Value of the polyclonal IgG study in the external infectious process

It is presented a descriptive analysis of the results from the scintigraphics study, by using polyclonal IgG in patients in whom it was suspected a post sternotomy osteomyelitis. Twenty eight patients were studied, 13 females and 15 males whose ages ranged between 37 and 78 years. These patients were assessed as requested by the vascular surgeon at the heart surgery postoperative period for the placement of a coronary bypass. In all these cases the presence of suppuration from the surgical wound or flux elements emphasized the suspicion of a possible coexistence of a sternal osteomyelitis as the cause for the persisting inflammatory phenomena in soft tissues. Patients were injected with 25 mCi of polyclonal IgG by endovenous route. Scans were carried out at 60 minutes, 6, 12 and 24 hours after the administration of the substance. In the 6, 12 and 24 hours scans tomography slices of SPECT were made in the thoracic area. Results: 19 of 28 studies ruled out the sternal involvement in the infection process, and the patients remained clinically asymptomatic. From the 19 studies , there was a negative image in 12 . In the rest, one showed a stronger uptake at the level of the sternal manubrium interpreted as not significant , another showed a stronger a pre- sternal focal process in the soft parts; the remaining 5 continued with low intensity lineal images along the projection of the sternotomy , but usually their intensity decreased after 24 hours . In one case, the patient's results were negative with a scintigraphy but after a scintigraphy with marked norfloxacin a sternal focus was detected . From the 9 positive cases 5 underwent surgery, where the sternal resection was performed, when the infection process was confirmed. From a scintigraphic point of view, all of them showed focal images with a greater intensity in the sternal projection , or images of a lineal uptake focally strengthened in later images. In two patients a surgical treatment was not performed. They corresponded to a focus with a weak uptake that disappeared clinically and scintigraphically after 20 days from the onset of antibiotic treatment . The other case corresponds to a patient who was treated with hyperbaric oxygen therapy for 20 sessions. After this period of two months the infection process could be arrested. In our experience, the scintigraphy with polyclonal immunoglobulin was markedly useful to rule out the infectious involvement of the osseous plane of the patients who underwent heart surgery. The scintigraphic pattern of low intensity lineal uptake showing a decrease after 24 hours seems to correspond more probably to a secondary element of surgical trauma than to an infection process. The focal pattern with a strengthened uptake after 24 hours was always accompanied by a sternal osteomyelitis. A serial study allowed us to carry out a follow-up of the medical treatment for infection processes, with a good clinical and imaging correlation