Japanese Prime Minister Shinzo Abe visited a Tokyo hospital on Monday for the second time within days, fanning further speculation about the state of his health.
Abe suffers from chronic ulcerative colitis and has spoken of struggling with it since junior high school. A flare-up in 2007 forced him to quit as prime minister.
Officials have declined to comment in detail on Abe's health, saying only that Monday's visit was connected to last week's check, itself a follow-up to a physical exam in June.
Here are details of the disease.
WHAT IS IT?
Ulcerative colitis is an inflammatory bowel disease that can cause ulcers in the lining of the colon and rectum. Symptoms include diarrhoea, abdominal cramping, weight loss and fatigue.
The cause is unknown, but both heredity and immune system malfunctions, in which the immune system attacks cells in the digestive tract, are believed to play a role. Diet and stress can aggravate the condition.
Complications may include an increased risk of colon cancer, clots in blood vessels, and a perforated colon.
WHAT IS THE TREATMENT?
Ulcerative colitis is incurable. While moderate to severe cases are treated with corticosteroids, this is not a long-term treatment as side effects can include bone loss, high blood pressure and weight gain.
A type of medication called 5-aminosalicylic acid (5-ASA) is the standard treatment, including Asacol, which Abe has said he started taking in 2009, when it was approved in Japan after having been available overseas.
"If this drug Asacol had taken more time to appear on the market in Japan, it's quite possible that I would not be where I am today," Abe said in a 2013 speech.
"For that very reason, I consider it both my role and my fate to restore and enrich the lives of patients suffering from intractable illnesses."
Side effects from the medicine, also known as mesalamine, can include nausea, headache or vomiting. Rarely, it can worsen ulcerative colitis symptoms.
Other treatments include immunosuppressant drugs that require careful supervision and are usually only used if patients do not respond to other treatments.
The most drastic treatment is surgical removal of the colon.
HOW DOES IT AFFECT QUALITY OF LIFE?
If kept under control, ulcerative colitis has minimal impact on daily activities between flare-ups, which can be caused by stress.
Some patients have frequent colonoscopies, such as every six months, to check for cancer. Abe undergoes a comprehensive physical exam twice a year.
In 2017, Abe said his treatment was fuelling his appetite, adding, "I now must worry about issues I once thought were completely unrelated to me, including gaining visceral fat, worrying about body fat, and my cholesterol level. I hit the upper limits on tests for each of these issues."