Teaching Case

A 48-year-old male patient was admitted to the emergency department due to sudden onset of severe left flank pain associated with hypersudoresis. There was no hypotension and the patient denied haematuria, dysuria, or fever. His previous medical history included high blood pressure, dyslipidemia, and nephrolithiasis.

A renal ultrasound (US) was requested to rule out hydronephrosis. This examination showed an extensive left perirenal heterogeneous collection, probably representing a hematoma (Fig. 1).

A computed tomography (CT) scan with intravenous contrast administration was requested to confirm the diagnosis and to exclude actively bleeding foci. CT showed a large left perirenal hematoma with a small contrast blush on its posterior segment, suggesting active haemorrhage (Fig. 2). No associated renal masses were identified.

The patient was transferred to the intensive care unit after proper clinical stabilization. Angiography was performed but, since there was no active haemorrhage at that time, embolisation was not required (Fig. 3).

Background

Wunderlich syndrome was first described in 1856. It is a rare clinical entity [1,2] defined by spontaneous haemorrhage limited to the subcapsular and perirenal spaces [3,4].

Clinical Perspective

Clinically, it is characterized by Lenk's triad, which includes acute flank pain, hypovolemia, and a palpable lumbar mass [1-6]. Other symptoms may also occur, but most of them are nonspecific, such as nausea, vomiting, headache, or macroscopic hematuria [1].

The aetiology of Wunderlich syndrome may be divided into renal and extrarenal causes. The first include angiomyolipoma, renal cell carcinoma, renal artery aneurysm, hydronephrosis, and calyceal rupture. Extrarenal causes comprise pheochromocytoma, adrenal myelolipoma, vasculitis (polyarteritis nodosa being the most common), coagulopathies, and arteriovenous malformations [1-3].

Imaging Perspective

Ultrasound may be important as a first-line exam in the emergency setting, but the findings are nonspecific.

CT is the most relevant modality in the diagnosis of Wunderlich syndrome. Besides its diagnostic capabilities, it can also detect renal masses and active haemorrhage [4,6].

Digital subtraction angiography has an essential role in diagnosing and managing Wunderlich syndrome [1].

Outcome

Wunderlich syndrome may be a life-threatening condition due to haemorrhage, with a mortality rate as high as 14%, according to the underlying cause [1,3].

Angiographic embolization performed by interventional radiology has gained more importance in the management of Wunderlich syndrome during the last years due to lower mortality rates, shorter hospitalization times, and lower complication rates when compared to other therapeutic options [2]. Moreover, it is a nephron-preserving treatment [3].

Nephrectomy (partial or radical) is required in cases of uncontrolled haemorrhage or if a malignant aetiology is suspected [2].

Take-Home Message / Teaching Points

-Although Wunderlich syndrome is a rare clinical entity, it is essential to differentiate it from other commoner causes of flank pain.

-An early diagnosis of Wunderlich syndrome is critical to improving the clinical outcome.

Written informed patient consent for publication has been obtained.