Episode Details

Episode 173: Acute Osteomyelitis

Future Dr. Tran explains the pathophysiology of osteomyelitis and describes the presentation, diagnosis and management of acute osteomyelitis. Dr. Arreaza provides information about    

Written by Di Tran, MSIII, Ross University School of Medicine. Editing and comments by Hector Arreaza, MD.

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What is osteomyelitis?

Osteomyelitis, in simple terms, is an infectious disease that affects both bone and bone marrow and is either acute or chronic.  According to archaeological findings of animal fossils with a bone infection, osteomyelitis was more than likely to be known as a “disease for old individuals”.Our ancestors over the years have used various vocabulary terms to describe this disease until a French surgeon, Dr. Nelaton, came up with the term “Osteomyelitis” in 1844. 

This is the beauty of medical terms, Latin sounds complicated for some people, but if you break up the term, it makes sense: Osteo = bone, myelo = marrow, itis = inflammation. So, inflammation of the bone marrow.

Traditionally, osteomyelitis develops from 3 different sources:

1. First category is the “hematOgenous” spread of the infection within the bloodstream, as in bacteremia. It is more frequent in children and long bones are usually affected. [Arreaza: it means that the infection started somewhere else but it got “planted” in the bones]
2. Second route is “direct inoculation” of bacteria from the contiguous site of infection “without vascular insufficiency”, or trauma, which may occur secondary to fractures or surgery in adults.  In elderly patients, the infection may be related to decubitus ulcers and joint replacements.
3. And the third route is the “contiguous” infection “with vascular insufficiency”, most seen in a patient with a diabetic foot infection.

Patients with vascular insufficiency often have compromised blood supply to the lower extremities, and poor circulation impairs healing. In these situations, infection often occurs in small bones of the feet with minimal to no pain due to neuropathy.They can have ulcers, as well as paronychia, cellulitis, or puncture wounds.

Thus, the importance of treating onychomycosis in diabetes because the fungus does not cause a lot of problems by itself, but it can cause breaks in the nails that can be a port of entry for bacteria to cause severe infections. Neuropathy is an important risk factor because of the loss of protective sensation. Frequently, patients may step on a foreign object and not feel it until there is swelling, purulent discharge, and redness, and they come to you because it “does not look good.”

Acute osteomyelitis often takes place within 2 weeks of onset of the disease, and the main histopathological findings are microorganisms, congested blood vessels, and polymorphonuclear leukocytes, or neutrophilic infiltrates.

What are the bugs that cause osteomyelitis?

Pathogens in osteomyelitis are heavily depended on the patient’s age.  Staph. aureus is the most common culprit of acute hematogenous osteomyelitis in children and adults.  Then comes Group A Strep., Strep. pneumoniae, Pseudomonas, Kingella, and methicillin-resistant Staph. aureus.  In newborns, we have Group B Streptococcal. 

Less common pathogens are associated with certain clinical presentations, including Aspergillus, Mycobacterium tuberculosis, and Candida in the immunocompromised.Salmonel