An inquest into the death of a 48-year-old woman, who died at Mayo University Hospital, has heard concerns about the treatment provided to her, after she presented with severe back pain.

The proceedings, before Mayo Coroner Pat O'Connor, relate to the death of Anne Marie O'Brien, from Castlebar, who died on 2 October 2016.

She went to Mayo University Hospital on two separate occasions in the week before she died, complaining of severe back pain.

She was not admitted on either occasion and was sent home with painkillers.

Ms O'Brien, who had a history of chronic obstructive pulmonary disease, took ill at home on 2 October and was taken to hospital by ambulance.

She had suffered a cardiac arrest and efforts to revive her were unsuccessful. She was pronounced dead shortly after 10pm that night.

A post-mortem examination found the cause of death was pneumonia due to antecedent causes.

Pathologist Dr Tomas Németh told the court that it was his view that Ms O'Brien had very serious pneumonia in the days before she died.

In a submission to the inquest this afternoon, the solicitor representing the deceased's family, Damien Tansey, said his clients had no complaints about the efforts made by hospital staff on the night Ms O'Brien died.

But he raised serious concerns about the manner in which she was treated on earlier visits to the hospital, in the days preceding her death.

He told Mr O'Connor there had been a "chaotic" process that led to her being sent home on her first visit on 25 September and that blood tests carried out at the time recorded values that were "off the wall".

Her oxygen saturation ratings were recorded at levels lower than normal and hemoglobin levels were also unsatisfactory.

A subsequent blood test showed a CRP (C-Reactive Protein) reading of 183, when the normal range is between 0 and 10. This test is used to check for the possibility of inflammation in the body.

Mr Tansey said that taken together, these should have raised concerns about the possibility of infection and the need for further care. 

When her condition showed no sign of improvement, Ms O'Brien returned to hospital on 29 September, again complaining of severe back pain.

Evidence relating to the care provided to her on both visits will be heard when the inquest resumes later this year. Mr Tansey told the inquest that if a "modicum of satisfactory treatment had been provided" on those visits, Ms O'Brien would be alive today.

The coroner agreed to hear witness statements from medical personnel who were on duty on these dates, after Mr Tansey submitted that this evidence was central to the inquiry into her death.

Proceedings have been adjourned to next November to gather these statements and to get medical records from the hospital about the treatment provided to Ms O'Brien.