Unrelenting lumbar pain in a female adolescent: Answers

Differential diagnosis must consider potential causes of left lumbar and flank pain of severe intensity including [1‐3] i) nephrourologic diseases, such as acute pyelonephritis, urolithiasis, cystic kidney diseases, and renal vascular alterations; ii) infectious, traumatic, or tumoral disorders involving spinal column; iii) gynecological diseases like endometriosis, and pelvic inflammatory disease; iv) abdominal inflammation or ischemia, including inflammatory bowel disease and acute intermittent porphyria; and v) psychosomatic problems.

The loin pain hematuria syndrome (LPHS) requires special mention in this section. The predominant clinical features of LPHS are recurrent flank pain and hematuria. The pain may radiate to the abdomen, inguinal area, or medial thigh. Although the pain most often is unilateral at the time of presentation, in the majority of patients, bilateral pain will eventually develop. Pain episodes may be associated with low-grade fevers and dysuria. Hematuria may be gross or microscopic and may be absent during pain-free periods. Most patients will have both flank pain and hematuria at the time of first presentation [4]. Our patient never had hematuria.

The results of the tests shown in Table 1 allow the potential causes of the intense lumbar pain to be ruled out, except for the finding of the retroaortic and double left renal vein (LRV).

The finding of a retroaortic LRV is a condition known as nutcracker anatomy. This anatomical position of the LRV not leading to symptoms is called the nutcracker phenomenon, but the presence of symptoms and signs related to LRV outflow obstruction defines the nutcracker syndrome (NCS). LRV entrapment may be of two types: anterior and posterior [5, 6]. The anterior one is more common and corresponds to the entrapment of the LRV between the abdominal aorta and superior mesenteric artery. Posterior nutcracker syndrome is a very rare entity caused by compression of the retroaortic LRV between the aorta and the vertebral body. Clinical manifestations include hematuria (microhematuria or macroscopically visible); orthostatic proteinuria; left flank pain (“renal or typical presentation”); abdominal pain; varicocele; dyspareunia; dysmenorrhea; fatigue; orthostatic intolerance; and symptoms of autonomic dysfunction such as hypotension, syncope, and tachycardia (“urologic or atypical presentation”) [7]. The pain can be strong and prolonged and become relentless, and the use of chronic narcotics may be required for adequate analgesia [2, 3, 8‐10]. The patient reported here had anatomic vascular findings compatible with posterior “nutcracker” disposition, presented unrelenting pain located in the left lumbar area and flank, and remained almost 3 months in bed, tending to adopt a fetal position, being intolerant to standing because of orthostatic hypotension. In addition, she was anorexic, lost significant weight, and developed muscular atrophy. She underwent repeated episodes of dysuria with negative urine cultures.

These symptoms altogether, even in the absence of hematuria and proteinuria, support the diagnosis of an atypical form of NCS [6, 9, 11].

The diagnosis of posterior NCS was confirmed by imaging studies, including Doppler ultrasound, computed tomography, magnetic resonance imaging, phlebography, and intravascular ultrasound. In addition to the radiological findings, the diagnosis of posterior NCS needs the association of compatible clinical manifestations and must not be diagnosed or treated only on the basis of imaging tests [5]. In our patient, computed tomography showed decreased left renal vein caliber by more than 50% after crossing behind the aorta without other alterations (Fig. 1). The increased venous pressure gradient between the LRV and the inferior vena cava (IVC), measured by phlebography or intravascular ultrasound, still remains the “gold standard” for the confirmation of NCS, despite being invasive. The pressure gradient found in our patient was 1 mmHg, a value usually considered to be the upper limit of normality [1, 6, 12, 13]. Gradients greater than 2 mmHg are indicative of NCS [5, 6, 14‐16], but the phlebography was performed in our patient in supine decubitus position, and sedative drugs were administered during the procedure, both factors likely leading to lessen the increased gradient pressure in our case. Furthermore, there is a wide range of pressure gradients in asymptomatic patients, as well as variability in pressure measurements with patient positioning. Thus, the IVC-LRV gradient pressure is a useful and contributory test for the diagnosis of NCS, but is not conclusive.

In summary, the location and severity of pain, which became medically untreatable; the orthostatism-related manifestations; the striking fetal position permanently adopted; the absence of other abnormalities in the exhaustive diagnostic study; the imaging findings; and the immediate and total remission of symptoms after surgical treatment all confirm the diagnosis of posterior NCS.

The treatment of NCS remains a controversial topic, both in the indications for treatment and in the best treatment modality for each patient. It should be based on the severity of symptoms and their expected reversibility with regard to the patient’s age and stage of the syndrome. In lean children, NCS symptoms may manifest during the pubertal spurt and resolve spontaneously once the individual gains weight and accumulates fat. Conservative management is especially recommended when patients are children or young people, and with mild and tolerable symptoms.

However, surgery may be needed for recurrent or persistent gross hematuria and for severe symptoms including intense flank or abdominal pain. Open surgical treatment modalities, including LRV transposition, nephropexy, renal autotransplantation, and gonadocaval bypass, have been performed in these patients. Stent placement using the by laparoscopic and endovascular techniques can also be carried out, but long-term patency and durability of the stent question this approach. On the other hand, disadvantages of endovascular stenting include that patients are required to be on anticoagulation and antiplatelet medication following stent insertion [1]. Both LRV transposition and renal autotransplantation to the left or right iliac fossa are the most suitable therapeutic options for NCS [12]. Renal autotransplantation is more invasive, but it offers the advantages of denervating the kidney and does not need a laparotomy incision. In the case here presented, as well as in a few other patients with NCS formerly treated in our unit, renal autotransplantation led to remission of the symptoms without significant complications.

The patient had marked loss of weight; muscular atrophy; important side effects of drugs used for pain control (constipation, neutropenia, respiratory depression, deterioration of awareness level); and serious psychological problems, such as depression, anxiety, and delirium. Multidisciplinary attention was required. During hospital admission, the patient was assessed by several medical services: general pediatrics, pediatric nephrology, pediatric surgery, pediatric radiology units, pediatric anesthesiology and child mental health, vascular surgery, urology, and the renal transplant team. The management of this case represented major challenges regarding the certainty of the diagnosis such as the cause of the life-threatening patient’s manifestations, the reluctance of some professionals to accept the diagnosis, the appropriate information being given to the family, the control of family and patient anxiety, the large amount of complementary tests progressively performed, and the delay in some results. A close coordination of the large group of professionals involved in the care of these patients and the careful, continuous, and reliable communication with the patient and her/his family are strictly needed to lead to a successful outcome.