Question

A child with a history of recurrent respiratory infections presented with complaints of pain around the knee and a high fever. X – ray shows lytic and sclerotic bone. His peripheral blood smear is shown in the image below. Aspirate from the joint will most likely show:

• A. Staphylococcus aureus
• B. Escherichia
• C. Salmonella
• D. Streptococcus

Answer 1

The Correct Option is C

To solve the problem, we need to analyze the symptoms and examination findings to narrow down the likely organism responsible for the condition affecting the child. Here's how we proceed:

The child presents with recurrent respiratory infections, pain around the knee, high fever, and lytic and sclerotic bone changes on X-ray. These findings are indicative of osteomyelitis, particularly focusing on the causative organism.

Given the history of recurrent infections, it suggests an underlying condition predisposing the child to infections. One common condition associated with recurrent infections and peculiar organisms is sickle cell disease.

In children with sickle cell disease, the most common organism causing osteomyelitis is Salmonella. While Staphylococcus aureus is the most common cause in the general population, salmonella species are more prevalent in the setting of sickle cell disease due to the peculiar environment this condition creates in the bone.

Thus, an aspirate from the joint is most likely to show Salmonella.

This analysis considers the medical history, typical infections in sickle cell disease, and radiographic findings to conclude. The peripheral blood smear, though not visualized here, would typically show signs supportive of sickle cell disease, such as sickle cells.

Organism	Likelihood
Staphylococcus aureus	Common in general population, less likely with sickle cell
Escherichia	Not typical in this context
Salmonella	Most likely given sickle cell association
Streptococcus	Possible but less likely than salmonella in sickle cell