Correct!
2. Measurement of right pleural liquid creatinine level
99mTcMAG-3 provides a measure of effective renal blood flow and renal function and is capable of detecting obstructive uropathy. This study shows no evidence of urinary tract obstruction. Dynamic images (not displayed here) showed significant prolonged bilateral renal cortical tracer uptake and bilaterally delayed tracer excretion. Areas of decreased tracer uptake / hypofunction are consistent with the extensive renal cysts bilaterally. Increased tracer accumulation is seen overlying the right thorax, indicating movement of radiopharmaceutical from the renal collecting system into the right pleural space (note the relative “brightness” of the right thorax compared with the left), establishing the presence of nephro-pleural fistula with urinothorax.
Measurement of pleural liquid fat, such as triglyceride levels, can be useful when chylothorax is suspected, but the clinical history and course as well as the imaging findings do not suggest this diagnosis. Thoracoscopic pleural biopsy is performed with infiltrative disorders of the pleura, particularly malignancy, are suspected as a cause of recurrent pleural effusion. The patient does have malignancy, but the malignancy has been controlled locally and both the lack of pleural thickening at imaging and the transudative nature of the right pleural effusion suggest that malignancy is probably not the cause of the recurrent with pleural effusion, Measurement of pleural fluid glucose can provide useful information in some infectious and inflammatory disorders that may affect the pleura, but such conditions are unlikely in this patient, Endovascular renal artery embolization has no role in this patient, and is typically employed to control hemorrhage (often due to trauma, microaneurysms, or persistently bleeding neoplasms).
Further clinical course: The right pleural fluid was sent for measurement of its creatinine content, and was found to be markedly elevated at 7.7 mg/dL, establishing the diagnosis of nephro-pleural fistula and right-sided urinothorax.
Diagnosis: Nephro-pleural fistula and right-sided urinothorax.
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References