Walking wounded with minor injuries and ailments were this week urged to abandon Hairmyres Hospital in East Kilbride, South Lanarkshire, and travel 15 miles to Wishaw General Hospital instead as doctors struggled to cope with demand.
One 85-year-old woman, who had fractured her sternum and wrist, was told she would have to spend a night on a trolley after waiting several hours to be seen as there were no spare beds.
It is the latest sign of the strain facing health services at a time of year in which hospitals' performance traditionally improves following the peak winter months.
Severe bed shortages were reported and operations were cancelled at the Victoria Infirmary in Glasgow on Monday night when its A&E department experienced an "unprecedented surge" in demand.
There are also fears emergency care in NHS Grampian is facing a meltdown unless new consultants can be recruited.
The number of senior doctors working in Aberdeen Royal Infirmary's A&E is projected to fall from 10 in August 2013 to two by August this year unless vacancies can be filled.
Consultants have raised concerns the staff shortages could hit patients requiring resuscitation and those suffering life and limb-threatening conditions. The health board said action was already being taken to avert a crisis.
Colin Campbell, who attended Hairmyres Hospital's A&E department with his mother on Tuesday, said: "My 85-year-old mother arrived by ambulance just after 1.30pm following a fall in which she fractured her sternum and wrist.
"It was clear that A&E was swamped and during the afternoon an announcement was made that those with minor injuries or ailments should try to make their way to Wishaw General hospital, which was apparently less busy. A number of the 'walking wounded' availed themselves of this advice.
"My mother's lengthy examination and treatment were concluded at around 7.30pm. However, we were then told she would most likely have to spend the night on a trolley in the A&E department, as no beds were available in the entire hospital."
He added: "Clearly, this wasn't a one-off situation."
Staff eventually located a bed for Mr Campbell's mother at 1am on Wednesday after he complained to a manager, almost 12 hours after her arrival.
The bed shortage is understood to have been caused by the outbreak of the vomiting bug norovirus, which led to hospital bosses closing wards.
David Hume, director of hospital services for Hairmyres Hospital, apologised to those affected, saying the outbreak, which continued throughout this week, had "impacted on the flow of patients throughout the hospital and on the availability of beds".
The development is likely to heap further pressure on Health Secretary Alex Neil, who last month survived a rare vote of confidence at Holyrood following allegations he had interfered inappropriately to save mental health beds at Monklands Hospital in his constituency.
Health services in his constituency are run by NHS Lanarkshire, which is responsible for Hairmyres.
Mr Neil said: "The Scottish Government has increased the number of doctors and consultants working in emergency medicine across our NHS. Health boards are clear in their duty to ensure they have the right number of staff in place to deliver safe and effective patient care. At this point in the annual training and recruitment cycle, boards take special care to identify the positions they need to fill in the coming months and take action to fill them."