A 62 year old male presents with a 2 days history of severe nausea and dizziness. Wife reports that the patient had a seizure like episode earlier in the day. The patient has a background history of hypertension and GORD. He takes omeprazole and enalapril/HCTZ. Below are the patients biochemistry results:

Na 142mmol/l                                  Mg 0.09 mmol/l

K 3.0mmol/l                                      Corrected Ca 1.7 mmol/l

Cl 101mmol/l

HCO3 25mmol/l

Ur 5.3mmol/l

Cr 57umol/l

1. What symptoms do patients present with who have hypomagnesemia?
2. What are the likely causes of the biochemical abnormalities in this case?