Head injuries may result from road traffic accidents, falls, workplace injuries, sports injuries or physical assault. Serious injuries may cause skull fractures, brain swelling, bruising or bleeding within the skull.

Emergency warning signs may include:

• Loss of consciousness

• Increasing drowsiness or difficulty waking

• Repeated vomiting

• Severe or worsening headache

• Seizures

• Confusion or unusual behaviour

• Weakness or numbness on one side

• Difficulty speaking, walking or maintaining balance

• Bleeding or clear fluid from the nose or ears

• Unequal pupils or visual changes

Intracranial haemorrhage refers to bleeding within or around the brain. It may occur following trauma, uncontrolled hypertension, rupture of an aneurysm or vascular malformation, abnormalities of blood clotting or the use of blood-thinning medicines.

Possible symptoms may include:

• Sudden, severe headache

• Vomiting

• Loss of consciousness

• New weakness or numbness

• Difficulty speaking or understanding speech

• Seizures

• Increasing confusion or drowsiness

• Loss of balance or coordination

Some haemorrhages require close observation, while others may need urgent surgery to remove the blood clot and relieve pressure on the brain.

Acute hydrocephalus occurs when cerebrospinal fluid accumulates rapidly within the brain, causing increased pressure. Patients with an existing shunt may also develop sudden symptoms if the shunt becomes blocked or infected.

Possible warning signs may include:

• Severe or progressively worsening headache

• Repeated vomiting

• Increasing sleepiness

• Confusion or altered behaviour

• Blurred or double vision

• Difficulty walking

• Seizures

• Loss of consciousness

• Irritability or a bulging soft spot in infants

• Redness, swelling or tenderness along a shunt

Compression of the spinal cord may be caused by trauma, a slipped disc, tumour, infection, bleeding or spinal instability. Rapid assessment is important because prolonged compression may result in permanent weakness, paralysis or loss of bladder and bowel control.

Emergency warning signs may include:

• Sudden or rapidly progressive weakness

• Numbness or altered sensation in the arms or legs

• Difficulty standing or walking

• Severe neck or back pain

• Loss of coordination

• New bladder or bowel dysfunction

• Numbness around the buttocks, inner thighs or genital region

• Breathing difficulty following a neck injury

Cauda equina syndrome occurs when the nerves at the lower end of the spinal canal become severely compressed. It may result from a large slipped disc, tumour, infection, bleeding or traumatic injury and requires immediate medical evaluation.

Warning signs may include:

• Severe lower-back pain with pain in one or both legs

• Progressive leg weakness

• Numbness around the inner thighs, buttocks or genital region

• Difficulty starting or controlling urination

• Inability to pass urine

• Loss of bladder or bowel control

• Reduced sensation during urination or defecation

• Sudden changes in sexual function

Infections involving the brain, spine or surrounding tissues may lead to an abscess, swelling or compression of neurological structures. Neurosurgical drainage or decompression may be required in selected cases, together with antimicrobial treatment.

Possible symptoms may include:

• Fever with severe headache

• Persistent vomiting

• Neck stiffness

• Increasing drowsiness or confusion

• New seizures

• Weakness or altered sensation

• Severe back pain with fever

• Progressive difficulty walking

• Recent surgery, wound infection or reduced immunity