A 31 year old man with prosthetic aortic valve replacement presented with sudden onset of colic right flank pain. Analysis of the urine revealed haematuria, and the international normalised ratio was suboptimal. The patient was misdiagnosed as having ureteral colic. On the second day, an ultrasound showed no signs of obstructive uropathy, and there was no evidence of absent function on intravenous pyelogram. Computed tomography with contrast agent was performed and revealed a right renal infarction. Renal angiography demonstrated total occlusion of the right renal artery. Fibrinolytic therapy and angioplasty were unsuccessful. To our knowledge, aortic prosthetic valve thrombus as a source of renal artery embolism mimicking renal colic has not been reported previously. This case underlines the importance of renal colic as a manifestation of renal infarction in patients with prosthetic valves and the need for a high index of suspicion of renal embolism.
- aortic valve replacement
- renal emboli
- renal colic
- renal infarction
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We report a case of renal infarction mimicking renal colic in patient with a prosthetic aortic valve.
A 31 year old man presented with sudden onset of severe colic right flank pain that radiated to his back. He had undergone a prosthetic aortic valve replacement (AVR) 2 years previously. Physical examination revealed tenderness to percussion of the right kidney, but otherwise normal findings. His intense flank pain was similar to features of renal colic, and subsided only with high dose and prolonged usage of narcotic analgesia. There was haematuria on urine analysis and the international normalised ratio (INR) was suboptimal (1.4). His ECG was in sinus rhythm. The patient was diagnosed as having ureteral colic and calculus. On the second day of admission, an ultrasound showed no signs of obstructive uropathy and there was no evidence of absent function on intravenous pyelogram. Computed tomography with contrast agent was performed and revealed right renal infarction with perfusion only of the upper pole (fig 1A). Renal angiography demonstrated a 100% obstructing embolus in the right renal artery (fig 1B).
The patient was treated by transcatheter fibrinolytic therapy, but fibrinolysis was not successful. Renal angioplasty was attempted, but despite passing the guide wire across the total obstructive thrombus, the balloon catheter did not pass the thrombus. The vascular surgery team discounted surgery as an option because of the absence of distal arterial perfusion and assumed filling of the thrombus in the small arterioles. Renal function was not compromised. Acceptable INR was obtained by coumadine treatment, and normal function of the aortic prosthetic valve was confirmed by echocardiography.
Renal artery embolism is an infrequent but important cause of renal infarction.1 Acute embolic renal infarction may manifest clinically as a pain similar to renal colic, and is often misdiagnosed as a renal calculus because of similar presenting symptoms. This leads to delay in the initiation of treatment and to increased morbidity. Few case reports exist relating cardiac emboli to acute renal infarction, and proper therapeutic intervention is not well established.1–6 Urgent treatment is necessary, as ischaemia can cause irreversible kidney damage in a few hours.7 The main complications are vasculorenal hypertension and renal failure. Acute vascular occlusion of the kidney must be considered in the differential diagnosis of acute flank pain. Absence of the nephrogram phase on an intravenous pyelogram should alert emergency physicians to this possible diagnosis and to the need for further investigations.7 Subsequent diagnostic evaluation should begin with renal ultrasonography to rule out obstructive uropathy. If hydroureteronephrosis is not present, follow up perfusion studies are necessary to confirm the absence of renal perfusion. Newer treatment modalities, including intraarterially injected low dose streptokinase and percutaneous transluminal angioplasty, have proved useful.8,9 Greater awareness of this uncommon clinical entity and its potential morbidity is essential to correct diagnosis and management.
To our knowledge, aortic prosthetic valve thrombus as a source of renal artery embolism mimicking renal colic has not been reported previously. This case underlines the importance of renal colic as a manifestation of renal infarction in patients with prosthetic valve and the need for a high index of suspicion of renal embolism.
Competing interests: none declared
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