Medical Emergencies: Uraemic and Renal Emergencies

 

Uraemic and Renal Emergencies

 Decide whether the patient has acute renal failure or chronic renal failure. If chronic renal failure search for any acute reversible element of like sepsis., dehydration, uncontrolled hypertension, obstruction or nephrotoxic drugs; in other words, does the patient have ‘acute or chronic renal failure’?

Acute Renal Failure (ARF)

Causes:

1.       Hypoperfusion of kidney (Pre-renal Failure)

-          Shock, severe dehydration, blood loss, trauma

2.       Obstruction to flow of urine (post-renal failure)

-          Stones, enlarged prostate, carcinoma, slough papilla.

3.       Renal parenchymal disease

-          Acute vascular disorders: malignant hypertension, polyarteritis nodosa (PAN), vasculitis

-          Acute tubular necrosis (vasomotor nephropathy)

-          Leptospirosis

-          Drugs (gentamicin, amikacin, cephalosporins, streptomycin, neomycin)

-          Interstitial nephritis: leptospirosis, drugs, toxins

The patient with ARF is usually not anaemic (unless due to blood loss)

Search for “Reversible Treatable” Chronic Disease:

1.       Vesico-ureteric reflux, analgesic, renal tuberculosis

2.       Hypercalcemia, hypokalemia

3.       Drugs, chemicals

4.       Obstruction – stones, enlarged prostate.

Search for “Reversible Factors” – ‘Acute Elements’: -

1.       Urinary tract infection, sepsis elsewhere

2.       Dehydration salt depletion

3.       Uncontrolled hypertension

4.       Obstruction due to stones, papillary necrosis

5.       Drugs – non-steroidal anti-inflammatory drugs (NSAID), gentamicin, amikacin, cephalosporins, streptomycin, neomycin

KUB X-ray and ultrasound of kidney are helpful in distinguishing the patient with Acute Renal Failure vs Chronic Renal Failure

Management of Acute Renal Failure:

1.       Anuric Patient

Exclude obstruction: if confirmed, refer surgeon for cystoscopy and retrograde pyelogram or antegrade pyelogram to determine cause and site of obstruction. Percutaneous nephrostomy is a useful way to relieve obstruction. It allows time for the surgeon to plan an elective operation.

2.       Non-Oliguric Renal Failure

 

Look for pre-renal factor (dehydration, sepsis. Nephrotoxic drugs).

3.       Oliguric Phase of ARF

 

a)       Fluid and electrolyte balance – 500 ml / day. Check electrolyte, intake / output.

b)      No fruits and fruit juices

c)       Anemia – transfuse with packed cells to avoid fluid overload

d)      Treat infection – antibiotics (dose important) and avoid nephrotoxic agents.

e)      Treat hypertension, heart6 failure

f)        Dialysis – for uremic symptoms, hyperkalemia, severe acidosis, pulmonary edema

N, B. If using gentamicin or amikacin – monitor levels to avoid renal damage and ototoxicity.

Management of Chronic Renal Failure:

1.       Hyperkalemia (Se K+ 6 E/l or more)

a)       IV 10 units soluble insulin + 50 cc of 50% dextrose, bolus dose

b)      Commence oral Resonium A 15 gm., 8 hourly.

c)       If patient can’t take orally commence Resonium retention enema 30 gm, 8 hourly

d)      Also give IV calcium gluconate 10 cc slowly to combat effects of hyperkalemia on the heart.

e)      Repeat Se K+ 4 hour later, Repeat treatment if necessary.

f)        If K + still high, consider dialysis.

2.       Hyponatremia

If Dilutional Hyponatremia: (↑ JVP, edema, crepitation in lungs)

 

a)       Give large doses of Lasix 240 mg. t.d.s. or more(small doses of Lasix are inadequate in renal failure). Bumetamide oral or IV is a useful agent. It has 40 times the potency of Lasix.

b)      Restrict fluids to less than 500 mls / day.

If salt depletion – replace salt.

Sodium Deficit

If body weight less than 65 kg and Se Na+ 120 mE / L

Na” Deficit = 140 – 120 = 20 mE / L

Body water = 60 % pf BW

Hence Na + deficit = 65 x 60/100 x 20 = 780 mE = 5 liters of 0.9 NaCl

(1 litre 0.9 % NaCl = 154 mE or Na+

Oral 1 gm NaCl = 17 mE.

1 litre 3 % NaCl = 512 mE of Na+

Give ½ the calculated Na+ deficit in 24 hours. Repeat Se Na+ next day using the same calculation. See how much more Na+ is needed. Do not be in a hurry to correct as there is a risk of pontine myelinolysis.

3.       Hypertension

a)       If diastolic BP 120 mmHg or more, give 10 mg Nifedipine sublingually: repeat 4 hourly prn.

b)      Or use IV or IM hydralazine 25 mg or 50 mg 4 hourly.

 

At the same time, start Nifedipine 10 mg t.i.d. or if patient is not in congestive heart failure, start propranolol or atenolol and hydralazine or prazosin

4.       Uraemic Acidosis

Correct id Se bicarb less than 15 mE/ L. Formula:

One-third X BW (kg) x Bicarb deficit (25 – Se Bicarb) = x mls 8.4 % NaHCO

If patient is overloaded do not give NaHCO, as this will precipitate pulmonary edema. Dialysis is the safest and best way to correct acidosis. Steam bath may also be an alternative option.

5.       Anemia

 

No urgency to correct unless Hb less than 6 gm or patient has symptoms. Give 1 unit of packed cells. If patient is overloaded delay transfusion. Best time to give blood is during dialysis

 

6.       Uremic Fit

Give IV valium 10 mg.

Check Se Na+. Se calcium, blood glucose and correct if abnormal.

Indication for Dialysis:

1.       Uraemic symptoms, hyperkalaemia, pulmonary edema.

2.       Tide patient over while diagnosis is being made.

3.       Acute or chronic renal failure, tide patient over acute element.

4.       Patient being considered for dialysis or transplantation programme or plans uncertain.

 

The mode of Dialysis can be acute Peritoneal Dialysis (PD) or Acute Hemodialysis (HD)

Acute Peritoneal Dialysis:

1.       Acute Peritoneal Dialysis can be performed by the bedside in the ICU as an emergency procedure> It is important to observe asepsis to prevent peritonitis.

2.       Catheterize the urinary bladder in order to avoid accidental puncture of the bladder by the PD catheter.

3.       Clean the abdomen and create ascites by infusing 2 L dialysate.

4.       With the patient tensing the abdomen. Insert the PD catheter through the anesthetized area.

5.       The usual point of insertion is in the midline about 3 to 4 cm below the umbilicus.

6.       Creation of ascites is necessary to avoid puncture of the intestines.

7.       Avoid closed PD if patient has previous abdominal surgery, has bleeding tendency or thrombocytopenia.

8.       For difficult cases, the surgeon can always insert a Tenckhoff PD catheter via open insertion under the direct vision. Patients with bleeding tendency can have fresh frozen plasma or platelet transfusion prior to surgery.

Acute Hemodialysis

1.       An alternative to PD is Acute Hemodialysis

2.       This is quick and efficient but requires the support of a renal physician and the HD machine

3.       A subclavian catheter can be  introduced into the subclavian vein or a femoral catheter inserted into the femoral vein to allow vascular access for hemodialysis (heparin-free dialysis) if indicated.

AV Hemofiltration

1.       Patients with unstable hemodynamics e.g., Acute Pulmonary Edema / Septicemia Shock can be treated with continuous arterio-venous hemofiltration (CAVH).

2.       This provides an efficient method of rapid fluid removal for the patient in the ICU setting with unstable cardiovascular hemodynamics and low blood pressure but who is in severe  fluid overload in greater danger of dying from pulmonary odema.

3.       Hemofiltration is effected by means of a hemofilter and the necessary blood lines and a vascular access (subclavian or femoral catheterization). A hemodialysis machine is not needed.

Source / Reference / Further Reading:

1.       PH Feng, KM Fock. Philip Eng: Handbook of Acute Medicine

2.       David M. Cline, O. John Ma, Judith E. Tintinalli, Ernest Ruiz, Ronald L. Krome: Emergency Medicine: Companion Handbook

3.       Richard Robinson & Robin Stott: Medical Emergencies: Diagnosis and Management

4.       Sonke Mulle: Memorix Emergency Medicine