Question

How the clinical history and the biochemical results aided your evaluation of the diagnosis. The underlying pathogenesis. What other conditions give rise to hyponatraemia and explain why these can be ruled out based on the clinical presentation.)

A 52-year-old man was admitted to A&E presenting with a fever, nausea and vomiting that has lasted over 2 weeks. However, in the last few days he has become irritable and confused. ON PRESENTATION Chest X-ray, ultrasound abdomen and echocardiography were all normal. Blood serum tests revealed the following: Serum analysis Test Result Reference range Sodium 125 mmol/L (135-145 mmol/L) Potassium 4.2 mmol/L (3.6-5.0 mmol/L) Chloride 100.0 mmol/L (98-107 mmol/L) Uric acid mg/dL (3.0-7.2 mg/dL) Urea 4.7 mmol/L (3.3-6.7 mmol/L) Creatinine 100 mol/L (50-110 [mol/L) Glucose 5 mmol/L (4.0-8.0 mmol/L) Serum osmolality 245 mOsmol/kg (275-295 mOsmol/Kg) 253.8 nmol/L (221-552 IU/L) 1.6 3.4 IU/L IU/L (0.5-9.0 (1.0-8.0 Serum cortisol nmol/L) LH FSH IU/L) GH Pg/L) TSH mU/L) Free T. pmol/L) 0.65 g/L (0.5-3.0 2.5 mU/L (0.2-4.0 16 pmol/L (12-25 Urine analysis (300- Urinary osmolality 524 mOsmol/kg 900 mOsmol/Kg) Sodium 44 mmol/L Fractional excretion > 1.2% of sodium