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Diagnosis Deconstructed

Diagnosis Deconstructed: Molecular Mimicry

Morchi, Ravi MD

doi: 10.1097/01.EEM.0000405493.39288.5f

    “See, there it went again,” said the grandmother.

    It was not rhythmic or regular, and did not coincide with arterial pulsation, but instead had a choppy, inconsistent quality to it.

    “Do you feel that?” I asked.

    “Yes,” said my patient, the granddaughter.

    “Do you feel it coming on? Can you stop it from happening?”

    “No, it just happens.”

    Doesn't sound like a simple tic in that case. No urge to perform. No release of underlying stress.

    Her neck had small nontender, anterior cervical triangle lymph nodes. Chest was clear and heart regular. Abdomen soft and no organomegaly. Extremities nontender, no edema, no rash.

    During her exam, she twitched multiple times. Short bursts, more frequent than when we were taking a history.

    “It's worse when she feels uncomfortable or knows she is being watched,” said her grandmother.

    “I see that.”

    It's three in the afternoon, and Grandma brought her granddaughter into our ED right after school, hoping not to alert or alarm the parents.

    Her movements occurred in flurries. Contractions of the obicularis oculi and obicularis oris. Mostly on the right side of her face and not the left. No other part of her body involved.

    The disease she had was of her body's own making. Other living organisms had long since departed the scene.

    “Have you seen your pediatrician for this?”

    “No.” They were not fond of their personal physician.

    “She is under a lot of stress lately. Her parents are separating, and I think she is under a lot of stress,” added her grandmother. “Once I watched her sleeping, and she didn't do it at all.”

    At 8, she is an only child, doing well in school, and has a stable set of friends and no social trouble inside or outside of the classroom. Not emotional, not acting out or defiant.

    They were short, brief thoughts on the part of her facial muscles. Not long, sustained meditation on a topic, as in dystonia. Not a flowing, snakelike, and writhing poetry recital as in athetosis. No, these were small investments of time and energy. Coarse but no so much as to fling an extremity wildly at a proximal joint. Not hemiballism. In their defense, her muscles were not yelling. No, I have to say less flagrant than that. Chorea? Possibly. But even quicker and involving just discrete muscle groups. This seemed more like myoclonus.

    Her vital signs were normal, and she appeared physically and mentally well developed for her age. She was mature, talkative, and relaxed for a child in an emergency department. I gathered she was an experienced patient, comfortable being prodded by physicians.

    “Have you been to the doctors' often?”

    She nods and smiles.

    “Oh, yes. Lots. She is always catching a cold. Sick with something or the other. We are in and out of urgent cares,” added Grandma.

    “And your doctor?”

    “We see her doctor, and all he does is give her antibiotics, sometimes shots, sometimes pills. He hardly does anything else. And they keep coming back. We are thinking of finding a new pediatrician.”

    Hmmm. The primary physician battling back the instigator. This entity is devious though. Months after you think you have things beat, it shows up. Sometimes abruptly and for no apparent reason at all. We expect it to come with its colleagues, partners in its crime more easily recognized. But we find that, more often, it surfaces in isolation.

    “So when did she finish her last course of antibiotics?”

    “Just about two weeks ago. Amoxicillin again.”

    Her posterior pharynx and tonsillar pillars appeared clear.

    She had fluent production and comprehension of speech, normal visual fields, and normal cranial nerve function. Her gait, coordination, and gross motor strength were unremarkable. No pronator drift. No subjective sensory abnormalities to her face or any other part of her body.

    The motor and sensory strips were intact. Cortical association areas firing. Motor tracts from the cerebrum down through the brainstem and spinal cord were transmitting impulses. This was not a problem with higher cortical areas or the pyramidal system. This problem was just laterally placed, in the basal ganglia. An extrapyramidal issue. Something concerned with the initiation, perpetuation, and extinction of motion.

    “Do you feel stressed?” I thought, being very mature for her age, she might be able to provide an honest answer to the question.


    “And what about your parents?”

    “Well, I don't want them to be apart.” She did not seem distraught over it, though. Nor did she seem to feel responsible for the whole thing. She claimed to understand that it had little to do with her. And by the way she carried herself during questioning, I believed her: no barrage of thoughts from her obiularis muscles.

    I have read that this entity can present without motor findings, just alterations to mood, personality, or cognition. At times associated with mental obsessions or compulsive behavior as the lead finding. The invading organism driven away by the primary physician and urgent care, it leaves its mark as a body in civil dispute. But how to lure it out?

    I step up to our patient. “Take my fingers and squeeze them. Both hands. As tightly as you can.”

    She had a rhythmic inconsistency to her squeeze. Letting up softly, only to re-grip tighter. And then let up slightly again. She did her best to maintain a constant tone, but when tempted with this maneuver the sign cannot help slipping out.

    Milkmaid's grip.

    “I think we need some blood work.”

    Of all the Jones criteria, Sydenham's chorea is the one that can occur in isolation: no fever, no murmur, no rash, no arthritis, no subcutaneous nodules. The name is misleading because it isn't necessarily chorea. Sometimes it is athetosis or a more prolonged dystonia. Other times, as in our patient, movements resemble myocolonic jerks. Better when relaxed and worse when under any mental stress. Personality disturbance, moodiness, or cognitive changes have led the way in many cases. All are components of an organism gone but not forgotten. Molecular mimicry at the center of a post-streptococcal autoimmune reaction targeting neural tissue.

    Her ASO titers turned out to be positive, and her future was secured with two more physicians added to the circuit: neurology and infectious disease.

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    Dr. Morchiis the director of the Medical Screening Examination program at Harbor UCLA Medical Center and an assistant professor of emergency medicine at UCLA's David Geffen School of Medicine.

    © 2011 Lippincott Williams & Wilkins, Inc.