SONOGRAPHIC ASSESSMENT OF UROLITHIASIS IN UNIVERSITY OF ABUJA TEACHING HOSPITAL, NIGERIA

CHAPTER ONE

INTRODUCTION

Background to the Study: Urolithiasis is the development of calculi anywhere in the urinary system which may result in many complications including renal failure (Tempkins, 1999). Renal calculi can cause obstruction and urinary stasis that ultimately leads to infection and possible destruction of renal parenchyma. They may be solitary or multiple and can vary in size from small stones to large staghorn calculous that fills the collecting system. Stones usually originate from the kidneys but may pass into the ureter and bladder (Krebs, 1993). A clearly defined cause of urolithiasis has not been established. What is known is that their development requires the presence of a nidus and an environment that supports the continuous precipitation of stone components (Porth, 1988).The saturation theory as presented by Kawamura (1999:373) attributes causes to the urine saturated with calcium, uric acid, salts, magnesium phosphates and cystine. Marak (2013) also stated that urinary calculi form when a crystallizable substance like calcium, oxalate, phosphates, uric acid and cystine exceeds its solubility in urine.

According to Olapade (2004), several epidemiological factors can predispose persons to urinary stone formation such as age, sex, race, infection, nutritional status and diet. Reduced water intake, high concentration of stone constituents, changes in urine PH and high environmental temperatures also tend to predispose to production of low-volume super-saturated uric acid and the attendant increased risk of stone formation. Dehydration from reduced fluid intake or strenuous exercises without adequate fluid replacement increases the risk of stone formation. In this regards, climate may be a risk factor for urinary calculi, since residents of hot and dry areas are more likely to become dehydrated and susceptible to stone formation. Metabolic abnormalities including inherited disorders of metabolism can alter the composition of the urine and increase an individual’s risk to stone formation. A number of different medical conditions can also lead to an increased risk for developing urinary tract calculi:

Gout results in chronically increased amount of uric acid in the blood and urine , hypercalciurea (high calcium in the urine)uric acid can also be absorbed from food and excreated into the urine where it forms calcium phosphate or oxalates stones. Chronic diseases such as diabetes, high blood pressure (hypertension), inflammatory bowel diseases and those who have undergone intestinal bypass colostomy surgery are also at risk of kidney stones.

Some medications such as diuretics, calcium containing antacids and protease inhibitors example Crixivan,(a drug used to treat HIV infection) can also raise the risk of Kidney stones (Wolf. J Stuart, 2010).According to Adams(2013), those who take vitamin C supplement which typically contain 1,000 milligrammes per tablets were twice at the risk of developing stones compared to men who take no vitamins. All these interplay of factors become even more significant where there is family history of urinary stones suggesting a complex interplay of factors, which may differ in various localities.

The diagnosis of urolithiasis is suspected when the typical pattern of clinical symptoms is noted and when other possible causes of abdominal or flank pains are excluded. Investigations to diagnose urolithiasis include urinalysis of freshly voided urine to identify heamaturia and crystals. Imaging tests are also conducted to confirm diagnosis. These may include plain X-rays, Intravenous urography (I.V.U), Computerized tomography (CT) and Ultrasonography (US).Intravenous Urography has a greater risk of complications, takes longer time and involves higher radiation exposures than plain X-rays where as CT is significantly more effective than plain X-rays and I.V.U. There is high radiation exposure hazard associated with the use of CT and the cost involvement makes it not to be a technique of first line of choice in the detection of Urolithiasis. Ultrasonography has been found to be non – invasive with high sensitivity and specificity for detection of Urolithiasis than plain X-rays and I.V.U. Its non use of ionizing radiation with little or no patient preparation, ready availability and low cost is also of great advantage over other modalities. Also, no sedation is involved in uncooperative patients. Doppler ultrasound scan of the renal vessels is important in the diagnosis of renal artery stenosis and intra renal heamodynamics in different pathological conditions (Kang et al, 2010).

Available literature indicates that the prevalence of Urolithiasis disease is higher in the developed countries when compared with their African Counterparts (Olapade, 2004). Studies in the United States of America (USA) shows that the estimated life time risk of developing a stone is 12% among whites, and approximately 50% of patients with previous urinary calculi have a reoccurrence within 10 years. The report also indicates that African Americans have a reduced risk of stone disease (1.7%) compared to Caucasians (5.9%) and Mexicans Americans (2.6%) (Trinohieric, 2008). In developing countries like Nigeria, the reported hospital prevalence varies according to geopolitical regions of the country. Osegbe (1987) in Lagos (Southwestern- Nigeria) reported a hospital incidence of 34per100,000. Similarly, Mungadi (2006) at Usman Dan Fodio Universty Teaching Hospital Sokoto (Northwestern- Nigeria), reported hospital incidence of 25.75 per 100,000 cases of urolithiasis. Another study by,Monu(1989) on the pattern of urolithiasis in university of Benin Teaching Hospital, Southsouth-Nigeria for a five year period(1980-1984) reported a prevalence of 6.3per 100,000 hospital patients. Mshelia (2005),reported this disorder in Maiduguri-Northeastern Nigeria to be 32 per 100,000 while Mbonu (1984) in a 5 year study at University of Nigeria Teaching Hospital-Southeastern Nigeria covering a period of(1976-1980) reported urolithiasis prevalence of 13per100,000.The burden of Urolithiasis increases the number of emergency visits, hospitalizations and Surgical Operations in the Hospitals(Litwin,2000).In addition to Surgical trauma, complications and cost of stone treatment; the presence of stones also leads to other medical complications most especially chronic renal failure.

A well documented epidemiological data on the prevalence and pattern of presentation of urinary stones is poor or non-existent in University of Abuja Teaching Hospital, North Central Nigeria. The need for adequate documentation and continued surveillance of this disease in this environment has prompted this study.

Statement of the Problem

The prevalence of urolithiasis in most hospitals situated in the Federal Capital Territory(FCT)has not been properly assessed and documented. This Geographical Region records high environmental temperatures that tend to predispose residents to production of low -volume supersaturated uric acid and attendant risk of stones formation (Agbo n.d).Average daytime temperature ranges between 28.20C -37.10C but in dry seasons temperatures can soar as high as 400C(Nigerian meteorological agency,n.d) in some areas . Despite the existing data on the hospital prevalence of urolithiasis in other Geopolitical Regions in Nigeria. There is paucity of documented scientific study on the prevalence of urolithiasis in the University of Abuja Teaching Hospital-Northcentral, Nigeria. To the best of the Researchers knowledge, research has not documented any scientific study on the prevalence and burden of urolithiasis from hospitals in this high risk Geographical Area .The need to address these gaps and provide a base line data for hospitals in this locality has prompted this study. The University of Abuja Teaching Hospital was chosen as the study location because it is one of the main referral centre for most hospitals in this locality. More than 10% of patients from other hospitals are being referred to this hospital on weekly basis.

Objectives of the Study

1.3.1 The main Objective of the Study is to determine the ultrasound prevalence and pattern of Urolithiasis in University of Abuja Teaching Hospital.

1.3.2 The Specific Objectives of the Study are to:

1. Determine the male to female ratio of patients with urolithiasis.

2. Determine the age distribution and the peak prevalent age of patients affected with urolithiasis.

3. Determine the common clinical signs and symptoms associated with the presence of urolithiasis.

4. Determine the anatomical site of stone distribution among the affected subjects.

Significance of the Study

1. The study will provide a baseline data of urolithiasis prevalence in the locality under study.

2. The study will provide documentation of clinical signs and symptoms of urolithiasis.

3. The study will define the gender mostly affected by urolithiasis in the study area.

4. Understanding the burden of the disease will contribute to the clinical and public health knowledge that will help appropriate planning by hospitals in this locality to undertake preventive measures.

Scope of the Study

This is a prospective study of all patients referred for abdominopelvic ultrasound scans at the department of Radiology, University of Abuja Teaching hospital from June2014 to May2015.

Operational Definition of Terms

Prevalence: Is the number of existing cases (both old and new) of a disease in a given population in a geographic area at a specified point or period of time.

Incidence: Is the frequency (number) of new occurrences of disease in the population during the time period being examined.

Urolithiasis: Is the development of calculi along the urinary tract. The urinary tract consists of kidneys, ureters and the bladder.