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
Get emergency help for signs of severe dehydration, such as fainting, confusion, extreme drowsiness, little or no urine, or an inability to keep any fluids down.
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 you:
Cannot drink enough to replace fluid losses
Are passing much less urine than usual
Have ongoing weight loss or difficulty eating
Have blood in your stool, black stools, high fever, or severe pain
Are pregnant, immunocompromised, or caring for an affected young child
Still have symptoms after completing treatment
A child who is difficult to wake, has no tears, or has very few wet nappies also needs urgent assessment.
3
Does any of this apply?
Book an appointment
Arrange a routine medical assessment if diarrhoea lasts more than several days, repeatedly returns, or follows untreated water exposure, travel, or contact with someone who has giardiasis.
Testing is especially useful before taking an antiparasitic medicine.
Every sign above is quoted from the sofidex article on Giardiasis. If you are not sure, err upward — it is always reasonable to be checked.