What could cause sudden headache and vomiting without a fever yet blood pressure body temperature are both normal?

Sudden headache and vomiting without a fever, with normal blood pressure and body temperature, can be caused by several factors:

1. Migraines: Migraines are intense headaches that can cause nausea and vomiting. They can be triggered by various factors, including stress, hormonal changes, certain foods, drinks, or weather changes.

2. Sinusitis: Sinusitis is an inflammation of the sinuses, which can cause headaches, nasal congestion, facial pressure, and sometimes nausea and vomiting.

3. Head Injury: A head injury, such as a concussion, can cause a sudden onset of headache, vomiting, and other symptoms like confusion, memory loss, and dizziness.

4. Food Poisoning: Consuming contaminated food or drinks can lead to food poisoning, causing symptoms such as headache, nausea, vomiting, diarrhea, and abdominal pain.

5. Vestibular Disorders: Disorders affecting the balance system in the inner ear (vestibular system) can cause dizziness, vertigo (a sensation of spinning), nausea, and vomiting.

6. Anxiety or Panic Attacks: Severe anxiety or panic attacks can sometimes trigger sudden headaches, nausea, and other physical symptoms.

7. Medication Side Effects: Certain medications, such as chemotherapy drugs, painkillers, antibiotics, or blood pressure medications, can have side effects that include headache and nausea.

8. Caffeine Withdrawal: Abruptly stopping caffeine consumption after regular use can cause withdrawal symptoms, including headaches and nausea.

9. High Blood Pressure: Although mentioned as normal in your statement, it's worth noting that a sudden spike in blood pressure, even if it's still within the normal range, can sometimes cause headaches and vomiting.

10. Carbon Monoxide Poisoning: Exposure to carbon monoxide, a colorless and odorless gas, can cause headaches, nausea, vomiting, and other serious health problems.

If the headache and vomiting persist or worsen, or if there are any accompanying symptoms such as confusion, vision changes, numbness or weakness, difficulty speaking, or a stiff neck, it's important to seek immediate medical attention. These could be signs of a more serious underlying medical condition.