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A 13-year-old boy with parapalegia
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A 13-year-old boy with paraplegia was admitted to the hospital for management of a chronic pressure sore on his right buttock over his right ischial tuberosity. The lesion was first noted by the father two to three months earlier and was seen at various clinics.
The boy was prescribed various oral and some injectable antibiotics, along with topical antibiotic ointments and wound care instructions, but there was no improvement. He was eventually referred to the surgery clinic for some debridement and continued on antibiotics; however, his wound appeared to worsen, and with the development of fever, some nausea and vomiting, he was admitted to the hospital. The boy’s wound was estimated as being about 3 cm wide and 1 cm deep at that time.
Pediatric Infectious Disease, Scott and White's Children's Health Center and Associate Professor of Pediatrics,
Texas A&M University, College of Medicine, Temple, Texas.
e-mail: jhbrien@aol.com
His past medical history is significant, as he became paralyzed due to an L1-L2 spinal cord injury after an automobile accident when he was 5 years old. He attends school, is normally active in a wheelchair and occasionally uses a standing frame. However, his activity had decreased significantly during the preceding few weeks due to feeling bad.
The boy’s immunizations were up to date, and he had no allergies.
His review of systems was positive for problems associated with his paraplegia and chief complaint, including a recent urinary tract infection due to Proteus mirabilis, but otherwise unremarkable.
Medications included oral trimethoprim/sulfamethoxazole for the UTI, along with an injection of ceftriaxone (Rocephin, Roche) prior to leaving the clinic.
Mitra Jafari, fourth-year Medical Student, Texas A & M University College of Medicine.
Examination revealed a pleasant 13-year-old boy in no acute distress but feeling bad overall. His vital signs revealed a fever (102.4ºF), tachycardia (123), blood pressure of 94/39 mm Hg with a capillary refill of three seconds, and a respiratory rate of 20.
Except for the paraplegia and associated problems, the only other finding was the pressure sore over the right ischial tuberosity (figure 1 after some local debridement). When probed, it was found that the defect was actually about 10 cm deep, as shown in figure 2. Plain radiographs revealed the defect with subcutaneous air noted (figure 3). A magnetic resonance imaging (MRI) of the pelvis was performed, revealing that the defect extended to the ischial tuberosity; enhancement on T2 imaging was consistent with osteomyelitis (figure 4).
For the admission lab tests, a complete blood count revealed a white blood cell count of 25,100 with 86% granulocytes, a C-reactive protein of 231, and an erythrocyte sedimentation rate of greater than 120. Cultures of the ulcer base, blood and urine are pending.
The patient’s diagnoses include paraplegia, recent UTI, deep pressure ulcer over the right buttock with underlying osteomyelitis of the right ischial tuberosity and possible sepsis.
How would you treat?
- Piperacillin-tazobactam (Zosyn, Wyeth) plus gentamicin and clindamycin
- Clindamycin plus ceftriaxone
- Vacuum-assisted wound closure device (VAC therapy, Kinetics Concepts Inc.)
- A and C
Answer
The correct answer is D, broad-spectrum antibiotics and the use of VAC therapy. There are several teaching points with this case, which will be discussed below.
The old term, decubitus ulcer, has largely been replaced with the more accurate term “pressure” ulcer or sore. The term “decubitus” is derived from the Latin word meaning “to lie down.” Many of these chronic sores, particularly in paraplegics, are caused by pressure placed on a bony prominence while sitting for prolonged periods without changing positions.
This was the case in the patient presented. If the sore occurs from sitting for too long, the bony prominence is likely to be the ischial tuberosity; however, if the sore occurs from lying in the same position for too long, it will probably form over the posterior superior iliac spine, iliac crest or sacrum, especially if lying supine. But pressure sores can occur almost anywhere, depending on the particular patient’s situation.
The pathophysiology is fairly straightforward; the soft tissue involved is squeezed between a bony prominence and the surface on which the patient is resting. This can cause impairment of the microcirculation to the point of tissue ischemia and eventual necrosis. The depth of the injury is more of a function of the duration and degree of pressure imposed on the soft tissue.
Most experts use a grading system, depending on the depth of the sore, from grade 1 to grade 4: grade 1 — the presence of erythema, swelling and pain (if able to feel pain) without skin breakdown; grade 2 — progression to skin breakdown with obvious sore development; grade 3 — when tissue breakdown extends to the subcutaneous soft tissues; and grade 4 — when there is damage to muscle and possibly bone involvement.
At the grade 4 level, there is also drainage of much inflammatory debris, which literally fills up the defect. This was the situation in the patient presented, in that the appearance of the sore gave the impression that it was only a couple of centimeters in depth; however, when probed, it was actually found to extend 10 cm below the skin surface as shown in figure 2. Also, the MRI of this patient revealed evidence of underlying bone infection.
Treatment
Wound healing is a much more complex process that can be impaired by accumulation of inflammatory debris, superimposed infection and ongoing chronic comorbidities, such as diabetes and malnutrition. Healing begins with an inflammatory response that stimulates phagocytosis with the migration of cells (mostly fibroblasts) to the site, which initiates the next phase of healing — the proliferative phase. After a few weeks of fibroblastic activity and new capillary formation, the wound moves into the remodeling phase, which may take weeks to years to complete, depending on some of the factors noted above.
For these healing phases to successfully occur, the underlying cause of the chronic sore, as well as any comorbidities, must be corrected. This usually includes surgical debridement of infected, necrotic material, systemic antibiotics if infection is likely and general wound care.
This takes us back to the answer noted at the beginning. When there is significant evidence of infection of the tissue, underlying bone or sepsis, a broad-spectrum combination of antibiotics should be used until culture results are known and clinical improvement is noted.
The choice given above is just one acceptable combination. Whichever combination of antibiotics is used, they should probably be directed toward Gram-negative rods (Pseudomonas, Klebsiella, Escherichia coli), Staphylococcus aureus and anaerobes, especially if the patient is possibly septic.
Negative pressure
One can “speed up” the healing process of these chronic pressure sores with the use of negative pressure wound therapy. Although research on this enhanced wound healing technique dates back to the mid-1980s, the VAC device (figure 5), which was developed by Louis Argenta, MD, and Michael J. Morykwas, PhD, of Wake Forest University Baptist Medical Center, Winston-Salem, N.C., in the mid-1990s, has become the most-used therapy for these chronic sores.
The beneficial effects that negative pressure has on the wound is primarily by active, continuous removal of cellular debris and fluids that may contain toxins; lowering the bacterial burden by physically removing many of them, thereby helping combat the tissue infection; and by stimulating angiogenesis.
Use of the device involves placing a special foam into the wound (figure 6-7), which has previously undergone debridement and cleaning. This is followed by placing an occlusive, transparent dressing over the wound, much like an ostomy bag, and cutting a hole in the center before placing an extension of the foam, as shown in figures 8 and 9, to create an airtight seal. Lastly, the tubing is placed into the proximal end of the assembly, as shown in figure 10; the other end is attached to the suction pump device and turned on, applying a negative pressure of about 125 mm Hg, either continuously or intermittently, at 15-minute intervals. Cleaning of the wound, along with dressing and sponge changes, is usually done every 48 hours.
Study data have shown that time of healing is significantly shortened as measured by time taken to reduce the volume of the defect when compared with conventional wound care.
The deep wound culture of the patient presented grew Pseudomonas aeruginosa and E. coli, and his urine culture grew P. aeruginosa; and the antibiotics were adjusted accordingly. He was treated for one month in the hospital with significant improvement, with marked “filling in” of the ulcer (figure 11) and improvement in the MRI of his ischial tuberosity, as well as his inflammatory markers. The patient was then transferred to a chronic care facility for continued systemic antibiotics and wound care.
In a case like this, the duration of antibiotic therapy is related more to the art of medicine than evidence-based medicine. The recommendation of the infectious diseases consultant was for at least two more weeks of antibiotics. Six months later, the patient remains well at his baseline.
Acknowledgement
If you are like me, you probably knew little about this enhanced healing of chronic pressure sores, being the primary domain of general surgeons. But, as we see more patients who have various neurological compromise being hospitalized for “medical” problems, we are likely to be more involved in managing these chronic sores. If interested in learning more about the fascinating science of negative pressure wound healing, an abundance of information is available in the online literature.
I would like to thank Ms. Mitra Jafari for researching and writing this case. Ms. Jafari is a fourth-year medical student at Texas A & M University System Health Science Center, College of Medicine. She is applying for a general surgery residency and will be a great addition to whichever program she joins. — James H. Brien, DO
What’s Your Diagnosis? is a monthly case study featured in Infectious Diseases in Children, with treatment information and discussion to follow.