The continued story of our visit to the Mayo Clinic.
We started our long day with a visit to metabolics. A detailed history was taken and we reviewed the family genetic history that I had provided a couple of days before. There was much discussion and review of Kate’s “episodes” and detailing what exactly occurs. We discussed specifics such as Kate’s blood lactate, muscle biopsy and results, and carnitine levels etc. I am still amazed at the amount of medical information and detail I carry around with me in my head. Details memorized and complicated medical jargon understood and able to be discussed as needed. (Where did I put that MD diploma?).
The metabolics resident – yes, we met with a resident first – was very interested in Kate’s sensory neural hearing loss, developmental delay, sideroblastic anemia and her episodes. She felt they are clearly pointed to a metabolic disorder. Again, this was not news to us, but good to hear from yet another source.
Something that was explained to us that I did not fully appreciate were the muscle biopsy results. Kate’s results were coming back negative for mitochondrial disease. In brief, she had many mitochondrion in the muscle and they are appeared to be healthy/normal. What was explained to us at the Mayo Clinic is that the tissue biopsy needs to come from affected muscle and/or the brain. A negative result can simply mean that tissue is not affected – at that time. As I have said before, mitochondrial disease can be a bitch to diagnose.
A Lesson on Mito
I got an extensive biology lesson at Mayo about mitochondrial disease:
– in kids the more common causes of mitochondrial disease are the nuclear genes (maternal DNA)
– mito is very difficult to diagnose (better now in 2013)
– not all mitochondrial diseases cause increase lactic acid in the blood or prolonged elevated blood lactate
– not all tissue are affected, e.g. in Kate her muscle tissue of the large rectis femoris leg muscle may not yet be affected, while other areas of her body are
– additional tests can be run on Kate’s tissue samples including; DNA deletion sequencing (I thought we had done that), expanded muscle tissue analysis (seems vague), and an EEG when she is having an episode.
We left this first meeting with metabolics feeling no more informed, but interested in what their attending physician would have to say once Kate’s muscle biopsy tissue arrived from Canada and was analyzed. Something that had not been sent in advance.
Our second meeting that day was with Dr.Mack from neurology.
Dr.Mack had reviewed the detailed information provided to his resident and had asked to meet with us again as our last meeting was cut short due to a long day for Kate.
Dr.Mack was convinced that Kate’s ‘episodes’ were episodes of cyclical vomiting syndrome. He felt that a drug cocktail would be able to slow/stop the episodes or at the least reduce their intensity. He proposed Amitryptiline and Riboflavin. He expected episodes to reduce in frequency and intensity and if not – then an extensive GI workup should be done.
Dr.Mack described to us how cyclical vomiting can be common as a stand alone condition at this stage/age in children, and it could be they way mitochondrial disease was presenting. He further described how it could be severe enough to last several days and require hospitalization as had been our experience to date. Though Kate had been prescribed amytriptyline before – Dr.Mack felt the dosage needed to be much higher which would require ‘ramping’ up the dosage over time and watching carefully for side effects such as; increased appetite, listlessness, prolonged QT on EKG.
I was skeptical about amytriptyline. Though cyclical vomiting syndrome seemed to fit for Kate, we had tried amytriptyline before and found Kate had side effects that were disconcerting for us; loss of balance, frequent falls, listlessness. I was not keen to try the drug again – but since it was being recommended by another neurologist (from Mayo), I felt like we should.
We also discussed with Dr.Mack Kate’s global developmental delay and her progression. There had been little information about Kate’s brain myelination pattern since her first MRI at the age of 12 months. A subsequent MRI showed little to no change and the information itself was not a diagnosis or a condition, it was simply a fact that Kate’s white matter was developing slowly and perhaps not creating the neural synapses her brain required to carry information from one area to another. Further, there can be no prediction on development with only this information, and there was nothing more we could find to describe Kate’s developmental delay. Dr.Mack was clear with us that Kate’s delayed myelination pattern was not causing her developmental delay, but that it was part of the bigger picture of Kate’s condition. As for a prediction for development we should look at the near past (3-6 months) as a prediction for how her development will progress. The long-term can’t be predicted with any accuracy.
And then we heard the words again, Mito is very difficult to diagnose, though with Kate’s clinical picture it is the top of the list.
You know what that makes me think of everytime I heard it…this…
Later that afternoon we were to meet with Dr.Lloyd, the coordinating pediatrician at the Mayo Clinic to have a ‘touching base’ meeting to discuss how our visit was going and any concerns we might have. I made a list to discuss at the meeting:
1. What is an appropriate protocol for Kate when she has an episode? i.e. at the ED
2. What other medical conditions can we expect Kate to develop?
3. Vaccines – are they safe for Kate? Should she follow the regular schedule
4. Can we review the step metabolics (at Mayo) are taking to diagnose Kate, e.g. deletion profile, mito DNA and nuclear DNA etc.
5. What is the working diagnosis for Kate?
6. Where can we find reliable, scientific information on mitochondrial disease (diagnosis, treatment, description)
7. What is the difference between a metabolic disorder and mitochondrial disease?
8. Discuss the proposed GI tests and the importance of doing them (i.e. neurology thought we should wait and go step by step)
9. Bloodwork results, bone marrow biopsy slides, muscle biopsy slides (have they arrived from Ottawa)?
10. What is the risk that Kate might suffer a catastrophic event due to this disease. Is there a spectrum?