[Fatal soft tissue infections after arthroscopy of the knee joint. A diagnostic or therapeutic problem?]

After detection of a bacterial infection of the joint, an absolute indication for intervention is given. Systemic antibiotic drug therapy is indicated and drainage of the joint has to be performed immediately. The following therapeutic algorithm regimen is a proven remedy in treating pyoarthrosis of the knee joint: During the initial period, the infection can be controlled by arthroscopic irrigation and systemic antibiotic therapy. Depending on the progredient findings or if the symptoms persist, curing the joint by open synovectomy is the next step of treatment. If open joint revision including synovectomy is not performed or is performed too late, there will be a threat of irreversible damage of the afflicted joint up to septic spread endangering the patient's life. We report on two patients suffering from generalized sepsis resulting in death after delayed therapy for knee joint infection. Regarding the presented cases, it can be concluded that indication to early surgical joint debridement including open synovectomy of the knee is still rarely seen after development of pyoarthritis.

A simple model to help distinguish necrotizing fasciitis from nonnecrotizing soft tissue infection

BACKGROUND

Necrotizing fasciitis (NF) has been associated with certain "hard" clinical signs (hypotension, crepitance, skin necrosis, bullae, and gas on x-ray), but these may not always be present. Using results of a previous study, we developed a simple model to serve as an adjunctive tool in diagnosing NF (admission WBC > 15.4 x 10(9)/L or serum sodium [Na] < 135 mmol/L) and determined its ability to distinguish between patients with NF and nonnecrotizing soft tissue infection (non-NF).

STUDY DESIGN

A retrospective review was conducted of consecutive NF (n=31) and non-NF patients (n= 328) treated at a single institution during an 11-month period. Comparison of admission vital signs, physical examination findings, radiology results, and number of patients meeting model criteria was performed.

RESULTS

Ninety percent of NF patients and 24% of non-NF patients met model criteria (p < 0.0001). The model had a sensitivity of 90%, a specificity of 76%, a positive predictive value of 26%, and a negative predictive value of 99% for diagnosing NF. Nineteen (61%) NF patients had no "hard" signs of NF; the model correctly classified 18 (95%) of these patients.

CONCLUSIONS

Admission WBC greater than 15.4 x 10(9)/L and serum Na less than 135mmol/L are useful parameters that may help to distinguish NF from non-NF infection, particularly when classic "hard" signs of NF are absent.

[The clinical characteristics, diagnosis and treatment of soft-tissue suppurative-inflammatory diseases in patients with narcotic dependence]

Comparative analysis of clinical course and the diagnostic methods of purulent-inflammatory disease of soft tissues was performed in 20 patients with drug abuse (the 1st group) and in 20 patients, who are keeping the normal way of living (2nd group). In 16 (80%) of patients of the 1st group the anaerobic non-clostridial infection (ANI) was diagnosed. The factors causing the ANI occurrence, were determined, the programme of treatment was introduced. In the 1st group 3 patients died. The duration of the stationary course in the 1st group was 18 days and in the 2nd one--3.8 days.

Necrotizing soft-tissue infections

Necrotizing fasciitis is a rare and often fatal soft-tissue infection involving the superficial fascial layers of the extremities, abdomen, or perineum. Necrotizing fasciitis typically begins with trauma; however, the inciting event may be as seemingly innocuous as a simple contusion, minor burn, or insect bite. Differentiating necrotizing infections from common soft-tissue infections, such as cellulitis and impetigo, is both challenging and critically important. A high degree of suspicion may be the most important aid in early diagnosis. Prompt diagnosis is imperative because necrotizing infections typically spread rapidly and can result in multiple-organ failure, adult respiratory distress syndrome, and death. Although group A Streptococcus is the most common bacterial isolate, a polymicrobial infection with a variety of Gram-positive, Gram-negative, aerobic, and anaerobic bacteria is more common. Orthopaedic surgeons are often the first physicians to evaluate patients with such infections and therefore need to be familiar with this potentially devastating disease and its management. Prompt diagnosis, immediate administration of broad-spectrum antibiotic coverage, and emergent aggressive surgical debridement of all compromised tissues are critical to reduce the morbidity and mortality of these rapidly progressing infections.

Staphylococcus lugdunensis: report of first case of skin and soft tissue infection in Singapore

We report the first case of skin and soft tissue infection due to Staphylococcus lugdunensis in Singapore. This is a coagulase negative Staphylococcus species known to cause a wide variety of more serious infections--brain abscess, sepsis, chronic osteomyelitis and infective endocarditis.

Mycobacterium marinum hand infection: case reports and review of literature

Three patients with Mycobacterium marinum infection are described. Key elements in the diagnosis of this infection are a high index of suspicion, taking a history with an emphasis on exposure to tropical fish or other potential sources of M. marinum infection, and tissue biopsy for culture and histology. The microbiologist should be informed about the suspicion of M. marinum infection so that appropriate cultures can be performed. As M. marinum does not grow under routine culture conditions, the diagnosis is easily missed resulting in delayed treatment. The treatment is essentially antimicrobial therapy for the superficial lesions supplemented by an appropriate surgical debridement especially when deep structures are involved.

[Abdominal infection by Pasteurella spp. A report of 3 cases]

Pasteurella spp. is a gram-negative coccobacillary micro-organism which is a common cause of soft-tissue infections caused by animal bite or scratch and more uncommonly at another locations. We report here the clinical and evolutive characteristics of three patients with different varieties of intra-abdominal infection caused by the microorganism as well as the potential exposure to pet animals.

[Infection of deep soft tissues of the neck in intravenous drug abuse]

BACKGROUND

Despite the availability of antibiotics deep neck space infections with anaerobic germs (Ludwig's angina) still carry the potential for significant morbidity and mortality with delayed treatment. Usually, odontogenic infections with involvement of the submandibular space are the source of deep neck space infections in adults, whereas in the pediatric population the most common cause is acute tonsillitis with involvement of the peritonsillar space. During the second half of this century intravenous drug abusers appeared as a new group of patients at risk for deep neck space infections. When peripheral veins sclerosis the addicts feel it necessary to either inject subcutaneously or use the major vessels of the neck and groin. Intravenous drug abusers injecting the major vessels of the neck risk delayed diagnosis because of dissimulation of their injection practices. Dangerous complications of deep neck space infections may be the result.

CASE

We report a clinical case with delayed diagnosis and fatal outcome.

CONCLUSION

Intravenous drug abuse is a rare cause for deep neck space infections but should be considered when swelling of the neck soft tissue of uncertain cause is presented. The search for the diagnose should not keep from taking quick therapeutic steps.

[Extra-intestinal salmonella infections in kidney transplant patients]

Immunosuppression to prevent rejection of solid organ transplants is accompanied by an increased risk of infections. The most frequent diseases include cytomegalovirus as well as bacterial infections of the urinary tract and the lung. The rate of enteric salmonella infections is increased in transplant patients. We report on four cases of extraintestinal salmonellosis after kidney allotransplantation.

Localized Mycobacterium genavense soft tissue infection in an immunodeficient HIV-negative patient

An HIV-negative woman with chronic lymphopenia related to past sarcoidosis situated in the bone marrow presented with an inflammatory lesion in the iliac region due to a localized Mycobacterium genavense soft tissue infection. The lesion resolved after 12 months of antibiotic therapy with clarithromycin, ethambutol and ciprofloxacin. The patient had no recurrence of the subcutaneous abscess during a follow-up period of 14 months after the end of the treatment.

[Fulminant streptococcus infection of soft tissue]

BACKGROUND

In recent years there has been an apparent increase in severe infections produced by group A beta-hemolytic Streptococci in developed countries. Necrotizing fascitis and myositis are two rare but fearsome complications caused by this microorganism.

METHODS

Two cases of fulminant soft tissue infection recently observed in the authors' center are presented and the clinical presentation and differential diagnosis commented upon.

RESULTS

The first case was a necrotizing fascitis at a surgical wound which appeared following a gynecological surgery. The second case reports gluteal myositis following intramuscular injection. In both cases the evolution was disastrous.

CONCLUSIONS

Streptococcus pyogenes may produce fulminant infections in patients without underlying disease either spontaneously or following minimum traumas. The most frequent involvement is of the soft tissues. This virulence at a local tissue and systemic level has been associated with the production of exotoxin.

Objective criteria may assist in distinguishing necrotizing fasciitis from nonnecrotizing soft tissue infection

BACKGROUND

Optimal treatment of necrotizing fasciitis (NF) requires rapid diagnosis. The purpose of the study was to identify objective admission measurements that help differentiate NF from nonnecrotizing (non-NF) infection and, among NF patients, to identify admission factors that predict mortality.

METHODS

Twenty-one NF cases were paired with matched non-NF controls. Statistical comparison of admission vital signs, laboratory values, and radiographic studies was performed.

RESULTS

On multivariate analysis, admission white blood cell count (WBC) >14 x 10(9)/L, serum sodium <135 mmol/L, and blood urea nitrogen (BUN) >15 mg/dL separated NF from non-NF patients. Mortality for NF patients was predicted by admission WBC >30 x 10(9)/L. Mortality was also significantly increased for patients transferred from an outside institution prior to definitive therapy.

CONCLUSIONS

Objective admission criteria (elevated WBC and BUN and decreased serum sodium) can assist in distinguishing NF from non-NF infections. The best objective predictor of mortality in NF patients is marked elevation of admission WBC.

A prospective, blinded comparison of clinical examination and computed tomography in deep neck infections

OBJECTIVES/HYPOTHESIS

To determine whether there is a scientific basis for the routine use of contrast-enhanced computed tomography (CECT) in the evaluation of suspected deep neck infection (DNI).

STUDY DESIGN

We conducted a prospective, blinded comparison of clinical examination and CECT in DNI.

METHODS

Thirty-five consecutive patients with suspected DNI were prospectively assessed by clinical examination and CECT for the presence and extent of surgically drainable purulent collections. Before CECT a surgeon recorded clinical data and predicted the extent of infection. A head and neck neuroradiologist, blinded to the clinical evaluation, predicted the extent of infection based on CECT. Final outcome (the presence of a purulent collection) was determined at surgery or in long-term follow-up. The clinical and CECT findings were compared with the final outcome to determine the sensitivity, specificity, and accuracy of each modality.

RESULTS

Twenty patients had purulent drainable collections. The accuracy of clinical examination alone in identifying a drainable collection was 63%, the sensitivity was 55%, and the specificity was 73%. The accuracy of CECT alone was 77%, the sensitivity was 95%, and the specificity 53%. When CECT and clinical examination were combined, the accuracy in identifying a drainable collection was 89%, the sensitivity was 95%, and the specificity 80%. If fluid collections with volumes of 2 mL or greater on CECT were considered, the accuracy of CECT would have been 85%, the sensitivity 89%, and the specificity 80%.

CONCLUSION

CECT and clinical examination are both critical components in the evaluation of suspected DNI.

Rhinocerebral mucormycosis: report of two cases

Rhinocerebral mucormycosis is a rare opportunistic infection caused by fungi. It is commonly fatal and aggressive infection localised paranasal sinuses and orbit. We report two cases had necrotising infection on the left nasolabial region. Despite aggressive surgical debridement and medical treatment, the patients died 6 and 7 days after admission. Plastic Surgeons should be aware when they have a patient with rapidly developing soft tissue infection over the paranasal sinuses and periorbital region. Combined treatment is mandatory for these patients. It usually results in death, but powerful efforts may save the patient.

Primary soft tissue hydatid disease: report of two cases with MRI characteristics

Hydatid disease of the soft tissues forms a rare mass lesion of the extremities. Two cases of primary hydatid disease in soft tissues are presented with MR imaging findings. A cystic mass with multiloculated or multicystic appearance was identified on MR images in both cases. The lesions were surrounded by a rim with two layers representing a collageneous and a vascularized pericyst. The contrast-enhanced images demonstrated the vascularized component of the wall clearly in the first case. In diagnosis of hydatid disease and in its differentiation from other cystic lesions of the extremities, we think that the described MR appearances can be used confidently.

Acute swelling of the limbs: magnetic resonance pictorial review of fascial and muscle signal changes

OBJECTIVE

This pictorial review analyzes the magnetic resonance (MR) fascial/muscular changes in 69 patients referred as emergencies with acute swelling of the limbs (ASL) from various causes.

METHODS AND MATERIAL

A prospective MR imaging (MRI) study of 69 patients referred as emergencies for ASL was performed. Our population consisted of 45 patients with skin and soft-tissue infections (cellulitis and necrotizing fasciitis, and pyomyositis), six patients with soft-tissue inflammatory diseases (dermatomyositis, graft-versus-host disease), 11 patients with acute deep venous thrombosis, three patients with rhabdomyolysis, one patient with acute denervation and three other patients with rare diseases. Hematomas, tumorous or infectious bone involvement and soft-tissue tumors were excluded. All studies included spin echo T1-weighted images and spin echo T2-weighted images. Gadolinium-enhanced spin echo T1-weighted images were obtained when an abscess was suspected on T2-weighted images. Selective fat-saturated T1- and T2-weighted sequences were also used. MRI analysis was performed to obtain a compartmentalized anatomical approach according to the location of signal abnormalities in subcutaneous fat, superficial and deep fascia and muscle.

RESULTS

In all patients with ASL, MRI demonstrated soft-tissue abnormalities involving subcutaneous fat, superficial fascia, deep fascia, or muscle. Although MR findings were non-specific, MRI appears sensitive for detecting subtle fascial and muscle signal changes.

CONCLUSIONS

In skin and soft-tissue infections, MRI can be helpful for therapeutic management by determining the depth of soft-tissue involvement, particularly within fasciae and muscles, which is partly related to the severity of cellulitis with severe systemic manifestations. MRI can also aid the surgeon in diagnosing abscesses. In inflammatory diseases, MRI can determine the best site for biopsy and also monitor therapeutic response.

Soft tissue and muscular infections (including group A streptococci)

Skin, soft tissue and muscular infections are very common and can progress to induce serious life-threatening local and systemic complications. They often occur in sites that have been compromised or injured by foreign bodies, trauma, ischaemia, malignancy or surgery. In addition to group A streptococci and Staphylococcus aureus, the indigenous local microflora is usually responsible for these infections. Anatomical sites that are subject to faecal or oral contamination are particularly at risk. The early recognition and proper medical and surgical management of these infections are of primary importance.

Obturator internus muscle abscess in children: report of seven cases and review

Obturator internus muscle (OIM) abscess is an uncommon entity often mistaken for septic arthritis of the hip. We describe seven children with OIM abscess and review seven previously reported cases. The most common presenting symptoms were hip or thigh pain (14 patients), fever (13), and limp (13). The hip was flexed, abducted, and externally rotated in 11 patients. Magnetic resonance imaging and computed tomography (CT) were diagnostic for OIM abscess in the 14 patients. Associated abscesses were located in the obturator externus muscle (5 patients), psoas muscle (2), and iliac muscle (1). The etiologic agents were Staphylococcus aureus (8 patients), Streptococcus pyogenes (2), Neisseria gonorrhoeae (2), and Enterococcus faecalis (1). Three patients underwent CT-guided percutaneous drainage, and three had surgical drainage. Three patients had ischial osteomyelitis in addition to OIM abscess. The 11 children with uncomplicated OIM abscess were treated for a median of 28 days. All patients had an uneventful recovery.

Head and neck mycetoma

Two cases of eumycotic mycetomas in the head and neck region are reported. The first case is the localized mycetoma which involved only the soft tissue of the neck. It was completely excised and the patient needed no further treatment. In the second case, the lesion extensively involved the structures in the parapharyngeal space, submandibular space and carotid sheath. The upper limit is the skull base. The patient was treated by combination of wide excision with radial forearm flap and antifungal agents, however, the prognosis is fair.

[The current characteristics in the treatment of suppurative diseases of the face and neck]

Clinical and laboratory criteria of 4 types of acute inflammations in soft tissues of the maxillofacial area and neck are presented. Protocols of surgical and conservative treatment of each type of inflammation are offered.

Necrotizing soft tissue infection masquerading as cutaneous abcess following illicit drug injection

OBJECTIVE

To assess factors that might predict serious necrotizing soft tissue infections following illicit drug injection.

DESIGN

A retrospective review of a consecutive case series.

SETTING

An urban municipal hospital.

PATIENTS

Thirty patients presenting with cutaneous abscesses resulting from illicit drug injections during a 5-year period. All cases presented clinically with fluctuance, erythema, or induration but required extensive debridement at the time of incision and drainage.

INTERVENTIONS

Operative treatment employed wide incision, routine subfascial examination, and aggressive debridement. Clinical management included broad-spectrum antibiotics, critical care support, and reconstructive procedures.

MAIN OUTCOME MEASURES

Mortality, extent of debridement, preoperative vital signs and laboratory values, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, bacteriologic and pathologic test results.

RESULTS

Postoperatively, all patients were housed in the intensive care unit for 8.4 +/- 14.5 days. Six patients died (20%). On arrival at the intensive care unit, systolic blood pressure was 80 mm Hg or less in 2 patients, 1 of whom died. White blood cell count on hospital admission was elevated in 27 of 30 patients (mean, 27.2 +/- 15.3 x 10(9)/L) and 2 patients were identified as having human immunodeficiency virus infection. All patients underwent initial surgery less than 24 hours after admission; following debridement, the average wound size was 276 +/- 238 cm2 (range, 15-783 cm2). Five patients required extremity amputation, and all other survivors underwent reconstruction with skin grafts and/or myocutaneous flaps. All but 1 patient were reexamined in the operating room within 12 hours and underwent an average of 3.1 +/- 1.6 operative procedures. Of those wound cultures obtained in the operating room, there was no pattern to the bacteriologic isolates. Seventeen patients had mixed isolates and 11 had single organisms. Pathologic findings in 20 patients included panniculitis (3 patients), necrotizing fasciitis (11 patients), myositis (6 patients), and osteomyelitis (1 patient). We failed to identify any clinical factor, including temperature, heart rate, systolic blood pressure, white blood cell count, base deficit, albumin level, PO2, or APACHE II score that could predict mortality or the requirement for extensive debridement.

CONCLUSIONS

Parenteral injections of illicit drugs can produce infections that present with signs of simple cutaneous abscess and yet unpredictably become extensive necrotizing soft tissue infections. Treatment requires a high index of suspicion along with an inquisitive operative approach to avoid missing these potentially serious infections.

MR imaging of pediatric musculoskeletal inflammatory and infectious disorders

Inflammatory and infectious disorders of the skeletally immature extraspinal musculoskeletal system affect the bones, contiguous soft tissues, muscles, and joints. MR imaging of osteomyelitis, soft tissue infection, inflammatory muscle disease, and acute and chronic joint disease are discussed in the context of underlying pathophysiology. Discussion includes imaging optimization, contribution of MR imaging to overall patient management, and differential diagnostic considerations for the pediatric patient.

[A swelling in the distal part of the thigh]

A swelling in the distal thigh may be caused by a tumour of bone or soft tissues, an aneurysm or an inflammation. Signs of inflammation may render interpretation more difficult. Four males aged 60, 48, 15 and 81 years had had a swelling in the popliteal space or above the knee, in some cases with pain. Supplementary examinations, especially MRI scanning and arteriography did not always result in a diagnosis. The diagnosis could be made, however, during operation: an empyemic thrombosed popliteal artery aneurysm, a liposarcoma, pyomyositis and suture dehiscence of a plastic prosthesis of the popliteal artery. After treatment, consisting of or started during the operation, uneventful recovery occurred.

Subcutaneous cysticercosis

With the increasing numbers of immigrants coming to the United States from areas where Taeniasis and cysticercosis are endemic, it is important to be familiar with some of these more common entities. We present a patient with both neurologic and soft tissue cysticercosis as well as a review of the available literature.

Subcutaneous mass of the right thigh

Images

Upper extremity infections in patients with the human immunodeficiency virus

Twenty-eight patients with upper extremity infections and positive for the human immunodeficiency virus (HIV) were identified. The risk factor for HIV infection was intravenous drug injection in 24 patients, homosexual contact in 3, and heterosexual contact in 1. Eight of the patients had the acquired immunodeficiency syndrome. Two of the cases were prolonged herpetic infections of more than 6 months' duration that did not respond to oral acyclovir. The other 26 cases were bacterial in origin. Twenty-six of 28 cases responded to therapy with resolution of the infection. One patient refused surgical treatment and one died of systemic illness before resolution of the hand infection.

Differentiation of necrotizing fasciitis and cellulitis using MR imaging

OBJECTIVE

This study was performed to evaluate the diagnostic value of MR imaging in differentiating necrotizing fasciitis from cellulitis.

MATERIALS AND METHODS

Spin-echo T1-weighted, T2-weighted, and contrast-enhanced T1-weighted spin-echo sequences were performed in 15 patients with clinically suspected necrotizing fasciitis. In two other patients, only unenhanced imaging was performed. The MR imaging results were correlated with the surgical findings in 11 cases, with autopsy in one case, and with the clinical outcome in five cases.

RESULTS

Cellulitis was diagnosed when subcutaneous thickening with fluid collections was revealed on T2-weighted images and when subcutaneous tissue or superficial fascia or both showed contrast enhancement. For the diagnosis of necrotizing fasciitis, imaging revealed additional involvement of deep fasciae with fluid collections, thickening, and enhancement after contrast administration. According to these criteria, we found 11 cases of necrotizing fasciitis and six of cellulitis. MR imaging identified all 11 cases of necrotizing fasciitis correctly when compared with the surgical findings. One false-positive case of cellulitis was overstaged and was thought to be necrotizing fasciitis. Contrast-enhanced T1-weighted sequences delineated abscesses and areas of necrosis more clearly than T2-weighted sequences did, but showed no additional lesions.

CONCLUSION

When no deep fascial involvement is revealed with MR imaging, necrotizing fasciitis can be excluded. However, because its sensitivity exceeds its specificity, MR imaging tends to overestimate the extent of deep fascial involvement. Therefore, the therapeutic regimen should be based on a combination of clinical findings and MR imaging.

Botryomycosis mimicking a liposarcoma

Botryomycosis is an atypical reaction of the host to a common bacterial infection. A case of botryomycosis mimicking a liposarcoma as suspected on clinical and radiological grounds is described. The diagnosis was made by biopsy and culture of the lesion. A review of the literature is given.

Update on imaging of orthopedic infections

Although the diagnosis of infection is only a small part of the orthopedist's job description, it is a important part. This article discusses the fundamentals of orthopedic infections and highlights the refinements on this topic from a radiologic perspective. In addition to reviewing the imaging appearance of musculoskeletal infections in bone and the surrounding soft tissues, we focus on the advantages and disadvantages of five imaging methods: radiography, sonography, CT, scintigraphy, and MR imaging. Finally, we review three specific situations that have garnered substantial attention in recent medical literature: chronic recurrent multifocal osteomyelitis, musculoskeletal infections in AIDS patients, and pedal infections in diabetic patients.

CT and MRI evaluation of musculoskeletal infection

While the plain film and nuclear medicine bone scan are still the traditional imaging modalities used in the evaluation of musculoskeletal infection, the cross-sectional imaging modalities, computed tomography (CT) and magnetic resonance imaging (MRI), have become critical in the delineation of many types of musculoskeletal infection. In particular, the evaluation of soft tissue infections, including cellulitus, myositis, fasciitis, abscess, and septic arthritis are often best evaluated by MRI or CT due to their excellent anatomic resolution and soft tissue contrast. Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. In cases where the plain film and nuclear medicine bone scan findings are complicated due to previous surgery, trauma, or underlying illness, the anatomic resolution and soft tissue contrast provided by MRI and CT are often necessary to determine if underlying infection exists. MRI's visualization of the bone marrow allows for the sensitive detection of osteomyelitis, although specificity for the diagnosis of osteomyelitis is aided by other findings, including cortical destruction. The CT and MRI findings in the spectrum of musculoskeletal infections are discussed and contrasted, and pitfalls in their evaluation of musculoskeletal infection are described.

Role of fine-needle aspiration in clinical management of transplant patients

Fine-needle aspiration (FNA) of superficial and deep seated lesions has been used with high sensitivity and specificity in the diagnosis of neoplastic and non-neoplastic entities. However, studies of FNA in post-transplant patients are virtually absent. Six hundred and seventy-four allograft recipients (cardiac 288, renal 250, lung 131 and heart-lung 5) were reviewed. A total of 30 (25 heart, 4 lungs and 1 renal transplant) patients underwent an FNA procedure. There were 26 males and 4 females. Ages ranged from 18-63 yr (mean 48 yr). The most common entity aspirated was post-transplant lymphoproliferative disorder (PTLD) in 12 cases, followed by inflammatory lesions in 10 cases, malignant epithelial neoplasms in 3 cases, and 1 case each of malignant mesenchymal tumor, pulmonary infarction, hamartoma of liver, fatty changes of liver, and a benign vascular lesion. Surgical or autopsy tissue was available in 19 cases (63.3%). There was an agreement between tissue diagnosis and FNA material in 18 cases (94.7%). One (5.2%) false negative case was recorded. This was a liver aspirate showing benign liver elements, which a surgical biopsy proved to be a bile duct hamartoma. No false positive cases were recorded. FNA is a highly sensitive and specific diagnostic tool in the management of post-transplant patients.

Fat-suppressed MRI of musculoskeletal infection: fast T2-weighted techniques versus gadolinium-enhanced T1-weighted images

PURPOSE

To investigate gadolinium's role in imaging musculoskeletal infection by comparing the conspicuity and extent of inflammatory changes demonstrated on gadolinium-enhanced fat-suppressed T1-weighted images versus fat-suppressed fast T2-weighted sequences.

DESIGN

Eighteen patients with infection were imaged in a 1.5-T unit, using frequency-selective and/or inversion recovery fat-suppressed fast T2-weighted images (T2WI) and gadolinium-enhanced frequency-selective fat-suppressed T1-weighted images (T1WI). Thirty-four imaging planes with both a fat-suppressed gadolinium-enhanced T1-weighted sequence and a fat-suppressed T2-weighted sequence were obtained. Comparison of the extent and conspicuity of signal intensity changes was made for both bone and soft tissue in each plane.

RESULTS

In bone, inflammatory change was equal in extent and conspicuity on fat-suppressed T2WI and fat-suppressed T1WI with gadolinium in 19 planes, more extensive or conspicuous on T2WI in three planes, and less so on T2WI in two planes. Marrow was normal on all three sequences in 10 cases. In soft tissue, inflammatory change was seen equally well in 20 instances, more extensively or conspicuously on the T2WI in 11 instances, and less so on T2WI in 2 instances. One case had no soft tissue involvement on any of the sequences. Five abscesses and three joint effusions were present, all more conspicuously delineated from surrounding inflammatory change on the fat-saturated T1WI with gadolinium. The average imaging time for the fat-saturated T1WI with gadolinium was 6.75 min, while that of the T2-weighted sequences was 5.75 min.

CONCLUSION

Routine use of gadolinium is not warranted. Instead, gadolinium should be reserved for clinically suspected infection in or around a joint, and in cases refractory to medical or surgical treatment due to possible abscess formation.

[Anaerobic infections of the soft tissues]

Anaerobic soft tissue infections are still life threatening infections. Although their frequency is actually moderate; they remain severe because physicians are often insufficiently aware of them. Although the classification between myonecrosis and necrotizing fasciitis is still valid, these infections share so many points in common that they can be considered together. Their origin is often traumatic or surgical but may also be secondary to an ulcer or a small wound in a high-risk patient: arteriosclerotic, diabetic. Hypoxia, traumatic muscle crush, heavy bacterial contamination as well as incorrect antibiotic prophylaxis are the major reasons for their occurrence. Management consists of antibiotics adapted to both anaerobic and associated aerobic bacteria, large and early surgical debridement, but with conservative excision, and intensive hyperbaric oxygen therapy. Strict prevention measures must be applied to avoid their occurrence.

Incidence and epidemiology of nosocomial infections in patients infected with human immunodeficiency virus

In a prospective study, we investigated the incidence, characteristics, and risk factors of nosocomial infections (NIs) in patients with human immunodeficiency virus disease. There was a total of 528 admissions of 405 eligible patients; 46 NIs (8.7% per discharge) were identified in 39 patients. The proportional frequencies of NIs were as follows: 16 skin and/or soft-tissue infections (including localized catheter-associated infections), 3.0%; 14 respiratory tract infections, 2.7%; 11 bloodstream infections, 2.1%; and 5 urinary tract infections, 0.9%. The most common etiologic agents were Staphylococcus aureus (27.6%), Pseudomonas aeruginosa (13.8%), and Enterobacter cloacae (13.8%). The duration of hospitalization was not significantly prolonged by NI in the cohort.

The use of intravenous contrast in MRI of extremity infection

Infection of the musculoskeletal system encompasses a variety of conditions, affecting skin, fascia, muscle, joints, tendon sheaths, and bone. In addition to features unique to each tissue site, these processes vary with respect to organism virulence, overall host condition, and the condition of the extremity itself, particularly its circulation. Treatment of musculoskeletal infection varies according to these features, and with respect to the presence of devitalized tissue. Unfortunately, while clinical examination is accurate for the presence of infection as a process in most circumstances, it lacks specificity for the variety of disorders within the spectrum of extremity infection. MRI examination using intravenous contrast is becoming the preferred modality to study complicated extremity infections, since it provides an accurate portrayal of the extent of osseous and non osseous involvement, and identifies areas of necrosis. This information provides a basis from which clinicians may more accurately choose from among treatment options.