Hillary Clinton is being treated for pneumonia and dehydration, her doctor said on Sunday, hours after she abruptly left a ceremony in New York honoring the 15th anniversary of the Sept. 11 attacks and had to be helped into a van by Secret Service agents.

The incident, which occurred after months of questions about her health from her Republican opponent, Donald J. Trump, and his campaign, is likely to increase pressure on Mrs. Clinton to address the issue and release detailed medical records, which she has so far declined to do.

Mrs. Clinton was taken from the morning event at ground zero to the Manhattan apartment of her daughter, Chelsea. About 90 minutes after arriving there, Mrs. Clinton emerged from the apartment in New York’s Flatiron district. She waved to onlookers and posed for pictures with a little girl on the sidewalk.

“I’m feeling great,” Mrs. Clinton said. “It’s a beautiful day in New York.”

Mrs. Clinton left in her motorcade without the group of reporters that is designated to travel with her in public. A campaign spokesman, Nick Merrill, indicated that she had returned to her Chappaqua, N.Y., residence sometime after 1 p.m., and Mrs. Clinton was not seen publicly the rest of the day.</s>The sun rises over the Pentagon on Sunday prior to a morning ceremony to commemorate the 15th anniversary of the September 11, 2001 terror attacks. The Pentagon Memorial commemorates the 184 lives lost at the Pentagon and onboard American Airlines Flight 77 that day.

A firefighter rings a bell as family members, emergency workers and others attend a commemoration ceremony for the victims of the September 11 terrorist attacks at the National September 11 Memorial and Museum on Sunday in New York City.

An American flag stands among names on the 9/11 memorial before the start of the 15th anniversary memorial service to 9/11 victims in New York.

A woman hugs a man during a commemoration ceremony for the victims of the September 11 terrorist attacks in New York.

A group of motorcycle riders look over the north memorial pool Sunday during services marking the 15th anniversary of September 11 at the 9/11 Memorial and Museum in New York.

A man honors a lost loved one at a commemoration ceremony for the victims of the September 11 terrorist attacks in New York City.

A girl cries while reading the names of the victims during a ceremony Sunday marking the 15th anniversary of September 11 attacks at the National 9/11 Memorial in New York.

An Army service member salutes during the a ceremony remembering the victims of the September 11 terrorist attacks at the National September 11 Memorial and Museum.

Family members embrace Sunday during the 15th-anniversary service at the 9/11 Memorial and Museum.

US military personnel attend a memorial ceremony on the 15th anniversary of the September 11, 2001 attacks at the International Security Assistance Force headquarters in Kabul, Afghanistan.

Attendees hold photographs of loved ones lost in the September 11 terrorist attacks at a commemoration ceremony Sunday at the National September 11 Memorial and Museum in New York.

United Airlines flight attendants Clarice Rinker and Janeen Brown embrace by the Wall of Names at the Flight 93 National Memorial near Shanksville, Pennsylvania, on the 15th anniversary of the terror attacks. Their fellow flight attendants and pilots were killed when Flight 93 crashed in a field near Shanksville.

Military personnel salute during a ceremony Sunday to mark the 15th anniversary of the 9/11 attacks at the Pentagon Memorial in Washington, DC.</s>Hillary Clinton, who had to leave a Sept. 11 ceremony early because she didn’t feel well Sunday, is being treated for pneumonia, her doctor said in a statement after examining the Democratic candidate at her house Sunday afternoon.

“While at this morning's event, she became overheated and dehydrated. I have just examined her and she is now re-hydrated and recovering nicely," said Dr. Lisa R. Bardack in a written statement.

Bardack said that Clinton was diagnosed with pneumonia on Friday.

“She was put on antibiotics, and advised to rest and modify her schedule,” the physician wrote.

Clinton’s early departure from the ceremony and a video that showed her struggling to stand as she left stoked speculation about the state of her health. Her critics and GOP rival Donald Trump have been questioning her physical fitness for office, pointing to her periodic coughing fits.

Bardack, Clinton’s physician for more than a decade, said in her statement that the Democratic nominee’s cough was related to allergies and the pneumonia was diagnosed during an evaluation of the cough.</s>Hillary Clinton's diagnosis of pneumonia is a serious concern, but something from which she soon should recover, several doctors and medical experts said Sunday.

Clinton, 68, unexpectedly left a 9/11 anniversary ceremony in New York after she became 'overheated and dehydrated,' her doctor said.

She went to her daughter's nearby apartment for a short stay, and emerged before noon to tell reporters, 'I'm feeling great'.

Several hours later, Clinton's physician said the Democratic presidential nominee was diagnosed on Friday with pneumonia.

'She was put on antibiotics, and advised to rest and modify her schedule,' said Dr. Lisa R. Bardack, an internist who practices near Clinton's suburban New York home.

Bardack added in a statement that Clinton, after an exam on Sunday afternoon at her home, 'is now rehydrated and recovering nicely'.

Pneumonia is an infection of the lungs. Often it's a bacterial infection that sweeps in after a cold or flu virus.

Each year, about 1 million people in the United States seek hospital care because of pneumonia.

It causes tens of thousands of deaths, according to the Centers for Disease Control and Prevention.

A presidential candidate is at high risk for such an infection, said Dr. William Schaffner, an infectious disease expert at Vanderbilt University.

'Candidates are constantly out in enclosed spaces, face to face with myriads of people,' he said. 'It's an ideal opportunity for the transmission of a respiratory virus.'

Dr Stephen Hargarten, head of emergency medicine at the Medical College of Wisconsin, added: 'I'm not surprised to hear this happen to someone engaged in the kind of frenetic schedule she has.'

WHAT ARE THE SYMPTOMS?

People with pneumonia usually feel ill, shivery, feverish and off their food. Sometimes they may also feel nauseous.

Symptoms are similar to flu, but people with pneumonia nearly always have a cough (often with mucky sputum).

Other symptoms are shortness of breath, with a feeling of tightness or pain in the chest when trying to breathe. Sufferers may even go bluish around the lips and nails due to lack of air.

Sometimes a sharp pain in the side, worsened by breathing, can occur if the infection also involves the lining of the lung, a condition called pleurisy.

Sufferers may also experience an outbreak of herpes (cold sores) around the mouth, which shows that the immune system is weak.

HOW DO YOU CATCH IT?

It can be caused by bacteria, such as Streptococcus pneumoniae, which is treated with antibiotics.

Most transmissions come when an infected person sneezes and another person inhales the bacteria from their saliva or nasal mucus.

Viruses like the flu or a chest infection can also lead to pneumonia - but these can only be treated with rest and hydration.

It is not clear which kind Clinton has.

Her doctor said she had been put on antibiotics, which implies a bacterial infection.

However, that is a first-step precaution most doctors take as they carry out further tests.

It is common for doctors to diagnose patients with pneumonia as the most likely cause of their symptoms before they get the scans back.

That said, it is also possible to get quick-fire results with rapid diagnostics or a chest X-ray.

WHY DID IT MAKE HILLARY CLINTON WEAK?

Like many bacterial and viral infections, pneumonia dehydrates the body and causes fatigue.

In extreme cases, it drives down oxygen levels in the lungs.

However, if this were the case in Clinton, she would have been hospitalized before the weekend, or straight after her tumble on Sunday.

It is most likely that Clinton was dehydrated, overheated, and not rested enough.

HOW IS IT TREATED?

Pneumonia is commonly treated quickly and effectively with antibiotics.

Speaking generally and not about Clinton's case, Schaffner said patients with a mild pneumonia can recover with antibiotics, a few days of rest and good hydration.

That's especially true of someone who does strenuous work, such as a rigorous campaign schedule.

Based on the available information, he said, 'this should not in any way impede her function going forward.'

But Clinton does need to take it seriously, some experts said.

People over age 65 have a harder time returning to normal than do younger patients.

Many people her age need a week or more to recover from even a mild case of pneumonia, said Dr Sharon Bergquist, an Emory University assistant professor of medicine who specializes in internal medicine.

'The body needs rest. The more she pushes, the harder it is for her to recover,' she said.

Clinton had a coughing fit while campaigning in Cleveland early last week. It was dismissed by her aides as allergies and by Clinton herself at that moment as stemming from 'talking so much.' It's possible Clinton may have assumed that symptoms from an earlier viral infection were due to allergies, Schaffner said. Clinton takes antihistamines, which can 'dry you out,' and dehydration leads to a person being susceptible to heat exhaustion, Bergquist said. Add in the possibility of fever, shortness of breath or other possible symptoms from pneumonia, and you have a constellation of factors that could have explained her feeling weak on Sunday, she said. Last year, Clinton's campaign released a letter from Bardack attesting to the former secretary of state's good health. The most notable events in Clinton's medical record included deep vein thrombosis - or a blood clot, usually in the leg - in 1998 and 2009, a broken elbow in 2009 and a concussion in 2012. Clinton got a stomach virus while traveling in 2012 that left her so dehyrdated that she fainted. She had a concussion that fall, and doctors treating her found a blood clot in a vein in the space between the brain and the skull behind her right ear. Clinton spent a few days in New York-Presbyterian Hospital for treatment and took a monthlong absence from her role as secretary of state. Bardack said testing the following year showed 'complete resolution' of the concussion's effects, including double vision, for which Clinton wore glasses with specialized lenses to address. - Her total cholesterol was 195; her LDL or 'bad' cholesterol was 118, and her HDL or 'good' cholesterol was 64 - all within healthy levels and not signaling the need for any medications - She had full cardiac testing, including an ultrasound exam of arteries in her neck, and all was well - Clinton has been diagnosed with hypothyroidism, a common condition in women older than 60, in which the thyroid gland doesn't produce enough of certain important hormones</s>Hillary Clinton embraced a young child after leaving her daughter's apartment - despite suffering from pneumonia.

The Democratic presidential candidate was diagnosed with the illness after she collapsed at an 'incredibly stifling' 9/11 ceremony in New York.

Pneumonia is a contagious illness that is spread from person-to-person when small droplets of water that contain the bacteria get into the air and people breathe them in.

Those infected usually spread the disease by sneezing while in close contact with others, who then breathe in the bacteria, according to the Centers for Disease Control and Prevention.

William Schaffner, an infectious disease expert at Vanderbilt University, said: 'Candidates are constantly out in enclosed spaces, face to face with myriads of people. It's an ideal opportunity for the transmission of a respiratory virus.'

Clinton was diagnosed with pneumonia on Friday and given antibiotics but had become dehydrated at the event in New York.

A dramatic video recorded by a bystander showed the Democratic candidate's knees buckling as she stepped off a kerb into a waiting van.

She had to be helped up by two Secret Service guards as her team rushed to help her and stopped her hitting the ground.

Clinton left after just 90 minutes of the ceremony at Ground Zero to mark the 15th anniversary of the September 11 attacks.

Her spokesman Nick Merrill said she felt 'overheated' and she was taken to her daughter Chelsea's apartment in the city in what was described as a 'medical episode'.

Another picture taken moments earlier showed the 68-year-old holding her chest with her right hand and looking uncomfortable.

Representative Joe Crowley, a New York Democrat, described the memorial as being 'incredibly stifling'.

An hour after arriving at her daughter's apartment, she emerged looking relaxed.

Asked if she was feeling better, Mrs Clinton said: 'Yes thank you, very much'.

She smiled and posed for pictures with the young girl before leaving for her home in Chappaqua, just northeast of Manhattan.

'I'm feeling great, it's a beautiful day in New York,' Clinton said.

Following her collapse she was forced to cancel a California fundraising trip on Monday and Tuesday.

Her campaign team also faced questions as to why it took them two days to reveal the illness.

The diagnosis puts the health of Clinton back into the spotlight with two months left in the US presidential election.

She has suffered numerous coughing fits on live TV, joking how 'every time I think of Trump I get allergic'.

Her critics have seized on photos of her which they claim show she has suffered seizures.

Should Mrs Clinton win the presidency she will be 69 when she takes office, making her the second oldest person to assume the title after Ronald Reagan.

Her Republican opponent, Donald Trump, 70, would be the oldest if he wins.</s>Hillary Clinton abruptly left a 9/11 anniversary ceremony Sunday after feeling "overheated," according to her campaign, and hours later her doctor disclosed that the Democratic presidential nominee had pneumonia.

A video showed Clinton slumping and being held up by three people as she was helped into a van after the event, and her doctor said in a statement that Clinton had become overheated and dehydrated. "I have just examined her and she is now rehydrated and recovering nicely," Dr. Lisa R. Bardack said in a statement.

The physician said Clinton has had an allergy-related cough, and that during a follow-up examination Friday, the candidate was diagnosed with pneumonia, put on antibiotics, advised to rest and modify her schedule.

Less than two months from Election Day, it was an unwanted visual for Clinton as she tries to project the strength and vigor needed for one of the world's most demanding jobs. Republican rival Donald Trump has spent months questioning Clinton's health, saying she doesn't have the stamina to be president.

Clinton's departure from the event was not witnessed by the reporters who travel with her campaign and aides provided no information about why she left or her whereabouts for nearly two hours. Spokesman Nick Merrill eventually said Clinton had gone to her daughter's nearby apartment, but refused to say whether the former secretary of state had required medical attention.

Clinton exited the apartment on her own shortly before noon. She waved to reporters and said, "I'm feeling great. It's a beautiful day in New York."

The video of Clinton posted to social media shows her being held up by aides as a black van pulls up. She stumbles and appears to fall off the curb as she is helped to the vehicle.

After leaving her daughter's, Clinton was driven to her home in Chappaqua, New York, and made no public appearances. She was scheduled to fly to California Monday morning for fundraising and it was unclear whether her schedule would change.

Trump, who attended the same event marking the 15th anniversary of the 9/11 attacks, was noticeably restrained. Asked by a reporter about Clinton's health incident, Trump said, "I don't know anything."

The incident compounds an already difficult stretch for Clinton as the presidential race enters its final stretch. Despite Trump's numerous missteps, the race remains close and many Americans view Clinton as dishonest and untrustworthy.

On Friday, Clinton told donors that "half" of rival Donald Trump's supporters are in a "basket of deplorables" — a comment that drew sharp criticism from Republicans. Clinton later said she regretted applying that description to "half" of Trump's backers, but stuck by her assertion that the GOP nominee has given a platform to "hateful views and voices."

Now Clinton is sure to face new questions about whether she's physically fit for the presidency. Trump and his supporters have been hinting at potential health issues for months, questioning Clinton's stamina when she takes routine days off the campaign trail and reviving questions about a concussion she sustained in December 2012 after fainting. Her doctor attributed that episode to a stomach virus and dehydration.

Clinton's doctor reported she is fully recovered from the concussion, which led to temporary double vision and discovery of a blood clot in a vein in the space between her brain and skull. Clinton also has experienced deep vein thrombosis, a clot usually in the leg, and takes the blood thinner Coumadin to prevent new clots.

Clinton spent about 90 minutes at the 9/11 event Sunday, standing alongside numerous other dignitaries, including New York's Democratic senators, Chuck Schumer and Kirstin Gillibrand. The weather was warm and humid in New York on Sunday, and there was a breeze at the crowded memorial plaza during the ceremony.

Rep. Joe Crowley, D-N.Y., said he spent time before the ceremony chatting with Clinton and watching her sign autographs and take pictures. He said he was standing behind her during the remembrance and "she did not seem out of the ordinary at all."

"It was stiflingly hot. I was sweating through my shirt," Crowley said. "I had to leave myself. I drank about a gallon of water."

Schumer said he also spoke with Clinton during the event and saw her leave "on her own accord."

Trump's personal physician has said the Republican presidential nominee is in excellent health both physically and mentally. But the 70-year-old has refused to release his own health records.

Dr. Harold Bornstein's report last December remains the only medical information released so far by the Trump campaign. Bornstein told NBC News he needed just five minutes to write a glowing public assessment of Trump's health as a limousine waited to carry the letter back to Trump.</s>Video emerged Sunday of Hillary Clinton struggling to stand and needing help to get into her vehicle as questions swirled about the Democratic presidential nominee’s health after she abruptly left a 9/11 ceremony in New York City.

In the 19-second video, a woman is seen clutching Clinton’s left arm as her vehicle approaches, and then two men grab both of her arms and help her into the vehicle as her knees appear to buckle.

Clinton was attending a 9/11 ceremony when she left around 9:30 a.m. because she felt “overheated,” according to campaign spokesman Nick Merrill.

“Secretary Clinton attended the September 11th Commemoration Ceremony for just an hour and thirty minutes this morning to pay her respects and greet some of the families of the fallen,” Merrill said in a statement. “During the ceremony, she felt overheated so departed to go to her daughter's apartment, and is feeling much better.”

Shortly before noon, Clinton left Chelsea Clinton’s apartment, wearing sunglasses and waving to diners at a nearby restaurant.

"I'm feeling great, it's a beautiful day in New York," Clinton said, before heading to her home in Chappaqua.

Republicans have focused on Clinton’s health on the campaign trail, with GOP nominee Donald Trump repeatedly questioning her strength and stamina.

Sunday’s incident will only amplify these questions, in part because of the abrupt nature of her departure from the ceremony and the lack of details about what occurred from her campaign. The reporters who were traveling with Clinton were not told about her condition or her whereabouts for 90 minutes after she left the ceremony.</s>Hillary Clinton's doctor has revealed the 68-year-old has pneumonia - hours after video showed her collapsing into the arms of her Secret Service agents after being rushed from the 9/11 memorial service at the World Trade Center.

Dr. Lisa R. Bardack released a statement through her campaign team after she performed a check-up on the presidential candidate at her home in Chappaqua, New York, on Sunday, after the 'medical episode'.

She said: 'Secretary Clinton has been experiencing a cough related to allergies. On Friday, during follow up evaluation of her prolonged cough, she was diagnosed with pneumonia. She was put on antibiotics, and advised to rest and modify her schedule.

'While at this morning's event, she became overheated and dehydrated. I have just examined her and she is now re-hydrated and recovering nicely.'

Clinton is now holed up in her upstate New York home after a bystander recorded her losing her balance, slumping at the knees and being held up by her aides while waiting to get in a minivan.

Her campaign had earlier blamed 'overheating' for the episode - which saw her rushed away from the ceremony at Ground Zero and back to Chelsea's apartment. Her press pool was not informed for 90 minutes of her whereabouts or given an explanation for the abrupt departure.

At the time the temperature was around 80 degrees and the humidity was low.

Clinton's collapse adds to growing fears for the 68-year-old's health, which began mounting on Labor Day when she broke out in a coughing fit during a speech in Ohio. It now seems that cough has developed into pneumonia, according to Dr Bardack's statement.

Katie Packer, a GOP strategist, told the Los Angeles Times that the incident will increase attention on the health of both Clinton and Trump, 70.

'This is the kind of thing that voters have a right to understand before they cast a vote,' she said.

'But Trump and Hillary are elderly. They are obligated to release full medical records and full tax returns to the American people. And the media, party leaders and American people should settle for nothing less.'

Clinton is due to fly to the West Coast earlier Monday morning, but it is unclear if she will now do so.

Several party leaders and Clinton backers told POLITICO that she needed to offer a fuller accounting of her health.

'There will have to be some kind of accounting for this,' said one former Clinton adviser.

Clinton was already facing calls on Sunday afternoon to release her full medical records.

In the footage, Clinton is seen standing on a curb near the site of the Twin Towers when she suddenly appears unable to stand.

She seems to nearly fall to the ground before she is caught by her aides, who hold her up. Her security detail then had to help her into the van by grabbing each of her arms.

The former Secretary of State then appears to fall forward towards the door of the van before being bundled inside.

Law enforcement sources told the Daily Beast she was thrown into the back seat like a 'side of beef'.

She appears to lose a shoe under the vehicle in the struggle before being driven to daughter Chelsea's apartment in Manhattan.

Despite the concerning footage, she emerged from the home just over two hours later at 11:45am on Sunday saying she was fine. She told a waiting crowd and reporters: 'I'm feeling great, it's a beautiful day in New York.'

A smiling Clinton was then greeted by a young girl on the street to pose for a picture. She waved at customers at a nearby restaurant before getting into a van.

Clinton then traveled to her home in Chappaqua, New York, according to her campaign.

It is not known whether she saw a doctor.

Nick Merrill, her traveling press secretary, said Clinton 'overheated' during the ceremony, but quickly recovered when she returned to Chelsea's apartment.

She recently said she had been suffering from allergy attacks since Labor Day and had upped her antihistamine dosage.

Clinton suffered two coughing fits this week while on the campaign trail, one while she was speaking publicly in Ohio on Monday and another while she was taking questions from reporters.

Dailymail.com had asked Clinton about her health Thursday pointing to notes released by the FBI as part of the bureau's email investigation that suggested Clinton may have suffered memory loss from the concussion she sustained in 2012.

'Can you clarify what you told the FBI about your concussion?' Dailymail.com had asked the candidate, to which Clinton replied curtly, 'read the reports,' offering no additional explanation.

There are also questions over whether the Secret Service had to adapt to the situation and shied away from standard procedure when they whisked Hillary away from the scene.

A source told the Washington Post that agents are supposed to wait for a car before they take a protected individual away.

In the video, Hillary is seen leaning against a bollard before the motorcade draws up.

They appeared to have rushed her departure, which meant lead agent Todd Madison had to leave her side to open the van door, which is also against protocol.

The Secret Service later denied they had broken protocol.

Today, shortly after 9:30am, the pool reporter covering Clinton at the World Trade Center notified the rest of the press that the Democrat had disappeared from the event with no notice from the campaign.

She had spent about 90 minutes at the memorial.

It wasn't until 11am that reporters were told where Clinton went and what had happened, though Fox News had already reported that Clinton had suffered from a 'medical episode.'

Trump said he had 'no idea' what happened when asked about his rival's health after the ceremony.

Trump's campaign did not respond to a request for additional comment from Dailymail.com.

Merrill said in a statement: 'Secretary Clinton attended the September 11th Commemoration Ceremony for just an hour and thirty minutes this morning to pay her respects and greet some of the families of the fallen.

'During the ceremony, she felt overheated so departed to go to her daughter's apartment, and is feeling much better.'

Clinton's press team later updated the statement to remove the word 'just,' stating it was a 'typo.'

Eyewitnesses said that Clinton had to wait a couple of minutes for her motorcade as it wasn't waiting for her when she exited the event.

Fox News reporter Rick Levanthal, who broke the initial story, quoted one person who was standing 15ft away from Clinton who saw her stumble off the curb.

Her 'knees buckled,' Levanthal tweeted, as she lost a shoe during this 'unexpected early departure.'

Her detail retrieved a shoe from underneath the van and helped the former secretary of state inside, according to reports.

The temperature was around 80 degrees at Ground Zero during the service. There was a humidity of 41%.

Clinton was standing in the middle of a crowd of politicians packed together in a small space.

Clinton's pool reporter wrote that she could not see whether the Democratic hopeful was standing in direct sunlight, though noted that there wasn't a lot of shade in the area where the politicians were gathered.

Clinton had already suspended campaigning on Sunday in a show of support for those who died on 9/11 and those who survived the terror attacks.

Earlier on Sunday she tweeted: 'We'll never forget the horror of September 11, 2001. Today, let's honor the lives and tremendous spirit of the victims and responders.'

Clinton was a senator from New York 15 years ago and did a sit-down interview with CNN's Chris Cuomo about her experience during and after the attacks.

She recalled being evacuated from the Senate office buildings in Washington, D.C. on 9/11 and then heading to New York City alongside her peer, Sen. Chuck Schumer, on Sept. 12.

She visited lower Manhattan on Sept. 12, alongside her Senate peer, Sen. Chuck Schumer, describing what she saw on the ground as 'hell.'

'We saw this curtain of black smoke that was stretched across the island.

'Occasionally it would be broken by a firefighter coming out. I remember one image so indelibly, dragging his ax, and it was as close to a depiction of hell that I have ever personally seen.

'There weren't that many survivors; the ones that did survive were grievously injured. The loss of life was overwhelming.

'But it was also my job and the job of other officials to get our city and state and country what we needed,' she said.

She noted in the CNN interview that she visited New York City before then-President George W. Bush and played up her role in helping the city get federal funding to rebuild and aiding first responders in getting proper medical care after being exposed to the dirty air coming from the burning remains of the Twin Towers.

Today's health scare, however, will likely bury the effect the CNN interview would have on her poll numbers, which have dipped into being within spitting distance of Trump's in recent days.

Instead, the fainting spell could lend proof to conspiracy theories that Trump's allies have pushed, which suggest Clinton's health is failing.

It was Trump surrogate Rudy Giuliani, the former New York City mayor, that brought these theories into the mainstream by saying on Fox News Sunday last month that voters should 'go online and put down "Hillary Clinton's illness." Take a look at the videos for yourself,' the Republican instructed.

This came a week after Trump himself had told a crowd that Clinton lacked the 'mental and physical stamina to take on ISIS.'

Clinton's campaign interpreted Trump's words to mean that he was peddling some of the right-wing conspiracy theories going around the internet including that Clinton had suffered a seizure on camera and that she was showing signs of dementia.

Trump's comment prompted the Clinton campaign to address her health and fitness for the first time since releasing a doctor's note a year before.

'While it is dismaying to see the Republican nominee for president push deranged conspiracy theories in a foreign policy speech, it's no longer surprising,' Clinton's communications director Jennifer Palmieri said in a statement.

'Donald Trump is simply parroting lies based on fabricated documents promoted by Roger Stone and his right wing allies,' Palmieri continued.

She then pivoted for a moment to blast Trump for not releasing any of his tax returns to the American public.

'Hillary Clinton has released a detailed medical record showing her to be in excellent health plus her personal tax returns since 1977, while Trump has failed to provide the public with the most basic financial information disclosed by every major candidate in the last 40 years,' she acknowledged.

'It's time for him to stop using shameful distractions to hide his own record,' Palmieri added.

Clinton's people included a new statement from her physician, Dr. Lisa Bardack, who had signed off on the Democrat's health in the beginning months of her campaign last year.

'As Secretary Clinton's long time physician, I released a medical statement during the campaign indicating that she is in excellent health,' Bardack wrote last month.

'I have recently been made aware of allegedly "leaked" medical documents regarding Secretary Clinton with my name on them. These documents are false, were not written by me and are not based on any medical facts,' she continued.

'To reiterate what I said in my previous statement, Secretary Clinton is in excellent health and fit to serve as President of the United States,' Bardack said.

In December 2012, Clinton fainted and suffered a concussion after contracting a stomach virus. She later developed a blood clot.

She’s been taking the anticoagulation drug, Coumadin, ever since.

In 2005, she fainted before a scheduled speech in Buffalo, New York, after suffering a similar stomach virus.

Beyond Giuliani and Trump, Clinton's health also became front-and-center when Dr Drew Pinsky said he was 'gravely concerned not just about her health, but her health care.'

'It just seems like she’s getting care from somebody that she met in Arkansas when she was a kid, and you’ve got to wonder. You’ve got to wonder,' Pinsky had said.

Dr Drew's HLN show was canceled several days after he made the comments with no explanation from the network, leading to speculation that the negative remarks were the cause.</s>Footage of Hillary Clinton prematurely leaving a 9/11 memorial event on Sunday show someone who was feeling weak and unwell.

There are many possible medical causes for a near faint, but the revelation that Mrs Clinton had been diagnosed with pneumonia two days previously could explain what her doctor subsequently described as an episode of “dehydration and overheating.”

Dr Lisa Bardack said in a statement, that 68 year-old Mrs Clinton has been experiencing a cough related to allergies and that an examination on Friday showed that she was suffering from pneumonia.

Pneumonia is a type of chest infection that affects the lungs and lower airways. Bronchitis is an infection of the upper and middle airways in the lung. Most bronchitis cases are caused by viruses, whereas most pneumonia cases are due to bacteria.

Despite the advent of powerful antibiotics, pneumonia remains a potentially fatal illness, especially in the under-5s and in older people.

In the US, about 2 to 3 million people develop pneumonia each year, and 60,000 of them die. Pneumonia, along with influenza, is the eighth leading cause of death in America.

Mrs Clinton’s illness is classified as community acquired pneumonia (CAP). The annual incidence of CAP in the western world is estimated at between 5 and 11 cases per 1,000 adults.

More than 100 different microbes have been linked with pneumonia; however the most common culprits are Streptococcus pneumoniae and Haemophilus influenzae.

Mild cases of CAP are treated at home by taking oral antibiotics, drinking plenty of fluids and getting plenty of rest. The fact that Mrs Clinton was still following a busy schedule on Sunday, some 48 hours after being diagnosed, suggests a hard campaigning politician who was possibly reluctant to take medical advice to rest.

The term “walking pneumonia” has been used in some media reports about Mrs Clinton. Apparently used to suggest a mild case of pneumonia that does not require rest, it is not a recognised medical term.

Now that she is resting, the Democratic presidential candidate should respond well to treatment. Complications are possible, however, and the need for hospitalisation cannot be ruled out if the infection doesn’t settle.

The main complication is pleurisy, where a thin lining between the lungs and the ribcage becomes inflamed. Fluid builds up in this space, causing severe pain and difficulty breathing. And like any other infection in the body, the bugs causing the pneumonia can invade the blood stream causing septicaemia.

This serious illness warrants hospital admission for intravenous antibiotics and fluids, and oxygen.

Even if she recovers rapidly, Mrs Clinton can expect to feel tired for a number of weeks. The cough which has been bothering her will persist for up to four weeks after the bacteria has been eliminated from her lungs.

As to the future, Mrs Clinton will be advised to have up to date influenza and pneumococcal vaccine jabs. And a chest X-ray in a number of weeks time to confirm the pneumonia has completely gone would be a wise move.</s>Pneumonia: Five things to know

US presidential candidate Hillary Clinton has cancelled campaign engagements after being diagnosed with pneumonia.

The 68-year-old fell ill at a ceremony to mark the 15th anniversary of the September 11 attacks, and appeared to lose her footing as she was helped into her vehicle.

Here are five things to know about the disease.

Pneumonia is an acute respiratory infection caused by bacteria, viruses or fungi that target the lungs.

When it strikes, the tiny air sacs inside the lungs fill up with pus and fluid, limiting oxygen intake and making it painful for the patient to breathe.

All types of pneumonia share similar symptoms including cough and fever, with wheezing being more common in viral cases.

Doctors usually diagnose pneumonia by conducting a physical exam, checking symptoms and carrying out a chest X-ray to ensure that the patient is not suffering from bronchitis or other respiratory infections.

Fungal pneumonia tends to be relatively rare, affecting people with weakened immune systems, such as AIDS patients, who become sick either when they inhale wind-borne spores or when a fungus already present in their bodies triggers symptoms.

Who is at risk?

Pneumonia can affect people of all ages but it can be particularly serious, even life-threatening, for the very old or the very young.

Smokers, as well as people with underlying medical conditions such as asthma, diabetes and heart disease, are particularly vulnerable, according to the US Centers for Disease and Control Prevention (CDC).

The infection is spread via air-borne droplets from coughs or sneezes.

Doctors say hand-washing is an effective way to reduce the risk of picking up pneumonia.

How dangerous is it?

When an otherwise healthy adult under 65 years of age gets pneumonia, his or her body can usually fight off the infection.

But patients with a weak immune system -- those who are very young or old, or those who have a pre-existing condition -- can struggle to cope and will sometimes develop complications.

As the infection sets in, it can cause oxygen levels in the body to fall. In extreme cases, this can lead to organ failure and death.

The World Health Organization calls pneumonia the single biggest killer of children under five worldwide, responsible for 15 percent of deaths in this age group every year.

What is the recommended treatment?

It depends on what kind of pneumonia it is.

Doctors advise patients to take rest and consume plenty of fluids.

The normal treatment includes antibiotics for bacterial cases, while viral pneumonia is treated with antiviral drugs and the occasional prescription of corticosteroid medicines.

Fungal pneumonia is usually treated with antibiotics or antifungal medication.

What is the usual recovery time?

Recovery time depends on the severity of the symptoms before treatment but in most cases, patients feel better after a course of medicines and a week of rest.
Hillary Clinton's doctor says she is being treated for pneumonia and dehydration after the Democratic Party presidential candidate fell ill and abruptly left a ceremony in New York City honoring the 15th anniversary of the September 11 attacks.