pulmonary infiltrate in immunocompromised host

Also see pulmonary infiltrate in patients with AIDS. Etiology: 1) non-infectious a) malignancy b) cytotoxic drug reaction c) radiation pneumonitis d) pulmonary hemorrhage e) pulmonary edema f) pulmonary embolism 2) infectious: majority of infiltrates, mortality 50% a) organ transplantation 1] 1st month post transplantation a] bacterial infections b] herpes simplex 2] > 1 month (time when immunosuppression is greatest) a] Nocardia species b] fungi (Aspergillosis, Cryptococcus) c] viruses (cytomegalovirus [CMV], varicella zoster) d] Pneumocystis carinii b) severe neutropenia (granulocytes < 500/uL) 1] Pseudomonas aeruginosa 2] Aspergillis species Laboratory: 1) sputum & blood cultures 2) arterial blood gas (ABG) Special laboratory: in patients who do not improve within 1-3 days 1) fiberoptic bronchoscopy a) bronchoalveolar lavage b) transbronchial biopsy 2) open lung biopsy (in rapidly deteriorating patients) Radiology: - chest radiographs Management: 1) supportive measures - oxygen - mechanical ventilation (with respiratory failure) 2) Empiric broad spectrum antimicrobial therapy after cultures obtained a) Initial coverage should include: - Staphylococcus - Pseudomonas b) Failure to respond to initial antibiotic therapy, add: amphotericin B

References

Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 250