Nephrology handbook Flashcards
What Hx taking for hyperK and need to rule out?
How do you manage hyperkalemia?
- Exclude pseudo-hyperkalaemia e.g. haemolysis in blood specimen, esp. in those with relatively normal renal function;
- Beware of increase K release from cells/ tissue breakdown and transcellular shift (acidosis)
- Check drug history e.g. K supplement, NSAID, ACEI/ ARB, K- sparing diuretic
Ix: repeat RFT CO2 Cl-, ECG
For urgent cases:
1. 10% Calcium gluconate 10 mL or calcium chloride 5–10 ml IV over 2–3 minutes with cardiac monitoring; repeat if no effect in 5 minutes (onset:1–3 min; duration: 30–60 min ). If digoxin toxicity is suspected, omit calcium gluconate infusion.
2. Dextrose-insulin infusion: give 250 mL D10 or 50 mL D50 with 8–10 units Actrapid HM over 30 minutes; repeat every 4–6 hours if necessary (onset: 30 minutes; duration: 4–6 hours ).
3. Sodium bicarbonate 8.4% 100–150 mL over 30–60 min; to be given after calcium infusion in separate IV line; watch out for fluid overload (onset: 5–10 minutes; duration: 2 hours).
4. Resonium C / A: 15–50 g orally Q 4–6 hrs or as retention enema; may be given in 100–200 mL 10% mannitol as laxative; one gram of resonium will bind 1 mmol of K. (onset: 1–2 hours; duration: 4–6 hours).
5. Salbutamol 10–20 mg in 3 mL NS by nebulizer (onset: 15–30 minutes; duration: 2–3 hours).
6. Diuretics: furosemide 40–80 mg IV bolus.
7. Emergency haemodialysis or peritoneal dialysis.
What is the Ix and Rx for chronic hyperkalemia cases?
Ix:
Detailed drug history
Consider checking cortisol, plasma renin activity, serum aldosterone
Rx:
1. Low K diet (< 2 g/day).
2. Diuretics: furosemide / thiazide
3. Correct acidosis with sodium bicarbonate 300-900 mg TDS (~10– 30 mmoles/day).
4. Fludrocortisone 0.1–0.2 mg daily (for Type IV RTA).
What are the causes of hypercalcemia and how to calculate it?
- Common cause: hyperparathyroidism, hypercalcaemia of
malignancy, drug-induced (vit D/ calcium supplement, thiazide
diuretics, vit A) - Commonly associated with dehydration
- Calculated corrected serum calcium level based on serum albumin concentration
- Corrected calcium = 0.02 * (40 g/L – patient’s albumin (g/L)) + serum Ca
What is the Ix and Rx for hypercalcemia?
Ix: Check ionized calcium, PO4, RFT, PTH, Vit D, thyroid function, 24h urine x calcium or fractional excretion of Ca. ECG
Rx:
1. Off calcium / vitamin D supplement if any.
2. Volume repletion with NS at 100–500 mL/hr infusion (Guided by
CVP / urine output); start furosemide after rehydration 20–40 mg IV Q4–12H; aim at a urine output of ~ 200 mL/h; close monitoring of Na K Ca Mg level and fluid status.
3. Pamidronate IV 30–90 mg (with reference to patient’s renal function) in 250–500 mL NS infused over 4-6 hrs. Maximum effect is not seen for several days; repeat another dose after a minimum of 7 days if necessary.
4. Zoledronate IV 4 mg infusion over 15 min (maximal effect at 72 hours)
5. Salmon calcitonin 4 units/kg IM/SC Q12H; Calcium level begins to fall within 2–3 hours; tachyphylaxis occurred within 2–3 days.
6. Hydrocortisone 50 mg IV Q8H then prednisolone 40–60 mg daily (onset: 3–5 days; useful in haematological malignancy, vitamin D intoxication, granulomatous condition)
7. Haemodialysis with zero or low Ca dialysate
8. Newer treatment: Denosumab / Cinacalcet
How to confirm true hyponatremia and what investigations to be done?
- Rule out pseudohyponatraemia and hyperosmolar hyponatraemia (Check glucose, lipid, immunoglobulin level).
- Check history of prostatic surgery/uterine surgery
- Check medication history (thiazide, anti-depressants)
Ix: RFT, serum/urine osmolality, spot urine [Na], cortisol, thyroid function
What are the causes and Rx of isovolemia hyponatremia?
Isovolaemia:
- urine Na >20 mmol/L and urine osmo >100 mOsm/L: SIADH,
hypothyroid, Addison’s disease
- urine Na <10 mmol/L and urine osmo <100 mOsm/L: water
intoxication, primary polydipsia, beer potomania
Rx:
- Restrict water intake < 1000 mL per day for SIADH (Calculate the {urine [Na] + urine [K]/ serum [Na]} ratio; free water loss if ratio < 1)
- Treat the underlying cause; discontinue culprit medication
- NaCl oral supplement ± Frusemide
- Correction of hypokalaemia
- Increase dietary solute load
What is the management of acute symptomatic hyponatremia?
- Consult ICU
- Very cautiously give IV hypertonic saline (100 ml 3% hypertonic
saline (513 mmol/L) over 20 min or 50 mL 5.85% NaCl (1000 mmol/L) over 30 min - Repeat if necessary until [Na] increase by 4–6 mmol/L or improvement in symptoms
- For patients with severe symptoms, [Na] should be corrected 1–2 mmol/L/hr for 3–4 hours
- Correction should not be > 8–12 mmol/L/24hr to avoid central pontine myelinolysis
- Adrogue formula: Change in serum Na with 1L of infusate =
[(Infusate Na + infusate K) – (serum Na)] / (TBW+1)
What are the causes and Rx of hypovolemic hyponatremia?
- urine Na <10 mmol/L: diarrhoea, vomiting, third space fluid loss,
dehydration, remote diuretic use - urine Na >20 mmol/L: diuretics, adrenal insufficiency, salt
wasting, bicarbonaturia
Rx: - Use isotonic saline (NS) 500 mL/hr till BP normal then replace the sodium deficit with saline/ Na supplement
- Rate of correction should not be > 8–12 mmol/L over 24 hrs (Beware of rapid increase in [Na] after restoration to euvolaemic state)
- Sodium deficit: Na+ requirement (mmol)
= total body water (0.6BW)(desired Na+–serum Na+)
What are the causes and Rx of hypervolemic hyponatremia?
(urine Na <10 mmol/L: CHF, cirrhosis; urine Na >20 mmol/L: renal failure)
Rx:
- Treat the underlying cause
- Restrict water intake <1000 mL per day
- Furosemide 40–80 mg IV / 20–500 mg PO daily
What is the sodium concentration of commonly used IV fluid?
What are the causes for high anion gap metabolic acidosis?
MULEPAK-P
M=methanol, U=uraemia, L=lactic acidosis,
E=ethylene glycol P=paraldehyde, A=aspirin, K=ketosis, P=pyroglutamic acid (panadol)
What are the causes for normal anion gap metabolic acidosis?
USED CAR
U=ureteroenterostomy, S=saline infusion, E=endocrinology e.g.: Addison, D=diarrhoea, C=carbonic anhydrase inhibitor, A=ammonium chloride, R=renal tubular acidosis (SJE, RA, SLE, PBC)
What are prerenal causes of renal failure?
Hypotension, effective volume depletion e.g. dehydration, cirrhosis, congestive heart failure, sepsis, 3rd space sequestration
What are postrenal causes of renal failure?
Urinary obstruction, stones, urethral obstruction, BPH
What are renal causes of renal failure?
Rapidly progressive glomerulonephritis, vasculitis, acute tubular necrosis, tubulointerstitial nephritis, etc.
What are the Ix for renal failure?
- CBP, RLFT, CO2, Cl, Ca, PO4, amylase, urate, LDH, arterial blood gas, CK;
- 24 hr urineNa K Cr, total protein;
(*Assessment of creatinine clearance/eGFR in non-steady state is not reliable) - Autoimmune markers: ANF, Anti-DsDNA, Anti ENA, C3/4, ANCA, anti-GBM,
- ASOT, cryoglobulin
- Ig pattern, Serum electrophoresis, urine electrophoresis
- Spot urine x TP/ Cr ratio, dysmorphic RBC, eosinophil;
- MSURM C/ST;
- HBsAg/Ab, anti HBc, anti-HCV (Urgent HBsAg and anti HCV if
haemodialysis is anticipated) - CXR, ECG
- Urgent KUB, USG kidneys
How to identify the potential of a organ donor for renal transplant?
Definitie dx, irreversible CNS damage
Brain death is imminent
Put on mechanical ventilation
GCS 3-5/15
Both pupils fixed to light
What is the exclusion criteria for renal transplant donor?
Uncontrolled fulminant infection;
Risk of transmission of disease caused by prions, including Creutzfeldt-Jakob disease, rapid progressive dementia or degenerative neurological disease;
History of IV drug abuse;
HIV +ve cases or has risk factors for HIV infection;
Presence or previous history of malignant disease (except primary basal cell carcinoma, carcinoma in-situ of uterine cervix and some primary tumour of CNS)
Unknown cause of death
Victims of intoxication of toxic substance
What is the aim of maintenance of organ perfusion of potential donor?
Maintain SBP 100–140 mmHg, AR 60–120 bpm
Maintain Mean BP > 80 mmHg
Maintain CVP of 8–12 cm H2O
Maintain hourly urine output ~100 ml
Maintain intake and output balance and cover insensible loss
Maintain SaO2 ≥ 95%
Maintain body temperature >36°C
What is management for potential renal donor?
a. Monitor BP, P, CVP, urine output, SaO2, ventilator status q1h, body temperature q2h
b. Monitor electrolytes, RLFT, Ca/PO4 q6–8h, H’stix q2–4h
c. Set two good IV lines, preferably one central line
d. Monitor BP:
- If persistently hypertensive (MBP >120 mmHg), start labetalol 5 mg IV over 1 min and repeat at 5 min intervals if necessary
- If persistently hypotensive (SBP ≤100 mmHg)
Start fluid replacement by infusing crystalloid or colloid
Add dopamine 2.5–10 micrograms/kg/min if BP persistently low despite adequate fluid replacement
Add adrenaline (1– 60 micrograms/min) or noradrenaline (3–60 micrograms/min) infusion
If BP persistently low: start hydrocortisone 100 mg stat & 100 mg q8h
e. Monitor urine output:
- If massive urine output (> 200 ml/hour)
Control hyperglycaemia (H’stix > 12 mmol/L persistently) by Actrapid HM infusion at 2–6 units/hour
Control diabetes insipidus (serum Na ≥150 mmol/L) by dDAVP 2–6 microgram IV q6–8h
Control hypothermia (body temperature ≤35°C) by apply patient warming system
- If oliguric (hourly urine <30 ml)
Check Foley patency
Oliguria with low or normal CVP, start fluid replacement
Oliguria with high CVP, start lasix 20–250 mg IVI
f. Add prophylactic antibiotics after blood culture if fever >38°C
What is the routine arrangement in potential renal donor?
a. Inform transplant coordinator via hospital operator at any time
b. Interview family for grave prognosis, do not discuss organ donation with family until patient is confirmed brain death
c. Once the patient meets brain death criteria, arrange qualified personnel to perform brain stem death test.
What are the Ix for hypokalemia?
What is important history assessment for hypoK?
RFT, total CO2 content, Cl-, Mg, TFT, cortisol
Simultaneous blood and urine x TTKG (transtubular K gradient) or 24h urine for K/urine K/Cr
Aldosterone renin ratio if confirmed urinary K loss (after correction of hypoK)
Check baseline ECG
Check drug history especially diuretic therapy
Usually associated with metabolic alkalosis
Consider Mg depletion if hypokalemia is resistasnt to treatment
Don’t give K replacement therapy in dextrose solution
What is the management of hypokalemia when serum K>2.5/<2.5?
Hypokalemia associated with metabolic acidosis?
If serum K >2.5mmol/L and ECG changes are absent:
Oral K replacement (syrup KCL 2-3g Q4H for 2-3 doses)
KCl 10-20mmol/hour in saline infusion (up to 40mmol/L) as continuous IV infusion
If serum K <2.5mmol/L and/or ECG changes present:
Consult ICU and cardiac monitor
KCl 20mmol/hour in saline infusion (concentration up to 80-100mmol/L; given via central vein for high conc KCl)
May combine with oral KCl 30-40mmol (3-4gm syrup KCl) Q4h
HypoK with metabolic acidosis
Give potassium citrate solution (1mmol/mL) 15-30mL 4x/day in juice after meals; start K replacement before HCO3- therapy in separate IV line if indicated