Most of us hear 'Salmonella' and immediately think of food poisoning.
Diarrhoea. Vomiting. A few days of misery after eating contaminated food.
But if you live with sickle cell, your body may provide the perfect conditions for Salmonella to evolve into its final form...
Salmonella Osteomyelitis.
Lets break down what this means.
Osteomyelitis means an infection inside the bone.
So how does infection end up here?
Well sickle cell puts in the ground work on your bones beforehand.
When you have a sickle cell crisis, sickled red blood cells can obstruct the tiny blood vessels supplying the bones. This can reduce blood flow and cause small areas of bone and bone marrow to become damaged and die.
These damaged areas can become particularly vulnerable to infection.
It's like bacteria are vultures and the tiny areas of dead bone are roadkill.
Normally there's no issue because these 'vulturous' bacteria are kept away from the bones.
However sickle cell creates a couple of holes in the bodies defence.
1) Functional loss of the spleen and other changes to the immune system.
2) Sickle cell crisis can damage the gut barrier. This makes it easier for Salmonella to enter the bloodstream from your intestines.
The process usually starts with Salmonella entering the body through contaminated food or water.
Raw or undercooked poultry and eggs are well-known sources, although they're certainly not the only ones.
Usually the infection remains in the gut.
Occasionally, however, Salmonella crosses through the intestinal wall and gets into the bloodstream.
Once in the blood stream it can travel through the circulation and settles in vulnerable areas of bone causing infection.
That's how Salmonella can go from a "stomach bug" to osteomyelitis.
And there is another important problem.
Osteomyelitis can look remarkably similar to a sickle cell pain crisis.
Both can cause significant bone pain. Fever and raised inflammatory markers can occur with either. Early imaging may not always give an immediate answer either.
So someone may initially be treated for what appears to be another painful crisis before it becomes clear that something else is going on.
That doesn't mean every prolonged or unusually painful crisis is osteomyelitis. Vaso-occlusive bone pain is much more common.
When should doctors consider osteomyelitis?
What investigations should be done to help diagnose it?
If osteomyelitis is confirmed, treatment is very different from simply treating a pain crisis.
Antibiotics are usually required for several weeks. The choice of antibiotic depends on the exact type of bacteria found in the blood or biopsy cultures. Because osteomyelitis can also be caused by bacteria other than salmonella.
And what about the penicillin that many people with sickle cell take preventatively?
Don't assume that protects you from Salmonella. Penicillin in sickle cell is primarily used to protect against serious pneumococcal infection. It doesn't remove the need to take Salmonella and food hygiene seriously.
So always be careful when preparing and cleaning up raw chicken and obviously make sure it's cooked properly!
Thats all for this week.
I hope you've either learnt something new or now understand a previous experience you've had with salmonella osteomyelitis a little better.
Stay Healthy,
Lewis
