Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Call emergency services for:
A first seizure
A seizure that does not stop promptly or repeats without recovery
Serious breathing difficulty or blue, grey, or very pale skin
Unresponsiveness or difficulty waking
Sudden severe weakness or loss of movement
Follow an existing seizure emergency plan if one has been provided.
PVL itself is not usually an emergency diagnosis, but sudden symptoms may be emergencies for other reasons.
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek prompt medical advice if a child suddenly loses a skill they previously used, develops new weakness, has repeated unusual staring or jerking episodes, or begins choking frequently during feeds.
These changes are not automatically caused by PVL and may need separate investigation.
3
Does any of this apply?
Book an appointment
Arrange routine follow-up if you notice delayed milestones, persistent muscle stiffness or floppiness, unusual movement patterns, feeding difficulty, or concerns about vision, hearing, speech, behaviour, or learning.
Early assessment can identify useful support even before a specific diagnosis is clear.
Every sign above is quoted from the sofidex article on Periventricular leukomalacia. If you are not sure, err upward — it is always reasonable to be checked.