Risk Factors for Prophylaxis Failure in Patients Receiving Aerosol Pentamidine for Pneumocystis carinii Pneumonia Prophylaxis

OBJECTIVE

The purposes of this study were (1) to determine the incidence of prophylaxis failure in HIV-infected patients receiving aerosol pentamidine (AP) for Pneumocystis carinii pneumonia (PCP) prophylaxis, and (2) to identify risk factors for PCP prophylaxis failure.

SETTING AND DESIGN

In Ontario, Canada, AP has been made available for outpatient PCP prophylaxis through a centralized government program, the Ontario Drug Distribution and Monitoring Program. Data from this administrative observational database were extracted for 2,227 patients who received AP between May 1989 and December 1998.

OUTCOME MEASUREMENTS

The incidence of breakthrough PCP (BPCP) was calculated from the database. A Cox regression model with time-varying covariates was created to examine factors associated with BPCP. The follow-up time was divided into three eras: 1989 to 1991, 1992 to 1994, and 1995 to 1998. These eras were meant to reflect major changes in antiretroviral medication regimens.

RESULTS

The overall risk of BPCP was 16.2% over a mean follow-up of 1.67 years. The overall BPCP rate was 9.7/100 patient-years, with rates of 8.8/100, 13.1/100, and 6.3/100 patient-years in each of the three treatment eras. In the multivariate analysis, significant risk factors for prophylaxis failure were low CD4 count, previous diagnosis of PCP, history of AIDS-defining conditions other than PCP, and antiretroviral treatment era defined above.

CONCLUSION

The overall rate of PCP prophylaxis failure has decreased significantly after 1995, coincident with the era of highly active antiretroviral therapies. Initiation of PCP prophylaxis remains necessary in patients with risk factors.

Effects of long-term aerosol pentamidine for Pneumocystis carinii prophylaxis on pulmonary function

OBJECTIVE

The purpose of the study was to evaluate the long-term effects of aerosolized pentamidine (AP) on the pulmonary function of HIV-positive individuals receiving AP for Pneumocystis carinii pneumonia (PCP) prophylaxis.

DESIGN

A retrospective analysis of serial pulmonary function tests (PFTs) performed on a cohort of HIV-positive patients who had received AP for >2 years.

METHODS

Of the 1,787 HIV-positive patients receiving AP prophylaxis in our database, 380 patients had been receiving AP for at least 24 months. Of these 380 patients, the PFTs at baseline and at 24 months after starting AP therapy were documented in 179. We compared the baseline PFTs of these 179 patients with results obtained 24 months later to evaluate if there was any change in pulmonary function parameters.

RESULTS

Baseline and 24-month PFT parameters (total lung capacity [TLC], FVC, residual volume [RV], FEV1, FEV1/FVC, maximum midexpiratory flow rate at 50% of vital capacity [MEF50], diffusion of carbon monoxide [DLCO]) were all within the normal ranges. However, AP therapy over 24 months was associated with a modest decline in lung volume parameters (TLC, FVC, RV), a slight reduction in flow rates (FEV1, FEV1/FVC, and MEF50), but no change in DLCO. The mean treatment duration was 23.8 months (range, 21 to 27 months).

CONCLUSIONS

Long-term AP therapy is associated with a mild combined restrictive and obstructive pulmonary defect. Since 24-month PFT parameters remained within the normal ranges, this level of decline is of unclear clinical significance. Overall, AP has good pulmonary tolerance when used up to 24 months for PCP prophylaxis in patients with normal baseline pulmonary function.

An effectiveness community-based clinical trial of Respirgard II and Fisoneb nebulizers for Pneumocystis carinii prophylaxis with aerosol pentamidine in HIV-infected individuals. Toronto Aerosol Pentamidine Study (TAPS) Group

STUDY OBJECTIVE

To compare the effectiveness of a standard jet nebulizer, Respirgard II, and a standard ultrasonic nebulizer, Fisoneb, for the administration of aerosolized pentamidine (AP) as primary and secondary prophylaxis against Pneumocystis carinii pneumonia (PCP) in HIV-infected individuals.

DESIGN

A retrospective, nonrandomized, parallel group comparative study.

SETTING

Patients were enrolled in a community-based AP program (APP) between May 1989 and April 1992 in Ontario, Canada. They received AP in either (1) a centralized treatment facility ("clinic") or (2) their attending physician's office or regionalized centers ("nonclinic"). Clinic administration of pentamidine was via Fisomeb; nonclinic via Respirgard II.

PATIENTS

The study group comprised of 1,762 HIV-infected individuals requiring AP for either primary (CD4 < 200/mm3) or secondary PCP prophylaxis. Of these, 1,151 used Fisoneb (clinic) and 611 used Respirgard II (nonclinic).

RESULTS

In the primary prophylaxis group, 41 of the 892 patients using Fisoneb (4.6%; mean follow-up, 18 months) compared with 16 of 435 patients using Respirgard II (3.7%; mean follow-up, 14.6 months) developed PCP (p = 0.44). A total of 28 of 259 (10.8%; mean follow-up, 15.3 months) patients using Fisoneb for secondary prophylaxis compared with 11 of 176 (6.3%; mean follow-up, 14.4 months) patients using Respirgard II for secondary prophylaxis developed PCP (p = 0.1).

CONCLUSIONS

Despite the difference in dosage (120 mg/mo vs 300 mg/mo), type of nebulizer (ultrasonic vs jet), and frequency of administration (twice vs once monthly), the results of this study indicate that both regimens of AP provide comparable protection against PCP. This study further supports the effectiveness of AP as a solid second-line prophylaxis for HIV-infected individuals who are intolerant to trimethoprim/sulfamethoxazole or dapsone.

High-pressure water-gun injection injuries to the extremities. A report of six cases

High-pressure water-gun injection injuries are different from injection injuries that are caused by other agents, in that they are associated with extensive subcutaneous emphysema but only slight soft-tissue inflammation or destruction. The cases of six patients who had such an injury were reviewed. It was found that local irrigation and débridement, together with a short course of penicillin or a broad-spectrum cephalosporin, resulted in complete recovery from this relatively benign variant of high-pressure injection injury.

Intervertebral disc impingement syndrome in a child. Report of a case and suggested pathology

Nerve root impingement syndrome is rare in children and adolescents. The symptomatology of the pediatric group sometimes differs from that of the adult. An accurate diagnosis is often delayed because of concerns for neoplasm, infection, and spondylolisthesis. A case report of an 11-year-old boy with symptoms and myelographic findings consistent with a herniated disc is presented. A review of the literature disclosed only four cases of herniated disc in children under the age of 12 years. Our case represents one of the youngest patients with documented intervertebral disc impingement syndrome. Rather than a herniation due to degenerative changes in the annulus, a slipping of the entire disc, and vertebral end-plate (a "slipped vertebral apophysis") may precipitate a central disc impingement in children and adolescents. This has been reported in cases of trauma previously. However, the authors think that this slipped vertebral apophysis may, in fact, represent a large number of the so-called herniated discs in adolescents. It is also suggested that this may be an identifiable syndrome with a susceptible age range, activity level and body habitus.