Genitourinary Flashcards
What is nephrolithiasis?
Presence of calculi within the urinary tract.
What are the clinical presentations of kidney stones?
- Many will be asymptomatic.
If they obstruct the collecting ducts in the kidneys:
- Renal colic pain (loin to groin).
- Commonly associated with nausea and vomiting.
What are the risk factors for kidney stones?
- Dehydration.
- Obesity.
- Male.
- Previous kidney stones.
- Older age.
- High salt intake.
What is the pathophysiology of renal colic pain?
- Kidney stone blocks the collecting ducts of the kidney.
- The stone increases the intraluminal pressure which stretches the nerve ends.
- This is felt as renal colic pain.
What are the main types of kidney stone?
Calcium stones (80% of all kidney stones):
- Calcium oxalate. 80% of all calcium stones, so the most common type of kidney stone overall.
- Calcium phosphate. The other 20% of calcium stones.
Uric acid stones. Approx. 10%
Stones can also be cystine or struvite.
What are the investigations used for kidney stones?
- Non-contrast CT of KUB (kidney, ureter and bladder) is the gold standard.
NOTE: Use USS rather than CT in people under 16. - Urinalysis. There is often microhaematuria.
- FBC. Raised WCC can be indicative of infective differential such as UTI or pyelonephritis.
- Serum electrolytes. Low calcium suggestive of hyperthyroidism being the cause.
- Pregnancy test (ectopic pregnancy?).
What is the treatment for kidney stones?
- If asymptomatic, watch and wait.
If smaller but symptomatic:
- Analgesia (ibuprofen 1st line, paracetamol 2nd line).
- Keep hydrated, and try to pass normally.
If larger:
- Surgical intervention (Shock wave lithotripsy SWL).
- Potentially other more invasive surgical intervention.
If there is a blockage:
- Fit a ureteric stent and achieve decompression before removing the stone surgically.
If there is an infection:
- Antibiotic treatment.
What are the differentials for kidney stones?
- Pyelonephritis.
- Ectopic pregnancy.
- Appendicitis.
- Bowel obstruction
The differentials can be differentiated through use of a KUB NCCT.
Which kidney stones are radiolucent? What does this mean?
- Pure uric acid stones are radiolucent.
- This means that they do not show up on XR.
What is acute kidney injury?
Rapid deterioration of renal function, which causes:
- Decreased urinary output.
AND/OR
- A rise in creatinine levels.
- What are the four types of AKI?
- Pre-renal AKI. Due to reduced kidney perfusion.
- Intrinsic AKI. Due to direct injury to the kidney parenchyma.
- Post-renal AKI. Due to obstruction in urinary outflow.
- Drug-induced AKI. Due to nephrotoxic drugs.
What are some examples of causes of pre-renal AKI?
PRE-RENAL: Overdiuresis, hypotension, haemorrhage
RENAL: Glomerulonephritis, interstitial nephritis. kidney insult (either surgery or septic).
POST-RENAL: BPH, cancer, UTI, renal stones.
Drug-induced AKI: “DAMN” drugs (diuretics, ACEI, ARB’s, Metformin, NSAIDs).
What is the pathophysiology of pre-renal AKI?
- Decreased kidney perfusion, resulting in reduced GFR. To try and compensate/maintain GFR, the body:
- More ADH is secreted from the pituitary, this increases water/sodium reabsorption.
- Baroreceptors in the carotid artery and aortic arch sense low BP and increase sympathetic activity.
- Afferent arterioles (towards the glomerulus) in kidney dilate, efferent arterioles (away from glomerulus) in kidney constrict.
NOTE: It would be the opposite to decrease the GFR.
What are the key nephrotoxic medications?
What common drug is not nephrotoxic?
“DAMN” drugs:
- Diuretics.
- ACEI, ARBs
- Metformin.
- NSAIDs.
- Gentamycin is also nephrotoxic.
- Paracetamol IS NOT NEPHROTOXIC.
What is the treatment for AKI?
“STOP AKI”
- Sepsis? SEPSIS-6
- Toxins. Stop any nephrotoxic drugs.
- Optimise bp/blood volume. Use fluids as appropriate but manage electrolyte levels. Consider use of desmopressin if fluids are not enough.
- Prevent harm. If the patient has: Hyperkalaemia, metabolic acidosis, hyperphosphataemia, volume overload (excess fluids), severe AKI ADMIT FOR EMERGENCY RRT (Renal replacement therapy).
What are some of the main potential complications of AKI?
- Hyperphosphataemia.
- Hyperkalaemia.
- Metabolic acidosis (inadequate nephritic removal of acid from the blood).
- Fluid overload (due to excess IV fluid administration).
What is chronic kidney disease (CKD)?
What are the risk factors for CKD?
Also known as chronic renal failure, CKD is:
- Abnormalities in kidney function/structure present for over 3 months.
Risk factors:
- Diabetes mellitus (most common cause DKD which is a type of CKD).
- Hypertension.
- Age > 50.
How is chronic kidney disease classified?
Stage 1 - GFR = >90mL/min BUT THERE IS EVIDENCE OF KIDNEY DISEASE.
Stage 2 - GFR = 60-89mL/min
Stage 3a - GFR = 45-59mL/min
Stage 3b - GFR = 30-44mL/min
Stage 4 - GFR = 15-29mL/min
Stage 5 (End stage/kidney failure) - GFR = <15mL/min
What is the clinical presentation of CKD?
Significant number of people will be asymptomatic. Can also present with:
- Fatigue
- Oedema (due to volemic overload).
- Nausea with/without vomiting.
- Pruritus due to hyperphosphataemia.
- Restless leg syndrome (due to hypercalcaemia, anaemia, iron deficiency.
What is the pathophysiology of CKD?
Renal damage causes:
- Increased renal pressure to try and restore the GFR.
- This results in glomerular scarring/fibrosis and inflammation.
What are the investigations used in CKD?
- Creatinine. Raised.
- GFR estimate: Will be reduced.
- Urinalysis: Proteinuria (hyperalbuminaemia) and haematuria.
What are the common complications of CKD?
- Anaemia (due to reduced production of erythropoietin).
- CV disease (poor glycemic control, hypertension etc.)
- Metabolic acidosis (impaired ability to excrete acid from the blood).
- Hyperkalaemia (reduced K excretion due to sodium/water retention).
What is the treatment for CKD?
Mainstay is to try and treat cardiovascular disease, as this is what causes most of the mortality in CKD:
Hypertension: treat with ACEI (ramipril) or ARB (losartan).
Dyslipidaemia: Give statin (atorvastatin) to reduce risk.
Poor glycemic control: 1st line is ACEI or ARB. If needed introduce a SGLT2 inhibitor (canagliflozin).
Next steps:
- If severe (stage 5), consider RRT (renal replacement therapy) or ideally a kidney transplant.
What is BPH?
- Benign prostatic hyperplasia.
- Increase in the size of the prostate gland without malignancy.
