A 56-year old female was referred from another hospital with complaints of recurrent gross hematuria. She had been diagnosed as having nephrotic syndrome with gross hematuria. A renal biopsy performed almost 2 months earlier reported amyloidosis involving the glomerular vascular wall with plasma cell dyscrasia (IgA myloma). A urine culture was positive for Actinobacter and she was treated with antibiotics plus prednisolone 30 mg/day. On arrival to your emergency department she complained of dizziness, general weakness and right flank soreness. She was receving a dopamine infusion.

Past history: No allergies, previous surgery or other systemic disease

Physical exam:
- Vitals: T 36, HR 95/min, RR 8/min, BP 68/54 mmHg
- Appearance: tired and pale but alert
- H & N: no jugular venous distention or lymphadenopathy
- Chest: breathing sounds clear bilaterally
- CVS: regular heart sounds, no murmurs
- Abd: soft, flat, non tender, no organomegaly, normal bowel sounds
- Ext: normal range of motion

What are the most important causes of hypotension to consider in this patient?