Ignoring some symptoms can come at a high cost. Emergency room doctors warn that suddenly being unable to urinate should never be ignored. This condition, called urinary retention, can signal a serious underlying problem that requires immediate medical care.

Along with urinary retention, physicians point to other red flags that should prompt an urgent visit to the ER, from sudden confusion to severe back pain. Let’s cover why not being able to pee is a medical emergency and review other symptoms experts say must never be dismissed.

Urinary retention: the sign you shouldn’t ignore

Urinary retention isn’t the same as constipation or simply going less often than usual. It means your bladder is full, but you’re unable to pass urine. ER doctors say this can happen when stool in the bowel becomes so impacted that it presses against the bladder, blocking urine flow. In men, an enlarged prostate can cause a similar blockage.

The danger is that urine builds up in the bladder and backs up into the kidneys, which can lead to kidney failure if untreated. Treatment often involves relieving the obstruction and, in many cases, placing a catheter to drain the bladder. If you suddenly stop being able to urinate, seek care right away. Left untreated, urinary retention can cause serious damage.

Other symptoms to pay attention to right away

While urinary retention is one of the most urgent red flags, it’s far from the only one. Emergency physicians caution against ignoring the following warning signs:

Sudden confusion or personality change: A person who quickly becomes disoriented, has garbled speech, or can’t recognize familiar surroundings may be having a stroke, severe infection, or low blood sugar. Immediate evaluation is critical.
Severe upper back pain: Intense pain between the shoulder blades can be a hidden sign of a heart attack or even an aortic dissection, a life-threatening tear in the aorta.
Shortness of breath while lying down: Gasping for air at rest could indicate heart failure or fluid in the lungs. Unlike being winded from activity, this symptom often signals a serious cardiac issue.
Unexplained leg swelling or pain in one leg: This may point to deep vein thrombosis, a blood clot that can travel to the lungs and cause a fatal pulmonary embolism.
Vomit that looks unusual: Throwing up bright red blood, dark brown material resembling coffee grounds, or green bile are all reasons to seek urgent care, as they may signal internal bleeding or intestinal obstruction.
Fainting without warning: Passing out while sitting, lying down, or exercising can be linked to dangerous heart rhythms or internal bleeding, not just dehydration.
A sudden sense of doom: Intense, uncharacteristic anxiety or dread—especially with chest tightness or dizziness—can accompany a heart attack, blood clot, or severe allergic reaction.

Taken alone, some of these symptoms might seem vague, but ER physicians stress that they can point to life-threatening problems. If you or someone you know is experiencing sudden urinary retention—or any of these other red flag symptoms—call your doctor or head to the nearest emergency room.