Spontaneous subcapsular renal hematoma is defined as the hemorrhage of the renal parenchyma that is confined in the subcapsular space. [1] It is not a common entity in clinical practice. Till date, the rupture of a renal tumor was considered to be its most common cause and the recommended treatment was radical nephrectomy for non-fatty lesions. [2] [3] We report our experience with a patient with no other obvious cause for the hemorrhage except from his treatment with double antiplatelet medication. Our patient was treated conservatively with good outcome.

A 64-year-old male presented to the emergency department of our hospital with complaints of acute pain located at his left upper lateral midback, subcostally, mimicking renal colic pain. The patient did not give any history of trauma. However, he was under double daily treatment with antiplatelet medication, consisting of clopidogrel 75 mg and acetylsalicylic acid 100 mg. He was taking this medication because he had recently suffered from an acute myocardial infarction and had been subjected to coronary angioplasty a month ago.

During physical examination, his temperature was normal and there was mild tenderness situated at the left costovertebral angle. Routine urine examination revealed microscopic hematuria. The laboratory examinations were normal, with initial hematocrit (Ht) 43%. The platelet count was 391x10³/µL. No further platelet aggregation studies were performed. Kidney-ureter- bladder (KUB) radiography did not reveal any radio-opaque stone, while the initial ultrasound imaging revealed a subechogenic collection of fluid at the posterior renal surface. For this reason an abdominal computed tomography (CT) scan was immediately performed, showing extensive subcapsular hematoma of the left kidney with partial diffusion of blood in the perineal space (Figure 1). No other renal lesion was identified.

Because of the patient's haemodynamic stability, it was decided that conservative treatment was preferable with strict bed rest, rehydration, analgesic and antibiotic therapy (cefuroxime 750 mg three times daily I.V, paracetamol 1000 mg three times daily I.V). After consultation with cardiologists, the antiplatelet medication was replaced with low molecular weight heparin (tinzaparin sodium 14000 IU once daily S.C). The patient's symptoms receded within three days, while a gradual decrease of Ht up to 33% was noted. The patient was undergoing daily comparative ultrasound and the abdominal CT scan that was repeated seven days after the original CT scan, revealed constant stable findings without extension or worsening of the hematoma. The ultrasound that was performed after one month, showed a partial recession of the hematoma (Figure 2), while the abdominal CT scan six months later, revealed its almost total dissolution (Figure 3).

Spontaneous subcapsular renal hematoma was initially described by Bonet in 1679. [4] Most common reported cases of spontaneous subcapsular renal hematoma in the absence of trauma include tumors (61.5%), vascular diseases, infections, peritoneal dialysis and post extracorporeal shock wave lithotripsy (ESWL). In 6.7% of cases the etiology cannot be found. [5] The incidence of tumors may be higher due to the fact that small, less than 2 cm in size tumors are undetectable by imaging techniques, including CT scan or angiography. [6] The most common associated renal tumor is angiomyolipoma (54%) followed by renal cell carcinoma (21%). [7]

Despite the fact that spontaneous subcapsular renal hematoma can present with Lenk's triad consisting of flank pain, tenderness and symptoms of internal bleeding, many other symptoms have been described in literature. [2]

Ultrasound is very valuable in rapid identification of a renal hematoma. However, the findings should be confirmed with CT scan which also gives more information regarding the cause of hematoma. [4] In our case there was no obvious responsible etiologic factor according to this imaging and the only cause that can be regarded is the dual antiplatelet medication of the patient. Captitanini et al. described a similar case of spontaneous subcapsular hematoma of the left kidney in a 67-year-old male. His therapy included acetylsalicylic acid (100 mg/day). A thoroughly investigation of his coagulation pattern was carried out revealing a platelet defect. [8]

There are two possible treatment options regarding the optimal management of a spontaneous subcapsular renal hematoma. The first recommends radical nephrectomy because of the high incidence of small renal tumors especially in hemodynamically unstable patients. On the other hand, like in our case, conservative treatment is proposed to patients when an underlying pathology can be ruled out. [2]

The cause of spontaneous subcapsular renal hematoma might not be evident in some cases. According to our case, the double antiplatelet may be the only predisposing factor and this rare complication may be attributed to this medication. Discontinuation of medication and close follow-up can save the kidney.

1. Yigla M, Vardi Y. Spontaneous renal subcapsular hematoma. an unusual presentation. Urol Int 1991;47(2):87–9.   [CrossRef]   [Pubmed]    
2. Baishya RK, Dhawan DR, Sabnis RB, Desai MR. Spontaneous subcapsular renal hematoma. A case report and review of literature. Urol Ann 2011;3(1):44–6.   [CrossRef]   [Pubmed]    
3. Morgentaler A, Belville JS, Tumeh SS, Richie JP, Loughlin KR. Rational approach to evaluation and management of spontaneous perirenal hemorrhage. Surg Gynecol Obstet 1990;170(2):121–5.   [CrossRef]   [Pubmed]    
4. Bonet T. Sepulchretum, sive anatomiapractica ex cadaverbius morbobdenatis. Geneva: L Chouet 1969.   [CrossRef]   [Pubmed]    
5. Zhang JQ, Fielding JR, Zou KH. Etiology of spontaneous perirenal hemorrhage: A meta-analysis. J Urol 2002;167(4):1593–6.   [CrossRef]   [Pubmed]    
6. Kendall AR, Senay BA, Coll ME. Spontaneous subcapsular renal hematoma: diagnosis and management. J Urol 1988;139(2):246–50.   [CrossRef]   [Pubmed]    
7. Yu ZX, Xia GP, Hu WH, et al. [Etiology, diagnosis and management of spontaneous per renal hemorrhage]. Zhonghua Yi Xue Za Zhi 2006;86(1):39–41.   [CrossRef]   [Pubmed]    
8. Capitanini A, Tavolaro A, Rosellini M, Rossi A. Wunderlich syndrome during antiplatelet drug therapy. Clin Nephrol 2009;71(3):342–4.   [CrossRef]   [Pubmed]