 Welcome to emergency medicine video. In this segment, we will approach headache. We will discuss both the common and the must-not-miss causes of headaches in the emergency department. We will divide this into inside the brain and outside the brain. We will discuss inside brain first. We will further classify the inside the brain reasons based on the structures. What are the different structures of the brain? There are blood vessels, both arteries and veins. There's the brain parankama itself and what surrounds the brain, the ninjies and CSF. Our causes will be based on each structure. First, we will start with blood vessels. There are both arteries and veins in the brain. What can happen to that that can lead to headache? Bleeding from a rupture artery either into the epidural space, subduro space, subarachnoid space. The artery can also go into vasospasm causing migraine. Let's move on to the veins. What can the veins do? It can clot or also known as cerebral venous thrombosis. Let's move on to the brain parankama. Any space occupying lesion in the brain parankama can lead to headache. They include blood, abscess or mass. Let's move on to outside with the CSF and meninges. With CSF hydrocephalus, an intracranial hypertension also known as pseudotumus cerebrae can cause headache. In the ninjies, infections such as meningitis and encephalitis can cause headaches. What about outside the brain? TMJ dysfunction can lead to headaches. So can an inflamed temporal artery also known as temporal arthritis. In the eye, acute angloclosure glaucoma will give people headache. Sinusitis can cause headaches. Going further down, tension headaches can be caused by tight muscles from the neck and shoulders. An external cause that we often forget is carbon monoxide poisoning. These will be the most common causes for headaches that's caused outside of the brain. Out of the ones we've discussed, which ones are the must not miss diagnosis? Inside the brain, almost all the diagnosis are must not miss. Therefore, it includes bleeding, thrombosis, space occupying lesions, infection and intracranial hypertension. Outside the brain, we must not miss acute angloclosure glaucoma and temporal arthritis because it can affect vision. The last one that is a must not miss is carbon monoxide poisoning. In summary, we discussed the causes of headaches. In part two, we would discuss the high yield history in physical. Thank you for watching.