week 2: pbl 2

Week 2: PBL 2

Manuel van Deventer

Week 2: PBL 2Sosobala 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.

• Name: Sosobala Mkhize

• Age: 40

• Marital Status: Widower

• Resident: Umzinto, Kwazulu Natal

Personal Details

• 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.

Social History

• No prior history of renal disease

• No previous history of confusion or memory loss

Past Medical History

Current Rx• Possibly self-medicates with herbal

remedies

White Plaque Confused, disoriented Dry mouth, flaccid skin

General Examination

• Blood Pressure: 90/50 lying;

• Pulse rate: 115/minute

• Jugular venous pressure was not raised with the patient lying flat

• CVS examination otherwise normal

CVS

• Bowel sounds present.

• No organomegaly or masses

• No bladder palpable

• Urinalysis: Oliguric

• Catheterisation produced a small amount of urine

Abdomen/UroGenital

InvestigationsFULL BLOOD COUNT & PLATELETS Reference Ranges

White Cell CountRed Cell Count HaemoglobinHaematocritMCVMCHMCHCRed Cell Distribution WidthPlateletsMean Platelet Volume

9.75.912.50.5486.32933.713.615610.2

x 109 / ℓx 1012 / ℓg / dℓℓ / ℓf ℓpgg/dℓ%x 109 / ℓf ℓ

4.00 - 10.00 4.89 - 6.11 14.3 - 18.3 0.43 - 0.55 79.1 - 98.9 27 - 32 32 - 36 11.6 - 14 137 - 373 7.0 - 11.4

Investigations

BIOCHEMISTRY Reference Ranges

Sodium Potassium Chloride Total CO2

Urea Creatinine PhosphateMagnesiumTotal ProteinAlbumin Creatine KinaseGlucoseHIV

1356.61011321.67701.60.811228963.2Pos

mmol / ℓmmol / ℓmmol / ℓmmol / ℓmmol / ℓμmol / ℓmmol / ℓmmol / ℓg/ℓg/ℓU / ℓmmol/l

135 - 147 3.3 - 5.3 99 - 113 18 - 29 2.6 - 7.0 60 - 120 0.8 - 1.4 0.65 - 1.1 60 - 85 35 - 52 25 - 195 4.1 - 5.6

Investigations

URINE BIOCHEMISTRY

Urine VolumeUrine SodiumUrine OsmolalityUrine CreatinineUrinary Myoglobin

3006026020negative

ml/24hmmol / ℓmOsmol/Kgmmol/l

Is this Acute / Chronic

Pre-Renal / Intrinsic

PrerenalUrea/Creat > 75U-Na < 10mmol/lFeNa < 1 %Urine:plasma Osmol

> 1.3

ATN

Urea/Creat < 75

U-Na > 20 mmol/l

FeNa > 1 %

Urine:plasma Osmo < 1.3

• Urea: 21.6 mmol/l

• Creatinine: 770 μmol/l

Urea / Creatinine

Urea 21.6 mmol/l

Creatinine 0.770 mmol/l=

= 28

ATN

UreaProtein

Amino acids

NH3

Cambamoyl phosphatase

Ornithine

Citruline Arginosuccinate

Arginine

Urea cycle

Aspartate

Glomerulus Proximal Tubule

Collecting duct

Distal Tubule

Urea

40-60 %

Creatinine

Creatine Phosphocreatine

Creatinine

Creatine Kinase

ATP ADP

• 60 mmol/l

U-Na

ATN

Fe-Na

FeNa = -------------- X --------------- X 100Urine [Na]

Plasma [Na]

Plasma [Cr]Urine [Cr]

FeNa = -------------- X --------------- X 10060

135

0.770

20

FeNa = 1.7 ATN

• 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

Osmolality

ATN

• Increased renal tubular cells and granular casts

U-Microscopy

ATN

Etiology of ATN in this patient

Electrolyte abnormalities

↑ Potassium

Pseudohyperkalaemia

K+ redistribution

K+ retention

Hemolysis

Thrombocytosis

Leukocytosis

Acidosis

Dehydration

Massive tissue Hypoxia

Insulin deficiency

Rhabdomyolysis

↓ K+ excretion

↓ Mineralocorticoids

Addison’sACE inhibitors

K+ sparing diuretics

AmilorideSpironolactone

↑ Potassium

High Anion GapMetabolic Acidosis

Normal Anion GapMetabolic Acidosis

DKA

Acute renal failure

Chronic Renal Failure

↓ mineralocorticoids

Obstructive uropathy

www.aafp.org/afp/20060115/283.html

↓ Potassium

Metabolic AlkalosisNormal Anion GapMetabolic Acidosis

Diuretic therapy

Vomiting

↑ Mineralocorticoids

Diarrhea

RTA

Cations = Anions

Cations - Anions

• Na+ + K+ – Cl- – HCO3-

↑ Unmeasured Anions (Proteins, PO43-, SO4

2-)

↑ 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

Anion Gap

http://upload.wikimedia.org/wikipedia/commons/a/a2/Renin-angiotensin-aldosterone_system.png

Na+

K+

H+

↑ Aldosterone

Distal Renal Tubule

Na+

K+

H+

↓ Aldosterone

Distal Renal Tubule

HyponatraemiaMeasure plasma

osmolality

↑ Increased Normal ↓ Decreased

↑ Increased other osmotically

active solutes

Pseudohyponatraemia

Assess ECF volume

Increased Normal Decreased

Renal loss Extrarenal loss

SIADH

H20

1. Clinically Euvolemia2. Plasma Osmolality < 270 mosmol/kg3. Hyponatraemie Na < 130 mmol/l4. Exclude

1. Cardiac2. Renal3. Thyroid4. Adrenal

5. Exclude1. Pituitary surgery2. Medication known to stimulate ADH

6. Urine Osmolality inappropriately high7. U-Na > 20 mmol/l

SIADH

↑ Na+

Hypervolaemia↑↑ Na+

↑ H20

Euvolaemia↑ Na+

Hypovolaemia ↓ H20

Hyperaldosteronism

Cushing’s

Hypertonic Saline

Salt Water Ingestion

Diabetes Insipidus U-Na > 20 U-Na < 10

Osmotic diuresis

Diuretic therapy and ↓ H20 intake

GIT Loss and ↓ H20 intake

• Bicarbonate (HCO3)

TCO2

↓ pH α ↓ HCO3

↓ PCO2

Total Protein

Rx

• Fluid management

• Avoid nephrotoxic drugs

Prevention

• Creatinine Clearance• = U*V

P

= 20 * 300/24/600.77

= 5.4 ml/min

Drug Dosaging

Rx of Complications

• Exchange resins – Kayexalate 30-60g po or pr 6hrly

• Insulin and dextrose

• Dialysis

Hyperkalaemia

Treated when:

•CO2 <15 and pH <7.2

•Bicarbonate

•Dialysis

Acidosis

• Complications of uremia

• What in the history and investigations of this patient suggestive of uremia

• Possible indications for dialysis

Uremia

• Aggressive diuresis if still passing urine

• Dialysis if oligoanuric

• Fluid restriction

Fluid Overload

• Acidosis (severe acidosis resistant to conservative measures)

• Electrolytes (Hyperkalemia resistant to conservative measures)

• Intoxication (alcohols and dialyzable drugs)

• Overload (of fluid)

• Uraemia

Indications for dialysis

Conclusion