NeNe Leakes' 23-year-old son is struggling to speak after having a stroke and heart failure. Here are the symptoms and who's most at risk.

• NeNe Leakes' 23-year-old son is struggling to speak after having a stroke and heart failure.
• The former "The Real Housewives of Atlanta" star said that she didn't know why he had these health issues.

Brentt Leakes, the 23-year-old son of former "The Real Housewives of Atlanta" star NeNe Leakes, is struggling to speak after he experienced a stroke and heart failure two weeks ago, according to his mother.

A stroke, or "brain attack," is when a blood vessel supplying the brain gets blocked or bursts, starving the organ of oxygen, which can cause brain damage. Heart failure is when the heart can't pump enough blood, and oxygen, around the body. Heart failure is a common cause of stroke.

On Instagram Stories on Monday, NeNe Leakes said her son was struggling to speak, but didn't share any further details about his condition, including if he was in the hospital.

She said that he had shown "some improvement" and was in "good spirits."

"Obviously, a stroke is a very serious thing," she said.

Having a stroke as well as heart failure at age 23 is "very rare," Dr. Judd Jensen, a neurologist in Colorado, told Insider.

A stroke can cause a numb face, while heart failure symptoms include shortness of breath

Symptoms of a stroke typically start suddenly and include: numbness or weakness in the face or limbs (usually on one side of the body), difficulty speaking, confusion, dizziness, trouble walking from a loss of balance or coordination, and vision changes in one or both eyes. The sooner stroke victims get help, the better their prognosis.

"Minutes matter in terms of saving brain tissue and brain function," Dr. Donald M. Lloyd-Jones, president of the American Heart Association, previously told Insider.

Heart failure can typically causes symptoms including shortness of breath, swelling of the ankles, feet or stomach, a cough, and generally feeling weak.

The condition can cause an upset stomach, nausea, vomiting, and appetite loss at an early stage.

People older than 65 are more likely to have strokes and heart failure

Strokes and heart failure are most common in people older than 65, but they can happen at any age, according to The National Institutes of Health. About 10% of strokes occur in people younger than 50, Lloyd-Jones said. Hailey Bieber, at age 25, was one of them.

NeNe Leakes said that doctors were investigating why her son had these conditions at a "really young" age. If doctors knew the cause, then they could treat the cause, she said.

Jensen, who was not involved in Brentt Leakes' care, said it's most likely the heart failure preceded the stroke. Research shows 10% to 24% of people who've had strokes also have heart failure, and that the heart failure is the cause of 9% of those strokes.

If Brentt Leakes' heart failure did indeed cause his stroke, Jensen said the question then becomes why he had heart failure at age 23.

Some possibilities include that he was born with a structural abnormality in his heart, he has a genetic condition that causes heart weakness, or he developed a viral infection of the heart muscle that leaves it weak. In any of those cases, clots can develop and lead to a stroke.

Doctors diagnosed Nene Leakes with blood clots on her lungs in 2013, but she said she didn't know if an inherited condition was underlying her son's illness. NeNe Leakes did not immediately respond to Insider's request for comment.

Other factors that can increase a person's risk of a stroke include diabetes, high blood pressure, obesity, high cholesterol, drinking alcohol, smoking cigarettes, taking cocaine, and not getting enough physical exercise, according to the CDC. The risk of having a first stroke is nearly twice as high for Black people than it is for white people, the organization says.

People are more likely to get heart failure if they have heart disease, previous heart attacks, high blood pressure, obesity, or diabetes. Smoking cigarettes, drinking excessive amounts of alcohol, not exercising enough, and a poor diet that's high in salt, fat, or cholesterol also increase the risk.

NeNe Leakes said her son didn't drink alcohol or take drugs, and that doctors didn't think his weight was a possible cause.

She said her son was "stressed out" in September because it was the first anniversary of his father's death, but didn't know if that was related.