Hi, thanks for asking from HCM. I can understand your concern. Headache with vomiting could be due to posterior fossa arachnoid cyst. It can be further suspected if : She is having optic disc changes in her both eyes. You have to consult ophthalmologist for it. He will do fundoscopy and look for Papilledema. If Papilledema is present, it means symptoms are because of high brain pressure as a result of arachnoid cyst compression. Arachnoid cyst is treated by surgical decompression and establishing connection with normal brain fluid spaces (cistern). : Another reason could be migraine - It presents as headache in half of head, visual blurring, watering in eyes, tingling sensation same side, aura symptoms before attack e.g. bad smell/bad taste/numbness. If her symptoms are such, then consult neurologist. It can be treated by preventive therapy like Propranolol/gabapentine/amitriptyline and abortive therapy like Sumatriptan/Ergotamine/Naproxen. Any one medicine will be sufficient for her in the beginning. Hope it will help you, If still no relief, you can consult doctor or ask another question. Thanks. Take care.