Online searches for Pneumonia spiked after Kim Kardashian posted that her two-year-old son fell ill with the lung infection this week.

Kim Kardashian has revealed her son Saint was hospitalised with pneumonia last week - but he is now 'all better'. 

Praising her 'resilient' two-year-old boy on Tuesday, the reality star revealed he rode an ambulance to a hospital in Los Angeles, where he was hooked up to an oxygen machine and multiple IV drips.

'My precious baby boy is so strong! After spending three nights in the hospital & seeing my baby get multiple IV’s and hooked up to oxygen machines, our end of year was challenging,' the 37-year-old TV star said on Instagram.

'Pneumonia is so scary. I just want to thanks every nurse & doctor out there who works so hard around the clock. We are so grateful for you all! He’s home and all better. He’s so resilient I’m sure he will still say the ambulance ride was cool! My strong Saint.' 

Kim and her husband Kanye West were reported to have taken turns in staying by their son's bedside, sharing overnight duties until he was released from the hospital on Saturday. 

Within minutes of Kim posting her news on Instagram, Google searches for 'pneumonia' had sky-rocketed. 

Here, we explain how pneumonia affects children, why it can be so hard to spot, and how it can be treated. 

It is common for a child's pneumonia infection to be severe by the time it is spotted.

Pneumonia, an infection that causes inflamed and fluid-filled lungs, can be is life-threatening for children, since their immune systems are not yet fully developed.

However, while children have a higher risk of pneumonia, their symptoms tend to be more subtle.

Adults tend to display clear symptoms of a dry cough and high fever.

Children, meanwhile, may experience a headache, fatigue, and a low-grade fever.

Once it progresses past the 'mild' stage to 'moderate', symptoms include a sore throat, a blocked nose, diarrhea, loss of appetite, and lack of energy.

Severe pneumonia, the far more serious stage, is typified by wheezing, sweating or chills and blue lips, and this requires hospitalisation.

The risk is higher for kids who have asthma or haven't received all their vaccinations, but all children are susceptible since their immune systems are underdeveloped.

A doctor's course of action depends on the type of pneumonia - whether it was contracted from a virus or bacteria. The doctor will perform a test to determine which one it is.

If it is bacterial pneumonia, it can be treated with antibiotics in hospital, sometimes delivered intravenously.

In the case of viral pneumonia, the patient will often be sent home, ordered to take Tamiflu, rest up, and drink lots of water.

Other types of pneumonia include fungal pneumonia, which is treated with antifungal medication, and aspiration pneumonia, when stomach contents are inhaled into the lungs. This may require a surgical procedure.

Saint West was also treated with an oxygen machine, since the infection can impair the lungs and make independent breathing strained or difficult. 

This year, the US is battling one of the most severe flu strains in years. 

-The Daily Mail