CASE 9933 Published on 20.03.2012

Acute abdomen in a patient on haemodialysis

Section

Uroradiology & genital male imaging

Case Type

Clinical Cases

Authors

Tonolini Massimo, MD.

"Luigi Sacco" University Hospital,
Radiology Department;
Via G.B. Grassi 74 20157 Milan, Italy;
Email:mtonolini@sirm.org
Patient

77 years, female

Categories
Area of Interest Urinary Tract / Bladder ; Imaging Technique CT
Clinical History
An elderly woman with chronic end-stage renal disease, undergoing regular haemodialysis three times a week for 2 years, was admitted to Emergency Department because of sudden, non-traumatic lumbar and right flank pain radiating to the ipsilateral thigh.
Physical examination revealed severe tenderness on her right abdomen, without peritonism.
Imaging Findings
After admission, progressive worsening of hemodynamic and respiratory parameters was observed. Laboratory revealed blood loss (haemoglobin 10.9 g/dL), normal platelet count and coagulation assays, serum creatinine (5.9 mg/dL) similar to the most recent available data.
Urgent multidetector CT detected a 5-cm thick right-sided subcapsular renal hematoma with characteristic hyperdensity of fresh blood on unenhanced scans, compression and scalloping of the residual renal parenchyma best appreciated on contrast-enhanced acquisitions. Both kidneys showed changes consistent with chronic end-stage disease and some small cortical cysts, without identifiable mass lesions and vascular abnormalities. A limited, peripheral focus of contrast extravasation indicating ongoing arterial bleeding was identified near the upper renal pole. Associated bloody effusion involved the ipsilateral perirenal and posterior pararenal retroperitoneal spaces.
Conservative treatment included haemodialysis and concentrated red blood cell transfusions. With persistently stable hemodynamic and biochemistry, unchanged hematoma size measured at CT, the patient was discharged from hospital 5 days later.
Discussion
Spontaneous (non-traumatic) perirenal haemorrhage (SPH) is a rare urological emergency. The majority (65%) of cases occur secondary to ruptured renal tumours, both benign (particularly angiomyolipoma) and malignant (renal cell carcinoma), whereas 20-30% of occurrences are related to vascular abnormalities such as polyarteritis nodosa, renal artery aneurysms or artero-venous malformations; rarely the underlying cause involves pyelonephritis, therapeutic anticoagulation or bleeding diathesis [1-3].
Although uncommonly, SPH with dissection of blood into the subcapsular and/or perirenal spaces may complicate end-stage renal disease: in these patients, the multifactorial pathogenesis of renal bleeding involves arterial intimal fibrosis, acquired cystic renal disease, qualitative platelet dysfunction and systemic heparinisation during haemodialysis [2-6].
Although ultrasound may promptly identify abnormal collections, its diagnostic accuracy is extremely limited because of patient-related technical factors and unreliable differentiation of echogenic clotted blood from solid tissue [1, 2].
Therefore, multidetector CT almost always represents the mainstay imaging modality to investigate suspected intra-abdominal bleeding, and has absolute (100%) sensitivity for the detection of perirenal haemorrhage. As demonstrated by this case, the hallmark of SPH is represented by hyperattenuating subcapsular and/or perirenal blood collection measuring 40 to 70 Hounsfield units (HU) density, depending on its more or less acute stage [1-4]. Furthermore, with a correct multiphasic acquisition protocol on current scanners, contrast-enhanced CT can usually identify contrast extravasation indicating active bleeding and the possible presence of renal masses or arterial abnormalities as the underlying cause of SPH. With end-stage renal disease, multiple cysts are usually observed in small, poorly perfused kidneys [1-4].
The most common perirenal haemorrhages secondary to bleeding angiomyolipoma, renal carcinoma or vascular abnormalities require surgical nephrectomy or angiographic embolisation. Conversely, in patients on haemodialysis because of end-stage renal disease conservative treatment is recommended, and usually successful, when renal masses and aneurysms are excluded at initial CT and hemodynamic conditions remain stable [2, 5-7].
Intra-abdominal bleeding conditions represent the second most common cause of acute abdomen in haemodialysis patients after mesenteric ischemia, and should be suspected with sudden abdominal or flank pain associated with variable-degree hemodynamic compromission [8]. Prompt diagnostic assessment with multidetector contrast-enhanced CT allows confident detection of this uncommon urological emergency, differentiation from other causes of acute abdomen such as aneurysmal rupture, identification of ongoing bleeding and of possible underlying causes [1-3, 8].
Differential Diagnosis List
Spontaneous subcapsular renal haemorrhage in a patient on haemodialysis
Leaking aortic aneurysm
Bleeding renal artery aneurysm or arterovenous malformation
Bleeding renal carcinoma
Ruptured renal angiomyolipoma
Pyelonephritis
Final Diagnosis
Spontaneous subcapsular renal haemorrhage in a patient on haemodialysis
Case information
URL: https://www.eurorad.org/case/9933
DOI: 10.1594/EURORAD/CASE.9933
ISSN: 1563-4086