24th February 2025

A 45-year-old woman presents to the emergency department with a 2-day history of fevers, chills, and a cough

A 45-year-old woman presents to the emergency department with a 2-day history of fevers, chills, and a cough.

On arrival, her observations are as follows: HR 112 bpm, BP 89/57 mmHg, RR 20, oxygen saturation 94% on room air, temperature 38.6 degrees Celsius.

Initial blood tests reveal: Hb 113 g/L (115-165 g/L), haematocrit 0.40 l/L (0.34-0.46 l/L), MCV 80 fL (80-100 fL), WCC 0.7 x 10⁹/L (4.0-11.0 x 10⁹/L), Neutrophils 0.3 x 10⁹/L (2.0-7.5 x 10⁹/L), Lymphocytes 0.9 x 10⁹/L (1.5-4.5 x 10⁹/L), Monocytes 0.2 x 10⁹/L (0.2-1.0 x 10⁹/L), Eosinophils 0.1 x 10⁹/L (0.0-0.4 x 10⁹/L), Platelet count 105 x 10⁹/L (150-450 x 10⁹/L), Na 140 mmol/L (133-146 mmol/L), K 5.2 mmol/L (3.5-5.3 mmol/L), Creatinine 140 µmol/L (45-104 µmol/L), Urea 7.6 mmol (2.5-7.8 mmol/L), CRP 131 mg/L (< 5mg/L), Random glucose 5.0 mmol/L.

On taking a full history, she explains she has recently started doxorubicin and cyclophosphamide chemotherapy for a recent diagnosis of breast cancer, and she last had treatment 8 days earlier. Other past medical history includes hypothyroidism and diet-controlled type 2 diabetes mellitus.

What is the most likely unifying diagnosis?

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