Thyroid Profile in Chronic Renal Failure

INTRODUCTION: Chronic Renal Failure is a clinical syndrome due to irreversible renal dysfunction leading to excretory, metabolic and synthetic failure culminating into accumulation of non-protein nitrogenous substances and present with various clinical manifestations. End stage renal disease is described as a terminal stage of chronic renal failure that without replacement therapy would result in death. Despite various etiologies, CRF is the final common pathway of irreversible destruction of nephrons ultimately resulting in alteration of ‘Milieu interior’ that affects every system in the body. One such system in the body is thyroid hormonal system. Kidney is closely related to thyroid in the fact that it is the only other organ that competes with iodide clearance. Patients with CRF have many signs and symptoms suggestive of thyroid dysfunction like sallow complexion, edema, dry skin, cold intolerance, decreased BMR, asthenia and hyporeflexia. So in cases of CRF, it is difficult to exclude thyroid dysfunction on mere clinical background. Various studies have been conducted on thyroid function in CRF patients. Since the beginning, the results were inconsistent. Hyperthyroidism, hypothyroidism and euthyroidism all have been reported. The relation between thyroid dysfunction and severity of CRF is not clear. Several previous studies debit conflicting results both positive and negative. Prevalence of hypothyroidism in end stage renal disease (ESRD) have been estimated between 0 and 9%. There is also increased prevalence of goiter in patients with ESRD. In view of variability of thyroid function test in patients with CRF in previous studies, a prospective clinical and biochemical study on thyroid function in CRF patient in Department of Nephrology, Government Stanley Medical College Hospital, has been undertaken. AIMS OF THE STUDY: 1. To study the prevalence of thyroid dysfunction in patients with chronic renal failure. 2. To study the correlation between thyroid dysfunction and severity of renal diseases. 3. To differentiate primary thyroid diseases from thyroid dysfunction due to chronic renal failure. MATERIALS AND METHODS: Patients admitted to the Nephrology Ward of Government Stanley Medical College Hospital with Chronic Renal Failure who are on conservative management. Study design: Single Centre, Non randomized prospective study Study period: Study was conducted between September 2006 and August 2007 for a period of 12 months. Sample size: In the study period of 12 months among patients admitted in Nephrology ward after applying inclusion and exclusion criteria, 50 patients were included in this study. Patients who fulfill the criteria for CRF and who are on conservative management. Thyroid profile is done in all patients who fulfilling the criteria. Informed consent was obtained from all patients. Criteria for Chronic Renal Failure: 1. Symptoms of uraemia for 3 months or more. 2. Elevated blood urea, serum creatinine and decreased creatinine clearance. 3. Ultra sound evidence of chronic renal failure a. Bilateral contracted kidneys – size less than 8 cm in male and size less than 7 cm in female, b. Poor corticomedullary differentiation, c. Type 2 or 3 renal parenchymal changes. 4. Supportive laboratory evidence of CRF like anemia, low specific gravity, changes in serum electrolytes, etc., 5. Radiological evidence of renal osteodystrophy. Exclusion criteria: 1. Patients underwent pereitoneal dialysis or hemodialysis. 2. Nephrogenic range of proteinuria. 3. Low serum protein especially albumin. 4. Other conditions like; a. Acute illness, b. Recent surgery, trauma or burns, c. Diabetes mellitus, d. Liver diseases, e. Drugs altering thyroid profile like amiodarone, steroids, dopamine, phenytoin, beta-blocker, estrogen pills, iodine-containing drugs. RESULTS AND OBSERVATIONS: 50 patients with CRF who were on conservative management were studied. Among 50 patients, 10 patients were female and 40 patients were male. The age varied from 12 – 70 years. Among 50 patients, 10 patients were 30 years and below, 33 patients were in the age group of 30 – 60 years and 7 patients above 60 years. Observation regarding CRF in this study. The duration of CRF in this study varied from 3 months to 5 years. The Creatinine clearance varied from 6 ml/min to 34 ml/min. 20 patients had GFR10 ml/min accounting for 40%, 20 patients GFR 11 – 20 ml/min accounting for another 40%, remaining 10 patients accounting for 20% had GFR more than 20 ml/min. Blood urea varied from 64 to 170 mg/dl and Creatinine varied from 3 mg to 17.2 mg/dl. 24 hours urinary protein excretion was less than 1 gm/day in all the patients in this study group. Serum calcium and phosphorous were normal in all the patients. 80% of the patients had anaemia with peripheral smear revealing normocytic normochromic anaemia in 72% and hypochromic anaemia in 8% of the patients. CONCLUSIONS: 1. Thyroid dysfunction occurs in 58% of the chronic renal failure patients. 2. Incidence of hypothyroidism is increased in patients with chronic renal failure. 3. Both clinical and biochemical parameters are essential to diagnose hypothyroidism in patients with CRF. 4. Excluding patients with hypothyroidism T3 level is low in 46% of the patients, T4 level is low in 20% of the patients. 5. Number of patients with low T3 and T4 syndrome progressively increase with severity of renal failure. 6 Serum level of T3 and T4 has no correlation with the severity of renal failure. 7. Alteration in the values of T3 and T4 occurs as a part of body adaptations mechanism to conserve energy.