WEEK 1: THE PATIENT WITH KIDNEY DISEASE

Question 1

State the predominant causes of kidney diseases.

Answer 1

1. Non-communicable diseases hypertension, diabetes and coronary artery disease.
2. HIV
3. Use of traditional medicine.

Question 2

State 6 functions of the kidney

Answer 2

1. Purification of blood/removal of waste products
   2.Regulation of fluid/electrolytes
2. Acido base buffer
3. Bones and minerals.
4. Blood pressure control
5. RBC production

Question 3

Describe how growth retardation can be a sign of kidney failure in children.

Answer 3

The kidney converts vitamin D into its active form which is essential for the absorption of calcium from food, growth of the bones and teeth and to keep bone healthy.

In kidney failure due to decreased active vitamin D, growth of bones is reduced, and they also become weak.

Question 4

How to diagnose kidney problems? What tests are normally performed?

Answer 4

To diagnose different kidney problems the doctor takes detailed history.

thoroughly examines the person, measures blood pressure and then advises appropriate tests.

Routinely performed and most useful tests are urine tests, blood tests and radiological tests.

Question 5

State the signs and symptoms of kidney failure.

Answer 5

1. High blood pressure - Hypertension
2. Oedema
3. Anemia
4. Loss of appetite, nausea, vomiting

Question 6

One way of detecting kidney failure is to do a Urinalysis.
What do we check for?

Answer 6

Hematuria
Proteinuria

Question 7

What is hematuria?

Answer 7

Strictly defined, hematuria is “blood in the urine.”

In conventional use, it means an abnormal number of red blood cells in the urine.

Question 8

State 6 main causes of hematuria.

Answer 8

1. Infections
   – Pyelonephritis cystitis
2. Glomerular
   – Glomerulonephritis
   – Hereditary glomerular diseases line thin basement membrane and Alport’s disease

Vasculitis
3. Interstitial
– AIN
– PKD
– Papillary necrosis

4.. Vascular
– Renal vein thrombosis –
– Malignant hypertension

5. Malignancy
   – Renal cell carcinoma
   – Transitional cell carcinoma
   – Carcinoma of prostate
6. Others
   – Calculi
7. Hypercalcemia
   – Hypercalciuria
   – Hyperuricemia
   – Coagulopathy

Question 9

State the main causes of hematuria amongst the following:

*0-20 yrs.
*20-49 yrs.
*40-60 yrs.
*Over 60 yrs.
-Males:
-Females:

Answer 9

*0-20 yrs. glomerulonephritis/UTI
*20-49 yrs. calculibladder and renal cell carcinoma
*40-60 yrs. urinary tract infection (more common in females)
*Over 60 yrs.

Males:
BPH
Bladder and renal cell carcinoma
Urinary tract infections

Females:
Urinary tract infectionsBladder and renal cell carcinoma

Question 10

Differentiate between glomerular and non- glomerular disease in causing hematuria.

Answer 10

• Glomerular disease is strongly associated with excretion of small (MCV <70 fL), misshapen (dysmorphic) poorly hemoglobinized (↓ MCHC) erythrocytes and excretion of erythrocyte containing casts
• Non-glomerular (urinary tract) disease is strongly associated with excretion of normal sized (MCV >90fL), normal-shaped (iso-or normomorphic), well hemoglobinized erythrocytes
• Glomerular disease is strongly associated with an increase in the urinary albumin to total protein ratio (on a “spot” urine)

Question 11

Commercial “dipsticks” detect 1-2 erythrocytes (in reality heme in erythrocytes) per HPF and are as sensitive as urinary sediment exams for detecting hematuria.

State some of the reason for false positive and false negative when using dipstick tests.

Answer 11

• False negative for erythrocytes) may occur with:

– Consumption of large amounts of Vitamin C:

Vitamin C, also known as ascorbic acid, can act as a reducing agent. In certain laboratory tests for erythrocytes, especially those that rely on oxidation-reduction reactions, high levels of vitamin C might interfere and lead to false-negative results.

• False positives (for erythrocytes) may occur with: – Semen contamination
  – Alkaline urine (pH >8.0)
  – Oxidizing agent contamination (cleansing agents) – Hemoglobinuria or myoglobinuria

Question 12

What is the normal urine protein excretion?
What is the most common urine protein?

Answer 12

PROTEINURIA and ALBUMINURIA
Normal urine protein excretion <100 – 150 mg/day
Most common urine protein is albumin

Question 13

Define the following terms:

Microalbuminuria.
Proteinuria.

Answer 13

Microalbuminuria is a medical term that refers to the presence of a small amount of albumin (a protein) in the urine.

Proteinuria: It is a general term for the presence of an abnormal amount of protein in the urine.

Question 14

UACR (Urine albumin to creatinine ratio) is a ratio of albumin to creatinine in a urine sample.

Unlike a dipstick test for albumin, UACR is unaffected by variation in urine __________.

State the units of measurement for UAGR.

What is the purpose of UACR?

State the UACR which represents albuminuria.

Answer 14

Measurement: Typically expressed in milligrams of albumin per gram of creatinine (mg/g).

Unlike a dipstick test for albumin, UACR is unaffected by variation in urine concentration.

Purpose: UACR is used to assess and quantify the amount of albumin in the urine, providing a more standardized measure that accounts for variations in urine concentration.

Albuminuria:
Definition: Albuminuria refers to the presence of an abnormal amount of albumin in the urine.

Diagnostic Marker for CKD: A UACR greater than 30 mg/g is considered indicative of albuminuria. This is often used as a marker for chronic kidney disease (CKD).

Question 15

Why do we care about GFR?

Answer 15

GFR is the best overall measure of kidney function.

The definition and classification system for CKD is based on level of GFR accurate estimation of GFR is central to the detection, evaluation and management of CKD.

Question 16

Outline the endogenous and exogenous filtration markers.

Answer 16

Endogenous
* Creatinine
* Urea
* Cystatin C

Exogenous
* Inulin
* 51Cr-EDTA
* 99mTc-DTPA
* 125I-iothalamate
* “Cold” iothalamate
* Iohexol

Question 17

What is chronic kidney disease?

Answer 17

A long-term condition where there is a gradual decrease in renal function and is irreversible.

Question 18

State the 3 components in the definition of CKD.

Answer 18

Definition of CKD – 3 Components
1. Anatomical or structural: with/out decreased GFR:
– pathologic abnormalities
– markers of kidney damage, including abnormalities in the composition of the blood or urine or abnormalities in imaging tests

2. Temporal component: > 3 months of abnormality
3. Functional component on its own: eGFR <60
   ml/min/1.73 m2, with or without kidney damage

Question 19

Describe the 5 stages of CKD.

Answer 19

Below shows the five stages of CKD and GFR for each stage:

Stage 1 with normal or high GFR (GFR > 90 mL/min)
Stage 2 Mild CKD(GFR = 60-89 mL/min)
Stage 3A Moderate CKD(GFR = 45-59 mL/min)
Stage 3B Moderate CKD (GFR = 30-44 mL/min)
Stage 4 Severe CKD (GFR = 15-29 mL/min)
Stage 5 End Stage CKD(GFR <15 mL/min)

Question 20

Differentiate between acute and chronic kidney disease.

Answer 20

Onset and Duration:

Acute Kidney Injury (AKI):
Develops suddenly over a short period, typically within hours to days. It is characterized by a rapid decline in kidney function.

Chronic Kidney Disease (CKD):
Develops gradually over an extended period, often over months to years. CKD is a long-term condition marked by a progressive decline in kidney function.
Cause:

Acute Kidney Injury (AKI):
Often results from sudden events or conditions that affect kidney function, such as severe infections, dehydration, major surgeries, medications, or conditions that disrupt blood flow to the kidneys.

Chronic Kidney Disease (CKD):
Typically caused by long-term conditions or diseases that slowly damage the kidneys, such as diabetes, hypertension, glomerulonephritis, and polycystic kidney disease.

Symptoms:

Acute Kidney Injury (AKI):
Symptoms may include decreased urine output, fluid retention (edema), fatigue, nausea, and confusion. Symptoms can develop rapidly.

Chronic Kidney Disease (CKD):
Early stages may not exhibit noticeable symptoms. As CKD progresses, symptoms may include fatigue, swelling, changes in urine output, and hypertension.

Reversibility:

Acute Kidney Injury (AKI):
In many cases, AKI is reversible with prompt and appropriate treatment. Once the underlying cause is addressed, kidney function may improve.

Chronic Kidney Disease (CKD):
CKD is generally considered irreversible, and the goal of management is to slow down its progression, manage symptoms, and prevent complications.

Diagnosis:

Acute Kidney Injury (AKI):
Diagnosis is based on sudden changes in kidney function, often measured by increased serum creatinine levels and decreased urine output.

Chronic Kidney Disease (CKD):
Diagnosis involves assessing kidney function over an extended period, typically based on laboratory tests measuring creatinine levels, estimating glomerular filtration rate (GFR), and detecting markers like albuminuria.

Treatment:

Acute Kidney Injury (AKI):
Treatment involves addressing the underlying cause, supportive care, and sometimes interventions like fluid resuscitation or dialysis.

Chronic Kidney Disease (CKD):
Treatment focuses on managing underlying conditions contributing to CKD, controlling blood pressure, maintaining a healthy lifestyle, and addressing complications. In advanced stages, treatments like dialysis or kidney transplantation may be necessary.

Question 21

Name the 2 Creatinine and urea are two important waste products, the amount of which in human body can easily be measured.

Their ‘value’ in blood reflects the function of the kidney.

State their normal values.

Answer 21

Creatinine and urea are two important waste products, the amount of which in human body can easily be measured. Their ‘value’ in blood reflects the function of the kidney. When both the kidneys fail, value of creatinine and urea will be high in blood test.

When the kidney function slows down, blood levels of creatinine and urea rise.

Normal value of serum creatinine is 0.9 to 1.4 mg/dl and normal value of blood urea is 20 to 40 mg/dl.

Question 22

State the Cockcroft and Gault equation for calculating creatinine clearance.

Answer 22

For men:
Creatinine Clearance (ml/min)
(140 − age) × weight (kg) / serum creatinine (mg/dL)
× 72
​

For women:
Creatinine Clearance (ml/min)
[(140 − age) × weight (kg) / serum creatinine (mg/dL)
× 72] × 0.85

Question 23

State the diagnostic tests for kidney disease.

Answer 23

1. Urine Tests
   Different urine tests provide useful clues for the diagnosis of different kidney disease.
   Routine urine tests
   It is a simple, inexpensive and very useful diagnostic test.
   Abnormality seen in urine tests provides important diagnostic clues
   normal urine report does not rule out kidney problems.
   Presence of protein in urine (proteinuria) is seen in various kidney diseases. It should never be neglected. Presence of protein in urine can be the first, the earliest and the only warning sign of chronic kidney disease (and even of heart disease). For example proteinuria is the first sign of kidney involvement in diabetes.
   Presence of pus cells in urine indicates urinary tract infection (UTI).
   Presence of protein and red blood cells provide diagnostic clue for inflammatory kidney disease (i.e. glomerulonephritis).
2. Blood Tests
   Various blood tests are necessary to establish proper diagnosis of different kidney problems.
   Creatinine and Urea
   Blood levels of creatinine and urea reflects the function of the kidneys. Creatinine and urea are two waste products which are removed from the blood by the kidney. When the kidney function slows down, blood levels of creatinine and urea rise. Normal value of serum creatinine is 0.9 to 1.4 mg/dl and normal value of blood urea is 20 to 40 mg/dl. Their higher values suggest greater damage to kidney. Creatinine level is a more reliable guide of kidney function than blood urea level.
3. Other blood tests
   Different blood tests frequently performed in kidney patients are: blood sugar, serum protein, cholesterol, electrolytes (sodium, potassium and chloride), calcium, phosphorous, bicarbonate, ASO titer, complement etc.
4. Radiological Tests
   Ultrasound of kidney
   Ultrasound is a simple, useful, quick and safe test which provides valuable information such as the size of kidney and the presence of cyst, stone and tumors. An ultrasound can detect blockage to urine flow anywhere in the kidney, ureters, or bladder. In chronic kidney failure both kidneys are usually found to be small in size.
   X-ray of abdomen
   This test is useful for the diagnosis of stone in the urinary system.
5. Other Special Tests
   Kidney biopsy, cystoscopy and urodynamics are special tests which are necessary for the exact diagnosis of certain kidney problems.
   Kidney Biopsy
   Kidney biopsy is an important test useful in the diagnosis of certain kidney diseases.
   A kidney ultrasound is a simple and safe test used to assess the size, shape, and location of the kidneys.