Renal Failure – How to approach? – 1

 

Renal Failure – A common problem in clinical practice.

– 5% of general ward patients

– 30% of ICU patients.

First let us go through the functions of the kidney
  • Excretion of waste products in the urine.
  • Regulation of blood volume and composition
  • Regulation of acid-base balance
  • Regulation of blood pressure
  • Vitamin D synthesis
  • Erythropoeitin release
Definition of renal failure
Inability to maintain the “milieu interior” due to decline in the excretory function of the kidneys.
Protocol to reach a diagnosis
By estimating serum urea and creatinine.Clinical symptoms are non-specific and non-reliable.
When and why should renal functions be checked?
  • To know the baseline renal function
  • To detect life threatening complications
  • Before giving drugs that requires dosage adjustment in renal failure
  • Before giving and during treatment with drugs that can cause renal failure.
  • Any patient at risk for renal failure
  • To get a clue regarding diagnosis
  • For prognostication and timely management / referral of patients.
Patients at risk for renal failure
  • Advanced age
  • Diabetes mellitus
  • Arteriosclerosis
  • Cancer
  • Pre-existing renal failure
  • Fluid and electrolyte imbalance
  • Those on other nephrotoxins- NSAIDs, ACEIs etc
Renal functions need to be checked in all hospitalised patients

Approach to renal failure varies according to the clinical situation

 

 

Is there any life threatening complication or emergency indication for dialysis?
  • Fluid overload (Pulmonary edema)
  • Hyperkalemia
  • Severe Metabolic acidosis
  • Uremic encephalopathy
  • Pericarditis
  • Severe dyselectrolytemias
  • Symptomatic uremia
  • Hypercatabolic state
  • Anuria > 24 hours
  • Toxin removal – Salicylate, ethylene glycol

First priority is for life threatening complications

  • Hyperkalemia
  • Pulmonary edema

Hyperkalaemia

Hyperkalaemia is most dangerous as it can cause sudden cardiac arrest.

Patients may be asymptomatic or report the following:

  •     Generalized fatigue
  •     Weakness
  •     Paresthesias
  •     Paralysis
  •     Palpitations

Treatment

  • Intravenous calcium (10 ml of 10% calcium gluconate, over 60 s, repeated until ECG improves)Acts instantly to ‘stabilize’ cardiac membranes (mechanism unknown); does not alter serum potassium
  • Intravenous insulin and glucose (10 units rapidly acting insulin + 50 ml 50% glucose, over 10 min).Insulin stimulates Na,K-ATPase in muscle and liver, thus driving potassium into cells; serum potassium falls by 1–2 mmol/l over 30–60 min

  • Salbutamol (10 mg via nebulizer) Stimulation of β2-adrenergic receptors leads to activation of Na,K-ATPase, thus driving potassium into cells
  • NaHCO3 Alkalosis favours shift of K+ into the cells.
  • Loop diuretics
  • Cation exchange resins, e.g. sodium or calcium polystyrene sulfonate (15 g by mouth 6-hourly or 15–30 g per rectum 6-hourly)
  • Exchange sodium or calcium for potassium in gut lumen and thus induce loss of potassium from body .
  • Haemodialysis/filtration/peritoneal dialysis

Pulmonary oedema

  •   Most serious complication of salt and water overload
  •   Regrettably, many cases are iatrogenic
  •   The patient is terrified, restless, and confused.
  •   Cyanosis, tachypnoea,
  •   Tachycardia, and a gallop rhythm
  •   Widespread wheeze or crepitations in the chest,.

Investigations

  •    Arterial hypoxaemia
  •    Widespread interstitial shadowing on the chest radiograph.
Management Protocol
  • Sit the patient up –  propped up position.
  • Give oxygen by face mask and reservoir bag in as high a concentration as possible
  • Frusemide, or other diuretic agents
  • Intravenous nitrate
  • Pulmonary oedema is one of the indications for emergency haemodialysis or haemofiltration.
  • In extremis, fluid can be removed by venesection
  • Pulmonary edema
  • Do not give extra fluid
  • Oxygen inhalation
  • IV diuretics   – loop diuretics
  • Higher doses required in renal failure
  • NTG if BP is very high
  • Antihypertensives
  • Hemodialysis

Continued in Part 2

One Comment

  1. vishnu says:

    Thank you sir.

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