Patient Collapse after Medical Round: Rupture of Infected Kidney Following Physical Exam

The “Lenk’s triad”, defined by acute onset of flank pain, tenderness and symptoms of internal bleed, should raise the suspicion of spontaneous kidney rupture in the absence of any trauma or surgery [1]. Several cases of spontaneous rupture of the kidney dating back to 1924 have been reported [2]. Parenchymal rupture is rare and usually complicated an underlying situation or disease such as pregnancy, malignancy (renal cell carcinoma), pyelonephritis, infected renal cyst, and obstructive stone and hydronephrosis [3-6]. However some reports dating back to the early fifties, discussed the issue of spontaneous kidney rupture with no underlying etiologies [2]. In 1966, Valtonem et al. [7] reported 4 cases of spontaneous rupture in previously normal appearing kidneys [7]. Very recently, a rupture of renal angiomyolipoma due to hard physical examination has been reported [9]. Herein, we report on a case of kidney rupture that occurred after physical examinations by a group of medical students in a patient with pyelonephritis.


Introduction
The "Lenk's triad", defined by acute onset of flank pain, tenderness and symptoms of internal bleed, should raise the suspicion of spontaneous kidney rupture in the absence of any trauma or surgery [1]. Several cases of spontaneous rupture of the kidney dating back to 1924 have been reported [2]. Parenchymal rupture is rare and usually complicated an underlying situation or disease such as pregnancy, malignancy (renal cell carcinoma), pyelonephritis, infected renal cyst, and obstructive stone and hydronephrosis [3][4][5][6]. However some reports dating back to the early fifties, discussed the issue of spontaneous kidney rupture with no underlying etiologies [2]. In 1966, Valtonem et al. [7] reported 4 cases of spontaneous rupture in previously normal appearing kidneys [7]. Very recently, a rupture of renal angiomyolipoma due to hard physical examination has been reported [9]. Herein, we report on a case of kidney rupture that occurred after physical examinations by a group of medical students in a patient with pyelonephritis.

Case Presentation
A 70-years old male patient was admitted for flank pain, and chills. Patient has a history of transitional cell carcinoma of the bladder that was treated by cystectomy and neo-bladder formation. Initial surgery was complicated by left ureteral stricture causing atrophic left kidney and impaired kidney function, i.e. serum creatinine level of 1.5mg/dL and estimated glomerular filtration rate at 49.18ml/min/1.73m2 ( according to MDRD equation).
History goes back to the same day of presentation, when he started complaining of left flank pain, radiating to the groin area, associated with chills, diaphoresis and high grade fever of 40 °C. At admission, the patient was hypotensive with a mean arterial blood pressure of 70 mmHg. Urine analysis revealed a white cell count of 160cell/mm 3 and red blood cells of 42cell/mm 3 . Patient has also elevated white blood count was 19200cell/mm 3 and elevated acute phase reactants. C-reactive protein was elevated at 18 mg/dL upon admission Empirical treatment with IV hydration of around 3.5L of normal saline and wide spectrum IV antibiotics (dose of Amikacin 1g IVD) was initiated. After clinical stabilization of the patient, CT scan abdomen and pelvis (without contrast) was done showing bilateral hydronephrosis, more on the left with enlarged calyx and thin kidney cortex (Figure 1). Urologist and interventional radiologist were urgently consulted for making decision on surgical or radiological intervention. Urolgist decided on nephrostomy on the next day as the patient clinical condition stabilized.  The patient was admitted to the intensive care unit for management of sepsis/pyelonephritis -obstructive in etiology. The patient was hemodynamically stabilized with a mean arterial blood pressure of 100mmhg not necessitating inotropes. The second day post admission, the patient was examined by the group of medical student during the morning medical round for costovertebral angle tenderness. Five minutes after examination, the patient started to complain of severe left flank pain grade 9/10 not relieved by pain killers. Clinical examination revealed a large mass on the left side of the abdomen with severe pain upon palpation. Urgent abdominal CT-scan showed a ruptured left kidney with hematoma surrounding it (Figure 2). On the spot, patient was transferred to operation block for radical nephrectomy. During the surgery, a large perinephric hematoma was identifies and large amount of purulent discharge was drained. Patient underwent nephrectomy.

Discussion
The entity of non traumatic spontaneous kidney rupture is rare. The kidney rupture is divided into two entities: kidneys with pathological changes and rupture of an apparently normal kidney. The majority of kidney ruptures are associated with an underlying etiology.
In the present case, there were several risk factors for kidney rupture. First, our patient had an obstruction due to the ureteral stricture that was responsible for hydronephrosis. Second, he had severe pyelonephritis that had led to a severe sepsis requiring an important hydration. The hydration with normal saline aiming to stabilize the septic patient had probably exacerbated the hydronephrosis. Furthermore, our patient had an atrophic kidney with a thin kidney cortex, and therefore a more vulnerable kidney, especially when infected. In summation, the aforementioned risk factors caused an increase in the intra capsular pressure in the left kidney and we speculate that the clinical examination of the patient was the catalyst that added the extra force needed to initiate the kidney rupture ( Figure 3). However, we may wonder if there was a role for a percutaneous nephrostomy in our patient. The principle indication for nephrostomy is the relief of urinary obstruction in the presence of hydronephrosis. Complications related to the procedure are not common. But due to the presence of a huge collection in the kidney, manipulation can exacerbate the urosepsis. Consequently, the procedure in our patient was delayed. But was it possible to prevent the kidney rupture if a nephrostomy was placed?

Conclusion
Spontaneous kidney rupture can occur if the favorable environment is present. Although condition is very rare, but medical team including students and residents should be aware of this possible complication in high risk patients. Having a patient with the risk factors and presenting with the lenk's triad, should trigger a more appropriate approach and smooth physical exam aiming to avoid the complication of this rare life threatening entity. Surgical or radiological intervention should not be postponed in septic patients, as delay may expose patients to clinical deterioration.