Clinical Characteristics Of 266 Patients With Renal Tubular Acidosis

Background:Renal tubular acidosis refers to a group of diseases characterized by normal serum anion gap or hyperchloremic metabolic acidosis,electrolytes disorder and urine acidification dysfunctions caused by the inability of the renal tubule to retain bicarbonate(HCO3-)or to secrete hydrogen ions(H+)in the presence of normal or moderately impaired glomerular filtration rate.Renal tubular acidosis often progresses without specific clinical presentation and could be ignored easily.However,it has a negative impact on life expectancy and quality of patients suffering from it,by causing hypokalemia,renal calcification,nephrolithosis,osteomalacia,rickets,pathologic bones fractures and chronic renal failure.Although,renal tubular acidosis is a common type of renal tubulointerstitial diseases,the rate of missed diagnosis and misdiagnosis are still high due to complicated underlying diseases,various and low-specific clinical manifestations,wide distribution of patients and low clinical concerns.In total,it is urgent to improve our knowledge of renal tubular acidosis.Objective:To explore the common clinical features of renal tubular acidosis,to compare the clinical characteristics between adults and children patients,and to provide practical and useful information for clinical practice.Methods:Subjects:Clinical data of patients with renal tubular acidosis diagnosed by Shandong Provincial Hospital affiliated to Shandong University from 1991 January to 2017 September were reviewed and finally 266 cases were enrolled after discarding duplicate cases,unconfirmed cases and cases without complete data.Methods:To explore the difference and consistency in clinical characteristics of renal tubular acidosis between adults and children.Statistical methods:Data were analyzed by SPSS 22.0 program.The count data were described in the form of percentage(%),and the measurement data approximately obeying to normal distribution were described in the form of mean(x±s).Results:1.Data from 266 patients were analyzed,including 206 adults and 60 children.The ratio of men to women was 1:5.8(39:227).Ages ranged from 2 months to 75 years old and the average age was(29.0±19.0)years old.The average inpatient days were(12.9±9.1)days.The average course was(30.8±44.8)months.Adult patients gathered in divisions of Endocrinology(45.1%),Rheumatology(33.5%),Nephrology(15.0%)and others(6.3%).2.Primary renal tubular acidosis accounted for 26.32%(70 cases),secondary RTA accounted for 73.68%(196 cases).89.81%of adult cases were secondary to other diseases,mainly autoimmune diseases(89.19%),especially primary Sjogren's syndrome.Most children cases(81.67%)were idiopathic,others largely originated from inherited systematic metabolic diseases.3.By retrospective analysis,266 cases were divided into 233 cases of distal renal tubular acidosis,15 proximal renal tubular acidosis,2 cases of mixed renal tubular acidosis and 2 cases of hyperkalemia renal tubular acidosis.The most common subtype was distal renal tubular acidosis both in adults and children.Proximal renal tubular acidosis was easier to be found in idiopathic renal tubular diseases of children.4.Chief complaints or starting symptoms were mainly composed of polydipsia along with polyuria(41.4%)and fatigue(35.3%),which were more outstanding in adults.Children were typical of growth retardation,rickets and digestive symptoms.RTA could easily complicate with nephrolithosis,renal calcification,osteomalacia,rickets,chronic renal failure,hydronephrosis and urinary tract infection,et al.5.The common laboratory feature of renal tubular acidosis was metabolic acidosis with normal anion gap or hyperchloremia,usually accompanying with hypokalemia(90.0%),hypocalcemia(57.0%),hypophosphataemia,paradoxical alkaline urine and low special gravity urine.6.The rates of missed diagnosis and misdiagnosis were 30.0 and 11.3 percent respectively and 41.4 percent in total.Renal tubular acidosis could be misdiagnosed as many diseases,such as central diabetes insipidus,diabetes mellitus,diabetic ketoacidosis,primary hypokalemia periodic paralysis,primary aldosteronism,rheumatoid arthritis and hyperparathyroidism,et al.7.Routine therapy consisted of healing metabolic acidosis and electrolyte disorders,treating underlying diseases and preventing complications.The majority of patients recovered in aspects of both clinical manifesltations and laboratory index.Conclusions:1.The majority of patients are women.The incidence of is increasing gradually.Adult patients mainly gathered in the divisions of Endocrinology,Rheumatology and Nephrology.2.The etiology of renal tubular acidosis is very complex.Most adult cases were secondary to other diseases.After the diagnosis of renal tubular acidosis,physicians should further investigate underlying diseases including autoimmune diseases,renal diseases,et al.Children with primary RTA are more common and have early onsets,which should be considered seriously.Part children patients may be secondary to primary Sjogren's syndrome and systemic metabolic diseases.Missed diagnosis should be avoided.3.If adult patients perform manifestations related to hypokalemia and urine concentration disorders simultaneously,physicians should be alert to the diagnosis of renal tubular acidosis.Patients with Sjogren's syndrome showing hypokalemia should be considered to have distal renal tubular acidosis.Premature infants,young children and preschool children with unpredictable metabolic acidosis,growth retardation and rickets should be considered to have primary renal tubular acidosis.Pediatricians should improve their awareness,early identification and intervention to prevent the occurrence of complications such as osteoarticular malformations and renal insufficiency.4.In addition to high-chlorinity metabolic acidosis,most patients have hypokalemia.Hypocalcemia occurred in more than half of patients.The patient's serum sodium level is normal.In order to avoid serious low Potassium hyperlipidemia or low calcium twitches,timely correction of water and electrolyte acid-base imbalance should be paid more attention to.5.Renal tubular acidosis could lead to many complications.The rate of missed diagnosis and misdiagnosis in renal tubular acidosis is high.Physicians should make diagnosis carefully in clinical practice.The majority of patients with renal tubular acidosis are relieved after timely treatment,with laboratory indicators improved and good short-term prognosis.