Investigations in Renal Medicine

Question 1

What are the Functions of the kidneys?

Answer 1

Regulate Extracellular Fluid (ECF) Volume and Electrolyte composition to compensate for wide daily variations in Water and Electrolyte intake
Regulation of water
Regulation of Electrolyte
Regulation of Acid-Base balance, which involves maintaining the pH (acidity/alkalinity) in body fluids
Excretion of metabolic waste products (of Protein and Nucleic acid): Urea, Creatinine, Creatine, Uric acid, Sulphate and Phosphate
Hormonal functions eg AVP, Aldosterone, Erythropoietin, Parathyroid Hormone (PTH)

Question 2

What are the ways of Renal Function Assessment

Answer 2

Can be done by assessing biochemical abnormalities in blood or urine.
Or by imaging modalities

Question 3

Discuss Sample Collection

Answer 3

1st morning specimen is preferred to assess renal parenchymal pathology

Mid-stream urine(clean catch)- for microbiological samples

Catheter urine

Suprapubic aspiration

Question 3

Discuss urinalysis

Answer 3

A simple initial test for renal function assessment

Gross physical properties , biochemical properties and microscopic appearance should be examined.

Color, Odor, Appearance, Concentration (specific gravity)

Protein, Glucose, Urine pH

Cellular elements eg red blood cells, white blood cells, and epithelial cells), Bacteria, Crystals, Casts

Question 4

Discuss Dipstick Testing and its drawbacks

Answer 4

Dipstick testing of urine provides a quick assessment of urine pH, specific gravity, and the presence of protein, blood, glucose, and bile.

Drawbacks:

Its semi-quantitative

Dipstick testing detects only albumin at concentration more than 250 mg/L. Separate sticks are available for microalbuminuria.

False-positive dipstick results for proteinuria are seen when urine pH is > 8, and when the patient is on penicillins, aspirin or oral hypoglycemic agents.

False-negative tests for detection of haemoglobin occurs with ingestion of ascorbic acid.

Question 5

Discuss various apperances of urine

Answer 5

Normal is pale amber but depends on level of hydration
Cloudy urine: leucocytes, epithelial cells, or bacteria.
Dark urine: blood, hemoglobinuria or myoglobinuria
Dark yellow/brown: conjugated hyperbilirubinaemia
Red urine: Beetroot
Orange urine: Rifampicin

Question 5

Discuss various apperances of odor

Answer 5

• No odour or ammoniacal smell if concentrated
• Offensive odour: usually denotes infection (bacterial ammonium production).
• Sweet smelling urine suggests ketones.
• Sweaty feet urine - Isovaleric acidemia
• Musty smell- PhenylKetonuria
• Maple syrup: maple-syrup urine disease