Abnormal urinalysis

Medicine > Renal

Differential Diagnosis Schema 🧠

Infective Causes

Urinary Tract Infection (UTI): Dysuria, frequency, urgency, and suprapubic pain.
Pyelonephritis: Flank pain, fever, and chills, with or without lower UTI symptoms.
Sexually Transmitted Infections (e.g., Chlamydia, Gonorrhoea): Dysuria, urethral discharge, or pelvic pain.

Glomerular Causes

Glomerulonephritis: Haematuria (often microscopic), proteinuria, hypertension, and possible oedema.
IgA Nephropathy: Episodic macroscopic haematuria often after an upper respiratory tract infection.
Post-Infectious Glomerulonephritis: Usually presents with haematuria and proteinuria after a streptococcal infection.
Rapidly Progressive Glomerulonephritis: Rapid decline in renal function with crescent formation on biopsy, haematuria, and proteinuria.

Tubular and Interstitial Causes

Acute Tubular Necrosis: Muddy brown casts in urine, often following ischaemia or nephrotoxin exposure.
Acute Interstitial Nephritis: Eosinophils in urine, fever, rash, and recent exposure to new medication (e.g., NSAIDs, antibiotics).
Chronic Interstitial Nephritis: Slow progression with mild proteinuria and decreased concentrating ability.

Vascular Causes

Renal Artery Stenosis: Hypertension that is resistant to treatment, possible abdominal bruit.
Atheroembolic Disease: Acute renal failure following a vascular procedure, possible livedo reticularis.
Malignant Hypertension: Severe hypertension with haematuria, proteinuria, and end-organ damage.
Thrombotic Microangiopathy: Microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury.

Metabolic and Systemic Causes

Diabetes Mellitus: Glycosuria and possible ketonuria, polyuria, and polydipsia.
Multiple Myeloma: Proteinuria (Bence-Jones proteins), normocytic anaemia, and hypercalcemia.
Systemic Lupus Erythematosus: Proteinuria, haematuria, and systemic symptoms such as rash and arthralgia.
Rhabdomyolysis: Myoglobinuria, raised CK levels, and muscle pain/weakness.
Hypercalcaemia: Polyuria and nephrocalcinosis.
Sickle Cell Disease: Haematuria, proteinuria, and possible renal papillary necrosis.

Key Points in History 🥼

Presenting Symptoms

Dysuria: Suggests UTI or sexually transmitted infections.
Frequency/Urgency: Common in UTIs, bladder irritants, or diabetes.
Haematuria: Can indicate glomerulonephritis, malignancy, or stones.
Oliguria/Anuria: Can suggest acute kidney injury or obstruction.
Polyuria/Nocturia: Common in diabetes, hypercalcemia, or diuretic use.
Frothy urine: Indicative of significant proteinuria, often seen in nephrotic syndrome.

Background

Past Medical History: History of diabetes, hypertension, or autoimmune diseases can suggest chronic kidney disease or nephropathy.
Drug History: Recent NSAID or antibiotic use may suggest acute interstitial nephritis.
Family History: Family history of polycystic kidney disease or hereditary nephritis (Alport syndrome).
Social History: Occupational exposure to nephrotoxins, recreational drug use (e.g., cocaine can cause rhabdomyolysis), and high-risk sexual behaviour (consider STIs).

Possible Investigations 🌡️

Urinalysis

Dipstick Analysis: Presence of leukocytes, nitrites, blood, protein, glucose, ketones, and pH. Useful for initial screening.
Microscopy: Identifies red blood cells, white blood cells, casts, crystals, and bacteria. Essential for diagnosing conditions such as glomerulonephritis or infection.
Culture and Sensitivity: Confirms infection and guides antibiotic treatment.

Blood Tests

Urea and Electrolytes (U&E): Assesses kidney function, electrolyte imbalance, and signs of acute or chronic kidney disease.
Full Blood Count (FBC): Detects anaemia, infection, and signs of systemic disease (e.g., eosinophilia in AIN).
C-Reactive Protein (CRP)/Erythrocyte Sedimentation Rate (ESR): Raised in infection, inflammation, or vasculitis.
Liver Function Tests (LFTs): May be altered in systemic conditions affecting multiple organs.
Autoantibody Screen: ANCA, ANA, Anti-GBM, and other specific antibodies for autoimmune causes.
Serum Calcium and Phosphate: To investigate hypercalcemia or hypophosphatemia related causes of renal disease.
Creatinine Kinase: Elevated in rhabdomyolysis.

Imaging

Ultrasound: First-line imaging for assessing kidney size, structure, and presence of obstruction or stones.
CT Scan: Useful for identifying renal stones, masses, and complications like abscesses.
MRI: Often used in more complex cases or where detailed anatomical information is needed (e.g., renal vein thrombosis).
Intravenous Urography: Occasionally used in structural abnormalities, though largely replaced by CT and MRI.

No comments yet 😉

Leave a Reply Cancel reply

You must be logged in to post a comment.

Don't take our word for it

"The stations you provide are strikingly similar to those I came across during my medical school finals (some even verbatim!), and I have tried many other exam platforms. I'm truly grateful for your priceless support throughout my final couple of years at medical school!"

Raza Q 🇬🇧

"It has absolutely everything for medical school, so many histories with detailed differential diagnoses, how to approach emergencies, commonly prescribed drugs..every kind go examination you’ll ever need in osces"

John R 🇬🇧

"Thank you SO MUCH for the amazing educational resource. I’ve tried lots of platforms and books with mock OSCE stations and yours is by far and away the best I’ve tried"

Ed M 🇳🇿

"Get this right away. So helpful for OSCEs but also general clinical learning and understanding. Wish I had brought it sooner"

Emma W 🇬🇧

"Without a doubt, your platform outshines all other OSCE resources currently available. In all honesty, I can confidently attribute my success in securing a distinction in my finals to OSCEstop."

Harish K 🇬🇧

"OSCEstop distinguishes itself from many other platform banks by offering a wealth of questions that mimic the demanding and complex aspects of our finals. This platform played a crucial role in ensuring I was ready for the level of difficulty that awaited me in my final exams."

Natasha W 🇳🇿

😃 More:

📖 Learning notes: 247

🏥 Stations available: 207

🧠 Qbank questions: 2255