Such fainting spells are likely to be episodes of unresponsiveness called Catatonia.
The causes of catatonia are: Neuroleptic Malignant syndrome, Encephalitis,
nonconvulsive status epilepticus, and acute psychosis.
The first three are neurological conditions and would be ruled out by MRI and/or spinal tap. Since she is due to consult a child neuro, these conditions will be investigated for by the neuro. You should discuss with the neurologist about these conditions.
It is likely that your daughter is having an episode of acute psychosis or a psychological disorder. This is much more common than an actual neurological disorder.
Such an episode is common in young girls of her age and usually can be treated well with sedatives and anti stress medicines.
You should discuss with her meurologist whether they think it to be an acute psychotic episode. You should also discuss with them about an EEG test to rule out a condition called 'nonconvulsive status epilepticus'.
I hope my answer has helped you. Please click on the green 'accept' button below for accepting this answer. Feedback/Bonus will be appreciated.