Renal Failure of Lithiasis Origin: Frequency and Management in the Nephrology and Haemodialysis Department of the Point G University Hospital in Mali

Background: The term urinary lithiasis (UL) from the Greek “lithos” refers to the disease characterised by the result of abnormal precipitation of normal constituents of the urine within the urinary tract. The aim of this work was to determine the frequency of obstructive renal failure (ORF) of lithiasis origin and to describe the therapeutic indications. Methods: This was a retrospective prospective study in patients hospitalised in the nephrology lithiasis a 26-month from 1 January 2018 to 1 February 2020 inclusive. Results: Among hospitalized patients, 32 met the inclusion criteria, i.e. a frequency of 1.7%. The male sex was 68.75% with a sex ratio of 2.2. The mean age was 48.38 ± 13.423 years with extremes of 20 and 65 years. Dysuria and urinary bilharzia were the main uro-nephrological antecedents, accounting for 25% of the cases each. Pain syndrome was the main functional sign, accounting for 100%. Ultrasound of the urinary tract (n = 28) showed stones in 92.85%. These stones were bilateral in 22.22% of cases. The dilatation was pyelocalic in 14 cases (51.8%). The uroscanner showed a pyelic location of the stones in both kidneys; 42.1% on the right and 33.3% on the left. Hydronephrosis was the most common dilatation: 37.8% on the right and 29.7% on the left. Renal lithiasis was complicated by acute kidney injury (ARI) in 17 cases (53.1%) versus 15 cases (46.9%) of chronic kidney disease (CKD). Urethral catheter was the means of drainage in 24 (75%) followed by nephrostomy in 8 cases (25%). Nephrolithotomy accounted for 9.4% of cases. The case fatality rate was 28.12% (9 cases). Deaths occurred in the context of uraemic coma 6 cases and cardiorespiratory arrest 3 cases. Conclusions: The management of urinary lithiasis complicated by renal failure calls for the correction of hydrolytic disorders, drainage of the excretory tract and treatment of the stone, of which percutaneous nephrolithotomy seems to be the modality of choice.


Introduction
The term urinary lithiasis (UL) from the Greek "lithos" refers to the disease characterised by the result of abnormal precipitation of normal constituents of urine within the urinary tract [1]. It is a major public health problem that nephrologists and urologists are regularly confronted with because of the recurrent nature of the disease [2]. It is currently the most common urinary tract disease; almost 10% of men and 5% of women have suffered or will suffer from renal colic at least once in their lifetime [2] [3].
In the vast majority of cases, it is a painful and essentially benign condition, however some forms of UL can lead to impaired renal function which may require replacement therapy [4].
Imaging is used to confirm the positive diagnosis of UL, to assess its impact on the excretory tract and the renal parenchyma, and to contribute to the etiological investigation [5]. The search for lithogenic factors involves anamnestic investigation, analysis of the stone and/or urinary crystals, and blood and urine biology. This is essential if effective preventive measures against recurrence are to be proposed [6]. Surgical treatment has made considerable progress with percutaneous surgery, extracorporeal lithotripsy and endoscopic surgery. Although usually reversible, some lithiasis tends to recur, increasing the risk of renal failure [5] [6]. UL affects 10% -12% of the French population and is responsible for 2% -3% of the causes of end-stage renal disease (ESRD) [7]. In sub-Saharan Africa, ESRD of lithiasis origin is an important factor in hospital morbidity and mortality due to the severity of the underlying pathologies and the high incidence of complications [8] [9]. In Ivory Cost at Treichville University Hospital, from June 2010 to June 2014, upper urinary tract obstructions were responsible for fatal renal failure in 29.23% of cases [8]. The prevalence of obstructive renal failure (ORF) was 10.32% in Cotonou in 2017 and its causes were dominated by Open Journal of Nephrology pelvic tumours and LU [9]. In Morocco, Zahra F [3] found 21% of renal failure cases of lithiasis origin.
In Mali, Diarra M [10] in his study in the urology department of the University Teaching Hospital of Kati found a frequency of ORF of 16.06%.
To our knowledge, there has been no study in Mali on ORF of lithiasis origin, hence the interest of this work which aimed to determine the frequency of ORF of lithiasis origin and to describe the therapeutic indications.

Type and Period of Study
This was a retrospective prospective study, spanning a period of 26 months from January 1, 2018 to February 1, 2020 concerning patients hospitalised in the Nephrology Department of the University Teaching Hospital of Point-G.

Study Population
All patients hospitalised in the nephrology department for lithiasis-induced renal failure (RI) during the study period constituted our study population.
These patients were subdivided into four groups according to the presence of renal failure, the latter being defined by a plasma creatinine greater than 132.75 µmol/l [11]: -Group 1: patients with urinary calculi complicated by chronic kidney disease (CKD) without urinary tract infection (UTI). -Group 2: patients with urinary calculi complicated by acute kidney injury (AKI) without UTI. -Group 3: patients with urinary calculi complicated by CKD with UTI. -Group 4: patients with urinary calculi complicated by AKI with UTI.

Inclusion Criteria
Any patient with AKI or CKD hospitalised in the department whose cause was radiologically confirmed lithiasis.

Non-Inclusion Criteria
-Presence of chronic/acute kidney disease or chronic/acute renal failure (CKD/ AKI) of non-lithiasis origin. -Non-usable records.

Data Collection and Analysis
Data were collected from the patient's file and hospitalization register including surname, first name, age, date of entry, origin, complementary examinations, daily treatment, and evolution (see Annexes). The standards used for the biological examinations were those of the different analysis laboratories in Bamako.
Each patient in the series was given an individual survey form (after obtaining the consent of the patient or a close relative) which enabled us to collect data classified into qualitative and quantitative variables.
The data was entered using Microsoft Word 2010. Data analysis was done using SPSS 22.0 for Windows. The statistical tests used for the comparison of these categorical variables were Pearson's Chi2 test and Fischer's test of accuracy. The expected level of significance was p < 0.05.

Operational Definitions
Elderly: The world health organization (WHO) has defined an elderly person as anyone over the age of 65 years [12].
Acute renal failure: ARF is defined as a sudden and significant drop in glomerular filtration rate (GFR) that is usually reversible after treatment (Table 1).

Results
During the study period, 1898 patients were hospitalized in the nephrology department of Point G University Hospital, and 32 patients met the inclusion criteria, i.e. a prevalence of 1.7%.  (Table 3).
The physical examination showed oedema of the lower limbs in 75% of the patients (24 cases) ( Table 5).
Arterial hypertension (AH) was observed in 40.6% (13 cases) with a mean blood pressure of 143.19/89.66 mmHg, extremes of 240 and 70 mmHg for systole and 150 and 40 mmHg for diastole. WHO grade 3 hypertension accounted for 53.8% of the 13 hypertensive patients.
The uroscanner performed in 20 patients showed a pyelic location of the stones in both kidneys; 42.1% (8 cases) on the right and 33.3% (6 cases) on the left.  Hydronephrosis was the most common dilatation: 37.8% (14 cases) on the right and 29.7% (11 cases) on the left (Table 6).
Anemia was found in 89.3% of patients (25 cases) with a mean hemoglobin level of 9.3 g/dl and extremes ranging from 4 g/dl to 16.10 g/dl. It was normocytic normochromic in 44% of cases and aregenerative in 88.9% of cases. Open Journal of Nephrology Urethral catheterisation was the means of drainage in 24 cases (75%) followed by 8 cases of nephrostomy (25%). Nephrolithotomy accounted for 9.4% of cases.
The three cases of nephrolithotomy were performed only in CKD patients.
Medical treatment consisted of analgesics and antispasmodics in 100% of cases. Antibiotic therapy was used in 96.9% of patients (31 cases).
Renal replacement therapy by haemodialysis was initiated in 12 patients (37.5%).
The outcome was favourable in 14 cases (

Frequency
At the end of our study, 32

Socio-Demographic Data
The mean age of our patients was 48.38 ± 13.423. The age of discovery of lithiasis in our series varied from 20 to 59 years. Studies by Daudon M [17], on the evolution of urinary lithiasis according to age, have shown the appearance of the first stone with a significant spread of the frequency peak between 30 and 55 years of age in both sexes. These results show that the age group frequently affected by urinary lithiasis is between the 3rd and 6th decade. This leads to the conclusion that many urinary tract infections occur during periods of genital and social activity, which draws attention to urogenital infections.
The male gender was predominantly with a sex ratio of 2.2 in favour of men. The male predominance can be explained by the multiplicity of organic factors that can favour lithogenesis (prostate hypertrophy, urethral strictures) [18].

Clinical Characteristics
All the patients in our study were referred by the health structures for nephrological consultation, the main reason being an increase in creatinemia, which accounted for 62.5% of the patients (20 patients).
High blood pressure was the most frequent morbid association (40.6%). Our rate is much higher than that of Zahra F [3] (8.5%). This high frequency could be explained by a late nephrological consultation on the one hand and on the other hand through ageing leading to an increase in arterial stiffness by replacement of collagen by elastic fibres [19].
These high frequencies testify to the endemic nature of urinary bilharziasis and demonstrate its role in lithogenesis through inflammation and fibrosis of the urinary tract, which leads to urinary stasis that favours the formation of urinary stones. Its low frequency in this study could be explained by the intensification of mass campaigns for the management of neglected tropical diseases in recent decades [22].
With regard to clinical symptoms, pain was the first revealing sign (90.62%) and anuria (6.2%). The series by Zahra F [3] also found pain to be the first revealing manifestation with a frequency of 95.4%; on the other hand, Agrawal et al. [23] found that the two main reasons for consultations leading to the diagnosis of renal failure of lithiasis origin were anuria and incidental discovery as part of a standard workup when the patients were totally asymptomatic.
However, most of our patients came to the clinic in the end stage with a manifest uraemic syndrome (physical asthenia, anorexia, vomiting, nausea, and insomnia).
On physical assessment, lumbar contact was found in 18.8% of our patients. This frequency is similar to that of Zahra F [3] who reported 15.3% of cases.

Medical Imaging Data
Ultrasound of the urinary tract and computed tomography (CT) were the medical imaging examinations performed with 87.5% and 62.5% respectively [24].
Ultrasound in 28 patients showed UL in 100% of cases and pyelocal dilatation in 92.85% of cases.
In the study by Zahra F [3], ultrasound found lithiasis in 73.9% and pyelocal dilatation in 69.2%.
CT, having benefited from helical acquisition, seems to be the imaging examination with the best sensitivity and specificity [24].
Uroscans were performed in 62.5% of our patients (20 cases). A single left kidney was found. Hydronephrosis was found in 37.8% on the right and 29.7% on the left; the latter was the most frequent dilatation.

Biological Data
The mean creatinine level was 598.15 µmol/l with extremes of 160 µmol/l and 2309 µmol/l. A lower mean was observed in the series of Allodé AS et al. in benign [25] 152.5 µmol/l with extremes of 128.5 µmol/l and 2159.6 µmol/l. This high rate was probably related to a delay in diagnosis.
In our series, anaemia was present in 89.3% of cases. It was severe in 7.2% of cases. The mean haemoglobin level was 9 g/dl with extremes ranging from 4 to 16.10 g/dl. Age and advanced stage of chronic kidney disease may explain this high frequency of anaemia [26]. Zahra F [3] reported a lower frequency of anaemia in her study, 69.1%.
On uroculture, Escherichia coli was the most frequent germ (50%). In the series by Dembélé M [27], the dominant germ was Enterococcus sp. with 13%. Open Journal of Nephrology In Mali, Dembélé Z [20] found a urinary tract infection in 35.2% and 42.9% of cases respectively. This shows that UTI is frequently associated with urinary tract infections. The UTI may be secondary to the stone or to a foreign body (JJ catheter, nephrostomy). Endo urological manoeuvres for calculi significantly increase the risk of UTI, mainly Escherichia coli and Proteus mirabilis. While the germs of stones secondary to infection are in more than 55% of cases Proteus or Pseudomonas [28].

Management of UL Complicated by Renal Failure
Correction of metabolic disorders constituted treatment of hyperkalaemia in 2 patients by emergency management with haemodialysis. Of the 24 patients (75%) with fluid overload, the three patients with acute lung edema received emergency haemodialysis.
With regard to surgical treatment. Urine drainage is essential. When the obstruction is acute, it must be carried out urgently because there is a risk of infection of the overlying urine, causing acute obstructive pyelonephritis [28].
In our series, urinary drainage was performed in all our cases, i.e. 100%: The placement of a simple urethral catheter was effective in 24 cases (75%) versus 8 cases of nephrotomy (25%). Our result is different from those of Abaydi A et al. [29] in whom the double urethral catheter was used as internal urinary drainage in 82.7% of cases.
In the literature, nephrostomy seems to be the modality of choice for drainage of the excretory tract in lithiasis patients with renal faillure, it allows to improve renal function and the results of treatment of UL thus decreasing the recourse to dialysis and renal transplantation [30].
In this study, only three patients were able to undergo nephrolithotomy, i.e. 9.4% of cases. In the postoperative evolution, an improvement in renal function was noted in all three patients. These three patients had benefited from a nephrostomy long before and all had chronic kidney disease. Hyams et al. have shown that nephrolithotomy is effective and does not lead to deterioration of renal function [31].

Evolution
In our series, the evolution was favorable in 43.75% of cases versus 81.5% for Zahra F [3]. Most of our patients had a low socio-economic level, which had an unfavorable impact on the early diagnosis and rapid management of the disease.
Patients with CKD of lithiasis origin had a favorable evolution compared to those with AKI, respectively 28.125% (9 cases) versus 15.62% (5 cases).
There was no significant relationship (P = 0.392) between outcome and type of renal failure.
The case fatality rate was 28.125% of cases, which is significantly lower than that of Lengani A et al. [32] in Burkina Faso where it was 44.2%. The two causes of death were, in order of frequency, uraemic coma (66.7%) and cardiorespira-tory arrest (33.3%).

Limitations of the Study
In the course of our work we encountered limitations including: -The very low socio-economic level of the patients.
-The files could not be used due to incomplete assessment.
-Lack of analysis of the lithiasis.

Conclusions
The management of urinary lithiasis complicated by renal failure calls for the correction of hydrolytic disorders, drainage of the excretory tract and treatment of the stone, of which percutaneous nephrolithotomy seems to be the modality of choice. It is a relatively easily curable condition, especially with the advent of endourology, although some conditions require open surgery. The lack of financial means for patients is a barrier to better management.  (2)