Found unconscious at home, a 40-year-old: a case to work up

Why unconsciousness of unknown cause matters

The unconscious patient needs several things at once: protect the airway, check the glucose, and look for clues. Many causes are metabolic, toxic or infective, and reversible if found quickly.

What to ask in the history

• When he was last seen well, and how he was found
• Diabetes or other illness; medicines, missed doses
• Vomiting, thirst, passing a lot of urine
• The painful foot: how long, any wound, swelling
• Alcohol, drugs, access to poisons
• Seizures, headache, injury

Red flags

• Airway at risk
• Abnormal breathing pattern
• Very high or very low glucose
• Shock
• Fever
• Unequal pupils or signs on one side

What to examine

• Airway, breathing, circulation; conscious level; glucose
• Observations
• Breath: smell, depth and pattern
• Pupils, neck stiffness, injuries
• Skin and feet: wounds, infection
• Hydration
• Neurological signs

First investigations

• Capillary glucose and ketones
• Blood gas: pH, bicarbonate, anion gap, lactate
• Electrolytes, kidney function, osmolality
• Full blood count, CRP, blood cultures
• Urine
• ECG
• Toxicology
• CT head if no metabolic cause is found or there are focal signs
• X-ray of the foot

Differential diagnosis of unconsciousness of unknown cause

Grouped, not ranked. Which one fits this patient is for you to work out in the case.

Common mistakes

• Not checking the glucose.
• Correcting a very high glucose too fast, or forgetting the potassium.
• Treating the numbers and not finding what set it off.