Appropriate Tests


Electrolytes, Creatinine, Urea, Full blood count and Blood film.

Blood gas arterial; Lactate, if patient is acidotic.

If patient is oliguric: Osmolality urine, Sodium urine, Creatinine urine (with calculation of fractional excretion of sodium).



  • Dehydration


  • Blood loss


  • Crush injury


  • Burn injury

See Burns

  • Addison’s disease

See under Adrenocortical insufficiency

  • Anaphylaxis


Cardiac causes, especially


  • Myocardial infarction


  • Arrhythmias


  • Pulmonary embolism


  • Cardiac tamponade, including


  • Pericardial effusion


  • Haemopericardium


Drug overdose, especially


  • Narcotics


  • Phenothiazines


Acute spinal cord injury




Toxic shock syndrome


Acute iron poisoning

See Iron toxicity