Hillary Clinton's medical history – and her tendency to keep personal and medical information far from view – is coming in for new scrutiny following revelations that the candidate got diagnosed with pneumonia Friday in advance of her stumble in New York.

Clinton's stumble, caught on camera Sunday after she had to leave Sept. 11th anniversary memorial services after about an hour and a half, was the latest in a line of health spats that have made it into the news during her career.

'Antibiotics can take care of pneumonia. What's the cure for an unhealthy penchant for privacy that repeatedly creates unnecessary problems?' asked President Obama's former message guru David Axelrod in a tweet Monday – a message promptly retweeted by Trump's campaign manager Kellyanne Conway.

In one serious incident, in 2012, Clinton got a bad stomach bug and fainted at her home in Washington – and got a concussion in the process. But information about what exactly had happened, and how it affected Clinton's job, emerged only slowly over time.

She wasn't seen in public between Dec. 7th and when she left the hospital in New York January 2, 2013.

Hillary Clinton's stumble in New York on Sunday and pneumonia diagnosis is prompting new examination of her health – as well as how her aides have closely guarded information

She experienced 'double vision for a period of time and benefitted from wearing glasses with a Fresnel prism,' her doctor, Lisa Bardack, wrote in a letter voluntarily released to the media in 2015 as part of her presidential campaign.

Her concussion 'resolved within two months,' Bardack wrote.

It was only in 2014 that Bill Clinton revealed that the injury 'required six months of very serious work to get over,' and called it a 'terrible concussion'

She was diagnosed with a blood clot in the brain, transverse sinus venous thrombosis.

Clinton had to work from home and postpone planned testimony before a House Benghazi committee.

When she did appear, she wore specialized glasses with prism lenses, which are prescribed to counter the effects of double vision.

Clinton, a frequent flier whose staff catalogued her persuit of the overall mileage record as secretary of state, twice suffered blood clots in the leg.

Clinton leaves New York Presbyterian Hospital with husband Bill and daughter Chelsea on January 2, 2013. The secretary of state, had not been seen in public since Dec. 7

HARD KNOCKS: Clinton got a fractured elbow in 2009, but still managed to negotiate with Hondouran leaders, and, according to her spokesman, text with one hand

Clinton had to shake with her left hand following her 2009 injury. She is pictured here with Palestinian Authority Salam Fayyad

Frequent jet travel can exacerbate blood clots, which is why some people make sure to walk around the cabin on long flights

The first occurred in 1998, while she was still first lady. Clinton experienced symptoms while attending a fundraiser for Sen. Charles Schumer of New York. Clinton got quietly taken to the National Naval Medical Center in Bethesda for treatment at the time. She was found to have a blood clot behind her knee, Clinton wrote in her memoir, 'Living History.'

She called it 'the most significant health scare I've ever had,' the Washington Post noted.

She had a second incident in 2009, as revealed by her doctor.

She takes a daily blood thinning medication for her deep vein thrombosis.

Also back in 2009, Clinton had to work from home for a while after she fractured her elbow during a fall, CNN recounted. She fell at the State Department on the way to the White House, and went to George Washington University hospital for treatment.

'She is working from home. She is already taking some calls, and I'm sure starting to learn the limits of movement - how well you can text with one arm in a sling,' quipped then spokesman P.J. Crowley at the time, in an early reference to Clinton's communications habits.

Clinton is 68 and would be 69 when she assumed office, second to Ronald Reagan in age taking office. Donald Trump is 70, and has released few details about his medical background.

Clinton campaigned in New York in June along with aide Huma Abedin. She was diagnosed with pneumonia Friday, according to her office

According to a letter Clinton released from her doctor in 2015, Clinton's 'current medical conditions include hypothyroidism and seasonal pollen allergies. Her past medical history is notable for a deep vein thrombosis in 1998 and in 2009, an elbow fracture in 2009 and a concussion in 2012.'

Hypothyroidism refers to an under-active thyroid gland.

'She participates in a healthy lifestyle and has had a full medical evaluation, which reveals no evidence of additional medical issues or cardiovascular disease. Her cancer screening evaluations are all negative. She is in excellent physical condition and fit to serve as President of the United States,' she wrote.

The letter released by Clinton's physician details her 2012 concussion and double vision

Clinton was a 'healthy-appearing female' during her last examination, according to Dr. Lisa Bardack

Hours after Clinton was taken away from the Sept. 11th ceremony, her office released a doctor's statement. '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 rehydrated and recovering nicely,' Clinton's doctor, Lisa Bardack, said in a written statement Sunday.'

'There's no other undisclosed condition. The pneumonia is the extent of it,' Clinton campaign spokesman Brian Fallon told MSNBC.

Fallon also acknowledged: 'I think in retrospect we could have handled it better in terms of providing more information more quickly.'