Urban warfare between the forces of two rival generals has triggered a "complete and total collapse of the healthcare system" in Sudan, according to the doctors' union.
Battles since 15 April between forces loyal to Sudan's army chief Abdel Fattah al-Burhan and his deputy-turned-rival, Mohamed Hamdan Daglo - the commander of the powerful paramilitary Rapid Support Forces (RSF) - have turned Khartoum into a war zone, shuttering hospitals and preventing health professionals from providing care.
With explosions, heavy gunfire and air strikes that have killed hundreds in the capital and in other parts of the country, "morgues are packed and the streets are littered with bodies," said Attiya Abdullah, general secretary of the Sudanese doctors' union.
According to the doctors' union, 13 hospitals nationwide have been shelled and 19 others evacuated since fighting began.
At least eight people have died in attacks on health facilities, according to the World Health Organization (WHO).
When the bombs start falling near hospital premises, doctors face a grim choice.
"We find ourselves forced to let patients leave," Mr Abdullah said. "If they stay, they would be killed."
Nearly three quarters of hospitals are shuttered, according to Mr Abdullah and "operational hospitals are only providing emergency services".
According to Mr Abdullah, even hospitals that have remained open, receiving mostly gunshot wounds, "are at risk of closure at any time".
"They don't have enough surgical equipment, not enough fuel to run generators, not enough ambulances or blood."
The WHO said 413 people had been killed and 3,551 wounded in the fighting across Sudan, as of yesterday, but the actual death toll is thought to be far higher, with doctors and humanitarian staff unable to reach those in need.
"Some hospitals have had the same team working" for eight days straight, Mr Abdullah told AFP.
"Some have only one surgeon. All are extremely exhausted."
Medics have made daily appeals for a ceasefire to allow humanitarian access to move through, transport the wounded and bury the dead.
But brief lulls in the fighting in Khartoum have repeatedly given way to the crackle of gunfire, cutting through the momentary silence, and no truce has taken hold.
As civilians rallied on social media to find any sources of medication for chronically ill relatives, UNICEF has warned power cuts and fuel shortages were putting at risk the cold storage of more than $40 million worth of vaccines and insulin.
On Friday, as a third ceasefire collapsed, the doctors' union shared advice on Facebook on how to handle, shroud and bury decomposing bodies.
Stench
Last week, leukaemia patient Ibrahim Mohamed turned in his hospital bed to find the patient next to him had died, but fighting that had erupted in Sudan's capital hours earlier meant the body could not be moved.
By the time Mr Mohamed, 25, was finally evacuated from the Khartoum Teaching Hospital on Tuesday, the body was still there.
"Because of the intense fighting, the person could not be moved and buried," Mr Mohamed's father, Mohamed Ibrahim, 62, told AFP.
"Decomposing dead bodies are kept in wards" for lack of anywhere else to put them, Mr Abdullah told AFP.
As Mr Ibrahim waited with his son in the hospital ward under ceaseless blasts, "the stench filled the room", the father said, made worse by power outages in the baking heat.
"We could either stay in the pungent room, or go outside and be met with gunfire."
At around 1pm on Tuesday, after three days with no food, water or electricity, the father and son finally left, but not to safety.
"The hospital was being shelled," Mr Ibrahim recounted.
He managed to shield his sick son from the crossfire, but "had to go on foot" through the streets, dashing from one safe point to another.
It took them five hours to get home "safely, but my son's health has deteriorated since", the father said.
According to Mr Abdullah, there was nowhere else Mr Mohamed could go.
"I just want all of this to stop so I can take my son to be treated," his father said.
