Detection of infection in loosened hip prostheses: efficacy of sonography.

OBJECTIVE: The purpose of this study was to determine the efficacy of sonography in the detection of infection in loosened hip prostheses. MATERIALS AND METHODS: The normal capsular morphology in 15 asymptomatic patients with total hip replacements was studied sonographically. Sonograms were then obtained in 33 patients who had pain in the hip after arthroplasty and radiologic findings of loosening of the prosthesis. These patients subsequently underwent aspiration and arthrography of the hip. Six of the 33 symptomatic patients proved to have prosthetic joint infection. RESULTS: On sonograms, the normal pseudocapsule is adherent to the proximal part of the anterior femoral cortex, and the capsule-to-bone distance is less than 3.2 mm (average, 2.6 mm). No hips with a capsule-to-bone distance less than 3.2 mm were infected. Sonograms in the six patients with infection showed marked intraarticular effusion with a mean capsule-to-bone distance of 10.2 mm. Five of these six had extracapsular fluid collections. Two patients with hip dislocations and four with aseptic loosening of the prosthesis had capsular distension on sonograms and cultures of aspirated material that showed no growth. CONCLUSION: Sonography can be used to diagnose infection around loosened hip prostheses. All patients who had an intraarticular effusion with extraarticular extension seen on sonograms had infection.

Detection of Pneumocystis carinii. Comparative study of monoclonal antibody and silver staining.

The sensitivity of Pneumocystis carinii detection using silver stain (Grocott method) was compared to that using the avidin-biotin-complex immunoperoxidase (IP) staining method with anti-P. carinii monoclonal antibody. Silver stain detected only cyst wall, whereas IP stained both cyst wall and trophozoites. Serial sections of formalin-fixed, paraffin-embedded autopsy lung specimens from 41 acquired immune deficiency syndrome patients in three disease categories were stained: I--premortem or autopsy diagnosis of P. carinii pneumonia (13 cases); II--history of treated P. carinii pneumonia but no P. carinii detected in autopsy tissue specimens (15 cases); and III--no clinical or autopsy evidence of P. carinii pneumonia (13 cases). Smears from 7 bronchoalveolar lavages (3 positive) and 11 induced sputa (1 positive) also were stained. All cases of P. carinii in category I were detected with equal sensitivity. P. carinii undetected by silver stain in category II and III cases and in bronchoalveolar lavages and induced sputa were not revealed by IP. Detection of trophozoites by IP did not improve sensitivity because the staining pattern was amorphous or focally granular, and thus easily confused with nonspecific staining of mucin or intracellular or free particulate material. Reliable identification of trophozoites could be made only with coexisting cyst structures. Silver staining was more advantageous because it also identified fungal infections and was faster and more cost effective than IP.

The diagnostic utility of the antibody-coated bacteria test in intubated patients.

PURPOSE: Pilot study to determine if the presence of antibody-coated bacteria (ACB) in sputum specimens obtained from endotracheal tube suctioning would aid in the diagnosis of lower respiratory tract infection (LRTI). PATIENTS AND METHODS: All endotracheally intubated and mechanically ventilated patients for a two-month period were recruited for study. The diagnosis of LRTI was based on a clinical suspicion sufficient enough to start or change antibiotic therapy. Specimens were obtained by blind endotracheal tube suctioning. After processing, sputum smears were stained with fluorescein-labelled antibody to the Fc portion of IgG, IgM, and IgA. More than five fluorescein-labelled bacteria per oil immersion field were considered positive smears. RESULTS: Seventy-one specimens were obtained from 36 patients. Eighteen specimens were positive in 12 patients, all of whom had LRTI. No specimen was positive in patients not diagnosed as having LRTI. The ACB test was positive in 12 of 25 patients with LRTI. Patients with LRTI but negative ACB were more likely to have received prior antibiotic therapy (p less than 0.001). ACB was positive prior to the clinical diagnosis of LRTI in seven of nine patients (av 4.1 days, range 2-6 days) and converted to negative in three specimens obtained seven or more days after starting appropriate antibiotics, while in three specimens it remained positive three-six days post treatment initiation. CONCLUSIONS: The ACB test appears to be highly specific for the presence of LRTI in intubated patients. Sensitivity of the test may be adversely affected by prior antibiotic therapy. A positive ACB test may predict the subsequent development of LRTI. Further study is warranted.

Response of Weeksella virosa peritonitis to imipenem/cilastin.

CAPD peritonitis is most commonly due to gram positive infection. Gram negative bacillary infection is less frequent but is often seen in hospitalized patients or in those on antibiotics. Weeksella virosa (formerly known as Flavobacterium II F) has been isolated from the vaginal secretions and urine of normal women. As gram negative colonization typically proceeds from the perineal region, Weeksella virosa peritonitis might be expected in women at risk for gram negative peritonitis. A 33-year-old woman on CAPD developed multiply resistant Weeksella virosa peritonitis after prior hospitalization for pericarditis and antibiotic treatment for pneumonia. Cultures became negative and cell counts returned to normal during treatment with intravenous imipenem/cilastin. Curative treatment was completed with intraperitoneal imipenem/cilastin and oral ampicillin. Treatment was well tolerated despite theoretical concerns about the risk of seizures in patients with severe renal insufficiency not on hemodialysis.

Systemic dissemination of Pneumocystis carinii in a patient with acquired immunodeficiency syndrome.

Pneumocystis carinii is usually considered a respiratory tract pathogen; however, there are reported cases of limited and generalized dissemination of the organism from the lungs of immunocompromised patients. We present the autopsy findings of a 29-year-old male with acquired immunodeficiency syndrome (AIDS) and recurrent Pneumocystis carinii pneumonia who developed abnormal liver function tests. The patient had received aerosolized pentamidine because of toxic reactions to other modes of therapy. The postmortem examination revealed Pneumocystis in the lungs, liver, spleen, kidney, myocardium, thymus, pancreas, thyroid gland, bilateral parathyroid and adrenal glands, gastrointestinal mucosa, perihilar and mesenteric lymph nodes, and bone marrow. A high index of suspicion, especially in patients treated with aerosolized pentamidine, may lead to an increased recognition of disseminated pneumocystosis. Dissemination of the infection may be due to failure of the aerosolized drug to achieve adequate blood levels. As AIDS patients survive longer because of the developing therapeutic arsenal, disseminated pneumocystosis may be encountered with increasing frequency in these immunocompromised patients.

Nocardia asteroides aortitis with perforation of the aorta.

A 53-year-old man died of nocardial aortitis eight months after undergoing aortic valve replacement. Autopsy revealed vegetation in the area of a previous aortotomy incision and a small perforation of the aorta enclosed by pericardium immediately above the prosthetic valve ring. Prosthetic valve endocarditis was not present. Multiple splenic infarcts, microabscesses of both kidneys, and myocarditis were identified. Antemortem blood cultures and postmortem cultures of the aortic vegetation grew Nocardia asteroides.

Paecilomyces javanicus endocarditis of native and prosthetic aortic valve.

A 41-year-old diabetic woman developed endocarditis of the aortic valve caused by Paecilomyces javanicus six years after insertion of a porcine mitral valve heterograft. The patient died shortly after aortic valve replacement. Autopsy revealed vegetations of the aortic heterograft, valve ring abscess and ascending aortitis due to Paecilomyces. There was no involvement of the mitral valve heterograft. Lesions due to mycotic emboli were found in the kidneys, spleen, and brain. Cultures of the surgically removed aortic valve and of the kidney at autopsy produced rapid growth of P. javanicus. The gross and microscopic pathologic and cultural characteristics of this organism are described with a review of the literature. Previously reported cases of Paecilomyces endocarditis occurred only in prosthetic heart valves. This is the first known report of P. javanicus endocarditis of a native valve and its prosthetic heart valve heterograft.

Parenteral cephalothin therapy for pelvic gonococcal infections.

The efficacy of intravenous cephalothin was studied prospectively in 20 patients with acute pelvic inflammatory disease, all of whom presented with lower abdominal pain, cervical and adnexal tenderness, fever, and leukocytosis. Blood, cervical, and cul-de-sac cultures were obtained on admission. The latter was transported anaerobically and inoculated in routine and prereduced medium. Transgrow medium with trimethoprim was used for endocervical cultures. Neisseria gonorrhoeae was isolated from the endocervix in 15 patients and from the cul-de-sac in four patients. All received intravenous cephalothin, 2 gm every four hours for seven days. Clinical improvement was observed in 48 to 78 hours. The cervical cultures were negative for N. gonorrhoeae after 48 hours, at the completion of treatment, and two weeks post-treatment. The drug was well tolerated. It was concluded that cephalothin intravenously is an acceptable alternative antibiotic for the treatment of gonococcal pelvic infection.