Concussion - Symptoms of concussion

Symptoms of concussion can be mild to severe and in some cases emergency treatment may be needed.

The most common symptoms of concussion are:

• headache
• dizziness
• nausea
• loss of balance
• confusion, such as being unaware of your surroundings
• feeling stunned or dazed
• disturbances with vision, such as double vision or seeing 'stars' or flashing lights
• difficulties with memory (see below)

Difficulties with memory can take one of two forms, or possibly both forms:

• retrograde amnesia – where you are unable to remember events that occurred before the concussion happened (this usually only affects the minutes immediately leading up to the concussion)
• anterograde amnesia – where you are unable to remember any new information or events after the concussion happened

Both retrograde and anterograde amnesia usually improve within a few hours.

Less common symptoms

Less common signs and symptoms of concussion include:

• loss of consciousness
• vomiting
• slurred speech
• 'glassy eyes' and a vacant stare
• changes in behaviour, such as feeling unusually irritable
• inappropriate emotional responses, such as suddenly bursting into laughter or tears 

When to seek emergency medical treatment

The following signs and symptoms suggest it is likely that the head injury has caused serious damage and you should phone 999 for an ambulance immediately:

• remaining unconscious after the initial injury
• difficulty staying awake or still being sleepy several hours after the injury
• having a seizure or fit
• difficulty speaking, such as slurred speech
• prolonged vision problems, such as double vision
• difficulty understanding what people say
• reading or writing problems
• balance problems or difficulty walking
• loss of power in part of the body, such as weakness in an arm or leg  
• clear fluid leaking from the nose or ears (this could be cerebrospinal fluid, which normally surrounds the brain)
• a black eye, with no other damage around the eye
• bleeding from one or both ears
• sudden deafness in one or both ears

When to seek medical advice

As a precaution it is recommended that you visit your nearest accident and emergency (A&E) department if you or someone in your care has a head injury resulting in concussion and then develops any of the following signs and symptoms:

• loss of consciousness from which the person then recovers
• amnesia (memory loss), such as not being able to remember what happened before or after the injury
• persistent headaches since the injury
• persistent vomiting since the injury
• changes in behaviour, such as irritability, being easily distracted or having no interest in the outside world – this is a particularly common sign in children under the age of five
• confusion
• drowsiness that goes on for longer than an hour when you would normally be awake
• problems understanding or speaking
• loss of balance or problems walking

There are a number of factors that make you more vulnerable to the effects of a head injury:

• being aged 65 or older
• having a previous history of having brain surgery
• having a condition that makes you bleed more easily, such as haemophilia, or having a condition that makes your blood more prone to clotting, such as thrombophilia
• taking anticoagulant medication, such as warfarin, to prevent blood clots or low-dose aspirin

It is also recommended that anyone who is drunk or high on recreational drugs is taken to A&E if they have a head injury resulting in concussion. It is often easy for others around them to miss signs and symptoms of a more severe injury.