The etiology, diagnosis and treatment of LPHS are highly controversial, and the current status of its research is reviewed in this paper as follows. I. Etiology The pathogenesis of LPHS is unknown, and most patients have completely normal imaging and histological examinations; therefore, it has been suggested that it is a psychosomatic disease, and psychiatric factors play an important role in the etiology of LPHS [2]. Hypnotherapy has been reported to significantly relieve the pain of LPHS, which reinforces its possible association with psychosomatic factors [3]. However, most studies have concluded that LPHS is an organic disease that may be associated with abnormal intrarenal coagulation mechanisms and vasospasm. Percutaneous renal puncture biopsy showed hematuria due to erythrocyte accumulation in the tubules, while glomerular immunofluorescence microscopy was normal, and more than half of the tissue specimens showed glomerular basement membrane thickening or thinning, so it is hypothesized that the pathogenesis of LPHS is related to glomerular basement membrane abnormalities, while pain may be associated with erythrocyte tubular or stone microcrystal obstruction and segmental vasospasm within the renal cortex, and basement membrane rupture may lead to The rupture of the basement membrane may lead to intra-tubular hemorrhage and obstruction, causing filtrate reflux, and interstitial edema leading to increased renal peritoneal tension causing low back pain [1]. It may also be associated with microvascular abnormalities, abnormal platelet function, microcrystal formation in the renal tubules and complement activation [4]. Some scholars have used ureteroscopy to find ring-shaped blood clots in the collecting system around the papillary vault of the affected kidney, speculating that possible hematuria may be related to glomerular origin and obstruction [5]. Since the intrarenal vessels are the only tissues in the renal parenchyma that contain pain-sensitive nerve fibers, sympathetic nerve fibers enter the kidney with the renal artery and are gradually distributed up to the perinephric tubules, and nerve endings may extend into the muscular layer of the arterial wall, and sympathetic nerve fibers mainly innervate the renal arterial vessels at all levels, abnormalities in the innervated nerves of the renal vessels and thus renal vasospasm may be an important etiology of pain. Pathological examination of patients who had failed denervation surgery and were nephrectomized revealed chronic interstitial nephritis and chronic obstructive changes in some of the affected kidneys, but it was not clear whether they were primary renal lesions or secondary changes due to analgesics and denervation therapy. To exclude obstruction-related renal colic, ureteral peristaltic aspects were studied specifically in patients with LPHS, but no urinary tract peristaltic problems were found, thus excluding an obstructive etiology of LPHS. In conclusion, the pathogenesis of LPHS is unknown, and further studies are needed. II. Clinical manifestations LPHS predominates in young and middle-aged women from 30 to 40, with the incidence in women being three times higher than that in men. The low back pain is mostly episodic and severe, mostly unilateral, but a few have bilateral or sequential onset, similar to renal colic, and some patients may have low-grade fever, which can be easily misdiagnosed as urinary tract infection. Bass reported 21 patients with LPHS with back pain lasting an average of 11 years (1 to 34 years) [6], and a few with a history of renal calculi. Hematuria is seen in most patients and can be either carnal or microscopic and is often present during episodes of low back pain. Although the symptoms of low back pain are obvious but the kidney function is not affected, a few patients have a good prognosis as the pain symptoms can be relieved by themselves after 2-5 years of onset. A small number of patients can have depression and other psychiatric symptoms during pain episodes. The diagnosis of LPHS is very difficult due to the lack of specific diagnostic criteria, and is often a diagnosis of exclusion. For patients with recurrent episodes of low back pain and hematuria without obvious causes, LPHS should be highly suspected after excluding urinary stones, obstruction, infection and other diseases that may cause low back pain and hematuria, especially those with a previous history of renal stones. The current study concluded that selective renal arteriography is specific and shows mainly dilatation, stenosis, tortuosity, obstruction, interruption and bead-like, segmental ischemia in the lower pole of the affected kidney, mainly in the interlobular, arcuate and interlobular arteries, while renal puncture can reveal C3 deposits in the arterial wall without abnormalities in the functional trunk and perinephric arteries [1]. However, these changes can also be seen in the contralateral asymptomatic kidney, and most patients have normal renal arteriograms, which do not exclude LPHS. Treatment 1. Drug and hypnotherapy. Since there is no ideal treatment for LPHS and about 30% of patients can have spontaneous relief after conservative treatment, painkillers are one of the main treatments for LPHS. Due to their addictive and dependent nature, they are generally used only during acute attacks. Clinical experience shows that it takes about 5 days to apply pain medication, and it is not necessary to use medication during the inter-episode period. Antispasmodic and anticoagulant treatments are effective only for a few people. Anticoagulants target microthrombosis and pathological changes of renal blood vessels, and angiotensin-converting enzyme inhibitors are applied to dilate small intrarenal arteries, reduce glomerular filtration, alleviate reflux and reduce back pain. Anticoagulants can be effective in preventing local microthrombosis, but the effect is usually poor. In some patients, symptoms persist or even worsen despite increased doses of pain medication. In view of the side effects of drugs and the development of dependence, some scholars recommend the use of hypnotherapy and psychotherapy, etc. It has been reported that pain, anxiety and other symptoms are significantly reduced after receiving 8 cycles of hypnotherapy for patients with ineffective pain medication [3]. 2. Renal pelvic perfusion therapy. Due to the side effects and addictive nature of painkillers, some people began to use capsaicin (capsaicin) intrarenal pelvic infusion therapy, but only half of the patients could only get short-term pain relief after infusion, while capsaicin had obvious side effects, including urinary tract infection, bladder pain, ulcers, ureteral stenosis and even irreversible kidney damage, kidney loss of function and nephrectomy rate of 20-67%, which is not suitable as routine method for the treatment of LPHS [7]. In view of the obvious side effects of capsaicin instillation, some scholars have used ureteral soft-scope renal pelvis instillation of bupivacaine to treat 17 cases of LPHS with satisfactory results, including 12 cases with an average of 2.9 instillations and 1-year follow-up with reduced back pain and no serious adverse effects [8]. 3. renal tip denervation treatment. The pain-sensitive nerve fibers that travel along the renal vessels are blocked by injecting anesthetics and destroying the renal nerves. The disadvantage of this treatment is that the nociceptive nerve fibers of the kidney cannot be completely destroyed, while the renal reinnervation is restored in about 6 months and the low back pain is prone to recurrence. For refractory LPHS also treatment with implanted electrodes to modulate the lumbar sympathetic plexus, together with continuous epidural pumping of opioid analgesics 50% of patients can achieve long-term relief of symptoms [9].Goroszeniuk reported a case of LPHS with hypertensive crisis, which was treated with antidepressants and analgesics after the exclusion of hypertension of vascular origin by imaging was ineffective, and percutaneous catheter puncture radiofrequency Ablation of sympathetic nerve fibers innervating the renal artery was performed, and pain relief without dependence on pain medication was achieved at 6 months of follow-up [10]. Recently, nine women with LPHS were treated with laparoscopic renal denervation with a mean follow-up of 28 months. 44% of these patients were cured, 22% required significantly less pain medication, and 66.66% had a significantly improved quality of life [11]. 4. autologous kidney transplantation and nephrectomy Autologous kidney transplantation as a method of nerve removal to preserve the kidney can be used in the treatment of certain low back pain hematuria syndromes and is a better way to obtain long-term relief in patients with LPHS for whom drug therapy has failed, based on the principle of irreversible renal denervation. Some studies have concluded that autologous kidney transplantation is superior to intraureteral infusion of capsaicin and renal denervation [2], and laparoscopic autologous kidney transplantation has recently been used to treat four cases of LPHS, two of which were no longer dependent on pain medication, while the other two required significantly lower doses of pain medication [12]. Autologous kidney transplantation cures some patients with LPHS, but nerve fiber regeneration may still occur after autologous kidney transplantation, and symptoms persist in a minority of patients. Although nephrectomy completely relieves the symptoms on the affected side, one-third of patients develop contralateral pain, suggesting that LPHS may be a systemic disease process and that nephrectomy needs to be employed with great caution. In conclusion, the etiology of LPHS is currently unknown, and there is a lack of objective and effective clinical diagnostic criteria. Conservative treatment based on analgesic drugs can be used first for those with mild symptoms, while minimally invasive renal denervation can be used for those with severe pain for whom conservative treatment is ineffective, etc. Autologous kidney transplantation and nephrectomy are not used as routine treatment and are only carefully chosen for those with severe long-term pain for whom all the above treatments are ineffective.