On this page
- Is a headache after a car accident serious?
- Danger signs: call 911 or go to the emergency department
- What is a concussion or mild TBI?
- Can a car crash cause a brain injury?
- Symptoms the CDC lists for mild TBI and concussion
- How long does recovery take?
- What the CDC says to do after a mild TBI or concussion
- Caring for someone who may have a brain injury
- Records and deadlines
- Questions
- Sources
CrashFirst is not a medical provider and cannot tell you what is wrong. If someone is unconscious, will not wake up, is having a seizure or is getting worse, call 911. For any head injury or lasting headache, see a doctor or other health care provider. Do not delay care.
Short answer
Is a headache after a car accident serious?
A headache after a crash can have many causes. MedlinePlus advises: "Get medical help right away if you have a headache after a blow to your head" [10]. The CDC lists a headache that "gets worse and does not go away" [1] as a danger sign: call 911 or go to an emergency department. For any head injury, see a health care provider and do not delay.
Call 911
Danger signs: call 911 or go to the emergency department
The CDC says some people develop a dangerous blood clot that crowds the brain against the skull [1]. For adults, the CDC says the people checking on you should "call 9-1-1 or take you to an emergency department right away" [1] if you have any of these signs:
| CDC danger sign (adults) | Source wording |
|---|---|
| Headache | "Have a headache that gets worse and does not go away" [1] |
| Nerves and movement | "Experience weakness, numbness, decreased coordination, convulsions, or seizures" [1] |
| Vomiting | "Vomit repeatedly" [1] |
| Speech and behavior | "Have slurred speech or unusual behavior" [1] |
| Eyes | "Have one pupil (the black part in the middle of the eye) larger than the other" [1] |
| Awareness | "Cannot recognize people or places, get confused, restless, or agitated" [1] |
| Consciousness | "Lose consciousness, look very drowsy or cannot be woken up" [1] |
NINDS gives a similar instruction: "Seek immediate medical attention if the person experiences any of the following symptoms, especially within the first 24 hours after an injury to the head" [7] Its list includes convulsions or seizures, unequal pupil size, clear fluids draining from the nose or ears, and new neurological problems such as slurred speech or weakness of arms, legs or face. Call 911 or go to an emergency department; do not wait to see if it passes.
Definitions
What is a concussion or mild TBI?
The CDC says a mild TBI or concussion is caused by:
- "A bump, blow, or jolt to the head" [2]
- "By a hit to the body that causes the head and brain to move quickly back and forth" [2]
MedlinePlus says "Concussions are a type of mild TBI" [8]. The CDC adds that providers may call these injuries mild "because they are usually not life-threatening" [2], but "the effects of a mild TBI or concussion can be serious." [2] A provider decides whether an injury is a concussion. The CDC says a CT scan "is not needed to spot a mild TBI or concussion" [2], though it may sometimes be used for people at risk for bleeding on the brain. Ask a health care provider what applies to you.
Crashes and TBI
Can a car crash cause a brain injury?
Yes, according to the sources below. A TBI does not require a hit to the head: the CDC says it can come from "a hit to the body that causes the head and brain to move quickly back and forth" [2].
| Source | What it says about motor vehicle crashes |
|---|---|
| CDC, Facts About TBI | "People most commonly get TBIs from a fall, firearm-related injury, motor vehicle crash, or an assault." [4] |
| NINDS | Causes of non-penetrating TBI include "falls, motor vehicle crashes, sports injuries, blast injury, or being struck by an object." [7] |
| MedlinePlus | "Motor vehicle crashes. This is the most common cause in young adults." [8] |
| CDC, TBI Surveillance Report (deaths, 2018 and 2019) | Unintentional motor vehicle crashes "accounted for approximately 17%" of all TBI-related deaths [6] |
| CDC, TBI Data | "approximately 214,110 TBI-related hospitalizations in 2020" [5] and "68,663 TBI-related deaths in 2023" [5] (all causes, not only crashes) |
The 17% figure is the CDC's wording for 2018 and 2019 deaths, across all ages. The two counts in the last row include every cause of TBI. Neither shows how many people hurt in crashes are injured or recover.
NINDS also notes that "Contusions can appear after a delay of hours to a day." [7] and MedlinePlus says "The head may look fine, but problems could result from bleeding or swelling inside the skull." [9] For adults who take blood thinners, the CDC says "These medicines may increase the risk for bleeding in the brain following a TBI." [4] and that providers should check older adults for TBI if they have "Been in a car crash." [4] Talk to a provider about your own medicines.
Symptoms
Symptoms the CDC lists for mild TBI and concussion
The CDC says "Some mild TBI and concussion symptoms may appear right away, while others may not appear for hours or days after the injury." [1] It also says "Symptoms of mild TBI and concussion are different for each person." [1] It groups them like this:
| Type | CDC list |
|---|---|
| Physical | Bothered by light or noise; dizziness or balance problems; feeling tired, no energy; headaches; nausea or vomiting (early on); vision problems [1]. |
| Thinking and remembering | Attention or concentration problems; feeling slowed down; foggy or groggy; problems with short- or long-term memory; trouble thinking clearly [1]. |
| Social or emotional | Anxiety or nervousness; irritability or easily angered; feeling more emotional; sadness [1]. |
| Sleep | Sleeping less than usual; sleeping more than usual; trouble falling asleep [1]. |
The CDC cautions that "A person may not recognize or admit that they are having problems" [1] and that "Problems may be overlooked by the person with a mild TBI or concussion, their family members, or their healthcare provider" [1]. Having any of these symptoms is a reason to see a health care provider, and any danger sign above is a reason to call 911.
Recovery
How long does recovery take?
The sources give a range, and none can predict one person's recovery:
- CDC: "Symptoms generally improve over time, and most people with a mild TBI or concussion feel better within a couple of weeks." [1]
- CDC: "Some people will have symptoms for months or longer." [3] It says to talk with a provider if symptoms "Do not go away within 2 to 3 weeks" [3] or "Get worse after you return to your regular activities" [3].
- CDC: "Recovery may be slower among: older adults, young children, and people who have had a concussion or other TBI in the past." [3]
- MedlinePlus: "most people completely recover in time." [8]
- NINDS: a concussion "could take minutes to several months to heal." [7] Post-concussion syndrome "involves symptoms that last for weeks or longer." [7]
- CDC, on moderate or severe injury: "People with a moderate or severe TBI may need ongoing care, such as rehabilitation services, to help with their recovery." [4]
If symptoms are not getting better or are getting worse, tell your health care provider.
What the CDC says to do after a mild TBI or concussion
From the CDC and MedlinePlus
Get medical care first. The CDC says "People with a mild TBI or concussion need to be seen by a healthcare provider." [2] MedlinePlus says "For a mild head injury, no treatment may be needed. However, contact your provider for medical advice and watch for symptoms of a head injury, which can show up later." [9] The steps below are the CDC's general home-recovery tips and do not replace a provider's instructions.
Helping someone else
Caring for someone who may have a brain injury
If the person has just been hurt, MedlinePlus says to call 911 if "You suspect a serious head or neck injury, or the person develops any signs or symptoms of a serious head injury." [9] Its first-aid page also says "Do not move the person unless absolutely necessary." [9] and "Do not shake the person if they seem dazed." [9]
For longer-term support, the CDC says "There are many organizations who can help you and your family as you recover from a brain injury." [11] Its page lists "Some groups that offer support for people living with a TBI, their family, caregivers, and loved ones" [11]. The CDC also advises: "Keep talking with your healthcare provider, family members, caregivers, and loved ones about how you are feeling." [3] We did not find a separate CDC caregiver-care guide, so we do not give one here.
Your records
Records and deadlines
CrashFirst does not give medical or legal advice. For keeping your own papers in one place, see how to get medical records and bills and the free crash journal, which has a page for symptoms and medical visits. The CDC's own advice is to "tell your healthcare provider" [3] if you are not getting better.
Legal deadlines exist and differ by state. They are separate from medical care; do not delay care because of them. See the pages for Tennessee, Alabama, Oklahoma and South Carolina, the deadline calculator, or ask an attorney how a deadline applies to you. For the neck and back side of a crash, see neck and back pain after a car accident. For the first steps after any crash, see what to do after a car accident.
Want to talk it through? A person usually calls you back in about 15 minutes (8am to 8pm Central). You never pay CrashFirst. CrashFirst is not a law firm or a medical provider, does not evaluate your crash and does not give legal or medical advice. For an emergency, call 911. General information as of November 9, 2026.
Sources
- CDC, Symptoms of Mild TBI and Concussion (updated Sept. 15, 2025) (checked November 9, 2026)Official source“gets worse and does not go away”“In rare cases, a dangerous blood clot that crowds the brain against the skull can develop.”“call 9-1-1 or take you to an emergency department right away”“Have a headache that gets worse and does not go away”“Experience weakness, numbness, decreased coordination, convulsions, or seizures”“Vomit repeatedly”“Have slurred speech or unusual behavior”“Have one pupil (the black part in the middle of the eye) larger than the other”“Cannot recognize people or places, get confused, restless, or agitated”“Lose consciousness, look very drowsy or cannot be woken up”“Some mild TBI and concussion symptoms may appear right away, while others may not appear for hours or days after the injury.”“Symptoms of mild TBI and concussion are different for each person.”“Dizziness or balance problems”“Problems with short- or long-term memory”“Irritability or easily angered”“Trouble falling asleep”“A person may not recognize or admit that they are having problems”“Problems may be overlooked by the person with a mild TBI or concussion, their family members, or their healthcare provider”“Symptoms generally improve over time, and most people with a mild TBI or concussion feel better within a couple of weeks.”“most people with a mild TBI or concussion feel better within a couple of weeks.”“may not appear for hours or days after the injury”
- CDC, About Mild TBI and Concussion (updated Sept. 15, 2025) (checked November 9, 2026)Official source“A bump, blow, or jolt to the head, or”“By a hit to the body that causes the head and brain to move quickly back and forth”“because they are usually not life-threatening”“the effects of a mild TBI or concussion can be serious.”“is not needed to spot a mild TBI or concussion”“a hit to the body that causes the head and brain to move quickly back and forth”“People with a mild TBI or concussion need to be seen by a healthcare provider.”“Contact your healthcare provider as soon as you can if you think you have a mild TBI or concussion.”“Patients experiencing mild TBI or concussion danger signs should seek care right away at an emergency department.”“Most TBIs that occur each year are mild TBIs or concussions.”
- CDC, What to Do After a Mild TBI or Concussion (updated Sept. 15, 2025) (checked November 9, 2026)Official source“Some people will have symptoms for months or longer.”“Do not go away within 2 to 3 weeks”“Get worse after you return to your regular activities”“Recovery may be slower among: older adults, young children, and people who have had a concussion or other TBI in the past.”“Resting is good the first few days after a mild TBI or concussion as this is when symptoms are more severe.”“Ask your health care provider for written instructions about when you can safely return to work, school, or other activities, such as driving a car.”“Ask your healthcare provider about medications that are safe to take during recovery to help with symptoms.”“Avoid activities that can put you at risk for another injury to your head and brain, such as playing sports.”“Keep talking with your healthcare provider, family members, caregivers, and loved ones about how you are feeling.”“tell your healthcare provider”“If you do not think you are getting better or your symptoms are getting worse, tell your healthcare provider.”
- CDC, Facts About TBI (updated Aug. 4, 2025) (checked November 9, 2026)Official source“People most commonly get TBIs from a fall, firearm-related injury, motor vehicle crash, or an assault.”“These medicines may increase the risk for bleeding in the brain following a TBI.”“Been in a car crash.”“People with a moderate or severe TBI may need ongoing care, such as rehabilitation services, to help with their recovery.”“Most people with a mild TBI or concussion can recover safely at home following a medical check-up.”
- CDC, TBI Data (updated Apr. 27, 2026) (checked November 9, 2026)Official source“approximately 214,110 TBI-related hospitalizations in 2020”“68,663 TBI-related deaths in 2023”
- CDC, TBI Surveillance Report, 2018 and 2019 (deaths by mechanism of injury) (checked November 9, 2026)Official sourceWhere: p.10, key findings, motor vehicle crashes 17%
- NINDS (NIH), Traumatic Brain Injury (TBI) (checked November 9, 2026)Official source“Seek immediate medical attention if the person experiences any of the following symptoms, especially within the first 24 hours after an injury to the head:”“falls, motor vehicle crashes, sports injuries, blast injury, or being struck by an object.”“Contusions can appear after a delay of hours to a day.”“could take minutes to several months to heal.”“Post-concussion syndrome involves symptoms that last for weeks or longer.”“Causes include falls, motor vehicle crashes, sports injuries, blast injury, or being struck by an object.”
- MedlinePlus (NIH/NLM), Traumatic Brain Injury (checked November 9, 2026)Official source“Concussions are a type of mild TBI”“Motor vehicle crashes. This is the most common cause in young adults.”“most people completely recover in time.”“If you start doing too much too soon, it may take longer to recover.”
- MedlinePlus (NIH/NLM), Head injury - first aid (checked November 9, 2026)Official source“The head may look fine, but problems could result from bleeding or swelling inside the skull.”“For a mild head injury, no treatment may be needed. However, contact your provider for medical advice and watch for symptoms of a head injury, which can show up later.”“You suspect a serious head or neck injury, or the person develops any signs or symptoms of a serious head injury.”“Do not move the person unless absolutely necessary.”“Do not shake the person if they seem dazed.”“The person is confused, tired, or unconscious.”“Symptoms of a head injury can occur right away or may develop slowly over several hours or days”
- MedlinePlus (NIH/NLM), Headache (checked November 9, 2026)Official source“Get medical help right away if you have a headache after a blow to your head”
- CDC, Where to Get Help (TBI support organizations) (checked November 9, 2026)Official source“There are many organizations who can help you and your family as you recover from a brain injury.”“Some groups that offer support for people living with a TBI, their family, caregivers, and loved ones”“people living with a TBI, their family, caregivers, and loved ones”
Page last updated November 9, 2026. Attorney review pending. General information, not legal advice. Fees, hours and rules change; confirm on the official page. How we source.
Questions
Can a car crash cause a traumatic brain injury?
Yes, according to the CDC [4]. NINDS lists motor vehicle crashes among the causes of a non-penetrating TBI [7]. Anyone who thinks they may have a head injury should be seen by a health care provider, and anyone with a danger sign should call 911.
What are the five danger signs of a head injury?
The CDC lists seven danger signs for adults, not five, and says to act on any of them [1]. They are in the table on this page: a worsening headache, weakness or numbness or seizures, repeated vomiting, slurred speech or unusual behavior, one pupil larger than the other, not recognizing people or places, and losing consciousness or being very drowsy. Call 911 or go to an emergency department if you see any of them.
What are the top 3 signs of a concussion?
The CDC does not rank signs. It says "Symptoms of mild TBI and concussion are different for each person." [1] Its list covers physical symptoms (such as headaches, dizziness or balance problems, and nausea or vomiting early on), thinking and remembering, social or emotional changes, and sleep changes. See a health care provider for any of them.
What is a mild traumatic brain injury?
The CDC says "Most TBIs that occur each year are mild TBIs or concussions." [2] It describes a mild TBI or concussion as caused by a bump, blow or jolt to the head, or a hit to the body that makes the head and brain move quickly back and forth. Providers call them mild "because they are usually not life-threatening" [2], but the CDC adds "the effects of a mild TBI or concussion can be serious." [2]
Does your brain ever fully recover from a concussion?
The sources describe a range. The CDC says "most people with a mild TBI or concussion feel better within a couple of weeks." [1] MedlinePlus says "most people completely recover in time." [8] NINDS says a concussion "could take minutes to several months to heal." [7] The CDC also notes "Some people will have symptoms for months or longer." [3] If symptoms are not improving, tell your health care provider.
How can I treat a concussion at home?
The CDC says "Most people with a mild TBI or concussion can recover safely at home following a medical check-up." [4] Its home steps are listed on this page. They come after a medical check-up, so see a health care provider first and follow their instructions. If you have any danger sign, call 911 or go to an emergency department instead.
How do you care for someone with a traumatic brain injury?
For someone who may have a head injury right now, MedlinePlus says to call 911 if "The person is confused, tired, or unconscious." [9] For ongoing support, CDC lists organizations for "people living with a TBI, their family, caregivers, and loved ones" [11]. The CDC also says "If you do not think you are getting better or your symptoms are getting worse, tell your healthcare provider." [3]
How long after a head injury can symptoms appear?
Some appear right away and some later. MedlinePlus says "Symptoms of a head injury can occur right away or may develop slowly over several hours or days" [9]. The CDC says symptoms "may not appear for hours or days after the injury" [1]. If a danger sign appears, call 911 or go to an emergency department.
CrashFirst is not a law firm and does not give legal advice. This checklist is general information. Every situation is different.
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