CHAPTER ONE
INTRODUCTION
1.1 Background
Chronic Kidney Disease (CKD) is defined as glomerular filteration rate (GFR) of less than 90mls/min or presence of markers of kidney disease for 3 months or more, which is accompanied in most cases by signs and symptoms of uraemia, or a need for initiation of renal replacement therapy. 1,2 The kidneys serve as the body’s natural filtration system removing waste products and fluids from the bloodstream and excreting them in the urine.
The kidneys maintain the body’s salt and water balance, which is important for regulating blood pressure.
When the kidneys are damaged by acquired or inherited disease they lose their ability to remove fluids and waste from the bloodstream, the syndrome of uraemia ensues.
CKD is known to cause different systemic manifestations due to accumulation of nitrogenous waste products which produces a number of manifestations including Otorhinolaryngological diseases.
Kidney disease can exist without symptoms for many years. Kidney failure progresses so gradually that CKD may not be detected until the kidneys are functioning at less than 25% of their normal capacity.
In Nigeria, the peak prevalence of CKD is between third and fifth decade of life.
The principal causes of CKD in adult Nigerians include chronic glomerulonephritis, hypertension, diabetes mellitus, obstructive uropathies and tubulointerstitial nephritis. 5,6,7 CKD can lead to total kidney failure, also known as end- stage renal disease (ESRD).
People with ESRD require either dialysis or a kidney transplant. Disease leading to kidney damage may be confined to the kidney, as in the kidney inflammation, or may affect multiple organs, like in hypertension or diabetes mellitus.
1.2 Presentation of CKD
The early symptoms of chronic kidney disease are similar to symptoms of other illnesses. These symptoms may be the only symptoms of kidney disease until the condition is more advanced. Features include body swelling, nocturia, polyuria, fatigue caused by anaemia, shortness of breath, bad breath caused by a build-up of waste in the saliva and sweat, an unpleasant taste in the mouth, and itchy skin, others are features of uraemia such as abnormally dark or light skin, bone pain, brain and nervous system symptoms like drowsiness and confusion, problems of concentrating or thinking, numbness in the hands, feet, or other areas, muscle twitching or cramps. 1,2
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1.3 Clinical stages of CKD
The stages of CKD are mainly based on measured or estimated glomerular filtration rate (eGFR). The GFR compares the level of waste product in the patients’ blood and his/her urine. It measures how many milliliters (ml) of waste the kidneys are able to filter per minute. The kidney of healthy individuals can typically filter over 90mls/minute.
The GFR was determined from serum creatinine using Cockroft-Gault equation. 8,9 Changes in GFR can assess how advanced the kidney disease is. There are five stages but kidney function is normal in Stage 1, and minimally reduced in Stage 2.
Stage 1 – Signs of mild kidney disease but with normal or better GFR (greater than 90mls/min) Stage 2 – Signs of mild kidney disease with reduced GFR (60 to 89mls/min). Stage 3 – Signs of moderate chronic renal insufficiency (eGFR 40 to 59mls/min) Stage 4 – Signs of severe chronic renal insufficiency (eGFR 15 to 39mls/min). Stage 5 – Signs of end stage renal failure (where the eGFR indicates less than 15mls/min).
1.4 Diagnosis of CKD
Renal function is clinically monitored by measurement of serum creatinine, blood urea nitrogen (BUN), and urinalysis. Estimated GFR of < 60mls/min, which is persistent for 3 months or more indicate that chronic kidney diseases are irreversible, and can progress to end-stage renal disease (ESRD). 10,11
Markers of kidney disease include: Persistent proteinuria- dipstick positive proteinuria; Haematuria- by dipstick or urine microscopy; Blood tests – full blood count usually reveal normochromic normocytic anaemia; bone profile - reduced calcium, increased phosphate, increased alkaline phosphatase (renal osteodystrophy); increased parathyroid hormone (hyperparathyroidism). Abnormal renal imaging- by various techniques such as ultrasonography, computed tomography scan, intravenous urography or plain radiograph, and renal scintigraphy. Renal ultrasound assess renal size and exclude obstruction; renal size generally small in CKD but normal or large renal size may be seen in polycystic kidney disease, diabetes mellitus, asymmetrical renal vascular disease, myeloma, amyloidosis, systemic sclerosis; other investigations such as chest x- ray, bone x-rays - may reveal renal osteodystrophy. Urine tests – mid stream urinalysis; creatinine clearance; 24 hour protein excretion- urinary protein excretions of over 3.5g/24hrs suggest primary glomerular disease. Renal biopsy - this investigation may be undertaken e.g. in patients with CKD and normal sized kidneys. 1,2
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1.5 Pathophysiology of manifestation of ORL diseases in CKD
Quick et al described the resemblance in the histological and biochemical pattern between the cochlea and the kidney particularly that of the stria vascularis and the glomerulus - both of which are epithelial structures and intimately associated with the vascular system hence factors leading to changes in the kidney can bring about similar
changes in the cochlea also.
The biochemical derangement in CKD leads to various manifestations of otorhinolaryngological diseases viz epistaxis, vertigo, sensorineural hearing loss, sore throat, candida infection, dry mouth, and sialadenitis. 13-16
Dryness of the mouth in ureamic patients is due to diminished secretion of saliva. This might be due to chemical sialadenitis which results from the liberation of ammonia by urealytic organism within the duct system of the salivary gland. 3,12 Multiple ulceration in the oral cavity and oropharynx can happen in CKD. This is because of the alteration in the normal bacterial flora due to pH change, which in turn predisposes to infection and ulceration. In CKD, urea is also excreted through mucosal secretions. The bacteria present in pharynx split this urea releasing ammonia producing chemical mucositis, which may be the possible cause of congestion, ulceration of pharynx and sub-mucosal haemorrhage. The palatal and laryngeal oedema in CKD is due to lower plasma osmotic pressure induced by kidney disease. 3,12 The oedema improves with improvement in renal parameters.
The sensorineural hearing loss is partly due to toxic effect of high blood urea from CKD and use of ototoxic drugs during treatment. 13-16 Vertigo may also be seen in chronic uraemia. Although the exact cause is not known, it is probably the effect of retained toxic products on the labyrinth. 17-19
In CKD, urea is also excreted through nasal secretions. The bacteria flora present in nasal cavity split this urea releasing ammonia producing chemical rhinitis, the possible cause of congestion, ulceration of nose and epistaxis.
However, there is paucity of study on manifestation of ORL diseases among CKD patients in our environment. The earlier studies done in our environment to the best of investigator knowledge were based on hearing threshold among CKD patients. 22,23,39
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1.6 Research problem
The common empirical belief is that patients suffering from CKD also have concomitant ORL diseases but literature on this is sparse from our environment. This is to determine the occurrence of ORL diseases among adult patients with CKD attending renal unit of OAUTHC, Ife.
1.7 Research question
Is there a difference in the occurrence and pattern of ORL diseases in adult patients with CKD compared with general population?
1.8.1 Null hypothesis
The occurrence and pattern of ORL diseases among adult patients with CKD are not different from that of general population.
1.8.2 Alternate hypothesis
The occurrence and pattern of ORL diseases among adult patients with CKD are different from general population.
1.9 Scope of the study
This study was performed on hospital patients with CKD attending renal clinic and ORL Clinic of Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife.
1.10 Justification of the study
Ear, Nose and Throat (ORL) diseases have been frequently observed in patients with chronic kidney disease. Many factors such as ototoxic drugs use for the treatment of CKD, associated conditions of renal failure such as electrolyte imbalance and alteration in blood urea have been implicated for these observations. Locally, most of the studies done have been on hearing threshold in chronic kidney disease patients. These researchers however did not look at other ORL diseases in details. 22,23,39 This study is being extended to cover other aspects of ORL diseases among adult patients with CKD.
1.11 Limitation of the study
Diagnosis of hearing loss was based only on clinical observations and pure tone audiometry, and that of paranasal sinus disease was based on clinical diagnosis and diagnostic nasal endoscopy with the aid of 0
and 30
endoscopes. More sophisticated diagnostic tools such as otoacoustic emissions (OAE), and auditory brainstem response (ABR) could have given a more accurate diagnosis but could not be deployed in this study because of unavailability.
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