Nurse!

Someone got stabbed after a Chris Brown performance Monday night ... and law enforcement tells us it's yet another case of trouble following Brown and his entourage ... something cops are quietly trying to stop.

Right after Brown finished his set at a YMCMB Drake/Lil Wayne after-party at Supperclub in Hollywood ... several people who were leaving got into a fight and someone got stabbed.

The victim was taken to a hospital and he's expected to be okay.

Law enforcement sources tell us ... they didn't make any arrests because no one would ante up any info ... which leads to the bigger issue. Our cop sources say they believe this is all about Brown's entourage. Wherever they go ... someone ends up bleeding.

We're told the LAPD has privately met with club owners, trying to pressure them into blacklisting Chris and his crew, but the clubs make too much money off them so they're welcome with open arms.

As one law enforcement source put it, "When Brown and his people show, we know what's going to happen. It's a headache for us."

Brown -- who does not keep his association with the Bloods a secret -- has not been accused of instigating the violence, but cops say they know it all emanates from the singer and his entourage.

When you need a calm, soothing voice to get you through a traumatic event, you don't think of Mike Tyson ... but that's exactly what happened to a motorcycle crash victim.

Ryan Chesley tells TMZ ... he was on his way to Las Vegas this week when a cab cut him off on the freeway ... sending him flying off his chopper.

Chesley says Tyson saw the whole thing ... slammed on his brakes and stopped traffic. Chesley says Tyson -- mindful the victim might be in shock -- kept him calm until paramedics arrived.

Chesley -- who has broken bones, muscles, ligaments, nerve damage and needs shoulder surgery -- tells TMZ he's sending Tyson a thank you note and a fruit basket.

One of the best selling sex toys in the world nearly made porn star Missy Martinez the ultimate fire crotch -- according to her the thing shot flames at her lady bits, and now she's demanding answers.

Missy claims the fiery scene went down Thursday on set -- in the Valley, of course -- when she turned on her Hitachi magic wand vibrator, and the handle immediately heated up. She tells TMZ ... sparks flew out of the base where the cord connects to the device.

The really scary part is it happened inches from her moneymaker, and a vaginal piercing on her porno scene partner ... according to Missy.

She says she fired off a harsh letter to Hitachi, claiming the device is defective and potentially deadly.

The girl Keyshia Cole allegedly assaulted for spending the night at her rumored BF's house says she's not Birdman's side piece ... and she has no idea why Keyshia would think they're banging.

Sources privy to the case tell us ... the alleged victim is Sabrina Mercadel -- a Cash Money employee for more than a decade -- and she's known Birdman since they were young.

We're told Sabrina was not alone with Birdman at his West L.A. condo ... 4 others were present when Keyshia came storming in at around 5 AM.

Our sources say Sabrina was walking out of the bathroom when Cole spotted her in the apartment ... and the singer instantly went on the attack, yelling, "What are you doing with my man?!"

TMZ broke the story ... Keyshia was arrested for allegedly attacking Sabrina ... who went to the ER and is now on pain meds.

Keyshia is now out on bail.

August Alsina's condition was much more serious than his camp initially let on -- the singer was in a coma for 3 days after fainting on stage in NYC ... but he is finally awake.

August posted a gnarly photo of himself Friday morning after regaining consciousness ... thanking friends and family for their "prayers and concerns." In the pic, his head is heavily bandaged and an oxygen mask is strapped to his face.

TMZ broke the story ... BET's Best New Artist of the Year collapsed and fell off a stage Monday night. The next day, Alsina's rep said he was suffering from seizures and was in ICU.

Alsina's rep now confirms he'd been in a medically induced coma since Tuesday, and on a breathing machine.

Joan Rivers personal ENT doctor did NOT take a selfie while the comedienne was under anesthesia shortly before she stopped breathing ... so claims the doctor herself.

Sources closely connected with the doctor say ENT specialist Dr. Gwen Korovin has made it clear ... she says the CNN story is absolutely wrong. The network reported a staff member at Yorkville Endoscopy clinic told investigators the doctor took the pic. Our Korovin sources say ... the network's source is "making up lies."

We're also told the doctor has made it clear ...she did NOT perform a biopsy on Joan. We pressed to find out if she performed some other procedure ... we did not get an answer.

A plane carrying Jackson Rathbone -- who played Jasper Hale in "Twilight" -- made an emergency landing in Long Beach Thursday ... after one of the engines exploded and his cabin filled with smoke.

Rathbone documented the whole thing on his WhoSay account ... after the right engine went kaput on a JetBlue flight heading for Austin, Texas from the LBC.

Jackson claims the oxygen masks didn't deploy when the plane got smoky -- so the flight attendant had to manually release them. According to reports ... one person was hospitalized for shortness of breath once they landed.

Rathbone says things got so scary while they were on the way down ... he grabbed his son/wife tightly and started praying.

Luckily they landed safely -- and when the plane stopped Jackson said screw his personal belongings and jumped down the inflatable slide with his family to exit the plane ASAP.

Joan Rivers' personal ENT who was performing a procedure on the comedienne when she stopped breathing was seen for the first time in NYC Thursday ... and she clearly didn't want to talk.

An independent photog asked Dr. Gwen Korovin if she took a selfie while performing a biopsy on Joan ... but she was having none of it as she entered her office building.

The doctor who was performing a procedure on Joan Rivers when she stopped breathing allowed cameras into her office for a Celine Dion documentary ... performing a vocal cord procedure and joking around with the famous singer.

Dr. Gwen Korovin checked out Celine's strained vocal cords for the singer's 2010 documentary, "Through the Eyes of the World."

The procedure is called a laryngoscopy ... in which the mouth/oral cavity is numbed so the patient can respond to the doctor's commands.

Check out the photos of her famous patients lining the walls ... patients that include Lady Gaga, Hugh Jackman, John Mayer and Brooke Shields.

Joan Rivers' personal doctor who was working on Joan when she stopped breathing is Dr. Gwen Korovin, who treats the biggest celebs in the world ... multiple sources tell TMZ.

We're told Dr. Korovin was not authorized to practice medicine at Yorkville Endoscopy center. CNN has reported Joan's personal physician took a selfie while performing a biopsy on the comedienne.

Dr. Korovin's patient list reads like a celeb who's who. Her patients include Celine Dion, Lady Gaga, Hugh Jackman, John Mayer, and Brooke Shields.

Dr. Korovin's Facebook page has a pic of the doc in her office with pics of her celeb patients lining the walls.

The doctor has done interviews in which she says she brings a black bag to the dressing rooms of A-list stars and administers "on-the-spot treatment."

Joan Rivers' personal doctor took a selfie while the comedienne was unconscious during a biopsy ... shortly before her heart stopped beating ... this according to a new report.

The doctor performing the endoscopy had just finished when Joan's personal ear nose and throat doctor began performing a biopsy which was done without her consent -- this according to the CNN report.

A staffer at the Yorkville Endoscopy clinic reportedly told investigators Joan's doc stopped to take the selfie.

As we previously reported ... Joan went into respiratory and cardiac arrest and never regained consciousness.

The clinic has denied a biopsy was performed.

August Alsina experienced multiple seizures after collapsing during a concert 24 hours ago ... and remains hospitalized Tuesday night.

A rep for the singer tells TMZ ... August is in the ICU of a New York City hospital and receiving treatment for the seizures. We broke the story when he fainted and fell off a stage Monday night.

The rep says doctors did not find any drugs -- other than marijuana -- in Alsina's system ... and at this point they believe the fainting was brought on by exhaustion and dehydration.

Singer August Alsina fell unconscious right in the middle of his performance Monday night in NYC ... and paramedics are on scene.

BET's best new artist of the year appeared to faint during his gig at Irving Plaza in downtown Manhattan. August was walking near the front of the stage when he suddenly fell over into the crowd.

Witnesses tell TMZ ... he appeared to be out cold when security guards ran to him in the crowd ... and quickly moved him backstage. Paramedics were seen entering the venue to treat the singer -- most famous for "Ghetto" (with Rich Homie Quan) and his "No Love" remix with Nicki Minaj.

Witnesses say August was taken out on a stretcher, but was alert enough to wave to fans on the way out. It's unclear what his condition is now. We've called his reps ... so far, no word back.

If you thought Kanye West refusing to perform until a wheelchair-bound concertgoer stood up sounded like an awkward scene ... wait till you watch the cringeworthy video.

As we previously reported ... the whole thing went down at the Qantas Credit Union Arena in Sydney, Australia Friday night -- and shortly after he stopped rapping, the crowd started booing the person in a wheelchair.

Kanye West refused to continue performing Friday night at his Australian concert until someone in the crowd stood up with everyone else ... problem is, the person was in a wheelchair.

Kanye was playing a gig at the Qantas Credit Union Arena in Sydney when he stopped rapping mid-song ... ordering the crowd to get on their feet before he'd continue.

An eyewitness told the Daily Mail Australia that Kanye said, "I can't do this show until everybody stand up. Unless you got a handicap pass and you get special parking and s**t."

One person in the crowd waved their prosthetic leg in the air and Kanye said they could sit.

Shortly after Kanye spotted another person in the crowd sitting down and once again stopped the show -- then sent one of his employees into the crowd to make sure the person was handicap.

Once the hired gun confirmed the disability ... Kanye said "it's fine" and rapped on.

As you may recall ... Kanye gifted his microphone to a wheelchair-bound concertgoer earlier this summer -- so it doesn't appear like he's got any issue with the disabled.

Lyssa Chapman -- who starred with her dad on "Dog The Bounty Hunter" -- was just involved in a serious car crash in Honolulu where she lives, TMZ has learned.

Her mother, Beth Chapman, tells TMZ ... Baby Lyssa was in an accident and had "all our kids in the car." Lyssa has two daughters.

Emergency crews were called to the scene ... it's unclear if there were any injuries or what caused the crash. But pieces of the car were strewn all over the road and the vehicle's airbags were deployed.

We're contacting Honolulu PD for more info ....

Story developing ...