Here's a deep dive into decubitus ulcers, and more specifically the scope of the ED in staging, recognizing when you should be worried about infection, and management tips.
Background: Decubitus ulcers are soft tissue injuries formed from prolonged pressure on the skin. For the decubitus (or lying down) patient, the points under most prolonged pressure involve the tissue between any bony prominence and the patient's bed. Common places we see decubitus ulcers, depending on the patient's position, are shown in the pic below:
Pathophysiology: Multifactorial with a combination of internal and external factors. But the end pathway is always ischemia and necrosis of tissue.
Internal risk factors: Anything that decreases blood flow to pressure sites, promotes inactivity, or decreases sensation are risk factors for decubitus injury. This includes vascular disease, DM, neurological injury, surgical patients, malnutrition. It just so happens that most of these are present in the elderly, and explains why they are the most at risk for decubitus ulcers. Specifically with neurological injury: pressure ulcers are oftentimes very painful. If the patient has decreased sensation, they may not feel the discomfort caused by the increased pressure, and may not readjust to relieve pressure.
External risk factors: Constant external pressure exceeds capillary pressure supplying blood flow to and from tissue. Ischemic tissue eventually becomes necrotic and progresses to pressure injury. Hard static mattresses, physical objects left under patients, and side railings all exacerbate the amount of pressure on vulnerable tissue. Wet tissue from bodily fluids, as well as friction between skin and clothing/bedding also encourage skin breakdown and worsening of pressure injury.
Some evidence suggests that as little as 2 hours of immobility can lead to tissue breakdown from pressure injury.
Staging: 1-4
Stage 1: Skin is INTACT, usually with nonblanchable erythema.
Stage 2: Exposed dermis; partial thickness loss of skin. Erythematous and moist.
Stage 3: Exposed fat. Full thickness loss of skin. Ulceration and granulation tissue likely to be present.
Stage 4: Exposed fascia, muscle, or bone. Erosion may form tracts deeper than what is initially visible.
Unstageable: Full thickness skin loss, but depth is unstageable because of existence of eschar or sloughed tissue. If unstageable ulcer is present, there is at least a stage 3 or 4 pressure injury. If the eschar is stable, defined as dry, intact, and no obvious signs of overt infection, then management is to leave it alone with no plans for debridement.
When to Suspect Infection:
At baseline, pressure ulcers are colonized with low levels of polymicrobial bacteria, consisting of skin, urine, and fecal flora. Infection, at least when we refer to an "infected ulcer,"occurs when this bacteria spreads to surrounding, healthier tissue. Infection usually starts with local surround cellulitis and then progresses to involve deeper soft tissue infection, osteomyelitis, and sepsis. Therefore, the extent of an infected ulcer may not be all apparent on physical exam and a high clinical suspicion is needed. Findings include surrounding erythema or discoloration, warmth, fluctuance, exudate, and frank necrosis.
If decubitus ulcer is suspected as the reason for your patient's sepsis, urgent debridement is necessary. In the meantime, start the patient with your normal sepsis cocktail including fluid and antibiotics. Obtain blood cultures for disseminated infection, as well as ESR and CRP if worried about osteo. Choice of antibiotics depends on extent of suspected infection; for mild cellulitis, oral therapy is indicated, but when they arrive to the ED with overwhelming infection, big guns with IV vancomycin and zosyn is a good place to start.
Imaging is not always needed. If diagnostic scans are needed, CT can be a good initial test, but MRI may be needed to measure extent of necrotic tissue.
As far as identifying pathogens in the wound, swab cultures are limited in the information they provide as the infection is often deeper. In this case, a biopsy of the deepest tissue associated with the wound obtained during debridement is the most helpful for goal oriented treatment.
Hope you enjoyed all the fun pictures!
Stay well, friends;
-SD
Sources:
https://www.ncbi.nlm.nih.gov/books/NBK553107/
https://reference.medscape.com/slideshow/classifying-pressure-injuries-6005748#38