Recently I was making our daily rounds at Randall Children’s Hospital and received a lesson from a very young patient of ours.  I say it over and over: “your patients are your teachers”, and it is really true.  I was first told this by Dr. Mizuo Tottori, pediatrician and mentor to many other pediatricians in Hawaii. And life itself has borne out the truth of it, again and again.

This particular little patient has anorexia nervosa and has done very well.  Her parents are competent and loving; but her illness is relentless and merciless. She had been in good remission until the latest bout of symptomatic resurgence.  The twist on the usual story has been the new emergence of “food phobia-like” symptoms along with the anorexic difficulties of eating at all.  She struggles to swallow and pools her saliva. Had presented like this initially, we would have made the diagnosis food phobia and consequently missed the early-onset AN, or at least for a while.  What we have discovered is the “magic food phobia dose” of Olanzapine (7.5 mg) seems to work as well for this mixed presentation as it does for pure food phobia (see also previous blogs).  For strict AN we don’t usually need this high of a dose.  Once we titrated our little girl up to 7.5 mg, her food phobia-like symptoms improved.

So walking back to the office from making rounds, her sweet face in my mind’s eye, I began to think about diagnoses in general and hers in particular.  I tried to think of other medical situations where we have a “mixed diagnosis”.

All diseases have a natural history.  Their natural history encompasses the totality of “how they act”, meaning what the onset is like (sudden, gradual, insidious), expected course of symptoms (rash, fever, weight loss, pain, appetite changes, sweats, etc., etc.), expected duration and course, etc.  Is it acute? Chronic? Does it wax and wane/remit and exacerbate? How does it respond to treatment? Is it fatal? Is it contagious? Does it burn itself out if the patient lives?

For example, if you diagnose a patient with smallpox, we know something about the natural history of this illness: it is caused by the variola virus (therefore “contagious”), there is an incubation period of about 10-12 days (before skin symptoms appear) and a prodrome towards the end of that period involving high fever, back ache, and diarrhea. Then the characteristic rash appears, first in the mouth and then all over the skin: multiple raised spots which blister all at the same time before finally going away (often with severe scarring).  30-35% of people who acquired smallpox (when it existed on planet earth) died of it.  

So now you know its natural history.  You can see why it matters to know this, both to the treating doctor and -- importantly -- to the patient.

But let’s say that, in the middle of a smallpox epidemic, you incorrectly diagnosed a patient with variola when what they really had was an infection with varicella (chickenpox).  Even if you could not do cultures or viral tests, you could likely tell that you had made a mistake by their differing, evolving natural histories.  Chickenpox is also contagious, with an incubation period similar to that of smallpox and a prodrome not entirely dissimilar either: nausea, loss of appetite, aching muscles, and headache.  If you were very experienced you might notice the lack of severe back pain.  But once the rash appeared you would know the difference: the chickenpox are pox at all different stages of blistering, redness and healing or rupture, not a mass of many pox all at the same stage, as is true for smallpox.  Ah hah!  They have a different natural history.  And to underscore why this is vital, almost no one will die of chickenpox.  

So are AN and food phobia like that?  Well, yes, in the sense that they have differing natural histories.  But how about a patient who shows features of both?

To think about that, I need to think about more complex illnesses and nothing’s more complex than rheumatology….  

Let’s say your patient has a strong family history of autoimmune disease (Hashimotos thyroiditis, type one diabetes, multiple sclerosis, etc.) and is suffering from joint pain, muscle inflammation, fevers, exhaustion and a strange thickening in the skin of the hands.  You first think scleroderma or lupus (SLE).  But then, they have features of rheumatoid arthritis and dermatomyositis… confusing.  After a period of watching their illness evolve and seeing how it responds (or doesn’t) to treatment, you decide they have “mixed connective tissue disease” (MCTD) with features of many autoimmune rheumatic illnesses, but a natural history somewhat different than any one of them.

Is AN with food phobia-features like this?  I believe it probably is.

Interestingly, MCTD does not seem to morph into SLE, for example, although they can share common diagnostic features.  Likewise, we do not have experience of food phobia morphing into anorexia nervosa; they seem to be independent illnesses, even when they both result in food avoidance.

I guess the bottom line is that we clinicians are still stuck in the 19th century folks, that’s right -- the 1800’s -- where the primary tool we have at our disposal is basically observation of the natural history. We know what to do, what seems to work, but we are not sure why. The basic biology of childhood eating disorders is still almost entirely unelucidated (not to mention the genetics). And until they are, until genetics and biochemistry replace observation of natural history as our teachers, our patients retain that honor.

In other words, Doctors, pay attention to your patients!