What do you think is today's greatest limitation to the treatment of severe and life-threatening illnesses?

I think this question need to be answered at several levels. Starting from the global level, some conditions like diarrhea, starvation, some infectious diseases, maternal mortality, pneumonia, and others are considered killer diseases (life-threatening) in some parts of the world (poor, developing countries, Africa, Asia, ...), while they are not in the developed & industrialized countries. AIDS for an example is now out of the top10 killer diseases in USA, while it still a killer in Africa (Sub Saharan). That lead to declare healthcare accessibility is the major factor that could limit the treatment of severe & life threatening illnesses at the global level. If you were a child who was born in Somalia then you had a25 times a chance to die before5 years of age than a child who was born in Europe or Japan. The low economic (& socio economic) status of countries & individuals also is a great limitation to treatment of severe & life-threatening illnesses, where a poor country or a poor individual doesn't have the required resources to be treated. Some political issues are among the limitations; take for an example the siege on Gaza Strip that forced by Israel, a few months old girl died because she was not permitted to cross outside Gaza Strip to have a proper treatment. Disparities also play a major role in what we discuss here. If some people couldn't have the rights to get healthcare services, then they will be at greater risk of being affected by the severe & life-threatening diseases. I must add also the low education status. The well educated people can handle the severe cases very much better than the not-educated people, and this include also the ignorance & neglect of some healthcare providers who don't educate their patients about how to manage & response to their conditions (and complications) properly. The insufficient emergency transportation system in some countries is a great limitation too. In those countries the angina (heart attack) patient may have to wait hours if he decides to wait for an ambulance to transport him to a medical center. Not to mention the traffic issues which are responsible for delaying the ambulances from getting to the hospitals in the right time. One important limitation unsuitable training & qualification of some healthcare provider. Some administration issues, like not assigning the right Cader in emergency department, or leaving a new fresh graduate or intern facing a patient with life-threatening case without any high level support. The low healthcare quality, and the new emerging unhealthy lifestyles are among the limitation factors too. In some countries (including Arab & ME), the absence of clear regulations for patients rights would maintain this level of limitations to the treatment of severe & life-threatening illnesses, and even worsen it.

Agreed to Mr. Ahmed Sharab...... my compliments to him on very nice and useful elabration of the topic. 

As far as the my region is ocncerned, the socio-economic conditions are the greatest hinderence to be treated for life threatening or chronic diseases as all of them cost too much here. ITS SAD BUT ITS TRUE FOR MILLIONS OF DISEASED LIVES.

The answer can vary as per demographic changes, under develop to developing countries, close to open culture societies, lower to upper socioeconomic status and ignorance to knowledge. It can be from one gender to another and even religious understanding can bound one from getting treatment of severe and life threatening illnesses. It is not only from patient’s perception, even physicians can be one of the reason. The better human understanding we develop within ourselves and our surrounding the more accessible solutions become. And this is the biggest challenge. Nothing in the world lives for ever, how we live that matters.

Emergence of multi drug resistant strains of bacteria 

many things like:

diet.

exercise.

healthy food.

working, i think this one is the most effect.