Eur J Nucl Med (1988) 14:424-426 ,.too°an Nuclear Journal of

Medicine © Springer-Verlag 1988

Focal lung uptake of Gallium-67 in patients with acquired immunodeficiency syndrome secondary to pneumocystis carinii pneumonia Martin Charron 1, Edward S. Ackerman 1, Gerald M. Kolodny 1, and Leonard Rosenthall 2 1 Beth Israel Hospital, Department of Nuclear Medicine, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA 2 Montreal General Hospital, Department of Nuclear Medicine, McGill University, Montreal, PQ Canada

Abstract. It is generally accepted that the lung uptake of 67Ga in patients with pneumocystis carinii pneumonia (PCP) is diffuse and bilateral. Three cases of focal lung uptake of 67Ga in AIDS patients with PCP but without other opportunistic infection are described. While focal lung uptake is characteristic of opportunistic infections other than PCP, we wish to emphasize that focal uptake of gallium in the chest does not rule out PCP and may represent its earliest stage of presentation.

Key words: Radionuclide imaging - Pneumocystis carinii - AIDS

Pneumocystis carinii pneumonia (PCP) has been recognized as a cause of pneumonia in immunosuppressed patients for approximately 40 years. It is the most common life threaten- ing infection in patients with AIDS and occurs at least once in about 60% of these patients (Catterall et al. 1985). PCP in AIDS patients presents a special diagnostic problem since the recognition of PCP is often delayed because the symptoms tend to develop gradually. Malaise, fever, cough and dyspnea are usually present. Physical signs in the chest are often absent and at the beginning of the disease the chest X-ray is often normal.

Numerous studies have demonstrated the value of gal- lium scintigraphy for the diagnosis of pneumocystis carinii pneumonia complicating AIDS. Uptake is described as dif- fuse and bilateral. Therefore, the presence of focal uptake suggests an infection by an organism other than PCP. This is the first report of focal gallium uptake secondary to PCP. Concomitant infection with another organism known to cause focal gallium uptake was not found.

Case report

Case 1

A 27-year-old homosexual man with proven AIDS was in- vestigated as an outpatient for PCP. His chief complaints were fever, weight loss, cough and dyspnea. The physical examination was unremarkable except for fine rales in the apices of both lungs. The chest X-ray was normal with the exception of multiple small calcified granulomata in the right upper lobe (Fig. 1 a). The PPD was non reactive. The WBC was 7.0, the RBC was 4.0, the HGB was 11.0

Offprint requests to: M. Charron

and the HCT was 33%. An initial 67Ga scan showed mod- erate focal uptake involving both upper lobes of the lungs and was interpreted as being consistent with an active in- flammatory and/or infectious process (Fig. I b). One month after the patient was admitted, a bronchoalveolar washing of the right upper lobe, right middle lobe, apicoposterior segment of the left upper lobe and lingula was done and revealed pneumocystis carinii. The direct AFB stain, gram stain, respiratory culture, AFB culture, and fungal culture were all negative. Blood and urine cultures done on two occasions were negative. Of note, an X-ray examination of the lung performed at that time revealed increased inter- stitial markings in both upper lobes (Fig. 2) consistent with PCP. The patient was started on pentamidine 240 mg IV qd for a 21 day course. At the conclusion of the treatment a follow-up 67Ga lung scan and a chest X-ray were normal (Fig. 3).

Case 2

JY is a 29-year-old homosexual man with AIDS who pre- sented at the Montreal General Hospital with a 2 month history of fever and non productive cough. The admission physical examination revealed a temperature of 39.3 ° C and oral candidiasis. His lungs were clear. Examination of his skin revealed nodules of Kaposi 's sarcoma. The white blood cell count was normal. Chest X-ray revealed an infiltrate in the left upper and lower lobes. A 67Ga scan (Fig. 4) showed focal uptake in the upper and lower lobes. Bron- choscopy was performed on the third hospital day and re- vealed pneumocystis carinii. Bacterial, fungual and myco- bacterial cultures were negative. The patient was treated with sulfamethoxazole-trimethoprim and responded well. A repeat gallium scan performed approximately six weeks after discharge (Fig. 4) was normal.

Case 3

This patient is a 39-year-old white male homosexual with AIDS admitted with progressive dyspnea. The chest X-ray revealed interstitial disease in both lungs with blurring of vascular detail and increased lung markings. The gallium scan showed severe increased uptake focally involving both upper lobes of the lungs (Fig. 5). The patient was started empirically on pentamidine since it has been our experience that PCP can present as focal gallium uptake (case 1). Four days later a toluidine blue stain revealed PCP. Again the direct AFB stain, gram stain, anaerobic cultures, fungal

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Fig. i a. The initial chest X-ray, one month before admission, shows only multiple small calcified granulomata in the right lung. b Con- current 67Ga scan of the chest shows increased uptake in the apices of the lungs which is atypical for PCP involvement

cultures, AFB culture and cryptococal antigen were all neg- ative. The patient responded well and was discharged after three weeks of treatment.

Discussion

Multiple studies have confirmed the utility of 67Ga scan- ning of the chest for disclosing PCP early in it's course, allowing earlier treatment (Barron et al. 1985; Kramer et al. 1987; Tuazon et al. 1985; Woolfenden et al. 1987). The chest radiograph is normal or equivocal in about 15%-35% of patients (Barron et al. 1985; Woolfenden et al. 1987).

Fig. 2. Chest X-ray, on admission, shows small, ill defined mild infiltrates involving the apices of each lung

The diagnosis of PCP is usually made by identification of the organism by bronchial biopsy and lavage. Current treat- ment consists of the combination of Trimethoprim-Sulfa- methoxazole or Pentamidine for at least 14 to 21 days. The relapse rate of PCP in AIDS patients has been reported to be 20%-30% (CatteraU et al. 1985).

Opportunistic lung infection is one of the major compli- cations in AIDS patients. Several microorganisms have been reported as the cause of these infections. When myco- bacterium avium intracellulare (MAI) is associated with PCP the mortality rate is 60%-76% (Kales et al. 1987; Peters and Prakash 1987). The clinical presentation and findings on chest radiograph in AIDS patients with lung infections are non specific (Delorenzo et al. 1987). 67Ga lung scintigraphy is the most sensitive and non invasive method to detect lung infection. The lung scan pattern in PCP has been described as diffuse, whereas MAI and other opportunistic infections other than PCP cause a focal up- take pattern. Early treatment of PCP can improve survival (Kales et al. 1987). For MAI, however, there is currently no established treatment, and hence differentiation between these two disease entities has implications both in terms of treatment and prognosis.

However, the cases reported herein demonstrate that focal gallium uptake does not exclude the diagnosis of PCP. In our patients, this pattern may have represented the earli- est stage of PCP. Therefore, one cannot assume that focal uptake excludes PCP. Culture and stains of bronchial biopsy and lavage specimens must be performed in order to exclude PCP and allow aggressive therapy against this organism to be instituted.

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Catterall JR, Potasman I, Remington JS (1985) Pneumocystis Car- inii pweumonia in the patient with AIDS. Chest 88 : 758-762

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Fig. 5. Severe increased uptake (greater than the liver) in the apices

Fig. 3. 6VGa scan of the chest one month after treatment is normal (a), as is the X-ray (b)

Delorenzo LJ, Huang CT, Maguire GP, Stone DJ (1987) Roent- genographic patterns of Pneumocystis Carinii pneumonia in 104 patients with AIDS. Chest 91:323-327

Kales CP, Murren JR, Torres RA, Crocco JA (1987) Early predic- tors of in-hospital mortality for Pneumocystis Carinii pneumo- nia in the Acquired Immunodeficiency Ayndrome. Arch Intern Med 147:1413-1417

Kramer EL, Sanger JJ, Garay SM, Greene JB, Tiu S, Banner H, McCauley DI (1987) Gallium-67 scans of the chest in pa- tients with Acquired Immunodeficiency Syndrome. J Nucl Med 28:1107-1114

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Received January 21, 1988

Fig. 4. Focal increased uptake secondary to PCP before and after treatment