Definition
Irreversible deterioration in renal function
Classification – 5stages
| Stage | Description | GRF (ml/min/ 1.73m3) | Action |
| 1 | Kidney damage with N/↑GFR | >90 | Investigate |
| 2 | Kidney damage w slightly low GFR | 60-89 | Renoprotection – BP, diet |
| 3 | Moderately low GFR | 30-59 | |
| 4 | Severe low GFR | 15-29 | Consider RRT |
| 5 | Kidney failure | <15 or dialysis |
Aetiology
| Disease | % |
| DM | 20-40 |
| HTN | 5-25 |
| Glomerular disease -IgA nephropathy common | 10-20 |
| Interstitial disease | 5-15 |
| Systemic inflammatory e.g. SLE, vasculitis | 5 |
| RAS | 5 |
| Congenital/inherited -PKD, Alports disease | 5 |
| Unknown | 5-20 |
History
Symptoms
Fluid overload – ankle swelling, SOB,urine output
Uraemic symtoms
· Anorexia, vomiting, , metalic taste
· Fatigue, weakness,hiccup
· Pruritus,bruise
Signs
Pallor, yellow skin pigmentation
V/S: ↑BP, ↑RR, Kussmaul’s respiration, pulsus paradoxus
Brown nail
Purpura, bruising, excoriation, AV fistulae
Conjuctival pallor
JVP ↑
Displaced apex beat, pericardial friction rub
Bibasal Crepitation
Tenckhoff catheter
Leg swelling
I(x)
| Blood HB ↓ (normochromic, normocytic) ESR U&E (↑ urea, ↑creatinine) ↓Ca2+, ↑PO43-, ↑ ALP (renal osteodystrophy) ↑PTH |
| Urine MC&S, dipstick, urine PCI or 24h urine protein |
| Imaging Renal US – TRO obstruction, measure size Small <9cm Large -DM, PKD, amyloidosis, myeloma, systemic sclerosis, asymmetrical renal vascular DTPA scan CXR – cardiomegaly, pleural/pericardial effusion, pulmonary oedema Bone X-ray – TRO renal osteodystrophy Renal biopsy |
Complications
| Anaemia | Def of EPO Diminished erythropoisis dt toxic effect of uraemia on BM ↓red cell survivors ↓dietary intake and absorption of iron |
| Bleeding | Capillary fragility, poor platelet function |
| Fluid and electrolyte balance | ↓concentrating ability |
| Acidosis | |
| Infection | Cellular and humoral immunity are impaired |
| Renal osteodystrophy | Impaired renal function (1) ↓PO43- secretion à ↑plasma [PO43- ] (2)↓1,25 (OH)2Vit D à↓Ca2+ absorption à↓plasma [Ca2+] Both (1),(2) àstimulate PTH gland (hyperplasia) à↑PTHà↑osteoclastic activityà↑bone resorption |
| Generalised myopathy | Dt combination of poor nutrition, hyperparathyroidism, Vid D def, disorder of electrolyte metabolism |
| Neuropathy | Dt demyelination of medullated fibres, longer fibres – earlier stage Sensory -paraesthesia -tx:amytriptaline, gabapentin Motor -foot drop Autonomic -delayed gastric emptying -diarrhoea -postural hypotension |
Treatments
Refer to nephrologist
Treat reversible causes
| I. HTN II. ↓ renal perfusion III. RAS IV. Hypotension dt drug treatment | V. Sodium, water depletion VI. Poor cardiac output VII. UT obstruction VIII. UTI IX. Nephrotoxic med |
| HTN – small Bp dropàimprove significant renal function | -Tx: ACE-i, A2A -target: 130/80, (125/75 if >1g proteinuric/d) |
| Oedema | – frusemide 250mg-2g/24h ± metolazone 5-10mg/24h PO mane -fluid restriction |
| Anaemia | EPO |
| Renal osteodystrophy | Restrict dietary phosphate e.g. egg, cheese, milk Vit D analogue – Alphacalcidol=1α-hydroxycholecalciferol Ca2+ supplement Phosphate binder in gut (e.g. Calchichew) |
| Restless legs | Clonazepam -0.5-2mg/d |
Renal replacement therapy
Indications (7)
1. Fluid overload
2. ↓urine output
3. Uraemic symptoms
4. Uraemic encephalopathy
5. ↑urea
6. Hyperkalaemia
7. Metabolic acidosis
Methods of RRT
1. Haemodialysis (HD)
Blood flows on one side of semi-permeable membrane, while dialysate flows in the opposite direction
Solute transfers occur by diffusion.
Ultrafiltration is the removal of excess fluid by creating negative transmembrane perssure.
Problems
i. Disequilibrium syndrome
ii. hypotension, arrhythmias
iii. Bleeding, haemolysis, air embolism
iv. Time consuming
v. Access
Fistula - thrombosis, stenosis, aneurysm, steal syndrome, ischaemic
Temporary line - infection, blockage
2. Haemofiltration
Blood is filtered continuously acoss highly permeable synthetic membrane.
Removal of waste product by a process called convection.
Ultrafiltrate is substituted with an equal volume of replacement fluid.
Advantage – less haemodynamical instability
Disadvantages – > expensive, longer than HD
3. Peritoneal dialysis
I. CAPD (continuous ambulatory
peritoneal dialysis)
2L bags aer changed 3-5 times/day, total dialysate of 10L
II. Automated peritoneal dialysis
Use cyler machine to enhance solute and fluid removal
Techniques (4)
i. CCPD (continuous cylic PD)
ii. IPD (Intermitted PD)
iii. NIPD (Night intermittent PD)
iv. TIPD (tidal intermittent PD)
Problems with PD
| exit site leak poor inflow/ outflow pelvic/ abdo pain faeculent/ bloody effluent | unilat pleural effusion poor metabolic control hyperglycaemia in DM patients peritonitis |
Haemodialysis vs peritoneal dialysis
| Haemodialysis | PD |
| Efficient | Less efficient |
| 4hrs, 3 times / week | 4 exchanges/day |
| 2-3 days bet treatment | Few hours bet treatment |
| Visit to hosp | Performed at home |
| Requires adequate venous circulation | Require intact peritoneal membrane |
| Compliance with diet and fluid restriction | Diet and fluid less restricted |
| Symptoms and haemodynamic instability | Asymptomatic, less haemodynamic instability |
| Infection related to vascular access | Peritonitis and catheter-related infection |
Complication of dialysis
1. Cardiovascular diseases
e.g IHD, CF, stroke > common
2. HTN
3. Anaemia – Rx: EPO ±haematinics
4. Bleeding tendency
-dt platelet dysfunction
-Rx – desmopressin, transfusion
5. Renal bone disease
-Rx: diet, alfacalcidol, Ca2+supplement, phospate binders
6. Infection –dt non-sterility procedure
7. Β2-microglobulin amyloidosis
-dt accumulation of amyloid
-compl: Carpal tunnel syndrome, arthralgia, #
8. Acquired renal cyst
-present with haematuria or malignant transformation
9. Malignancy
e.g. urothelial tumour in analgesic nephropath
Discussion
Haemodialysis fluid (dialysate)
1. K3 (low calcium)
2. K5 (standard calcium)
3. K6 (high calcium)
3 types of fistula (AVF)
1. Brachiocephalic fistula (BCF)
2. Brachiobasillic fistula (BBF)
3. Radio cephalic fistula (RCF)
Factors involved in determining site of fistula
1. Non dominant hand
Risk of steal syndrome
2. Distil first – radio àbrachial
Types of Temporary line
1. Femoral catheter – last <1w
2. IJC – last up to 2 months
Only for good cardiac function
Buy time for AVF to mature
Hand grip exercise 3h/d àspeed up maturity of fistula
Screening before starting HD
1. Hep B
2. Hep C
3. HIV
Aim: to avoid contamination of the machine, thus transmission of infection
Eat High calcium food
Avoid high phosphate food
Hyperkalaemia findings on ECG
1. Absent P wave
2. Prolong PR interval
3. Widening of QRS complex
4. Tall T wave
Hyperkalaemia in CRF
Rule out causes for hyper K
1. ACE-i, suxamethonium
2. K-sparing diuretics
3. Massive blood transfusion
4. Delay in analysis – K leak out of RBC
5. Rhabdomyolysis, burn
6. Metabolic acidosis
7. Addison’s disease
8. Excess K therapy
Treatment of hyperkalaemia
1. Calcium
10ml of 10% calcium gluconate IV over 2min
2. IV glucose + insulin
50ml Dextrose 50% + 10U Actrapid insulin IV over 30min
MOA: insulin stimulates intracellular uptake of K+, lowering serum K+ by 1-2mmol/l over 60min
3. Salbutamol 5mg nebulizer
4. Haemodialysis
No comments:
Post a Comment