Case Author(s): J. Philip Moyers, MD and Tom R. Miller, MD, PhD , 1/17/96 . Rating: #D1, #Q3

Diagnosis: Infection of peritoneal dialysis catheter tunnel

Brief history:

Peritoneal dialysis

Images:

Anterior image from In-111 WBC scintigraphy

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Full history/Diagnosis is available below


Diagnosis: Infection of peritoneal dialysis catheter tunnel

Full history:

This patient presents with end- stage renal disease on peritoneal dialysis with a peritoneal dialysis catheter in place. At the time of the study, the patient had signs, symptoms, and laboratory findings of acute peritonitis. Purulent material was noted to be draining from the peritoneal dialysis catheter skin site. It was unclear to the clinicians whether this represented purulent material from the peritoneum draining back along the tunnel vs a tunnel/tract infection.

Radiopharmaceutical:

490 uCi In-111 labeled white blood cells

Findings:

Anterior views of the abdomen were obtained 3 hours after injection of In-111 labeled white blood cells. There is a linear collection of activity overlying the abdomen along the expected course of the peritoneal dialysis catheter. Otherwise, normal distribution of the radiopharmaceutical is noted. These findings were felt to be consistent with a tunnel/tract infection at that time, and no delayed images were obtained.

Discussion:

In-111 oxine is the agent most widely used for labeling white blood cells. Oxine is lipophilic and chelates metal ions such as In-111. Initially, the complex is lipid soluble and diffuses through the cell membranes of all blood cells. Inside the cell, In-111 separates from the oxine and becomes bound intracellularly. The technique for labeling of white blood cells includes removal of approximately 30-50 ml of venous blood, which has been separated by a combination of sedimentation by gravity and centrifugation to remove the patient's white blood cells. The In-111 oxine is then mixed with the white blood cells and the white blood cells are resuspended in the patient's separated plasma. The normal biodistribution includes the liver, spleen, and bone marrow. Unlike gallium, In-111 should not be seen in the gastrointestinal tract under normal conditions. Therefore, sites of activity outside the liver, spleen, and bone marrow are considered suspicious for a localized inflammatory process. Potential causes of false- positive studies include swallowed activity from upper or lower respiratory tract infection, gastrointestinal bleeding, accessory spleens, or possibly infarcted organs.

References: Diagnostic Nuclear Medicine. Sandler and Coleman, eds. 3rd ed. Williams and Wilkins Publishers, 1996.

Followup:

The patient was started on antibiotic therapy. The peritoneal dialysis catheter will be removed if the patient fails antibiotic therapy.

ACR Codes and Keywords:

References and General Discussion of Indium -111 WBC Scintigraphy (Anatomic field:Gasterointestinal System, Category:Inflammation,Infection)

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Case number: iw003

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