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Week 2: PBL 2 Manuel van Deventer
Week 2: PBL 2 Sosobala Mkhize, a forty year old widower who works as a herbalist, is brought into casualty by his daughter. She says that he had been suffering from a white painful plaque in his mouth for three weeks and that he had just returned from a one week visit to his homeland in search for medicinal herbs. Over the past three days he had not eaten anything and drank only a small amount of fluid, this morning, when she went to take him to his shop, she found him weak and unable to coherently explain what was happening. On admission he was intermittently confused. His blood pressure was found to be low and an IV saline was commenced. On catheterisation of his bladder, very little urine was drained.
Personal Details • Name: Sosobala Mkhize • Age: 40 • Marital Status: Widower • Resident: Umzinto, Kwazulu Natal
Social History • Mr Mkhize is herbalist. • Since his wife died he has lived with his daughter in a small town in the KwaZulu Natal • He is independent in all activities. • Smoked up until the age of 30. • Drinks 3 or 4 beers per week.
Past Medical History • No prior history of renal disease • No previous history of confusion or memory loss Current Rx • Possibly self-medicates with herbal remedies
General Examination • White Plaque • Confused, disoriented • Dry mouth, flaccid skin
CVS • Blood Pressure: 90/50 lying; • Pulse rate: 115/minute • Jugular venous pressure was not raised with the patient lying flat • CVS examination otherwise normal
Abdomen/UroGenital • Bowel sounds present. • No organomegaly or masses • No bladder palpable • Urinalysis: Oliguric • Catheterisation produced a small amount of urine
Pre-Renal / Intrinsic Prerenal Urea/Creat > 75 U-Na < 10mmol/l FeNa < 1 % Urine:plasma Osmol > 1.3 ATN Urea/Creat < 75 U-Na > 20 mmol/l FeNa > 1 % Urine:plasma Osmo < 1.3
Urea / Creatinine • Urea: 21.6 mmol/l • Creatinine: 770 μmol/l Urea 21.6 mmol/l Creatinine 0.770 mmol/l = = 28 ATN
Protein Distal Tubule Amino acids Glomerulus Proximal Tubule NH3 Urea Cambamoyl phosphatase Ornithine Arginine Urea cycle 40-60 % Citruline Arginosuccinate Collecting duct Aspartate Urea
Creatinine Creatine Kinase Creatine Phosphocreatine ATP ADP Creatinine
U-Na • 60 mmol/l ATN
Fe-Na Urine [Na] Plasma [Cr] FeNa= -------------- X --------------- X 100 Plasma [Na] Urine [Cr] 60 0.770 FeNa= -------------- X --------------- X 100 135 20 FeNa= 1.7 ATN
Osmolality • Measured Osmolality • Freezing point depression • Calculated Osmolality • 2 Na + Urea + Glucose = 2(135) + 22 + 3 = 295
Osmolality • U-Osmolality = 260 • = 260/295 = 0.88 • Also U Osmo < 350 ATN
U-Microscopy • Increased renal tubular cells and granular casts ATN
Anion Gap Cations = Anions Cations - Anions • Na+ + K+ – Cl- – HCO3- ↑ Unmeasured Anions (Proteins, PO43-, SO42-) ↑ Anion Gap
Anion Gap 135 + 6.6 – 101 – 13 = 27.6 ↑
Anion Gap • M = Methanol toxicity • U = Ureamia of renal failure • D = Diabetes Mellitus • P = Paraldehyde toxicity • I = Isoniazid / Iron toxicity / Ischemia • L = Lactic acidosis • E = Ethylene glycol toxicity • S = Salicylate toxicity
http://upload.wikimedia.org/wikipedia/commons/a/a2/Renin-angiotensin-aldosterone_system.pnghttp://upload.wikimedia.org/wikipedia/commons/a/a2/Renin-angiotensin-aldosterone_system.png
↑ Aldosterone Distal Renal Tubule Na+ K+ H+
↓ Aldosterone Distal Renal Tubule Na+ K+ H+
SIADH H20
SIADH • Clinically Euvolemia • Plasma Osmolality < 270 mosmol/kg • Hyponatraemie Na < 130 mmol/l • Exclude • Cardiac • Renal • Thyroid • Adrenal • Exclude • Pituitary surgery • Medication known to stimulate ADH • Urine Osmolality inappropriately high • U-Na > 20 mmol/l
TCO2 • Bicarbonate (HCO3) ↓ pH α ↓ HCO3 ↓PCO2
Prevention • Fluid management • Avoid nephrotoxic drugs
Drug Dosaging • Creatinine Clearance • = U*V P = 20 * 300/24/60 0.77 = 5.4 ml/min
Hyperkalaemia • Exchange resins – Kayexalate 30-60g po or pr 6hrly • Insulin and dextrose • Dialysis
Acidosis Treated when: • CO2 <15 and pH <7.2 • Bicarbonate • Dialysis
Uremia • Complications of uremia • What in the history and investigations of this patient suggestive of uremia • Possible indications for dialysis
Fluid Overload • Aggressive diuresis if still passing urine • Dialysis if oligoanuric • Fluid restriction
Indications for dialysis • Acidosis (severe acidosis resistant to conservative measures) • Electrolytes (Hyperkalemia resistant to conservative measures) • Intoxication (alcohols and dialyzable drugs) • Overload (of fluid) • Uraemia