Thunderclap headache

35 year-old female comes into the emergency department with the worst headache of her life. How would you assess the patient?

I would start by taking a focused history regarding the headache, specifically looking at the onset of symptoms and whether the headache is progressive or not. I would look for red flag features in the headache and ask for any focal neurological symptoms as well. I would also inquire about systemic symptoms. After this, I would do a focused A to E assessment

• Airway: I would ensure the airway is patent and if necessary insert an airway adjunct such as OP or NP airway. If the patient is tolerating an airway adjunct I would be really worried and seek the help of the critical care team after my assessment if there was a problem with the airway assessment.
• Breathing: I would look at the observations specifically the oxygen saturation and the respiratory rate. If the patient is hypoxic or if the patient has an increased work of breathing I’ll start the patient on supplemental oxygen therapy. I would also get a PEFR and an ABG done for this patient to see what the pH, pO2, pCO2 and HCO3 and lactate. I would be very concerned if the HCO3 and pH are very low. I would also keep an eye out on the electrolytes on the blood gas that was done. I would also arrange a portable CXR for the patient.
• Circulation: I would look at the observations specifically the BP, heart rate and CRT. If there is evidence of hypotension or tachycardia I would give a fluid challenge to the patient to see if there is an adequate response. And if the patient remains hypotensive despite the first fluid challenge I will give another fluid challenge and ensure the critical care team is aware of the patient. I would also ensure the patient has a working cannula and send basic bloods including septic screening. I would also request an ECG for the patient.
• Disability: I would check the patients blood glucose and capillary ketones, temperature and do a focused neurological assessment that includes GCS. Specifically if the GCS is less than 8 or if there are focal neurological deficits I would be concerned and investigate this further. Given that she has come in with a thunderclap headache, I would arrange an urgent CT head for this patient.
• Exposure: I would examine the patients abdomen and look for evidence of an intra-abdominal pathology.

Question: the onset of headache was 12 hours ago and there is no evidence of focal neurological signs on exam. Blood gases are unremarkable. What are your differentials and what would you do next?

As the patient has come in with a thunderclap headache I would discuss with my senior and send some bloods including clotting screen. I would aim to get the CT head with an angiogram done as soon as possible and consider a lumbar puncture to look for xanthochromia.

My differentials in this case would be SAH, RCVS, Cervical dissection and other rarer causes such as viral meningitis that can present with a thunderclap headache. Once these secondary causes are ruled out I would consider one of the primary headaches as a potential diagnosis here and refer the patient to the Neurology team for the review.