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Diagnosis Deconstructed

Diagnosis Deconstructed: Not of an Iron Lung

Morchi, Ravi MD

doi: 10.1097/01.EEM.0000413156.70183.ec
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    “I think there is something wrong with him. Physically wrong, I mean. I don't know what it is.” — New York Sun journalist James Kahn, 1938

    “Something's wrong with this guy. He has something. I'm just not sure what.” — Harbor UCLA EM resident, 2011

    “I mean, he has had trouble speaking for almost two months. I don't think it's a CVA. I can't really understand what he says. He slurs his words. He sounds intoxicated,” the resident continued.

    I enter the room to find a 55-year-old Caucasian man sitting upright in bed. He appears comfortable. At first he seems to withhold words, but with coercion he will speak.

    My eyes meet his; attention and focus are normal. He is bothered by how distorted he sounds. He knows something is wrong, and he can no longer cover it up. Cognition and higher cortical function, check.

    He sits nicely, does not sway. He seems to have good posture and balance. Cerebellum and axial muscle strength, check.

    He watches me cross the room. Smooth, no limitations to eye motion. Midbrain and upper pons, check.

    He is not sitting in a pool of his own drool. He is not spitting into a cup. The epiglottis is able to cover the tracheal inlet while he swallows his own secretions. Cricothyroid and strap muscles are functional. Airway patency, check.

    His voice is muffled. Words are drawn out, and consonants have lost their sting. Vowels tend to merge with one another, and the rhythm to his speech is off. He periodically breaks into a smile as he tries to speak.

    Why is he smiling? At least his peri-oral facial muscles are intact, VII working. Lower pons, check.

    Say “ca, ca, ca,” I instruct.

    “Nga, nga, nga,” he barks.

    I've heard that before. Movements of his posterior soft palate and the base of his tongue stifled. On inspection, neither side of his soft palate rises well with “ahhh.”

    IX or X? We are down to the medulla.

    Say “la, la, la.”

    “Ah, ah, ah.”

    XII is also involved. The tip of his tongue cannot reach his hard palate. So the medulla it is. Maybe ischemic, demyelinating, or neoplastic. Unlikely metabolic or a nutritional deficit. To see this area in detail, an MRI is in his future.

    Localization. Grip strength in his left hand is 4/5, but otherwise he is 5/5 in the right upper extremity and both lower extremities. He has a left pronator drift, but reflexes are diminished throughout. Toes downgoing bilaterally.

    Although he has bilateral palate and pharyngeal paresis, he has only mild and asymmetric upper motor neuron weakness in his left arm. The medial and ventral brainstem lesions I proposed would almost certainly pierce, not just jar, the corticospinal tracts. His extremity deficits should be much greater.

    So maybe this is not a brainstem issue? I step out of the CNS: degeneration of cranial nerve axons or their myelin sheaths? The acute form is Guillain-Barre, and it has variants that start from the top rather than the bottom. His symptoms are longstanding, however. It would have to be a chronic, not acute, demyelinating process.

    Another option. Multiple nerves picked off as they exit the brainstem and pierce through meninges on their way out of the CNS. We see such lower brainstem involvement with tuberculosis meningitis and other purulent, thick meningeal infiltrates that gather near the base of the brain. Or with malignant skull base metastases encasing cranial nerves as they course through bony foramen. But he has no headache or alteration in mentation, and he is not systemically ill. Nothing in him points to inflammation, and he has no known malignancy.

    Go further out: the neuromuscular junction? Myasthenia would fluctuate with use and effort, not classically a constant problem. Lambert-Eaton is in a different distribution, and botulism does not have a chronic course.

    Step out of the nervous system altogether and into the myofiber. Myositis or myopathy with a predilection for pharyngeal muscles? He does not endorse sensory symptoms. This could fit except a pronator drift should not be present.

    Nonlocalizable. I concede it is not a localized process. Sitting among myofibers, I decide to do a cardiac exam. If skeletal muscle, why not cardiac muscle, too? He removes his gown, and I notice something.

    Worms. Crawling all under his skin within his deltoids, pectoralis, and sternocleidomastoids. I follow them cephalad, and see them squirming underneath the mucosa of his tongue. He cannot control them. Myofibers choosing to contract asynchronously from their neighbors. No coordination of fiber movement. This is anarchy of multiple muscle groups. In the heart, it would be ventricular fibrillation. In skeletal muscle, we call it fasciculation.

    Oh, no. I can feel the depth of his illness now. It will consume all his motor faculties, but his cognition will cruelly remain intact. He will shrivel up, lose the ability to control his secretions, be confined to bed, and eventually stop breathing due to respiratory muscle fatigue. Infection may intercede to spare him months of misery. But there is no cure. He must exist, alone, aware of his demise, and neither he nor I nor the field of medicine at large can do anything about it.

    Fasciculations are not characteristic of a myofiber problem. They imply lower motor neuron disease of the anterior horn cell or its axons. As input to normal muscle is lost, the myofibers get antsy. It takes a few weeks for them to speak up, but certainly they do. Without central regulation, anarchy ensues in the local muscle groups. Fortunately, other anterior horn cells recognize this and begin to sprout buds off their axons to reinnervate the lonely, neglected myofibers. In this way, larger motor units are eventually formed, and now, under some central neural control, myofiber fasciculations cease. That is, at least until the said altruistic motor neuron also succumbs to our patients neurodegenerative process.

    Most polio was asymptomatic or had only mild gastrointestinal symptoms, sometimes an “aseptic” meningitis. But the ones we read about were the significant minority that had anterior horn lower motor neuron death.

    Our patient does not have the disease of an iron lung but one of an iron horse. Not an attack on anterior horn cells in particular but an attack on motor neurons in general, lower and upper. His fasciculations and slurred words are a testimony to lower motor neuron demise. His pronator drift and staccato arrhythmic speech point to upper motor neuron degeneration.

    New York Sun journalist, James Kahn 1938: “I have watched him very closely, and this is what I have seen: I have seen him time a ball perfectly, swing on it as hard as he can, meet it squarely — and drive a soft, looping fly over the infield. In other words, for some reason that I do not know, his old power isn't there….”

    “Touch my finger with your finger.”

    True to form, he can hit a target. His coordination and comprehension of spatial relationships intact, he has simply and solely lost power.

    Eerily, he smiles again. Pleased that he can touch my finger?

    Pseudobulbar hyperemotionality. The term bulbar palsy means lower motor neurons in the medulla have given up. Words are hollow, nasal, muffled, “intoxicated.”

    In our patient, the coordinating upper motor neurons are also dying. Medullary lower motor nuclei liberated in this way produce an irregular, arrhythmic, strained quality when words are strung together. This is pseudobulbar palsy.

    And the lower brainstem released in this manner means a tendency for any hint of an emotion to result in a physical response. Unregulated by upper motor neurons, he smiles for no apparent reason. He cannot control it. An ominous finding that places a shorter time course on his life. Pseudobulbar hyperemotionality.

    The weight of his illness is apparent to me in the room. My shoulders feel heavy. Is it apparent to him? I should tell him. I take his hand in mine. I am losing it now … control over my own emotions, that is.

    He smiles.

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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.

    FastLinks

    ▪ Read all of Dr. Morchi's past columns in the EM-News.com archive.

    ▪ Comments about this article? Write to EMN at emn@lww.com.

    In Brief: Egleston Receives Level I Distinction

    The Egleston campus of Children's Healthcare of Atlanta gained a Level I trauma level after demonstrating model care while acting as a Level I facility for a year. Children's at Egleston and Children's at Scottish Rite, a Level II pediatric trauma center, are the only two pediatric trauma centers in the state. They offer access to pediatric specialty coverage including general pediatric surgery, neurosurgery, orthopedics, plastic surgery, hand surgery, maxillofacial surgery, and rehabilitative services.

    © 2012 Lippincott Williams & Wilkins, Inc.