The role of lung biopsy in children with perinatally acquired AIDS

CMV pneumonia in HIV-infected ventilated infants

BACKGROUND

The contributing role of cytomegalovirus (CMV) in infants treated for Pneumocystis jiroveci pneumonia (PJP) is unknown. High dose steroids used in the treatment of PJP may further immunocompromise these infants contributing to the development of CMV pneumonia.

AIM

The aim of this study was to determine the role of CMV pneumonia in infants being ventilated for suspected PJP.

METHODS

In this prospective study HIV infected infants being treated with trimethoprim-sulfamethoxazole (TMP/SMX) and ventilated for suspected PJP were included if they had not responded to treatment. Open lung biopsy was performed if there was no improvement in ventilatory requirements.

RESULTS

Twenty-five HIV positive infants with a mean age of 3.3 months were included. Lung biopsy was performed in 17 (68%) and post-mortem lung tissue was obtained in 8 (32%). After evaluation of the histology, immunohistochemistry, and viral cultures from lung tissue, the most likely causes of pneumonia were: CMV and PJP dual infection 36% (n = 9), CMV pneumonia 36% (n = 9), and PJP 24% (n = 6). The pp65 test for CMV antigen was falsely negative in 24%. The mean blood CD4 count was 287/microl. There was an association between the CD4 lymphocyte status and the final diagnosis, with the CMV and PJP group (CD4 110/microl) having the lowest CD4 status (P = 0.0128). Pediatric Intensive Care Unit (PICU) mortality was 72% (n = 18) and in hospital mortality 88%.

CONCLUSION

Of the ventilated infants failing to respond to treatment, 72% had histologically confirmed CMV pneumonia, probably accounting for the high mortality in this cohort. The incidence of CMV disease in HIV infected infants being ventilated for severe pneumonia warrants that ganciclovir is used empirically until CMV disease is excluded. The role of lung biopsy in these circumstances needs to be researched.

The Impact of Open Lung Biopsy on Diffuse Pulmonary Infiltrates in Patients with AIDS

The evidence concerning open lung biopsy (OLB) for diffuse pulmonary infiltrates in patients with AIDS is limited. This study retrospectively evaluated the diagnostic and therapeutic yields of OLB compared with bronchoscopy for patients with AIDS with diffuse pulmonary infiltrate treated in the National Taiwan University Hospital from 1997 to 2004. There were 15 and 46 patients enrolled in the OLB and bronchoscopic groups in this study, respectively. As compared with the bronchoscopic group, patients from the OLB group had a higher chance of acquiring a specific diagnosis and possible change of therapy (73 vs 32.6% and 60 vs 21.7%, respectively; P < 0.05). There were two (13.3%) patients with prolonged air leak (greater than 7 days) in the OLB group, whereas four patients (8.7%) had procedure-related complications in the bronchoscopic group. There was no procedure-related mortality in the OLB group. This study demonstrated that OLB can be safely performed in select patients and provide a superior diagnostic and therapeutic benefit compared with bronchoscopy for diffuse pulmonary infiltrates in patients with AIDS. This procedure should be performed early in the clinical course to avoid irreversible clinical deterioration of the patients with severe illness.

Acquired Nonneoplastic Neonatal and Pediatric Diseases

The lung biopsy is an established procedure to procure a pathologic diagnosis in a child with a suspected pneumonic process of undetermined etiology. Improvements in pediatric anesthesia and surgery have reduced the operative complications to a minimum. A biopsy can usually be taken through a small intercostal incision when localization is not especially important in a patient with diffuse changes (see Chapter 1). The alternative method for tissue sampling is the endoscopic transbronchial biopsy. There is less risk to the patient, but the specimen is smaller and crush artifacts from the instrument are more common.

Intraoperative techniques to prevent air leaks

Persistent air leaks prolong chest tube duration and hospital stay after lung surgery. Air leaks also may lead to life-threatening empyemas. Preventing postoperative air leaks and BPFs is the best treatment for air-leak complications. Meticulous closure of parenchymal, pleural, and bronchial defects is the mainstay of air-leak control. The reinforcement of parenchymal suture and staple lines, pleural apposition, and well-vascularized tissue-flap coverage of bronchial suture and staple lines further reduce the incidence of prolonged air leaks and BPFs.