Whether it's a car or bike accident, or a fall down the stairs, a simple bump on the head can turn into something far worse.

"It happens to all of us. We have a little fall, get up, and say I'm fine,” said neurosurgeon Dr. Sami Khoshyomn of St. John’s Hospital.

Khoshyomn has seen many cases that have not turned out as well in the end.

"In a small number of cases, something more serious is wrong."

In many cases, it's a minor car accident, or a fall from a bicycle, but a strong enough impact can cause bleeding in the area between the skull and the brain. Everything seems fine for awhile but, with every passing minute, the bleeding grows worse.

"The decline is very rapid,” the doctor said.

Even after an hour, the damage can prove irreversible and even fatal, making the minutes after impact all the more important.

Khoshyomn says it's important to look for these symptoms: headache, vomiting without nausea, malaise, sleepiness, and seizure, any of which should be a sign to head to an emergency room immediately.

"Unfortunately, sometimes all these signs are absent."

According to the Centers for Disease Control, 1.4 million people are affected by head injuries every year; 50,000 die and 1.1 million head to emergency rooms, often too late, making prevention all the more important.

"Wearing a helmet is crucial, as well as seatbelts when in the car,” said Khoshyomn.

You can put that in perspective by considering this: upwards of 80 percent of head injuries are preventable with a helmet. For a demonstration of how to property fit a helmet, click here.

Khoshyomn says about 1 to 1.5 percent of all head injuries result in a bleeding injury, making it all the more important to monitor an individual who suffers a head injury and to look for those warning signs, including someone who might remember everything around the accident, but not the accident itself.