renal + GU Flashcards
Which drugs can cause prerenal damage?
drugs that cause excessive GI loss (d+v) or volume depletion
NSAIDs (renal underperfusion)
ACEi in patients with compromised renal perfusion
Why should you be cautious when prescribing an NSAID with and ACEi?
in combo can cause an acute deterioration in renal function
What issues can renal impairment cause in prescribing?
Failure to excrete a drug or its metabolites.
Many side-effects being poorly tolerated by patients with renal impairment.
Some drugs ceasing to be effective when renal function is reduced
What are the risk factors for AKI?
Advanced age
Underlying kidney disease
Toxin exposure
DM
Excessive fluid loss
Drug overdose
Surgery
Haemorrhage
Pancreatitis
Cardiac arrest
Sepsis
What is an acute kidney injury?
an acute decline in kidney function, leading to a rise in serum creatinine and/or a fall in urine output
What is stage 1 of an AKI?
Creatinine rise of 26 micromol or more within 48 hours
OR
Creatinine rise of 1.50–1.99 x baseline within 7 days
OR
Urine output less than 0.5 mL/kg/hour for more than 6 hours
What is stage 2 of an AKI?
- (2.00–2.99 x baseline) creatinine rise from baseline within 7 days
- Urine output less than 0.5 mL/kg/hour for more than 12 hours
What is stage 3 of AKI?
- Serum creatinine levels: 3-fold higher than baseline
- Creatinine rise to 354 micromol/L or more with acute rise of 26 micromol/L or more within 48 hours or 50% or more rise within 7 days or
- Urine output less than 0.3 mL/kg/hour for 24 hours or anuria for 12 hours
What are the 3 categories of aetiology for AKI?
Pre-kidney
Intrinsic
Post-kidney
What are the pre-kidney causes of AKI?
Reduced kidney perfusion:
- hypovolaemia
- haemorrhage
- sepsis
- overdiuresis
- hepatorenal syndrome
What are intrinsic causes of AKI?
- Acute tubular necrosis
- Rapidly progressive glomerulonephritis
- Interstitial nephritis
What are post-kidney causes of AKI?
mechanical obstruction of the urinary outflow tract:
- Retroperitoneal fibrosis
- lymphoma
- stones
- tumour
- prostate hyperplasia
- strictures
- ascending urinary infection
- urinary retention
What is pre-kidney AKI?
injury due to impaired kidney perfusion
What is intrinsic AKI?
direct injury to the kidney parenchyma.
What is post-kidney AKI?
injury due to urinary outflow obstruction
Presentation of an AKI
Reduced urine output
Often asymptomatic, look at risk factors
What is the pathophysiology of pre-renal AKI?
Reduction in blood flow leads to reduction in GFR
More urea and creatinine in the blood as less is filtered out and more reabsorbed.
Sodium and water also reabsorbed.
Low GFR leads to low NaCl conc, macula densa cells sense and stimulate renin release.
RAAS stimulated. Increase in aldosterone and ADH leads to even more water and sodium reabsorption
What is the urine like in pre-renal AKI?
lower urea, sodium and water
Osmolality high, very concentrated
What is the urine like in an intrarenal AKI?
More water, sodium and urea
Lower osmolality than pre-renal, less concentrated
What is seen in the blood in a pre-renal AKI?
More urea than creatinine in blood
What is seen in the blood in an intra-renal AKI?
More creatinine than urea
What is the pathophysiology of intra-renal AKI?
Some form of kidney tubule injury, dysfunction of excretion and reabsorption.
Kidney tubule cells die and flake off, forming clumps and casts.
Casts block tubule and cause backlog, pressure rises within tubular system.
Less filtration, accumulation of urea and creatinine.
Creatinine also can’t be excreted so blood creatinine increases
What is the pathophysiology of an early stage post-renal AKI?
Obstruction of flow.
Lower GFR, increase in urea and creatinine as less filtered. Urea can be reabsorbed and creatinine excreted still as no damage to kidney cells.
Sodium and water also reabsorbed.
RAAS stimulated by low GFR
What is the urine like in an early stage post-renal AKI?
low sodium, water and urea
similar to pre-renal in early stages
What is the urine like in the later stages of a post-renal AKI?
High water, sodium and urea
resembles intrinsic
What is the pathophysiology of a later stage post-renal AKI?
Pressure continues to increase, blood vessels compressed and blood flow reduced.
Low GFR, kidney cells damaged.
Urea can’t be reabsorbed or creatinine excreted.
Reduced sodium and water reabsorption
What is the key investigation for AKI?
U&Es, creatinine + bicarb
What investigations would be done for AKI?
U&Es
Urinalysis: dipstick + osmolality
FBC
When is urine osmolality increased in AKI?
Above 500 in pre-renal and early stage post-renal
When is urine osmolality low in AKI?
Intrinsic (intra-renal) and late stage post-renal
What are the main presentations of an AKI?
Reduced urine output
May be symptomatic: check for risk factors, can also show as nausea, vomiting and dehydration
What are the differentials of AKI?
CKD
Drug side effects
How do you manage an AKI?
treat underlying cause where possible
monitor fluid and electrolyte balance closely
optimise haemodynamic status with appropriate fluid therapy
Screen for and treat sepsis
Complications of AKI
Uraemia
Hyperkalaemia
Hyperphosphataemia
CKD
What is the definition of CKD?
GFR of less than 60mL/minute/1.73 m² or presence of kidney damage for 3 months or more
progressive, irreversible condition, reduced kidney function/damage, >3 months
What is glomerulonephritis?
Broad term that refers to a group of parenchymal kidney disease – inflammation and damage to glomeruli
What syndromes can glomerulonephritis present with?
Nephritic
Nephrotic
What is nephritic syndrome?
Clinical manifestations that occur within nephritis
What can cause nephritic syndrome?
Post-strep
IgA nephropathy
SLE
Rapidly progressive (crescentic) GN
Goodpasture’s disease (anti-glomerular basement membrane antibodies)
What are the main features of nephritic syndrome?
Haematuria
RBC casts in urine from glomerular bleeding
Sub-nephrotic proteinuria
Hypertension and fluid retention
Oliguria
Sterile pyuria (WBC without bacteria)
What are the symptoms of fluid retention/overload in nephritic syndrome?
- Hypertension
- Pulmonary oedema/effusions
- Peripheral oedema
- Raised JVP
- Orthopnea and SOB
- Increase in weight
What can cause glomerulonephritis
- Infections, e.g. Hep B/C, HIV, Strep, Malaria
- Systemic inflammatory conditions: SLE, Goodpasture’s, rheumatoid arthritis
- Drugs
- Metabolic disorders (DM, hypertension)
- Malignancy
- Hereditary disorders (Alport’s)
- Deposition disorders (amyloidosis)
What is bacteriuria?
presence of bacteria in the urine
What is an asymptomatic bacteriuria UTI?
presence of significant levels of bacteria in the urine in a person without signs or symptoms of UTI
What is an uncomplicated UTI?
infection of the urinary tract by a usual pathogen in a person with a normal urinary tract and with normal kidney function
What is a complicated UTI?
UTI with increased likelihood of complications such as persistent infection, treatment failure and recurrent infection
anatomical, functional, or pharmacological factors predispose
What are some complications of long-term catheterisation?
UTI/Pyelonephritis
Stones
Obstruction
Chronic inflammation
What is pyuria?
Presence of leucocytes in the urine
What are the upper UTIs?
pyelitis
pyelonephritis
What are lower UTIs generally?
infection of the bladder (cystitis)
What are the different classifications of UTIs?
Lower/ upper
Asymptomatic bacteriuria
Complicated
Uncomplicated
What are the most common pathogens causing UTIs?
E.coli (more than 50%)
proteus (10-15%)
klebsiella (catheter associated)
enterococci
Staph.saprophyticus
What is incontinence?
lack of voluntary control over urination or defecation
What is stress incontinence?
Loss of urine with exertion/sneezing/coughing
What is urgency incontinence?
leakage accompanied by/ or immediately preceded by urinary urgency
What is mixed incontinence?
Loss of urine associated with urgency, also exertion, effort, sneezing or coughing
What is lower urinary tract dysfunction?
Failure to store/ void
- bladder or outlet issue
What is total incontinence?
Continuous urine leakage
Normally anatomical problems
Risk factors for incontinence in women
Increasing age
Obesity
Pregnancy
High exertion
Dementia and CNS disorders
Whar does the cough stress test for incontinence consist of?
filling the patient’s bladder to 300 mL
having the subject perform a series of forceful coughs in upright position or dorsal lithotomy position
Management for incontinence in women
Behavioural and lifestyle changes
e.g. pelvic floor exercises, weight reduction if obese, caffeine reduction
How are NSAIDs nephrotoxic?
disrupt the compensatory vasodilation response of renal prostaglandins to vasoconstrictor hormones released by the body
hypoperfusion of kidney and decrease in GFR
Which drugs should be stopped in AKI?
stop the damn drugs
Diuretics
ACEi/ARBs
Metoformin
NSAIDs
What are voiding LUTS?
- Hesitancy : a longer than usual wait for urine flow to begin
- Weak stream
- Intermittency : urine flow that stops and starts
- Terminal dribbling : weak urine flow continues after an attempt is made to stop
- Straining : the need to increase abdominal pressure in order to urinate
What is benign prostate hyperplasia?
increase in size of the prostate gland without malignancy present
What are storage LUTS?
- Dysuria : pain or burning on urination
- Frequency : the passing of small volumes of urine at frequent intervals
- Urgency : a sudden urge to pass urine
- Urge incontinence : urgency leading to involuntary loss of urine
- Nocturia : waking at night to pass urine
What can be used to assess the severity of lower urinary tract symptoms?
international prostate symptom score (IPSS)
What’s the epidemiology of BPH?
Commonly affects men
prevalence increasing with age
(40% of men age 50-60, 82% of men age 70-80)
What does 5-alpha reductase do and what condition is this relevant for?
Converts testosterone into dihydrotestosterone.
Prostate cells respond to DHT and continue growing into BPH
Therefore 5-alpha reductase is inhibited in treatment of BPH
How does BPH cause LUTS?
prostatic hyperplasia can result in bladder outlet obstruction
increased stromal:epithelial ratio
How does BPH present?
Voiding symptoms: hesitancy, intermittency, weak stream, straining, incomplete emptying, and post-void dribbling
Storage symptoms: urinary frequency, nocturia, and urgency
older men
What are the risk factors for BPH?
Men age over 50
Family hx of BPH
How can BPH be investigated?
Digital rectal examination
Frequency/volume chart voiding diary for 3 days by patient
Prostate specific antigen- unreliable (lots of false +/-ves)
Urinalysis (dipstick)
What are the possible differentials of BPH?
Overactive bladder
Prostatitis
Prostate cancer
Urinary tract infection (UTI)
Bladder cancer
Why is the prostate specific antigen test not ideal?
unreliable
with a high rate of false positives (75%) and false negatives (15%)
What are some common causes of a raised PSA?
Prostate cancer
Benign prostatic hyperplasia
Prostatitis
Urinary tract infections
Vigorous exercise (notably cycling)
Recent ejaculation or prostate stimulation
What are the medical therapies for BPH?
Alpha-blockers (e.g., tamsulosin) relax smooth muscle, with rapid improvement in symptoms
5-alpha reductase inhibitors (e.g., finasteride) gradually reduce the size of the prostate
What’s an important side effect of tamsulosin for patients needing to undergo cataract surgery?
intra-operative floppy iris syndrome
What’s the most common surgical therapy for BPH?
Transurethral resection of the prostate
What are the complications of BPH?
UTI
Bladder stones
Urinary retention
Tamsulosin can cause ejaculatory dysfunction
What is nephrolithiasis?
Nephrolithiasis refers to the presence of crystalline stones (calculi) within the urinary system (kidneys and ureter)
kidney stones
What are renal stones?
crystalline mineral depositions that form from microscopic crystals in the loop of Henle, distal tubules, or the collecting duct
What typically causes renal stones to form?
elevated levels of urinary solutes such as calcium, uric acid, oxalate, and sodium
decreased levels of stone inhibitors such as citrate and magnesium
Low urinary volume
abnormally low or high urinary pH
all can lead to urine supersaturation
What is the basic pathophysiology of renal stones?
Urine becomes super saturated by concentrated solutes
These solutes are precipitated, form crystals and act as a nidus for more crystal formation
What are the different types of kidney stone?
composition
Calcium (80%)
Uric acid
Cystine
Struvite
What are the 2 types of calcium kidney stone?
Calcium oxalate
Calcium phosphate
What are the risk factors for developing a calcium oxalate kidney stone?
low urine volume
hypercalciuria
hyperuricosuria
hyperoxaluria
hypocitraturia
What are the risk factors for a calcium phosphate kidney stone?
low urine volume
hypercalciuria
hypocitraturia
high urine pH
primary hyperparathyroidism
renal tubular acidosis
What causes uric acid stones?
urinary pH <5.5
hyperuricosuria can also contribute
What causes cystine urine stones?
cystinuria
What does staghorn calculi mean in kidney stones?
the stone forms in the shape of the renal pelvis, giving it a similar appearance to the antlers of a deer stag
most commonly occurs with struvite stones
What are struvite kidney stones?
infection stones, e.g. Proteus, Pseudomonas, and Klebsiella
composed of magnesium, ammonium, and phosphate
They frequently present as staghorn calculi
What is the cardinal symptom of kidney stones?
severe, acute flank pain
Apart from severe, acute flank pain, what other symptoms may be present with kidney stones?
Haematuria
Nausea or vomiting
Reduced urine output
What investigations should be run for kidney stones?
Non-contrast CT within 24 hours of presentation
Urinalysis: haematuria
FBC
Serum chemistry (calcium, electrolytes, serum urea/creatinine, phosphorus, and uric acid)
What are the differentials for kidney stones?
Acute appendicitis
Ectopic pregnancy
Ovarian cyst
Diverticular disease
Bowel obstruction
Acute pancreatitis
What are the management options for kidney stones?
Maintain adequate hydration
NSAIDs for pain relief, e.g. IM diclofenac
asymptomatic renal stone <5 mm: watchful waiting
stones ≥10 mm or smaller intolerable stones: surgical treatment
- 5-10mm shockwave lithotripsy
- 10-20 mm shockwave lithotripsy OR ureteroscopy
- > 20 mm percutaneous nephrolithotomy
What are the 2 ways of categorising chronic kidney disease?
glomerular filtration rate category (G1-5)
albuminuria category (A1-3)
What are the different G stages for CKD?
G1- Over 90
G2- 60-89
G3a - 45-59
G3b- 30-44
G4- 15-29
G5- Under 15
Below 60 is reduced GFR, G5 is need for renal replacement therapy (end stage)
What are the 3 different A stages for CKD based off albumin-creatinine ratio? (ACR)
A1 Under 3 mg/mmol
A2 3-30 mg/mmol
A3 Above 30 mg/mmol
What can cause chronic kidney disease?
Diabetes – most common
Hypertension – second most common
Glomerular kidney disease, e.g. glomerulonephritis
Medications (e.g., NSAIDs or lithium)
Polycystic kidney disease
What is the basic pathophysiology of CKD?
Renal damage/injury, e.g. from high blood pressure causing arteriosclerosis
Inflammatory cell recruitment
Fibroblasts activated
Fibrosis and glomerulosclerosis
Decrease in GFR
What is the epidemiology of CKD?
Increases with age, higher incidence of DM and HTN
Associated with socioeconomic desparities
What are the risk factors for CKD?
diabetes mellitus
hypertension
age >50 years
childhood kidney disease
smoking
obesity
How might a patient with CKD present?
Haematuria
Foamy urine (proteinuria)
fatigue
oedema
nausea with/without vomiting
pruritus
restless legs
anorexia
HTN
patients can be asymptomatic + symptoms are non-specific
What investigations should be done for CKD?
- Serum creatinine: elevated
- eGFR: <60 mL/minute/1.73 m²
- Urinalysis: looking for haematuria + proteinuria
- Albumin excretion rate (AER) or albumin to creatinine ratio (ACR): increased
What is accelerated progression in CKD?
a sustained decline in the eGFR within one year of either 25% or 15 mL/min/1.73 m2
What are some differentials of CKD?
Diabetic kidney disease
Hypertensive nephrosclerosis
Ischaemic nephropathy
Obstructive uropathy
Nephrotic syndrome
Glomerulonephritis