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Chronic Renal Failure

Sep 18, 20246 min read

CHRONIC RENAL FAILURE

DR WAQAR

NORMAL FUNCTIONS OF THE KIDNEYS

  • Excretion of wastes ( Urea, creatinine )
  • Acid-base balance ( excretion of acids produced in the body)
  • Electrolyte balance ( Na, K, P etc)
  • Erythropoeitin production ( for RBC synthesis). It is a hormone.
  • Salt & water balance ⇒ maintain BP
  • Activate Vit D, thus managing Ca & Phosph.

EFFECTS OF RENAL FAILURE

  • High urea & creat. ( uremia)
  • Acidosis
  • High K & Phosphorus
  • Decreased erythropoeitin ⇒ anemia
  • “If” water retention ⇒ HTN, edema
  • No Vit D activation ⇒ Vit D deficiency, which causes : bone disease
TYPES OF RENAL FAILURE

The level of creatinine does not tell you whether the renal failure is acute or chronic. It just tells you the severity of the disease

  • A patient with ARF can have creatinine: 5Z
  • A patient with CRF can have creatinine: 3Z

CHRONIC KIDNEY DISEASE

DEFINITION: Renal failure which persists for > 3 months. It is usually progressive & finally leads to ESRD(end stage renal disease)

ETIOLOGY:

  1. DM MOST COMMON CAUSES
  2. HTN MOST COMMON CAUSES
  3. Family hist. of CRF
  4. Glomerulonephritis, tubular damage and all post renal causes (which we discussed before) can cause CRF, if they become chronic
  5. Polycystic kidney disease (ADPKD)
  6. Congestive heart failure ( due to hypoperfusion)
STAGES OF CKD (CRF)

CRF is divided into 5 stages, based on the GFR (glomerular filtration rate).

Normal GFR > 90ml/min ( it means that in 1 min., > 90 cc of fluid is filtered at the glomerulus). - As renal failure progresses, GFR falls.

Stage GFR 1 >90 cc 2 b/w 60-90 3 b/w 30-60 4 b/w 15-30 5 less than 15 (ESRD)

(S/S)

  • Asymptomatic. Incidentally found by blood tests ( high urea, creatinine) or abnormal renal ultrasound
  • Can present as any of the complications
  • Nausea/vomiting, loss of appetite, general weakness (very common presentations)

COMPLICATIONS OF CRF

  1. CVS:
  • HTN
  • Pulmonary edema
  • Pericarditis (uremic pericarditis)
  1. CNS:
  • Uremic encephalopathy (mental status changes, siezures etc)
  • Peripheral neuropathy
  1. Anemia:
    Causes pallor, fatigue, weakness
  • Due to low erythropoietin +/- low iron levels
  • Always check & correct iron def. first. (otherwise, erythropoietin injections wont work)

  1. Electrolyte disturbances: ( high K, high P, low Calcium)

  2. Acidosis: Metabolic acidosis ( kidneys can’t excrete the normal acids)

  3. Edema

    • Peripheral
    • Pulmonary/Pleural
    • Face (periorbital)

  4. Skin: Itching due to high phospho.

  5. Bone: Bone pain & fractures. - Involvement of the bone in CRF is called “Renal osteodystrophy”. Pathogenesis: In CRF ⇒ no activation of vit.D in the kidneys ⇒ def. of vit D ⇒ low serum Ca & high P ⇒ this leads to release of PTH (secondary hyperparathyroidism) ⇒ bones become weak( Osteoporosis, osteomalacia)

What is “tertiary hyperparathyroidism” ?

In CRF, if secondary hyperparathyroidism is not corrected, it changes into Tertiary type. ( behaves like an adenoma)

Screening for CRF

Patients who are at increased risk of developing CRF should be screened annually by the following tests:

  1. Serum creatinine
  2. eGFR (glomelrular filtration rate)
  3. Urine albumin (see next slide for how to check this)

CHECKING FOR URINE ALBUMIN

  1. Simple urine analysis or dipstick
  2. 24 hour urine collection to check albumin
  3. A urine sample to check albumin: creatinine ratio (uACR)Z

(number 3 is the best)

MANAGEMENT OF CRF

In the management of CRF, we basically manage the complications which have happened.

First we try conservative/medical treatment. If that fails, then dialysis or renal transplant.

GENERAL MEASURES

  • Good control of DM and HTN
  • Avoid nephrotoxic drugs( NSAIDs, aminoglycosides)
  • Control albuminuria (with ACE). (albumin in urine damages the kidney more)
  • Avoid i.v. contrasts
  • Fluid restriction not LAAZIM in every case

TREATMENT OF COMPLICATIONS

  1. Uremia ( high urea & creatinine) Rx : Low protein diet( urea & crea. is formed from protein). May need dialysis

  2. HTN: ACE inhibitors are 1st choice ( even if creatinine is high)

  3. Edema: Pulmonary/peripheral/pleuralRx:

    • Low salt and water intake
    • Diuretics

  4. High K ( moderately high) Rx: Low K diet ( no bananas, tomato, potato) May need drugs which bind with K in the GIT & prevent its absorption ( K binding resins eg. Kayexalate, patiromer )

  5. Anemia: Rx:

  • Check for Fe deficiency & correct it first - then
  • Erythropoeitin injections

“ Aim of Hb. in CRF is between 10 to 12g%. NOT more than 12”

  1. ACIDOSIS: Due to accumulation of acids.
  • Give Na bicarbonate tabs

  1. Pneumovac & flu vaccine

  2. Neuro. S/S + PERICARDITIS:
    Treatment is only Dialysis

  3. Treatment of bone disease( due to sec. hyperpara.)

    • Give calcium and vitamin D orally.
    • Once serum calcium & vit D are normal, PTH will normalize.
    • Sometimes, Cinacalcet ( inhibits PTH release)

  4. High phopsphorus:

  • Diet control ( no dairy products & MUKASSARAAT)
  • Phosphate binders : Sevelamer, Calcium carbonate

Dont forget to adjust the doses of all medicines in patients with renal failure.

LATEST DEVELOPMENTS

SGLT 2 INHIBITORS

  1. A group of drugs used to treat DM.
  2. Shown to have very good effects on chronic renal failure ( they slow the progression of renal failure, even in non DM patients)
  3. If CRF patient has proteinuria, start ACE plus SGLT2 inhibitors

Dietary Restrictions in CRF

  1. Protein restriction
  2. Salt & water restriction ( if needed)
  3. Potassium restriction
  4. Phosphorus restriction

RAPID FIRE QUES

  • 2 commonest causes of CRF?

  • Name some other causes?

  • Patient with CRF. Kidneys are palpable. What can be the cause?

  • How many stages of CRF?Z

  • Most complications occur below which stage?

  • Which renal hormone causes RBC production?

  • Why is there bone disease in CRF?

  • In CRF, what happens to serum K, Ca, and phospho?

  • In the early phases of CRF, what kind of hyperparathyroidism do you have?

  • What is the cause of this hyperpara?

  • What is the treatment of this hyperpara?

  • What is the etiology of anemia in CRF?

  • Name 3 most common presenting features of CRF?

  • In CRF, what complications can occur in the CVS & lungs?

  • Before giving erythropoeitin, what to correct first?

  • Aim of Hb in CRF? Why?

  • Name some complications/symptoms of CRF?

  • Which acid base disturbance in CRF? What is the treatment?

  • To do annual screening for CRF in high risk patients, which 3 things?

  • Name 3 methods of checking albumin in urine? Which is the best?

  • What to do if there is albuminuria?

  • Name the 3 step wise methods of CFR (caf?) treatment?

  • Fluid restriction LAAZIM in all CRF patients, right or wrong?

  • Name the 3 medicines to treat bone disease in CRF?

  • Whats the treatment of uremic pericarditis & uremic encephalopathy?

  • Chronic management of high K in CRF?

  • What happens to the skin if phosphorus is high?

  • What is tertiary hyperpara?

MEMORISE THIS FOR HOSP EXAM

HOW WILL YOU TREAT A PATIENT WITH CRF?

  • Control DM and HTN
  • Treat the underlying cause
  • Avoid renal damaging agents: NSAIDs, aminoglycosides, i.v. contrast
  • Low protein diet
  • Anemia: Fe and erythropoietin
  • Fluid overload: Diuretics, low salt and water
  • Proteinuria: ACE
  • Pericarditis only dialysis
  • Neuro symps only dialysis
  • Acidosis : Na bicarb tabs
  • Bone problems: Vit D, Calcium, sometimes cinacalcet ( to suppress PTH)
  • Finally, may be dialysis or transplant, if there is indication

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