Return to Case List with Diagnoses or Case List as Unknowns

VASOVAGAL RESPONSE LEADING TO AN ABNORMAL CLEARANCE CURVE ON A LASIX RENAL SCAN
Authored By: Kartikeya Kantawala and Jerold Wallis, Assoc Prof of Radiology.
Patient: 39 year old male
History:  with left ureteropelvic junction obstruction, status post pyeloplasty and stent placement. Stent was removed 10 weeks ago.
Image Size:[small][as-submitted]

Fig. 1
Radionuclide angiographic phase

Fig. 2
Sequential renal images

Fig. 3
Post Lasix

Fig. 4
Post Lasix

Fig. 5
Lasix renal curves
Image Size:[small][as-submitted]

Findings: RADIOPHARMACEUTICAL: 7.5 mCi Tc-99m MAG 3 i.v. and 40 mg furosemide i.v.

FINDINGS: The posterior abdominal radionuclide angiogram demonstrates normal, symmetrical perfusion of the kidneys. The kidneys are normal in size and morphology. There is prompt uptake and excretion of the radiopharmaceutical by both kidneys. There is mild retained activity in the left collecting system, which is mildly dilated. This retained activity persisted after erect positioning.

To evaluate for obstruction, the patient was given 40 mg furosemide via slow intravenous injection approximately 30 minutes after the start of the examination. Sequential images were obtained for an additional 20 minutes. Initially, there was slight clearance of tracer activity bilaterally. However, approximately 3 minutes after administration of the diuretic, there is increasing accumulation of tracer activity within the kidneys bilaterally.  Subsquently, there is decreasing activity in both kidney regions. (see lasix graph)
Diagnosis:

Vasovagal response after diuretic administration.
 
Approximately 3 minutes after administration of the diuretic, the patient had a vasovagal response, slouched in his seat, and became unresponsive for approximately 5 seconds. After this point, there was accumulation of tracer activity within the kidneys bilaterally. The patient was promptly given intravenous fluids, and he quickly responded. As the patient responded, there was rapid, near-complete clearance of tracer activity from the kidneys bilaterally

General Discussion: FULL PATIENT HISTORY:

39-year-old male with left ureteropelvic junction obstruction, status post pyeloplasty and stent placement. Stent was removed 10 weeks prior to the study.

The patient had a vasovagal response, slouched in his seat, and became unresponsive for approximately 5 seconds, 3 minutes after diuretic administration. Per the patient, this happened on a prior diuretic renal study as well

DISCUSSION:

Vasovagal syncope is characterized by the common faint, resulting from "vagally" mediated cardioinhibition. The resulting bradycardia reduces cerebral blood flow to a level inadequate to maintain consciousness.  The vasovagal response is caused by excessive venous pooling with vasodilatation and bradycardia rather than the appropriate physiologic responses of vasoconstriction and tachycardia. Other modulating factors that may be present during syncope include serotonin, adenosine and opioids.  Precipitating factors may be the sight of blood, a loss of blood, sudden stress or pain, surgical manipulation or trauma. Before the syncopal event, the patient may report weakness, lightheadedness, yawning, nausea, diaphoresis, hyperventilation, blurred vision or impaired hearing
Specific Discussion: Hypotension can be a cause of a false-positive diuretic renal study.  Adequate hydration is important, with additional fluids as needed if the patient becomes hypotensive.
References:

aafp.org/afp/20010515/tips/7.html
Comments:
No comments posted.
Additional Details:

Case Number: 125447Owner(s): Kartikeya Kantawala and Jerold Wallis, Assoc Prof of RadiologyLast Updated: 02-07-2013
Anatomy: Genitourinary (GU)   Pathology: Other
Modality: Nuc MedAccess Level: Readable by all users, writable by NucMed Certifiers
Keywords: rsnmACR: 80000.12174

Case has been viewed 29 times.
Certified by Jerold Wallis on 06-24-2009

The reader is fully responsible for confirming the accuracy of this content.
Text and images may be copyrighted by the case author or institution.