Case 3- Illness

Question 1

Nephritic syndrome

Answer 1

Nephritis causes inflammation which increases the permeability of the filtration membrane. More water, proteins, and blood can leak across so can cause haematuria, proeteinuria and hypertension. Red blood cell casts are present

Question 2

Nephrotic syndrome

Answer 2

Increases permeability so large amounts of proteins can go across the barrier. In response the liver produces more lipoproteins. Causes proteinuria, hypoalbulminemia and oedema. Diagnosed with dipstick

Question 3

Hyponatraemia

Answer 3

Too low sodium in the blood <135mM. Causes low plasma osmolarity

Question 4

Hypernatremia

Answer 4

Too high levels of sodium in the blood >145mM. Causes high plasma osmolarity

Question 5

Major causes of Hyponatraemia- Hypoaldosteronism

Answer 5

Due to lack of aldosterone which causes Na reabsorption. Causes include Addison’s disease and adrenal insufficiency

Question 6

Major causes of Hyponatraemia- thiazide diuretics

Answer 6

Inhibit a coupled NaCl cotransporter leading to a decrease in Na reabsorption

Question 7

Other causes of Hyponatraemia

Answer 7

1) Vomiting/diarrhoea/sweating- disturbance in salt balance
2) Excess water intake
3) When formula milk is made with more water then recommended when access to formula is restricted i.e. in poverty

Question 8

Causes of Hypernatraemia- salt balance

Answer 8

Too much salt in diet, too much saline in the IV. Hyperaldosteronism (too much aldosterone promoting the absorption of sodium). Hyperaldosteronism can be due to a tumour in the adrenal gland

Question 9

Causes of Hypernatraemia- water balance

Answer 9

When there is decreased water intake. Could be because the patient is unconscious, a lack of access to water and vomiting. When there is increases insensible loss of water in exercise. Can be sensible losses such as vomiting/diarrhoea and no ADH due to diabetes insipidus

Question 10

Syndrome of inappropriate ADH secretion- SIADH

Answer 10

Excessive ADH secretion leads to a high urine osmolality which increases total body water. This leads to hyponatremia, hypo-osmotic blood plasma and hypervolemia. The kidney recognises the increase in blood volume so reduces its production of Renin. This causes a decrease in Angiotensin 2 which decreases Mineralocorticoid production which decreases sodium absorption in the blood. Meaning there is more sodium in urine so Hyponatremia gets worse. Can be causes by stress, head trauma, tumours and some drugs (opiods, anti-depressants and nitocine)

Question 11

Diabetes insipidus

Answer 11

Non-functional ADH system which results in excessive loss of water. Can cause Polyuria (urinating more), polydipsia (wanting to drink more), hypernatremia and hypotension.

Question 12

The 2 types of diabetes insipidus

Answer 12

Neurogenic DI- failure of ADH secretion, can be due to lesions or tumours in the hypothalamus or pituitary, so no signals are sent out. To treat this you provide synthetic ADH.
Nephrogenic DI- the failure of the principal cells to respond to ADH, caused by V2 receptor mutation which binds to ADH setting up the camp signalling cascade. Treat with a restricted Na+ diet.

Question 13

Thiazide diuretics- renal

Answer 13

Most commonly prescribed diuretic. Inhibit the Na+/Cl- cotransporter in the early DCT on the apical surface. Promotes sodium excretion by blocking reabsorption. This increases the osmolarity of the filtrate, more water remains in the filtrate and is excreted. Example of thiazides= chortalidone and indapamide.

Question 14

Loop diuretics

Answer 14

Works on the thick ascending limb of the loop of Henle. They antagonise the Na+/K+/2Cl- cotransporter and inhibit its action. Promotes sodium excretion by blocking its reabsorption. This increases the osmolarity of the filtrate so more water remains to be excreted. Example- Furosemide and bumetanide.

Question 15

Potassium sparing diuretics

Answer 15

Work on principal cells found in the late distal convoluted tubule and in the collecting duct. They fall into two main classes: aldosterone antagonists such as Spironolactone. And we also have ENaC antagonists such as Amiloride.

Question 16

Aldosterone antagonists

Answer 16

Prevents aldosterone from binding to the mineralocorticoid receptors. Sodium is unable to be reabsorbed, so more sodium and water is excreted as water follows sodium. Potassium channels are also not created so stops K+ from being transported to the filtrate and excreted, so K+ is spared.

Question 17

How do aldosterone antagonists spare K+

Answer 17

It is able to “spare” K+ because the Na+/K+ ATPase is not created so the potassium cannot be moved from the interstitium into the principal cells. As there is less sodium it is less likely Na+ and K+ will be exchanged using this pump. The net charge of the filtrate becomes more positive so there is no concentration gradient for K+ to move from the principal cells to the tubular fluid.

Question 18

ENac antagonists

Answer 18

Prevent the formation of ENaC channels in the principal cells of the late DCT and collecting duct. Preventing the reabsorption of sodium from the filtrate promoting its excretion. “Spares” K+ in the same way as Aldosterone antagonists.

Question 19

Hypokalaemia

Answer 19

When the Potassium levels are below 4mM. Cells become more negative and less sensitive to depolarisation. Can lead to muscle weakness and paralyses (calcium channels dont open and no nerve impulses). As well as abnormal neural conduction leading to confusion and coma. There will also be decreased cardiac excitability.

Question 20

Hyperkalaemia

Answer 20

When extracellular K+ levels are above 5mM.They are more excitable meaning they depolarise more; this can lead to cardiac arrhythmias and increased risk of cardiac arrest. Also causes abnormal neuronal conduction.

Question 21

Causes of Hypokalaemia

Answer 21

When they are unable to obtain or digest food, when their diet is deficient in K+. Can be lost in increased sweating, vomiting and diarrhoea. Patients on loop diuretics or increased Aldosterone levels will stimulate K+ loss. Alkalosis or administration of insulin where K+ moves from the extracellular to intracellular

Question 22

Effects of Hypokalaemia

Answer 22

1) Neuromuscular manifestations- muscle weakness, fatigue, cramps and tenderness. This can lead to Paraesthesia and paralysis.
2) Renal manifestations- polyuria, urine with low osmolality and polydipsia.
3) Gastrointestinal manifestations- anorexia, nausea and vomiting as well as constipation, abdominal distention and paralytic ileus.
4) Cardiovascular manifestations- arrhythmias and increased sensitivity to digitalis toxicity. Can also cause metabolic alkalosis

Question 23

Causes of Hyperkalaemia

Answer 23

Increased dietary intake, people with poor renal function may not be able to compensate for this. Decreased renal function, treatment with potassium sparing diuretics or decreased Aldosterone levels (Addison’s disease). Can also be due to a transcellular shift where K+ moves from the intracellular to the extracellular. This can be due to metabolic acidosis, can be a response to extreme exercise or seizures or tissue injury (burns or crushing). When you get a tissue injury, cells will be damaged and break up releasing the intracellular K+ causing an increase in plasma K+. Insulin is administered to reabsorb the K+

Question 24

Effects of Hyperkalaemia

Answer 24

1) Gastrointestinal manifestations- anorexia, nausea, vomiting, diarrhoea
2) Cardiovascular manifestations- ventricular fibrillation and cardiac arrest
4) Neuromuscular manifestations- paraesthesia, muscle cramps, weakness and tiredness.
Can also cause metabolic acidosis

Question 25

Risk factors of a UTI

Answer 25

Female, increased age, recent antibiotic use (destruction of normal bacteria flora), recent sexual activity, new sexual partner, use of spermicide, diabetes, presence of catheter (CAUTI- catheter associated urinary tract infection). Institutionalisation, for example, being in a care home or hospital for a long time. Pregnancy as well

Question 26

Uncomplicated UTI

Answer 26

Woman can develop a UTI when they are healthy and have no abnormalities. When the infection is in a structurally and neurologically normal urinary tract

Question 27

Why are women more likely to get UTI’s

Answer 27

They have a small urethra and their vagina is near the anus

Question 28

Complicated UTI

Answer 28

A UTI when there are abnormalities in the urinary tract. Can be caused by diabetes, kidney stones, blockages and developmental abnormalities.

Question 29

What must happen for a UTI to be caused

Answer 29

Bacteria must get into the urinary tract, adhere to the epithelial surface, multiply and elicit an inflammatory response

Question 30

The ascending route in UTI’s

Answer 30

Where bacteria colonise and ascent the UT by bowel flora, this is more common in females the males, goes from the bottom of the UT to the bladder

Question 31

The Haematogenous route for UTI’s

Answer 31

When blood borne bacteria cause infections in the urinary tract, mainly the renal parenchyma

Question 32

Bacteria which cause UTI’S

Answer 32

Similar in males and females. UPEC (gram negative rod) is the leading cause. Many of the bacteria are normal flora that become opportunistic when they enter the UT, can include fungi

Question 33

CAUTI’s

Answer 33

UTI’s caused by catheters. You get pooling of urine in the bladder and side of the catheter as bacteria is not flushed out. Bacteria can also colonise the inside of a catheter and block it. Bacteria can drop of the catheter causing infections in other parts of the urinary tract. You would remove and replace the catheter.

Question 34

Vesicouretic reflux (VR) causing UTI’s

Answer 34

This is when there is an abnormality in the ureter. There are five different grades, the higher the grade the more abnormal it is. At grade 5 you have a distended ureter with little flow out of it, and get urine pooling in it. This leads you more susceptible to infection. Urine is a good growth factor for bacteria.

Question 35

Tests which can be done to diagnose UTI’s

Answer 35

• A dipstick analysis on urine can be done to confirm this, it can be done in a GP surgery, shows what’s present in the urine. A urine microscopy can be performed, leukocytes indicate presence of infection.
• A urine culture will be performed to grow the bacteria in the urine in order to identify them, also look at their antibiotic sensitivity. A urine culture should always be performed in men with a history suggestive of UTI regardless of the results of the dipstick test.
• An ultrasound evaluation of the upper urinary tract

Question 36

How is a UTI diagnosed in women

Answer 36

Normally empirically based on their history

Question 37

UTI- in what groups should urine be cultured before starting antibiotic treatment?

Answer 37

• Men
• Pregnant woman
• Children under three years old
• In patients with suspected upper urinary tract infection (flank pain)
• Complicated or recurrent infection
• If resistant organisms are suspected
• If urine dipstick testing gives a single positive result for leucocyte esterase or nitrite
• If clinical symptoms are not consistent with dipstick testing results.

Question 38

Treatment for lower UTI

Answer 38

Trimethoprim (avoid during pregnancy) and nitrofurantoin, this is based on empirical history. If you know the organism and its resistance to antibiotics this will influence what you do

Question 39

Treatment for Pyelonephritis (kidney infection)

Answer 39

Treated with Cefalexin. Can change with microbiology results

Question 40

Frequency of UTI’s

Answer 40

UTI’s are far more common in woman, can occur in woman where there is no underlying problem. Uncommon in men and children, when they do occur it is likely there is an underlying abnormality in the urinary tract. Increases in both sexes with age.

Question 41

Frequency of UTI’s in infants

Answer 41

1-2% per year

Question 42

Frequency of UTI’S in preschool children

Answer 42

More common in preschool girls (4.5%). When it occurs in boys (0.5%) its usually associated with serious congenital abnormalities.

Question 43

Frequency of UTI’S in schoolchildren

Answer 43

Girls 1.2%, boys 0.03%

Question 44

Frequency of UTI’S in adults

Answer 44

Between 1-3% in young non-pregnant woman. 10-20% of females experience a UTI at some point in their life. Less then 0.1% in men until later years when it rises.

Question 45

Frequency of UTI’S in over 65’s

Answer 45

At least 20% in men and 20% in woman. High rate of spontaneous cure and re-infection.

Question 46

Urine appearance in renal and urinary tract diseases

Answer 46

Urine can be frothy, cloudy or red

Question 47

What is a UTI

Answer 47

An infection in any part of the urinary system

Question 48

Symptoms of a UTI

Answer 48

Change in urination frequency, Dysuria (painful urination), passing only a small amount of urine frequently, Haematuria (blood in the urine), pyuria (foul smelling and or cloudy urine). You also have urgency which means that you constantly feel like you should urinate but not passing any urine. Urinary inconstance, you have leakage. Can have flank pain
More severe symptoms can be rigors where you shiver and feel feverish. May have pyrexia (high temperature) as well as nausea and vomiting. For elderly people they may have an acute confusional state

Question 49

Bacteriuria

Answer 49

Bacteria present in the urine. Asymptomatic bacteriuria is without symptoms

Question 50

Significant bacteriuria

Answer 50

The number of bacteria in voided urine that exceeded the number usually due to contamination from the anterior urethra (>10^5 bacteria/ml).

Question 51

Relapse- UTI

Answer 51

When you have a UTI with the same bacteria from your last UTI. So will be bacteriuria with the same infecting bacterium

Question 52

Reinfection- UTI

Answer 52

When a bacterium different to the original infecting bacterium infects you

Question 53

Urethritis

Answer 53

Infection of urethra

Question 54

Cystitis

Answer 54

Infection of the bladder

Question 55

Pyelonephritis

Answer 55

Infection of the kidney

Question 56

Symptoms of kidney infection (acute pyelonephritis)

Answer 56

Upper back and flank pain, high fever, shaking and chills, nausea, vomiting

Question 57

Symptoms of bladder infection (cystitis)

Answer 57

Pelvic pressure, urge incontinence, lower abdomen discomfort, frequent urination, painful urination (dysuria) and blood in the urine

Question 58

Symptoms or urethra infection (urethritis)

Answer 58

Burning with urination

Question 59

Urinary dipstick tests

Answer 59

A stick covered in small square patches that have various assays and enzymes on them, you dip it into a sample of urine. The bottle will have a reference picture printed on it which you compare the dipstick to, first thing you do when you suspect a renal cause

Question 60

What does a urinary dipstick test for

Answer 60

Blood, proteins, nitrates, Leukocyte esterase, Glucose, bilirubin, Urobilogen, specific gravity, pH ketones. The top 5 are more routinely looked at by clinicians but the bottom 5 can be useful. Leukocyte esterase detects white blood cells

Question 61

Urinary tract stones

Answer 61

When solutes become super saturated in urine they can precipitate and crystalise, forming a stone. This can happen because of increased solute or decreased solvent i.e. dehydration. Vary in size from mm to cm and can be anywhere along the urinary tract. Some migrate along the urinary tract others stay in place, the migration can cause symptoms.

Question 62

Urinary tract stones- calcium oxalate

Answer 62

Formed by a calcium cation binding with an oxalate anion to create calcium oxalate. Most common form of calculi, present in 60% of cases. Most likely to form in acidic conditions. They are radio opaque, meaning they show up on an x-ray as a white dot.

Question 63

Urinary tract stones- calcium phosphate

Answer 63

Formed by calcium binding with phosphate and hydrogen. Account for 15% of cases, more likely to form in alkaline conditions. Also radio-opaque

Question 64

Urinary tract stones- struvite

Answer 64

Bacteria using urease to break down urea to create ammonia which favours precipitation of Magnesium and phosphate in the urine to create Struvite. 15% of cases. Commonly called Staghorn calculi and can fill the whole of the renal pelvis or multiple clayces. Associated with infection. Radio-opaque. Made of Magnesium, Ammonium and Phosphate

Question 65

Urinary tract stones- uric acid

Answer 65

The urate anion binds to the sodium cation to form monosodium urate. Accounts for 10% of stones. Radiolucent i.e. they don’t show up on an x-ray

Question 66

Urinary tract stones- cystine

Answer 66

An amino acid, about 5% of stones. Associated with cystinuria (autosomal recessive disease inheritance) with high levels of cysteine in the urine. Radio-opaque

Question 67

Urinary tract stones- risk factors

Answer 67

• Structural abnormalities affecting flow of urine e.g horseshoe kidneys
• Loop diuretics e.g. furosemide
• Relative dehydration
• Diet high in purines (e.g. red meat, oily fish) increases risk of uric acid stones
• Hypercalcaemia- for calcium containing stones
• Increased levels of oxalate in the urine can be due to genetic defects which cause increased oxalate excretion or high dietary intake (beer, rhubarb, kiwis)
• Metabolic disorders e.g. cystinuria
• Can be caused by necrosis following AKI
• History of renal calculi or recurrence.

Question 68

Renal stones- symptoms

Answer 68

Many small calculi are asymptomatic and pass without the patient realising. Patients will often be sweating with pallor, nausea, vomiting and some dysuria. Often haematuria (can be non-visible). Renal stones if obstructive can be associated with infection. Stones high up in the kidney will cause flank pain that may not radiate anywhere else, a dull pain. Stones that are moving down the ureter to the bladder will cause pain that radiates from the loin to the groin due to spasm and dilation of the ureter, called renal colic. The pain is not always intermittent but can be constant. There may be short periods of relief but a persisting dull ache. As calculi move further down the pain can radiate to the labia or scrotum.

Question 69

Urinary stones- Examination and findings

Answer 69

You check their vital signs then a general inspection, what’s the appearance of the patient, sweating, pallor, obvious pain. You then examine the abdomen, there should be nothing to see externally and the abdomen should be soft. Depending on the location of the stone examination findings may vary but tenderness can be present over the flanks (over the kidneys) and radiate round and down to the groin. Next urinalysis should be done to check for haematuria. Look for systemic signs of the patient being unwell. Looking for signs of infection which may be associated with an obstructing stone or staghorn calculus.

Question 70

Urinary stones- diagnoses

Answer 70

Imaging is used to confirm diagnoses. You can use an x-ray as most stones contain calcium so are radio opaque. Better to use CTKUB (CT kidney-ureter-bladder) which is more sensitive than IVU (intravenous urogram) and can identify non-radio opaque calculi. USS (ultrasound scan) can be used and is preferable in groups where exposure to radiation should be avoided i.e. pregnant women. Can be useful in situations where the patient is acutely unwell e.g. sepsis from obstructed stone and preference would be to initiate management rather than wait for CT scan results. It will be tender on palpation

Question 71

Urinary stones- management

Answer 71

People who should be hospitalised= fever (infection), solitary functioning kidney, persistent pain, anuria (no urine), cant take adequate fluids (vomiting), pregnancy and people over 60

Question 72

Urinary stones- medication

Answer 72

• Analgesia (usually NSAIDs to PR/IM diclofenac if vomiting or PO. Opiates will relieve less pain in this group and increase nausea further
• Anti-emetics and rehydration (IV fluid)
• Antibiotics if infection is present.

Question 73

Urinary stone size

Answer 73

Split into three groups, <5mm, 5-10mm, 10-20mm and >20mm

Question 74

Urinary stones- conservative management

Answer 74

Stones that are small (<5mm) should pass spontaneously within a few weeks. If stones can be captured, by sieving the urine they can be sent to the laboratory for testing.

Question 75

indication for active removal of renal stones

Answer 75

Obstruction caused by stones, infection, symptomatic stones (pain or haematuria), stones >15mm, combability, social situation of the patient.

Question 76

Urinary stones- medical expulsive therapy

Answer 76

Alpha blockers (e.g. tamsulosin) and calcium channel blockers (e.g. nifedipine) can be used to reduce ureteric spasm with the aim to help stones pass. This is only given to patients with stones 5-10mm that are distal and could pass spontaneously given assistance.

Question 77

Urinary stones- extracorporeal shockwave lithotripsy (ESWL)

Answer 77

Uses high energy shock waves to break the stones down into smaller crystals so they can pass. Success can vary. Routine antibiotic prophylaxis is not required. Complication include fragments reforming and the fragments causing renal colic. Can also cause UTI and infection, tissue damage within the kidney (increased shockwave rates and energy and cardiovascular dysrhythmias. In the kidney used for for stones between 0-2cm, in the ureter it can be used for stones under 10mm

Question 78

Urinary stones- uteroscopy (URS)

Answer 78

Performed under general anaesthesia. You insert a ureteroscope into the ureter via the external meatus to directly extract the stone. The retrograde approach, the scope will travel up the ureter from the bladder towards the kidney. The antegrade approach would be percutaneous (through the skin) and travel down the ureter to find the stone. This is used less often and would be for larger stones, stones lodged in the distal collecting duct of the kidney or when the retrograde approach has failed. Not used when you cant remove the stone completely, instead use SWL during ureteroscopy. Stents can be inserted to decompress the ureter (e.g. with an obstructing stone). Used in the ureter when stones are under 10mm and over 10mm if you have a fever or nausea/vomiting

Question 79

Urinary stones- percutaneous nephrolithotomy (PNL)

Answer 79

Involves key-hole access through the flank to the kidney itself. An antegrade approach. Done under anaesthetics for larger stones. Involves a high risk of bleeding so anticoagulants must be stopped. Contradicted in pregnancy, untreated UTIs, where there is potential malignancy in the kidney or ureter near the access sites. Intracorporeal shockwave lithotripsy can be used in this procedure to fragment stones. Nephrostomies (draining system connected to an artificial exterior collection vesicle, similar to stroma) can also be placed. Possible complications include bleeding, infection, and organ injury. Used in the kidney when the stones is >2cm

Question 80

Renal stones- surgery/laparoscopic

Answer 80

Not used a lot anymore. Surgery is offered in cases where shock wave litripsy, retrograde or antegrade ureteroscopy and percutaneous nephrolithotomy have failed or are unlikely to be successful.

Question 81

Complications of Urolithiasis (kidney stones)

Answer 81

• Recurrence- someone with lots of risk factors is at higher risk of recurrence. Cystinuria increases recurrence
• Failure of stone to pass- The bigger the stone the less chance they will pass spontaneously.
• Obstruction- can completely obstruct the ureter. The build up of pressure of urine behind the stone can lead to the formation of hydronephrosis, if not decompressed this can lead to permanent kidney damage. Hydronephrosis is dilation of the renal pelvis and/or calyces due to increased pressure in the ureter and kidneys. Anuria suggests there is complete blockage, as no urine can get passed the stone, they should be hospitalised.
• Infection- Can develop around an obstructed stone, can either be localised or systemic. If a patient develops systemic infection secondary then it’s sepsis