Approach to A Patient Presenting With Unconciousness

A patient with unconsciousness is usually brought o the emergency department and is categorized as having a GCS of less than 8.
There may be many causes that can lead to unconsciousness. A list of these are given below:

Causes;

1. Trauma:
   
- Head injury:

• Diffuse axonal injury.
• Extradural hemorrhage. 
• Subdural hemorrhage. 

2. Metabolic causes: 

• Hypothermia
• Hypoglycemia
• Hyperglycemia
• Hypernatremia
• Diabetic ketoacidosis

3. Organ failure: 

• Cardiac/circulatory failure
• Respiratory failure
• Liver failure leading to encephalopathy.
• Renal failure (uremic coma)
• Hypothyroidism

4. Vascular causes: 

• Stroke.
• Subarachnoid hemorrhage. 

5. Infections:

• Meningitis
• Encephalitis
• Cerebral malaria.

6. Toxins or Drug Induced: 

• Alcohol
• Overdose of opiates tricyclics, benzodiazepines
• Carbon monooxide poisoining

7. Neurologic Causes: 

• Brain tumor
• Brain abscess
• Epilepsy

Clinical History: The history of an unconscious patient is usually obtained from the ambulance crew, relatives, friends or witnesses. other sources of information are previous hospital notes and records kept by general practitioners and tablets or prescriptions found at the patient's premises.

Presentation: The circumstances regarding the discovery of the patient is usually the first piece of information to be reported. 

 - Trauma patients may have been transported from the sites of road traffic accidents, fire or have been assaulted on the street. 

- When teenagers and young adults are brought unconscious from a night club , it is important to exclude alcohol intoxication and use of illicit drugs. 

- Attempted suicides may have an accompanying note, or empty drug bottles at the scene. 

- Carbon monoxide poisoning occurs with suicide attempts in enclosure areas with running engines. Alternatively it can also be a complication in victims involved with fires. 

Onset: With witnesses present , the information regarding the speed of onset of unconsciousness may help in determining the underlying cause. Sudden onset of unconsciousness is characteristic of a seizure or a vascular event. 

Trauma: Head injuries are a common cause of coma following trauma; not all causes are associated with blunt trauma to the cranium. 

- Diffuse axonal injury results from shearing forces on the brain, a sequel to rapid acceleration and deceleration forces. 

- Blunt head injuries may cause extradural hemorrhages as a result of skull fractures with laceration of meningeal arteries. There is usually a history of  an injury with transient loss of consciousnesses, a lucid interval when the patient feels and appears well , followed by drowsiness, headache, vomiting, progressive hemiplegia and eventually coma. 

- Subdural hemorrhages are a consequence of severe trauma with cortical lacerations or less severe trauma with laceration of bridging veins. Chronic subdural hemorrhages may result even in the absence of trauma especially in elderly people. 

- In addition to head injuries , coma or loss of consciousness may also complicate any other injuries severe enough to result in circulatory or respiratory insufficiency.

Headache: The onset of sever headache prior to coma , may be caused by trauma, subarachnoid hemorrhage ( classically patients complain of a sudden onset of blinding headache, the worst ever experienced in their life), or meningitis ( headache associated with photophobia and neck stiffness) . Progressive headache, worse in the morning and associated with vomiting may be due to raised intracranial pressure from a cerebral tumor.

Predisposing Factors: The history of a predisposing factor is useful when assessing the comatose patient.
- The presence of diabetes should lead to the consideration of ketoacidosis (type I diabetes) and hypoglycemia ( when using insulin or oral hypoglycemics) .
- Patients with known hepatic or renal failure may deteriorate to coma as a result of encephalopathy or uremia respectively.
- Coma may also complicate severe hypothyroidism. 

- Previous suicide attempts or a history of depression should lead to the consideration of drug overuse.
- Epileptic patients may be in status epilepticus or postictal recovery state.
- Preexisting cardiac or respiratory disease may result in coma as a terminal event.

Examination: 
1. Body temperature should be taken in all patients presenting with unconsciousness to exclude hypothermia and hyperthermia.
2. A through inspection of the whole body should be done which might necessitate removal of clothing and rolling to examine the back.
3. Examine the scalp for bleeding, hematomas or fractures.
4. Look for periorbital hematoma or cerebrospinal fluid rhinorrhea which may indicate an anterior fossa fracture of the skull.
5. Patients with carbon monoxide poisoning appear bright red.
6. Patients with myxedema are characteristically obese, with coarse features , dry skin and brittle hair.
7. The arms should be carefully examined to look for needle punctures which indicate drug abuse.
8. Occasionally a petechial rash will be visible on the skin with meningococcal meningitis.
9. Each organ system should be examined to look for any malfunction.
10. Neurological assessment is done to determine GCS, look for focal deficits, and reflexes are checked.
11. Examining the pupils can give important information. Pinpoint pupils occur with opiate overdose, small pupils with brain stem lesions and large pupils with cocaine and amphetamine use.

Investigation: The intial investigations should include:
1. A complete blood count. (elevated WBC indicates infections like meningitis)
2. Blood glucose
3. Urinalysis ( look for ketones to for diabetic ketoacidosis)
4. Urea and creatinine: are elevated in renal failure.
5. LFT's: help determine liver function and a possible encephalopahthy secondary to liver failure.
6. Toxicology screen
7. ECG; to diagnose any arrhythmia that may cause syncope and loss of consciousness.
8. CT head; In case of trauma to look for epidural or subarachnoid hemorrhage.

Management: depends on the underlying cause but follow the basic ABC(Airway, Breathing & Circulation. ) for all cases of unconscious patients. Then proceed to determine the cause and treat accordingly.