My daughter definitely had headaches, fatigues, Seizures, weakness, crying and hyperventilating.........I started taking her to the dr. with my concerns at the age of 12 mos. My concerns were dismissed several times........I finally insisted on a pediatrician appt. and an EEG at our local hospital........EEG came out fine.............my concerns were dismissed. She continued to have headaches...what we now know were TIA's etc at daycare...several more trips to the local dr., pediatrician refused to see me........then the ER dept.--finally I emailed a clinic in Toronto ON, then was seen by a pediatric neurologist........had another EEG--which was normal........finally she was diagnosed at age 6........had 2 surgeries, a stroke after each surgery............she continues to have an occasional headache, some abnormal movements, few to no TIA's. WE are now 2 years post stroke, and post surgery.........she is progressing very well and has recovered well from strokes.........some limited left hand movement and her swallow--is going to be assessed soon.
I have learned to listen to my daughter's symptoms and trust my instincts.........all moyamoya cases are unique......but definitely fatigue, hydration, headaches, weakness, abnormal movements, "dizzy, tingly" sensations seem to be quite universal among Moyamoya patients. ofcourse we feel blessed/lucky that our child is doing so well.....but being ignored, feeling helpless as a parent early on was the biggest frustration in dealing with this disease.

Dawn

Headaches and fatigue from me too.

My Neurologist said the headaches are related to my MM and the fatigue a part of it as well. When I get too tiered or fatigued then the headaches come. Or the headaches are triggered from outside influences.

All of it is related to your blood flow like Shari said.

My daughter had headaches and that's how we found the moyamoya.  Had surgery on one side but still has lots of headaches.  Recently started having numbness in her face.  Not sure if it's medications she on or if it's TIA's.  She goes for a CT Angio next week to see how things are flowing.

Yes, definitely.  My daughter had severe headaches since she was a toddler, and was seen at a nationally known headache clinic for years.  They did not think about doing an MRI-MRA till age 15, when the MM was found.

Had bilateral by-passes.  Still has daily throbbing headaches, related to blood flow in brain.  Also, gets periods of numbness, with dizziness.

My daughter had 4 focal seizures age during first 2 years of life, put on tegretol, saw neurologist then taken off tegretol by age 4.  Started with headaches while on tegretol.  Kept a diary for pediatrician,  found it was mostly related to over excitement, tiredness and busy activities - "nothing to be concerned about".  Kept monitoring them, then started seeing spots, still with headaches, passed out twice, went back to Neurologist - ordered mri, eeg and retina specialist.  first step was mri- passed out there and found MM, diagnosed age 7.  Had bilateral pial synagiosis age 9.  Still having headaches and still tired during holidays or lots of activity.    She gets pale, and this look that instantly i can tell she will wake up with a headache.  Her headaches are always in the early morning, she throws up mucous and they are mainly frontal.  (was later told one of focal seizures was a tia).
I believe fatigue, headaches and seizures are associated with MM. 
It is good to do research like this.  THere are a lot of kids with headaches that get ignored.
TAmmy

my daughters neurologist has advised us to avoid any activities like blowing into musical instrument or blowing up balloons as it affects your co2 levels which in turn affects brain perfusion.

Kyle had 2 major migraine episodes about 4 months prior to the mjr stroke in the left hemisphere that sent us to TX childrens' where he was DX'd w/ MM (age 3 1/2).  Had surgery on both sides (EDAS + dura-inversion).  A few yrs later I mentioned his evening tiredness to a Neurosurgeon at a brain forum and he said that is normal after brain injury due to unaffected areas of the brain having to do more work (crossover, etc) than otherwise would and so they get more tired easier than the normal kid.
He's continued to have a migraine 3-4 X yr, always wakes up w/ them and had nausea when younger. He's now 17 1/2 and taking Depakote for migraines and it is doing a good job of preventing them.  He has daily mild headaches the DR associates with out-of-alligned neck/shoulder muscles from the paralysis.  Kyle won't do the strengthening exercises to help that. Maybe someday.
To my knowledge, he's never had a seizure.
From our experience and all that I've read on this msg bd, all of these symptoms are typical with MM.