1st April 2022

A 17-year-old girl is admitted to A&E with an episode of collapse

A 17-year-old girl is admitted to A&E with an episode of collapse. She was found by her friend, collapsed in the kitchen and was brought in immediately. On taking a collateral history you do not note anything significant which points to a specific cause. Her friend tells you the patient is normally well and healthy although she has been feeling increasingly weak and tired over the past few months. On examination, you note a slightly weak, low volume pulse, tachycardia, sunken eyes and decreased skin turgor. On examination of her dry mouth, you also notice some buccal pigmentation. You cannot take a lying and standing blood pressure as the patient is not feeling comfortable as she is vomiting intermittently. You order some blood tests and initiate a management plan based on your initial suspicion. 

Which of the following diagnoses most likely explains the blood test results shown below for this patient? Normal ranges are given respectively in brackets.

• Serum sodium 126 (135–145 mmol/L) 
• Serum potassium 5.7 (3.5–5.0 mmol/L) 
• Serum Urea 5.2 (2.5-7.0  mmol/L) 
• Serum Glucose 3.2 (3.5-5.5 mmol/L) 
• Plasma Osmolality 268 (275–295 mOsm/kg) 

Select the SINGLE most appropriate option from the list below. Select ONE option only.