Why salmonella causes osteomyelitis in sickle cell anemia?

Question

Also which is the commonest etiology of osteomyelitis?

Answer 1

People with sickle cell disease are susceptible to infections including osteomyelitis due to:
1. Hyposplenism
2. Impaired complement activity
3. Presence of infarcted or necrotic bone (due to microvascular occlusion caused by increased adhesiveness of sickled erythrocytes, leukocytes and platelets)

The peculiar susceptibility of patients with sickle cell anemia to osteomyelitis caused by salmonella and gram negative enteric bacteria is due to spread of bacteria from intestine facilitated by patchy microinfarction of bowel caused by intravascular sickling. The infarcts in bone become infected either by transient bacteremia or by activation of dormant foci of salmonella in bone marrow when tissues are infected.

Comments

The commonest etiology of Osteomyelitis is Staphylococcus aureus.

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Thanks for the detailed answer. But which is the most common cause of osteomyelitis in Sickle cell disease?

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There is controversy in this thing. Different studies have shown different results but still many accept Staphylococcus aureus as the commonest cause in both the population with and without sickle cell disease.

Answer 2

Here is a simple picture demonstrating osteomyelitis pathogenesis:
![Osteomyelitis pathogenesis][1]


[1]: http://img.tfd.com/mk/O/X2604-O-14.png