Osteomyelitis template key

1. What are the criteria for admitting this patient, as opposed to managing them as an outpatient? Why would they come to the hospitalist service (compared to a subspecialist or a transition bed)?

Patients with osteomyelitis might require admission because of an inability to ambulate, or being unable to tolerate the recommended treatment regime as an outpatient. They tend not to be dramatically unwell, although sometimes could be septic with a focus in the bone (in which case admitting to MTU might be more appropriate). Those with a clear need for surgical intervention might still be admitted to our service, with podiatry or orthopedics following. They might even perform a debridement or more invasive surgery, but could still be looked after by the Hospitalist team. Any patient with infection of a prosthetic joint should be admitted by the Orthopedic service, as they will require removal of the implant in most cases. ______

2. What is your differential diagnosis? Include at least three most likely, as well as at least one sinister hypothesis.

● arthritis ● avascular necrosis ● cellulitis ● vasculitis ● Charcot’s foot ● trauma ● foreign body infection (joint replacement with seeded hardware) ● ingrown toenail ● muscle abscess ● neuropathy ● ulcer ● osteosarcoma ● giant cell tumor ● septic arthritis ● gout ● bony metastasis ● tuberculosis ● fungal invasion ______

3. What investigations will you order? What ongoing follow-up should be done during the admission?

Serum CBC, ESR might be normal or elevated. Check for diabetes, as this would change the presumed bacterial entities in the infection. This or any signs of immune compromise would lead to treatment of multiple organisms.

Blood cultures should be drawn, and might be positive in up to half of cases. Any local wound should be swabbed and sent for culture as well.

There is no noninvasive test that can definitively establish the presence of infection in bone. Plain films might show change of periosteal thickening and focal osteopenia, but these are late signs.

Radionucleotide scans might yield some more information, but are not confirmatory. Bone scans become positive in 24-48 hours from symptom onset, with increased flow activity and increased uptake in a focal area. Sensitivity is reasonable but specificity decreases when it is present simultaneously with cellulitis, with recent trauma or surgery, and in diabetes. White cell scans have better specificity, unless the infection is chronic or there is hardware or neuropathy.

CT can provide good detail of bony abnormality and any gas in the tissues. MRI is more sensitive at differentiating between soft tissue and bony infection. ______

4. What will be the management principles for the most likely condition? Include both pharmacologic and non-pharmacologic management. What contra-indications could exist for these choices? Be ready to discuss these with your preceptor in detail.

● antibiotic therapy is typically 4-6 weeks, and Clindamycin, rifampin, Septra, and quinolones are all effective in simple infections.

● antibiotic therapy is rarely enough for chronic osteomyelitis, and surgical debridement is often needed

● many diabetic patients with foot infections will have underlying osteomyelitis, and these tend to be polymicrobial. Ciprofloxacin with Clindamycin, or Ancef with Flagyl are reasonable antibiotics to start until culture results are available. Glycemic control should be as tight as possible, and a sliding scale of insulin can help. Diabetic management should use basal-bolus regimens instead of simple sliding scale for better glycemic control. Diabetic management may involve diabetic nurse referral as well as outpatient diabetic clinic referral on discharge.

● local wound care, especially of any areas that might have introduced infection, is important. Many topical treatments (antibiotics, or silver sulfadiazine) are available. Wound care team can be consulted in hospital to aid with wound management.

● hematogenous osteomyelitis is expected in patients with sickle cell disease, or IV drug users. Emperic treatment involves Cloxacillin or Ancef. Infectious disease specialists should be consulted in such cases.

● patients with suspected MRSA should be treated with Vancomycin, and stepped down to Septra or Doxycycline. ______

5. What complications could arise during this patient’s stay? How could you attempt to prevent these?

The infection can become limb or life- threatening in a serious case, and so prevention of spread and good antibiotic coverage are essential. Consider broad-spectrum antibiotics in patients with diabetes or immune compromise. Get consultations early in patients who are not healing as expected.

Consider necrotizing fascilitis in patients where pain is out of proportion to the degree of obvious infection. These should be biopsied intraoperatively on an urgent basis. Necrotizing fasciitis spreads in a matter of hours and limb salvaging surgery depends on early diagnosis. Visible lesions should be demarcated on the skin and reassessed regularly (rapid spread should be acted upon) but care should be taken as spread of nec fasc often spreads as a deep infection. ______

6. What other resources can you enlist to assist you in the management of this patient?

Definitive diagnosis and ability to tailor antibiotic therapy is done with biopsy of bone, typically intraoperatively. This would be done by either podiatry or orthopedic services. In addition, they can implant antibiotic-impregnated beads to the open area during surgery.

Any patients with a complicated course should be seen by the Infectious Disease consult service. They can assist in tailoring antibiotic therapy, or insert a PIC line for ongoing treatment (this is better in patients who are on IV therapy for weeks), and arrange for HPTP (home parental outpatient IV treatment) in appropriate patients.

Vascular assessment is often useful in patients where blood supply is in question. If there is inadequate flow, then antibiotics and healing white cells will not reach the infection. Vascular surgery might need to intervene to improve circulation before an infection can heal.

The ET nurse is a specialist in wound care management, and can be asked to give advice on the patient with an open wound. ______

7. How will you know this patient is ready for discharge – what parameters will be your guide and what needs to be in place at their residence?

Patients do not necessarily need to stay for the duration of therapy, since it is often one month or more. Those who do tend to be patients who are noncompliant with no fixed address or an addiction, or those who are not mobile enough to return for follow-up appointments. Social issues can often delay discharge, and social workers can be a valuable resource to help expedite safe discharge. Once the plan is in place, and the patient is ambulatory, the ID service can arrange the ongoing management. ______