ALTERED MENTAL STATE / CONFUSION / COMA

• Mental state abnormalities can be considered to occur on a continuum - ranging from behavioural change to profound coma
• The range of possible causes are generally similar regardless of the severity of brain derangement (see also causes of seizures)
• See functional versus organic causes of abnormal mental state

see The poisoned patient

COMMON/IMPORTANT CAUSES

Severe coma:

• Drugs/Toxins (especially in younger patients)
• Space-occupying lesion
• Brainstem stroke

Confusion:

• Infection
• Hypoxia
• Hypoglycaemia
• Electrolyte disturbance
• Drug toxicity/drug withdrawal
• Sub-dural haematoma

ALL CAUSES

Structural lesions

• Intracranial bleeding - traumatic, spontaneous
• Brainstem lesion
• Neoplastic
• Meningitis/Encephalitis

Non-structural systemic causes

• Drugs/Toxins (see The poisoned patient)

• The 'failures'

• Circulatory failure - hypotension

• Respiratory failure - hypoxia or hypercarbia
• Organ failure - uraemia, hepatic encephalopathy
• Endocrine failure - myxoedema coma, DKA
• Biochemical failure - Glucose, Sodium, Calcium
• Temperature failure - Hypothermia/Hyperthermia

• Sepsis

Other

• Post-ictal
• Post arrest

RESUSCITATION

Airway/Breathing

• Nurse in semi-prone position
• Intubate/Ventilate (unless easily reversible cause found e.g.  hypoglycaemia, opiate toxicity)

Circulation

• Support as necessary

Disability

• BSL (give 50% glucose if BSL < 2.6)
• GCS (test each side independently for motor response - differences suggest structural lesion)

Empirical treatment with glucose, naloxone, thiamine, flumazenil not indicated
(Hyperglycaemia harmful in stroke, Flumazenil may cause intractable seizures and death)

Exposure

    Correct temperature (?mild hypothermia useful in post cardiac arrest and head injury)

• Hypothermia
• Hyperthermia

CLINICAL ASSESSMENT

Cause

Look specifically for:

• Head injury
  • Head/face injuries
  • Signs of basal skull # (haemo-tympanum, CSF rhinorrhea/otorrhea, Raccoon's eyes, Battle's sign)\
• Systemic disease - stigmata of liver failure, chronic renal failure/fistulas, diabetes/injection sites, goitre
• Drug abuse/Overdose - track marks, previous self harm
• Focal neurological signs - especially pupils, unequal movement/reflexes
• Signs or sources of infection - including urinalysis and CXR

Complications

• Aspiration pneumonia (CXR)
• Pressure areas/neuropraxias
• Compartment syndrome
• Rhabdomyolysis (CK, urinalysis)

INVESTIGATION

• BSL
• Electrolyte and renal function
• LFT
• ABG
• Paracetamol level (if overdose considered)
• CT brain (if no other cause found or evidence of head injury, meningism or focal deficit)

MANAGEMENT

Directed towards cause

DISPOSITION

Admit all moderate to severe altered mental states to ICU unless easily reversible cause found e.g.  hypoglycaemia, opiate poisoning

Do not admit to psychiatric ward unless organic causes ruled out