Spontaneous renal hemorrhage (SRH) is an exceptional but potentially life-threatening urological emergency.
The classical (Lenk’s) triad of symptoms including acute abdominal pain,
palpable flank mass and hypovolemic shock is observed in severe SRH.
Most usually,
however,
clinical manifestations are varied and nonspecific.
Causes of SRH include (Fig.
1):
- Renal tumours (angiomyolipoma (fig.
02),
renal cell carcinoma)
- Vascular diseases (polyarteritis nodosa,
renal artery aneurysms,
artero-venous fistulas)
- Renal infections
- Cystic kidney disease
- Coagulation disorders and anticoagulation therapy (fig.
03)
Idiopathic SRH is diagnosed in approximately 7% of cases.
Goals of diagnostic imaging include:
- To promptly identify SRH
- To assess the severity and anatomical extent of SRH
- To characterize the underlying cause
Ultrasound (US) is a valuable first-line diagnostic approach,
as it rapidly detects blood collections.
However,
it is unreliable in the extent assessment and in identification of the underlying disease causing SRH.
Multidetector Computed Tomography (MDCT) represents the gold standard in the diagnosis of intra-abdominal haemorrhage,
as it allows confident detection of extraluminal blood with absolute (100%) sensitivity.
Universally available,
MDCT is the preferred imaging modality to investigate suspected SRH.
Furthermore,
multiplanar reformations provide an accurate assessment of size,
topography and underlying cause.
Thanks to the excellent soft tissue resolution,
Magnetic Resonance Imaging (MRI) is helpful to characterize the underlying disease.
Usually unavailable in the emergency setting and cumbersome to perform in critical conditions,
MRI may be performed in stable patients when the bleeding source is not identified during initial investigations.
Currently,
Angiography should only be performed when embolization is planned.
Immediate surgery is associated with high mortality,
therefore a conservative management is recommended,
and usually successful.
Superselective embolization of renal artery branches provides prompt control of active bleeding avoiding loss of renal function.
Surgery is mandatory when malignant tumours are diagnosed,
and in hemodynamically unstable patients.
Preoperative trans-arterial embolization can be considered to achieve hemostasis before an open surgical procedure.
Determining the aetiology or SRH may be challenging.
The underlying disease is unclear or obscured by perirenal blood during initial imaging workup in 10-20% of patients.
When the cause is initially undetermied,
repeated MDCT until haematoma resolves and sometimes MRI are recommended to identify or exclude subtle underlying disorders.