Tag Archives: autoimmune

Teaching about recurrent fevers in a small-group setting

This is  video from a small-group teaching session that I led based on the case of a child with recurrent fevers.  This case was done as part of my Rabkin Fellowship in Medical Education. I would appreciate your feedback on this teaching session!

What the heck is rheumatology?

When I meet someone for the first time and tell them that I’m a rheumatologist,  I usually get blank stares, as if I had spoken to them in a foreign language.  It doesn’t matter if they are a medical student, family member,  or even an immigration officer.  It doesn’t matter if they have a PhD or they are a high school dropout.  I even see patients in my rheumatology clinic who have no idea what rheumatology is, nor how I’m supposed to help them.

I can’t blame them.  Rheumatology is a weird field.  Just look at the origin of the word “rheumatology.”  The prefix “rheuma,” meaning “to flow,” was first used by a Greek physician 2000 years ago,  referring to the phlegm that flows from the nose when a person is ill.   But rheumatology, as it is practiced today, has nothing to do with phlegm (talk about false advertising!).  Cardiologists don’t have this identity problem because they, of course, manage the heart.   Dermatologists treat your skin.  Proctologists…well, you get the picture.  

A quick web search about rheumatology is not fruitful either.  Rheumatology is defined as: “the medical specialty that manages rheumatic diseases.”  My rheumatology textbook doesn’t even try to define what field is all about.

In addition, we’re not a popular specialty.  I don’t know of one famous rheumatologist.  We’re not usually in the news.  We’re not  the heroes in any movie.  In fact, I don’t  think I’ve ever seen a TV character who is a rheumatologist (even though there is at least one paleontologist on TV!).   The TV character that most closely approximates what a rheumatologist does is my hero Dr. House (no relation, unfortunately) on the TV show House, MD.  He is actually board certified in nephrology and infectious diseases, but he gets consulted on very complicated cases, much like rheumatologists often do.  However, he’d make a lousy rheumatologist because, according to him, “it’s never lupus!”

As I see it, rheumatology is the study of inflammation (swelling, redness, warmth, and pain) occurring in the structures that hold up the body, such as the bones, muscles, and joints.  Arthritis, or inflammation of the joints, is the most common disease that we see, both in children and adults (kids get arthritis too!).  Arthritis comes in a variety of flavors, including juvenile, rheumatic, psoriatic, gouty, osteoarthritis, etc..

We also take care of complex diseases such as systemic lupus erythematosus, systemic sclerosis,  and dermatomyositis, in which the immune system attacks various different organs.  Vasculitis, or inflammation within a blood vessel, is another disease which we treat.  Other strange illnesses (with even stranger names) such as Kawasaki disease, Sjögren syndrome, and relapsing polychondritis are all within the field of rheumatology.

Most of the above-mentioned diseases are considered autoimmune, in which the immune system loses the ability to recognize self from non-self.  When a cell of the immune system passes through the kidney, it should be able to recognize it and say: “Hello! You are my kidney, I will protect you against infections!” However, in autoimmune diseases, the immune cell gets confused and says: “Whoa! What is this bean-shaped organ doing here? You look foreign, I will fight you to the death!”   As a result, the immune cell begins a process of inflammation that causes organ damage.  Many different organs can be affected in autoimmune diseases, and the name of the disease depends on which organ is affected.

At the other end of the rheumatology spectrum are autoinflammatory diseases (my favorite!).  These diseases occur when the machine that produces inflammation goes awry.   Immune cells are tightly regulated to produce inflammation only when needed (such as in response to a microbe or to damaged tissue).  However, in most autoinflammatory diseases, there is a mutation within the inflammation machine that causes it to produce inflammation at inappropriate times.  The immune cell in autoinflammatory diseases says: “Darn, I’m leaking inflammatory fluid yet again!”  Thus, the patient develops episodes of fevers, rashes, and joint pain without any other explanation.

As you can see, rheumatologists manage a wide variety of illnesses that affect many different organs.  Most of these diseases do not have clear causes, which makes rheumatology a fascinating field to study.  At least until a smart marketing team comes up with a better name for our specialty (I vote for “inflammatology!”), you won’t have to look at me weird when I tell you what I do for a living.

Autoinflammatory vs. autoimmune….what’s the difference?

Last week during our weekly physician conference,  I discussed a patient with an autoinflammatory disease.  An elderly male, he had a history of recurrent fevers, hives, and elevated inflammatory markers, which had gone untreated for many years.  Eventually, he developed renal amyloidosis (accumulation of amyloid fibers in the kidney causing kidney failure), and was finally referred to rheumatology clinic for further evaluation.  Although he had many of the classic signs and symptoms of an autoinflammatory disease,  his physicians had not recognized it.  Even at  the conference, some physicians were  unaware of these group of diseases.

Autoinflammatory diseases are a newly described set of illnesses that cause systemic inflammation due to problems in the innate immune system.   The innate immune system includes several types of white blood cells such as neutrophils, macrophages, and natural killer cells.  These cells are the first responders to an infection because any one of them is able to recognize common patterns that are present in many types of pathogens (such as the cell wall in a bacteria).  In response to a pathogen, these cells secrete inflammatory molecules (cytokines) that alert other cells of the immune system and get the body ready to fight.

Autoinflammatory diseases are often caused by genetic mutations within the cells of the innate immune system.  These mutations lead to episodes of unprovoked activation of the immune system (production of inflammatory cytokines, recruitment macrophages, neutrophils, etc).  In a sense, the body acts as if an infection were present, even when there is none.  This is why many of the symptoms of autoinflammatory diseases–such as fever, rashes, joint pain–mimic infections, and why these diseases are often difficult to diagnose.  The best characterized autoinflammatory condition is Familial Mediterranean Fever, which causes recurrent, brief attacks (12 to 72 hours) of fever, abdominal pain, chest pain, joint pain, and evidence of inflammation on blood tests.

In contrast, autoimmune diseases arise from problems in the adaptive (humoral) immune system.  The adaptive immune system is more sophisticated than the innate, and  is made up of very specialized B cells and T cells.  Each B and T cell in our body is unique, and is only able to recognize a specific  pathogen.  Thus, it takes much longer for a B or T cell to recognize that a pathogen has invaded the body.  However, once the pathogen is identified, the cell divides and multiplies, leading to a very effective and direct attack on the pathogen.  B cells also produce antibodies, which help to neutralize the pathogen.  Unlike the innate immune system, the humoral immune system develops “memory,” so that it is better able to fight the pathogen when it reencounters it in the future.

In autoimmune diseases such as lupus, the B and T cells of the adaptive immune system lose the ability to differentiate self from non-self.  That is, they start seeing specific organs in the body as foreign (almost as if they were pathogens!), and thus begin to mount an attack against those organs, often leading to organ damage or destruction.  In lupus, B and T cells often target the kidney, lungs, or heart, often leading to damage or destruction of these organs.  However, autoimmune diseases can target almost any organ in the body.  For example, in multiple sclerosis,  cells attack the brain.   In rheumatoid arthritis, the joint is the target organ.  In pemphigus, the body attacks the skin.  For reasons that are still unknown, autoimmune diseases more often affect women, whereas autoinflammatory diseases usually affect both sexes equally.

In the end, I think my patient may have had Muckle-Wells syndrome, an autoinflammatory disease caused by mutations in the NLRP3 gene.  Autoinflammatory disorders are  are still underdiagnosed and poorly understood.  It seems like every month, a new autoinflammatory disease is discovered (take a look at this week’s New England Journal of Medicine).  Furthermore, various pathways that are abnormal in autoinflammatory diseases have been implicated to play a role in  more common diseases such as heart disease and diabetes.  Thus, by understanding these rare disorders, we may gain a better understanding of  diseases that afflict millions of people throughout the world.