to proptosis retroperitoneal fibrosis manifesting as chronic abdominal and back pain and lymphadenopathy less common but still well-described manifestations include fibrosic thyroiditis pulmonary inflammatory pseudotumor interstitial pneumonia pleuritis fibrosic mediastinitis vasculitis to below interstitial nephritis and renal failure

Despite the condition being immune mediated fever and other signs of systemic inflammation are rare weight loss can be seen but is typically limited to those with pancreatitis while it is possible to have only a single organ affected by igg4 rd which makes diagnosis particularly difficult most patients have more than one organ affected at some point in the course

Of illness some relatively vague phenotypes of rgg4 rd have been described in which patients tend to have clusters of affected organs for example one population of patients tends to have disease predominant in the pancreas liver and biliary system while another has prominent disease only in the head and neck the underlying reason for these phenotypes is suspected

To be genetic in nature but is not well understood regarding the pathogenesis as stated it’s believed to be if not autoimmune at least immune mediated some strong indirect evidence for this is the rapid clinical improvement usually seen with immunosuppressive medications as the name implies the igg4 subclass of antibodies are strongly associated with the disease

And are believed to be central to the pathogenesis however not every affected patient has elevated igg4 antibodies and elevation of igg4 antibodies is not specific to this disease entity so there is clearly something more going on than just circulating igg for antibodies it just hasn’t been figured out yet moving to diagnosis a diagnosis requires consideration of

All the following consistent clinical features consistent radiographic features elevated serum igg4 levels which are only seen in about two-thirds of patients and most critically consistent pathology following biopsy i have not personally ever heard a physician cite the diagnostic criteria for igg4 rd but criterium has been proposed it consists of clinical and

Radiographic features as one unified category a serum igg4 level above 135 milligrams per deciliter and two of three characteristic pathologic features seen on a biopsy of an affected organ if all three of these criteria are present the patient is said to have definite igg4 rd if only one and three are present they are said to have probable disease and if only

One and two are present either because the pathology is inconsistent or because a biopsy has not yet been performed the diagnosis is said to be possible owing to the number of different organs and locations that igg4 rd can manifest and its ability to be either systemic or very focal the disease is often misdiagnosed there are many other diseases that can present

Similarly but some of the more common include solid tumors of almost any organ primary sclerosing cholangitis a variety of autoimmune diseases including both connective tissue disease and vasculitis a condition called castleman disease that presents with diffuse lymph adenopathy and sarcoidosis particularly when there are prominent lung manifestations of the

Igg4 rd when it comes to treatment the literature is relatively sparse and preferred approaches vary between experts and across geography as a general rule steroids are used first for almost all symptomatic individuals atypical regimen would be something like prednisone 40 milligrams daily for several weeks followed by a slow taper azathiopine and mycophenolate

Are options for patients with a strong contraindications to steroids rituximab is sometimes used for patients with multi-organ disease or unusually high levels of igg4 and maintenance therapy after disease remission is sometimes used but the optimal medication and duration for this is currently not known in addition to medications surgery or other interventional

Procedures are sometimes indicated for example biliary stenting repair of aortic aneurysms relief of hydronephrosis and debulking of sclerosing mesenteritis i’ll end with prognosis as you might guess the natural history and prognosis of igg4 rd is not well defined but appears to depend heavily on the specific organs affected by the disease causes of significant

Morbidity and mortality include aortic aneurysms cirrhosis biliary obstruction renal failure and diabetes from pancreatitis thanks for watching this brief overview of igg4 related disease consider subscribing to strong medicine for more videos and underappreciated diseases like this one and a variety of other medical topics

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IgG4 Related Disease By Strong Medicine