Disorders of acid base balance

1. Disorders of acid base balance Gamal El Naggar Internal Medicine Department Tanta Faculty of Medicine Nephrology Unit. by

2. Respiratory alkalosis Causes (hyperventilationCO2 wash) • Hypoximia and tissue hypoxia: as high altitude ,drowning , bacterial or viral pneumonia , pulmonary oedema , cyanotic heart disease , and hypotension: • Stimulation of chest receptor: asthma , pneumonia , pneumothorax , cardiac failure. • CNS stimulation: • Psychosis ,anxiety , voulantary • Subarachinoid haemorrhage , CV accidents. • Tumour ,truma. • Drugs and hormones:salicylates , angiotension II , catachelamines , nicotine. • Iaterogenic: under ventilatory support • Recavery from metabolic acidosis

3. Clinical features (usually minimal) • Manifestation of the cause • Neurological manifestation :irritation (low ionized Ca++): parathesia , tinnitus , neuromuscular irritability , tetany ,and • Cerebral vasoconstriction • Hyperventilation. • Cardiac arrhythmia , INVESTIGATION: • High pH of the blood • Low HCO3 & PCO2 TREATMENT: • Correction of the underlying causes • Reassurance • Rebreathing into a closed system (eg paper bag )to inspire the expired air with its high level of CO2.

5. Investigation of renal diseases Gamal El Naggar Internal Medicine Department Tanta Faculty of Medicine Nephrology Unit. by

6. Investigation of kidney diseases 1- urine examination: These are characters of the normal , freshly voided urine • Physical examination: 1-colour:amber yellow 2-aspect:clear 3-volume/day:600-2000ml/day 4-specific gravity: 1018-1030 5-odour:urinephrous odour 6-reaction:acidic 7-no necroturia, no pneumatouria

7. Chemical examination: the normal chemical constituent of the 24 hour-urine for average individual on the usual diet are as follows: • Inorganic constituent 1-k+ :2.0-2.2gm 2-Na+ :4-5gm 3-CL(as Nacl) :9-16gm 4-Ca++ :0.1-0.2gm 5-phosphate(phosphrus):1.0-1.2gm 6-sulphate (sulfer) :0.7-3.5gm 7-bicarbonate :0.1gm 8-Mg++ :0.05-0.2gm 9-iodine :50-250ug 10-arsenic :50 or less ug 11-lead :50 or less ug

8. Organic constituent • nitrogenous: 1-urea: :16-35gm 2-uric acid :0.4-1.4gm 3-creatinine :1-1.8gm(2.0mg/kg) 4-amonia :0.3-1gm 5-proteinuria :<150mg 6-albuminuria :<30mg 7-urinary pigment :0.5-2mg (urobilinogen) • Non-nitrogenous 1.hippuric acid :0.1-1.1gm 2.oxalic acid :15-20gm 3.indican :4-20gm 4.coproporphyrin :60-280gm 5.puric bases :10gm 6.ketone bodies :3-15mg 7.sugar :Nil 8.vit C :Nil 9.phenol :0.02-0.5gm 10.allatoin :30mg

9. Abnormal urinary constituents: • Proteinuria(>300mg/day)albumin uri>30mg/day) • Sugars:glucosuria,lactasuria • Blood pigment :haematuria,haemoglobinuria and, myoglobinuria • Bile pigment (bilirubin) : in obstuctive and hepatic jaundice • Bile acid : obstructive jaundice • Urobilinogan increased in hepatic and prehepatic jaundice • Ketone bodies (acetone,acetoacetic acid , and B-hydroxybutyric acid) • Nitrites: in cases of G-Ve bacteriuria 3)Microscopic examination: the examination is done on deposits from fresh urine by centrifusion The examination includes

10. Organized elements 1-cells:RBCs(n=5HPF)WBCs and puscells,(n=<5HPF)epithelia cells and neoplastic cells 2-pasasites and ova:B , filariasis,and trachomonas 3-bacteria, virus , condidiais 4-sperms 5-cast (cylinderuria),hyaline(normal),granular,lipid(fatty or waxy),broad,haemoglobin,drug crystals,and cellular casts:pus castes which included WBC, RBCs cast which contain RBCs ,and epithelial cast which contain epithelial cells b) Non organized elements (crystalluria) 1-acidic urine: uric acid crystals, amorphous urate, calcium oxalate 2-alkaline urine: amorphous phosphate, ammonium urate, triple phophate

11. Renal function tests: 1-Measurement of renal blood flow (RBF) or effective renal plasma flow (ERPF) 2-Tests for glomerular functions(NPN): a.serum creatinine. (normal for male=0.4-1.4 for female 0.2-1`.2 mg/dl). • It is the best single guide for renal function . • The level of serum creatinine depends on the rate of its production by muscle bulk (which is fixed in the steady state)and its excretion , through the kidneys (GFR). • It is muscle bulk dependent (independent of protein in take) so it is high in male and low children, women and elderly.

12. b.blood urea (n=15-50mg/dl) blood urea nitrogen( BUN) (N=8-12mg/dl) • BU,BUN correlate with uremic manifestation • BU and BUN are rough indexes (less reliable than serum creatinine) for renal functions and should not de used isolated , because of the following defects: • False increase in BU and BUN eg. High protein intake, dehydration, GIT bleeding, tissue catabolism, drugs as corticosteride,thiazid, and tetracycline and decrease in renal tubular flow as prerenal azotaemia • False decrease in BU and BUN :as high fluid intake , or decrease synthesis caused by anabolic drugs, liver cirrhosis, low protein intake, starvation pregnancy ,malabsorption syndrome • Moreover these tests start to rise if GFR falls to below 30% of normal so mild degrees of renal failure can not be detected by simple estimation of BU, BUN or serum creatinine ratio of BU/serum creatinine (BU/C=20:1) BUN/C(10:1) c. other non protein nitrogen (NPN)=serum uric acid amino acids ,creatine, ammonia N.B.:the differential function of both kidney is assessed by comparing the composition of urine sample obtained from two sides by urerteric catheter or by scanning of the two kidneys(renography)

13. 3.Measurement of GFR: GFR estimation is the best index of overall renal function in health and disease (GOLD STANDARD) • Normal value for adult male 97-137m/min/1.73m2(180L/day) . • Adult female is approximately 8% lower 88-128 ml / min .in men there is decrement of GFR by about 10ml/min/1.73m2 per decade of age after 40 years. • Mild degree of renal impairment can be detected by this test , before actual rise of of BU,BUN or serum creatinine. Estimation: 1.Through collection of 24 hour urine: Creatinine clearance= UxV = urine concentration of creatinine x urine flow rate/min P serum or plasma concentration of creatinine In practice :we use endogenous creatinine which is filtered in the glomeruli but there is some excretion through tubules , so creatinine clearance overestimates GFR. Also ,incomplete urine collection is a major source error 2.Estimation of creatinineclearance from serum creatinine . (cockcroft and gault formula)

14. For men creatinine clearnace = (140-age)xweight / kg serum creatinine x 72 For females creatinine clearance = (140-age)xweigh/kg x0.85 serum creatinine x 72 3. Estamation of creatinine clearance from using exogenous filtration marker: the test is conducted using :99mTc DTPA or 151 Cr-labeled EDTA or isothalamate isotope renal scan . Although it is very accurate , it remains largely a research tool. Relation of BU or serum creatinine to GFR • The relationship is hyperbolic (reciprocal) one rather than linear i.e rapid rise in SC or BUN occurs in late renal disease where as earlier there may be considerable renal function loss (by GFR estimation) with the very little change in creatinine or BUN. • In other words , these tests start to rise if GFR falls ;below 30% of the normal.

15. 4.Tests for tubular functions: • Urine acidification test : • The ability of the kidney to acidify urine (secrete H+). • Ammonium chloride 100mg/kg body weight is given in flavored mixture in the morning.a urinary pH of 5.3 or below should be found in at least one sample passed in the following 8hour . • This test is used for the diagnosis of renal tubular acidosis. • Urine concentration test : If early morning specimen for osmolality>700mosmol/L (SG=1018-1020) concentrating capacity is considered normal and there would be no need for further investigation. Otherwise , we may either do water deprivation test or vasopressin (ADH)test to diagnose diabetes insipidus • Urinary B2-microglobulin (n=0.1-0.4mg/ml):which is a marker for Tubular diseases eg. Analgesic and toxic nephropathies. • Urinary excretion of sodium This is helpful in differentiating impaired kidney function which is due to tubular necrosis from prerenal failure.

16. III- blood investigations: • Complete blood count., • ESR • Blood chemistery. <>serum lipids, protein and A/G ratio , blood glucose <>serum iron , iron binding capacity and ferritin <>serum electrolytes and pH (Na+, K+ , Ca++,Cl-,Mg++,phosphate and bicarbonate)

17. IV.Immunological tests for diagnosis of kidney disease • Complement:hypocomplementmia is a feature of some renal disease such as postinfectious GN ,shunt nephritis , and lupus nephritis. • Immunoglobulins :as serum IgA and IgE concentrations • Circulating immune complexes (CIC): as cryoglobulinomias,SLE and collagen disease. • Autoantibodies: these include antinuclear (ANA),anti-DNA, anti neutrophil cytoplasmic auto-antibodies(ANCA) and antiglomerular basemement membrane anti bodies (anti-GBM)

18. V.Radiological examination : 1.ultrasonography: <>it is cheap, easy , non invasive and non hazardous. It can demonstrate clearly the renal size ,contour, echotextures ,stone , back pressure, renal mass or cyst, and perirenal collection, also show the upper and lower parts of the ureter. <>pelvic ultrasonogrophy may show mass and calculate the residual urine <>it is useful for guiding needle for renal biopsy or aspiration of perirenal collection. Doppler flow imaging of the renal vessels will assess both anatomy (structure) and physiology (flow) of the blood supply of the kidney. So it may help in diagnosis of renal artery occlusion or stenosis , renal vein thrombosis and kidney transplant rejection.

19. 2.plain abdominal x-ray (KUB):(kidney ,ureter, bladder)may show a.stones b.calcification of the kidney ,urinary bladder, seminal vesicles. c.renal contour and soft tissue shadow 3.Intravenous urography (IVU): shows the anatimy of the kidney and urinary system ,any mass ,stones ,back pressure changes and also demonstrates kidney function and obstruction. It should be done in the light of renal function . 4.Cystography and voiding cystourethrography to show vesicoureteric reflux (VUR) and residual urine. 5.Urodynamic studies: these will give anatomic and physiologic assessment of the lower urinary tract. 6.angiography: this includes a.renal arteriography (either conventional or digital subtraction). It is mainly indicated for diagnosis of renovascular hypertension or persistent haematuria following trauma. b. renal venography. This is indicated for diagnosis of renal vein thrombosis.

20. 7. Computerized tomography (CT):it is strongly indicated in patients with obstructive uropathy with non-evident cause. 8.Radionuclides imaging (renogram): a.static renal imaging to diagnose renal scaring ,renal tumours anatomic abnormalities. b.dynamic renal imaging which is helpful in examining renal perfusion and dynamic parenchymal images and excretion into bladder (vascular phase)and so diagnosing renal vascular occulsion ,narrowing as well as ureteric obstruction and measurement of the total or individual kidney GFR. 9.Magnetic resonance imaging (MRI) MRI provides excellent anatomical information which are helpful in studying malignancies of the urinary tract and assessment of renal vessels by MRI angiography.

21. VI. Kidney biopsy • It shows the pathology of the underlying renal disease. • The biopsy should be examined by light microscope (LM) ,electronic microscope (EM) and immunofluorescent microscope (IF) • Very helpful in diagnosing, prognosis and therapeutic guidance.

22. VII. cystoscopy, ureteroscopy. • Diagnosis : of bladder disease , (tumour)by direct vision or biopsy. • Therapeutic: ureteric catheter: also , ascending pyelography , differential renal function.

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