Question:

I have a curious case question to put to you. I just saw a 9-year-old boy with a dx of myotonic dystrophy for a swallow evaluation. However, his mother reports no actual difficulty with swallowing food and liquid, but that he has experienced 4-5 acute episodes of gagging/choking behavior with no oral intake at all, over the last 6 months or so. Apparently, with no liquid or solid material being consumed, he has begun to have episodes where he will cough/gag/choke with such severity that he has difficulty breathing, and it’s very frightening to his teachers/family.

I did a bedside swallow eval and observed very low muscle tone in his tongue, lips and face, but no drooling and no anterior/lateral spillage of bolus textures. There is poor coordination and mastication of solid textures, and often food is swallowed not-fully-masticated, but he showed no s/s of aspiration or penetration with the liquid and solid textures I gave him. I never saw this coughing/gagging behavior today, and don’t quite know what to tell the parents.

My suspicion is that he is aspirating on his own saliva, which does pool in the anterior portion of his oral cavity frequently. But why would this just start to affect him to such an extent, when that has been his baseline for years?

Have any of you heard of this happening with MD? Any ideas a) what is causing the episodes and b) any way to help?

Answer:

Sounds like there are multiple pieces to this puzzle. The systemic hypotonia both distal and proximal makes me wonder about overall motility and integrity throughout the aerodigestive pathway, both oral, pharyngeal, and esophageal and beyond. The lack of adverse overt events reported by family may be an artifact, given that typically hypotonia and hyposensation often go hand in hand. That may be why, along with a likely delay r/t ineffective supra and infrahyoid function, that he does not sense the excess saliva in his oral cavity which you described. The incompletely masticated foods can then be swallowed, likely pharyngeal constrictors are lax to some degree, and the lack of bolus clearance is not sensed until a sufficient volume triggers the altered sensory system, or it eventually migrates toward the airway post feeding.

The likely co-occurring etiology of esophageal dysmotility (EER/LPR) and/or structural/emptying alterations of the esophagus or lower GI tract, or an outpouching, may also be part of the differential. It’s not uncommon for proximal hypotonia to affect the entire body, which would include motility throughout the GI system. Children with postural hypotonia often are high risk for constipation due to poor GI motility and that can create havoc for digestion, provoke reflux and create or exacerbate maladaptive swallowing and feeding behaviors.

Sounds like a VFSS with UGI and small bowel follow through would be very helpful to explore the aerodigestive pathway and objectify his swallowing physiology. I would not be surprised if results indeed raise concerns about silent airway invasion and multiple competing etiologies. I like Amanda’s idea of then pulling in neurology, as his myotonic dystrophy may indeed be worsening and be another part of your differential.

You are doing a great job sorting out a very complex presentation. Our kids like to keep us thinking outside the box.

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