Some quotes hit me hard. Here is one:

“How did you go bankrupt?” Bill asked. “Two ways,” Mike said. “Gradually and then suddenly.”

This dialogue is taken from Ernest Hemingway’s 1926 novel The Sun Also Rises. And as I am reading it, I think about all the things besides bankruptcy, medical and otherwise, that appear sudden, but are the result of gradual, often slow transformation. From a relationship that has gradually turned sour ending in a “surprising,” painful separation to the fall of the Roman Empire–a careful retrospective examination of the time leading to a sudden event can often change our response from “This came out of a clear blue sky,” to “How didn’t we see it coming?”

In medicine the “Gradually and then suddenly” principle appears frequently and prominently. I see it unfolding daily in my clinic. Here are two examples:

Two weeks ago, a 71 year old man arrived in my office after he was seen in the emergency department with urinary retention. “I woke up in the morning,” he told me, “and suddenly, I couldn’t pee!” Examining him, I found that the man’s prostate was enlarged.

Shaped somewhat like a bagel, the prostate sits around the urethra, just below the urinary bladder. The urethra is the channel through which urine flows from the bladder into the outside world. The urethra passes through the “bagel hole” within the prostate. In order to void, to empty his bladder, my patient’s bladder needs to contract and his urethra needs to be open. When I asked my patient about his urination, he admitted that his urinary flow has gotten slower over the past several years, “but nothing like that has ever happened before,” he told me, referring to his urinary retention.

In my mind, of course, my patient’s story belongs with narratives that take place gradually, then suddenly. It’s because I know that when a man gets older, his prostate grows larger. It grows outwards and inwards pressing upon the urethra, making it narrower. And when the urethra becomes too narrow, an obstruction ensues and the patient won’t be able to urinate. Doctors call it urinary retention.

A week later, I saw another patient who followed the “gradually, then suddenly” narrative. She was 32 and was seen the day before in the emergency department for renal colic. She told me that she felt “a pain so bad, much worse than the pain I had when I delivered my baby.” The pain appeared suddenly, “out of nowhere,” and was accompanied by nausea and vomiting. A CT scan–a computerized X-ray imaging study–showed a stone in her ureter, the tube that channels urine from the kidney to the bladder. The stone was stuck midway and didn’t allow urine to pass through the ureter. This resulted in a complete obstruction of the ureter and in widening of the segment of the ureter above the point of obstruction. It is this widening that caused the patient to experience “the worst pain ever.”

Again, in my mind, this second patient’s story also belongs with narratives that take place gradually, then suddenly. It is because the stone wasn’t formed, or became stuck in a day. Instead, it was most likely a process that took place over weeks, months, perhaps even years. It started, likely, with a single molecule of calcium oxalate that formed in my patient’s kidney. Gradually, additional molecules of calcium oxalate stuck to the first molecule, the way a snowball becomes bigger as it rolls down a snowy hill. The stone then sat idly in my patient’s kidney causing no problem at all for weeks, months, perhaps even years, until it started to move downwards along the ureter. It progressed unnoticed along the way until it reached a narrow point where it got stuck. It was then that my patient felt intense, sudden pain.

In my next article, I will tell you another “gradually, then suddenly״ story about a man with involuntary movements and unresponsiveness. I׳m trying to make a point here: events that seem sudden are often gradual in nature. By recognizing the gradual nature of events, we can often interfere in time, and prevent sudden, often devastating consequences.

Dr. Shahar Madjar specializes in urology. He is the author of an upcoming book “The Dieting Doctor; A Memoir in Essays and Recipes.”