Renal Flashcards
What is AKI?
a sudden decline in renal function over hours or days that leads to an inability to maintain fluid, electrolyte, and acid base balance. Diagnosed by measuring serum creatinine.
What is the criteria for the diagnosis of an AKI?
- Rise in creatinine of ≥26 micromol/L in 48 hrs
- Rise in creatinine of ≥50% in 7 days
- Urine output of <0.5 ml/kg/hour for >6 hours
Risk factors for AKI
- CKD
- History of AKI / urological hx e.g., stones
- Heart failure
- Diabetes
- Liver disease
- > 65 yo
- Cognitive impairment
- Nephrotoxic medications – NSAIDs, ACEi, aminoglycosides, ARBs, diuretics
- Contrast medium in CT scans (iodinated)
- Sepsis
- Hypovolemia
- Emergency surgery
What are the 3 categories of causes of AKI?
- Pre-renal: most common, due to inadequate blood supply to kidneys
- Intrinsic disease: due to reduced filtration of blood
- Post-renal: obstruction to outflow of urine from kidney, and the back pressure causes reduced kidney function
Pre-renal causes of AKI?
- Dehydration- haemorrhage, burns, vomiting, diarrhoea
- Hypotension (shock)
- Heart failure
- Renal artery stenosis / thrombosis
Intrinsic causes of AKI?
• Glomerulonephritis
• Interstitial nephritis (caused by penicillin, rifampicin, NSAIDs, allopurinol & furosemide – fever and rash)
• Acute tubular necrosis – brown granular casts in urine
* Rhabdomyolysis
* Tumour lysis syndrome
Post-renal causes of AKI?
- Kidney stones (in ureter or bladder)
- Masses – Ca in abdomen or pelvis
- Ureter / urethral strictures
- BPH / Prostate Ca
signs of AKI
- Hypotension
- Kidney insults
- Reduced urine production
- Lower urinary tract symptoms if there is obstruction
- Symptoms of volume overload if there is HF
- Vomiting / nausea
- Haematuria if there are kidney stones, infection, tumour or acute glomerulonephritis
- Pulmonary and peripheral oedema
- Arrhythmias - secondary to changes in K and acid-base balance
- Features of uraemia - pericarditis or encephalopathy
Ix for AKI
- U&Es
- LFTs
- Serum potassium
- FBC
- Bicarbonate
- CRP
- Blood culture
- Urinalysis
a. Leukocytes + nitrates = infection
b. Protein + blood = acute nephritis
c. Glucose = diabetes - Urine culture
- Urine output monitoring
- Fluid challenge
- US urinary tract – to look for obstruction
- VBG
- CXR – for signs of overload
- ECG
Mx of AKI
- Continual monitoring of fluid balance
- Fluid rehydration – IV fluids / if patient is hypervolemic, fluid restriction +/- diuretics
- Stop nephrotoxic medications
- Relieve obstructions
- Specialist input for severe (stage 3) AKI
- If there is hyperkalaemia:
o 10 ml 10% calcium carbonate (to protect the myocardium)
o Insulin + dextrose and salbutamol (to move potassium from extracellular to intracellular compartment) - Calcium resonium, loop diuretics and dialysis (to remove K from body )
Medications safe to continue in AKI
Paracetamol Warfarin Statins Aspirin (at 75mg) Clopidogrel B blockers
Medications that should be stopped in AKI as they worsen renal function
NSAIDs Aminoglycosides - genatmicin, neomycin ACEi ARBs Diuretics
Medications to stop during AKI due to increased risk of toxicity (not because of worsening kidney function)
Methotrexate
Lithium
Digoxin
Pneumonic for remembering assessment and management of AKI
RENAL DRS 26
- R = Record baseline creatinine (+ do regular U&Es)
- E = Exclude obstruction
- N = Nephrotoxic drugs stopped
- A = Assess fluid status
- L = Losses +/- catheterisation
- D = Dipstick (blood +/- protein)
- R = Review medications
- S = Screen (consider acute renal screen)
- 26 = creatinine rise for AKI diagnosis
Complications of AKI
- Hyperkalaemia
- Fluid overload, heart failure and pulmonary oedema
- Metabolic acidosis
- Uraemia (high urea) – can lead to encephalopathy or paricarditis
When is haemodialysis required in AKI?
When the patient doesn’t respond to medical treatments
Complications e.g., hyperkalaemia, pulmonary oedema, acidosis or uraemia
How can AKI be staged?
stage 1, 2 or 3
Using The kidney disease: improving global outcomes (KDIGO) criteria
What is a stage 1 AKI?
Increase in creatinine to 1.5-1.9 times baseline, or
Increase in creatinine by ≥26.5 µmol/L, or
Reduction in urine output to <0.5 mL/kg/hour for ≥ 6 hours
What is a stage 2 AKI?
Increase in creatinine to 2.0 to 2.9 times baseline, or
Reduction in urine output to <0.5 mL/kg/hour for ≥12 hours
what is a stage 3 AKI?
Increase in creatinine to ≥ 3.0 times baseline, or
Increase in creatinine to ≥353.6 µmol/L or
Reduction in urine output to <0.3 mL/kg/hour for ≥24 hours, or
The initiation of kidney replacement therapy, or,
In patients <18 years, decrease in eGFR to <35 mL/min/1.73 m2
What is benign prostatic hyperplasia?
common condition affecting older men causing hyperplasia of the stromal and epithelial cells of the prostate. Usually presents with LUTs.
Pathology of BPH
BPH is a hormone dependent process involving testosterone and dihydrotestosterone production. There’s failure of normal apoptosis and abnormal epithelial & stromal proliferation.
Proliferation occurs primarily in the transition zone = restriction of the prostatic urethra and urinary flow.
Symptoms of benign prostatic hyperplasia
- Hesitancy
- Weak flow
- Urgency
- Frequency
- Intermittency
- Straining to pass urine
- Terminal dribbling
- Incomplete emptying
- Nocturia
- Retention = acute or chronic
What scoring system is used to assess the severity of LUTS?
International prostate symptom score (IPSS) = scoring system that can be used to assess the severity of LUTS.
- 0-7 mild
- 8-19 moderate
- 20-35 severe
Ix for BPH?
- DRE: irregular enlargement think cancer. Benign prostate = smooth, symmetrical, soft with maintained central sulcus
- Abdominal examination
- Urinary frequency volume chart
- Urine dipstick – to check for infection
- FBC, U&E, LFT
- US – abdominal or transrectal to evaluate the size of the prostate
- MRI prostate – to diagnose malignancy
- Prostate specific antigen: Unreliable test with high rate of false positives and false negatives
common causes of raised PSA
Prostate cancer BPH Prostatitis UTI Vigorous exercise e.g., cycling Recent ejaculation / prostate stimulation
Mx for BPH
- Exclude malignancy
- Conservative watchful waiting
- Medical management - alpha blockers (tamsulosin) and 5-alpha reductase inhibitors (finasteride)
- Surgical -
- Transurethral resection of prostate (TURP)
- Transurethral incision of prostate (TUIP)
- Prostatic urethral lift
- folium laser enucleation of the prostate (HoLEP)
- Open prostatectomy
Mechanism of action of tamsulosin in BPH & side effects
Alpha blocker
Inhibit the action of moradrenaline on smooth muscle in the prostate = reduces tone
SE:
- Postural hypotension
- Ejaculatory dysfunction
- Intra-operative floppy iris syndrome
Mechanism of action of finasteride in BPH & side effects
5-Alpha reductase inhibitor
Reduce the production of dihydrotestosterone which mediates androgen effects on the prostate
gradually reduces size of the prostate - 6 months to reduce size
Used if patient has significantly enlarged prostate & is at high risk of progression
SEs:
- Reduced libido
- Erectile dysfunction
- Ejaculatory dysfunction
Complications of transurethral resection of prostate
retrograde ejaculation urinary infection urinary catheter clot retention urinary incontinence urethral stricture erectile dysfunction
TURP syndrome - caused by irrigation with glycine during procedure (hyponatraemia, hyper ammonia, visual disturbances)
Complications of BPH
Urinary retention
What is interstitial nephritis and what are the 2 types?
inflammation of the space between cells and tubules (the interstitium) in the kidney
Two types: acute interstitial nephritis and chronic tubulointerstitial nephritis
Histology of acute interstitial nephritis
marked interstitial oedema and interstitial infiltrate in the connective tissue between renal tubules
Causes of acute interstitial nephritis
- Drugs : o Penicillin o Rifampicin o NSAIDs o Allopurinol o Furosemide
- Infection
o Hanta virus
o Staphylococci - Systemic disease
o SLE
o Sarcoidosis
o Sjogrens syndrome
Presentation of acute interstitial nephritis
- AKI
- Hypertension
- Symptoms of generalised hypersensitivity reaction:
o Rash
o Fever
o Eosinophilia
o Arthralgia
What are urinalysis results for acute interstitial nephritis?
Stile pyuria (^WCC in urine) White cell casts
Mx for acute interstitial nephritis
- Treat underlying cause
- Steroids to reduce inflammation
- Stop causative medication
What is bladder cancer?
cancer of the epithelial lining of the bladder (urothelium) and most are non-invasive of the muscle (superficial) at presentation.
What is the typical exam hx for a bladder cancer patient?
retired dye factory worker with painless haematuria
Risk factors for bladder cancer
- Smoking
- Increased age
- Aromatic amines – in dye and rubber industry
- Schistosomiasis = squamous cell carcinoma of the bladder (in countries with high prevalence of the infection)
what is the type of cancer seen in bladder cancer?
- Transitional cell carcinoma (90%)
- Squamous cell carcinoma (5%)
- Rarer causes = adenocarcinoma, sarcoma and small cell carcinoma
What is the presentation for bladder cancer?
- Painless macroscopic haematuria
2. Some may present with incidental microscopic haematuria
when to do a two week wait referral for bladder cancer
- <45 yo + unexplained visible haematuria (without UTI or persisting after tx for UTI)
- > 60 yo + microscopic haematuria + dysuria/raised WCC
Ix for bladder cancer
Cystoscopy (rigid or flexible) + biopsy
Staging for bladder cancer
TNM staging (tumour, lymph node, metastasis)
- Clear distinction required between: non-muscle invasive bladder cancer and muscle invasive bladder cancer
- Non-muscle invasive bladder cancer =
o Tis / carcinoma in situ = cancer affecting urothelium and flat
o Ta = cancer affecting urothelium and projecting into bladder
o T1 = cancer invading connective tissue but not muscle
- Invasive bladder cancer: T2-T4 & any lymph node or metastatic spread
Mx for bladder cancer
- Transurethral resection of bladder tumour (TURBT) – remove tumour during cystoscopy
- Intravesical chemotherapy – chemotherapy given into bladder through a catheter
- Intravesical bacillus Calmette-Guerin (BCG) – BCG vaccine given into bladder to stimulate immune system
- Radical cystectomy with urostomy and ileal conduit
- Chemotherapy
- Radiotherapy
What is chronic kidney disease?
chronic reduction in kidney function. Is permanent and progressive.
Causes of CKD
- Diabetes – diabetic nephropathy
- HTN
- Age related decline
- Glomerulonephritis
- Polycystic kidney disease
- Medications = NSAIDs, PPIs and lithium
- Chronic pyelonephritis
Risk factors for CKD
- Older age
- HTN
- DM
- Smoking
- Use of medications that affect the kidneys
Presentation of CKD
- Asymptomatic and diagnosed on routine testing
- Loss of appetite
- Nausea +/- vomiting
- Oedema
- Muscle cramps
- Peripheral neuropathy
- Pallor
- HTN
- Uraemia symptoms: restless legs, pruritis
Ix for CKD
- Estimate glomerular filtration rate (eGFR)
a. On a U&E
b. Need 2 tests, 3 months apart to diagnose CKD - Urine albumin:creatinine ratio
a. Proteinuria >/= 3mg/mmol - Urine dipstick
a. Haematuria
b. If haematuria, ix for bladder cancer - Renal USS
a. Do if theres:
i. Accelerated CKD
ii. Haematuria
iii. Family hx of polycystic kidney disease
iv. Evidence of obstruction
How do you stage CKD?
according to GFR AND Albumin:creatinine ratio (for proteinuria)
What is CKD stage 1?
eGFR >90 ml/min
With some sign of kidney damage on other tests – U&Es and proteinuria (if all the kidney tests are normal/score A1 = no CKD)
What is CKD stage 2?
eGFR = 60-98 ml/min
With some sign of kidney damage on other tests – U&Es and proteinuria (if all the kidney tests are normal/score A1 = no CKD)
what is CKD stage 3a?
eGFR - 45-59 ml/min
A moderate reduction in kidney function
what is CKD stage 3b?
eGFR = 30-44 ml/min
A moderate reduction in kidney function
What is CKD stage 4?
eGFR - 15-29 ml/min
A severe reduction in kidney function
what is CKD stage 5?
eGFR Less than 15 ml/min
Established kidney failure – dialysis or kidney transplant may be needed
What is the A score used in the classification of CKD?
A score is based on albumin:creatinine ratio and shows whether there’s proteinuria
A1 <3 mg/mmol
A2 3-30 mg/mmol
A3 >30 mg/mmol
When should you refer a patient with CKD to a specialist?
- eGFR <30
- ACR >/= 70 mg/mmol
- Accelerated disease progression
- Uncontrolled HTN despite >/= 4 antihypertensives
Management of CKD
- Slow the progression of CKD
a. Optimise diabetic control
b. Optimise HTN control
c. Treat glomerulonephritis - Reduce the risk of complications
a. Exercise, maintain healthy weight and stop smoking
b. Special dietary advice about phosphate, sodium, potassium and water intake
c. Offer atorvastatin 20mg for primary prevention of CVD - Treat complications
a. Sodium bicarbonate for metabolic acidosis
b. Iron supplementation and erythropoietin for anaemia
c. Vitamin D for renal bone disease
d. ACEi/ARB to treat proteinuria (if ACR >30 + HTN or if just ACR >70)
e. Dialysis in end stage renal failure
f. Renal transplant in end stage renal failure
Complications of CKD
Anaemia (normocytic) Renal bone disease CVD Peripheral neuropathy Dialysis related problems
Why do patients with CKD get anaemia and how is it managed?
o Normochromic, normocytic anaemia
o Kidney cells produce erythropoietin (hormone that stimulates RBC production).
o Give exogenous erythropoietin in anaemia after treating any iron deficiency anaemia
What are the symptoms of renal bone disease?
osteomalacia, osteoporosis, osteosclerosis
What sign is seen on an x-ray of the spine in patients with renal bone disease?
sclerosis of ends of the vertebra & osteomalacia in centre of vertebra = rugger jersey spine
Why do patients with CKD get renal bone disease?
High phosphate (kidneys usually excrete phosphate)
Low vitamin D (kidneys usually metabolise vitamin D into active form)
Low calcium (vitamin D needed for calcium absorption)
Secondary hyperparathyroidism from low calcium, high phosphate and low vitamin D = increased osteoclast activity
Get osteomalacia from low calcium
Get osteosclerosis as osteoblasts increase activity in response to high osteoclast activity
Get osteoporosis due to increased age and steroid use
How is renal bone disease managed?
calcitriol (vitamin D),
low phosphate diet,
bisphosphonates for osteoporosis
Symptoms of dehydration
- Dry mucous membranes
- Loss of skin turgor
- Sunken eyes
- Tachycardia
- Hypotension
- Delirium
What is diabetic nephropathy?
kidney damage caused by type I and type II diabetes mellitus
Diabetic nephropathy is the most common cause of glomerular pathology and CKD in the UK.
What is the pathology behind diabetic nephropathy?
chronic high level of glucose passing through the glomerulus causes scarring = glomerulosclerosis
Risk factors for diabetic nephropathy
- Family hx
- Poor control of diabetes
- Long duration of diabetes
- Poor control of hypertension
- Obesity
Symptoms of diabetic nephropathy
Asymptomatic
Ix for diabetic nephropathy
Proteinuria + progressive reduction in GFR in the setting of a long duration of diabetes (>10 years)
- Screen annually with urinary albumin:creatinine ratio (ACR)
- Early morning specimen
- ACR > 2.5 = microalbuminuria
Mx of diabetic nephropathy
- Control hyperglycaemia
- Dietary protein restriction
- BP control
- Statins
- ACEi / ARB = reduce constriction of efferent arteriole = lower pressure in glomerulus (give ACEi even if they have a normal BP in diabetic nephropathy)
what is epididymitis? and what’s the function of the epididymis?
Inflammation of the epididymis
Epididymis are found posterior to each testicle, sperm are released from the testicle into the head of the epididymis and travel through the head, body then tail of the epididymis. Sperm mature & are stored in the epididymis then drain into the vas deferens
What is orchitis?
Inflammation of the testicles
what is epididymo-orchitis?
usually result of infection that spreads from the genital tract or the bladder in the epididymis and testicle on one side
Causes of epididymo-orchitis
- Escherichia coli
- Chlamydia trachomatis
- Neisseria gonorrhoea
- Mumps
Mumps symptoms
parotid gland swelling and unilateral orchitis, can also cause pancreatitis
Presentation of epididymo-orchitis
- Acute onset over minutes to hours
- Testicular pain
- Dragging or heavy sensation
- Swelling of testicle and epididymis
- Tenderness on palpation, especially over epididymis
- Urethral discharge if chlamydia/gonorrhoea
- Systemic symptoms = fever / sepsis
Key differential diagnosis of epididymo-orchitis
testicular torsion (<20 yo, severe pain and acute onset)
Ix for epididymo-orchitis
- Urine MC&S
- Chlamydia and gonorrhoea NAAT testing on first pass urine
- Charcoal swab for gonorrhoea culture & sensitivity
- Salvia swab for PCR testing of mumps
- Serum antibodies for mumps (IgM = acute infection, IgG = previous infection/vaccine)
- US – for testicular torsion or tumours
Mx for epididymo-orchitis that is suspected to be caused by an STI
GUM referral
Unknown organism but STI likely = ceftriaxone 500mg IM stat dose + doxycycline 100mg PO BD 10-14 days
Mx for epididymo-orchitis that is not suspected to be caused by an STI
ofloxacin 14 days
What is nephrotic syndrome?
the basement membrane in the glomerulus becomes highly permeable to protein, allowing proteins to leak from the blood into the urine.
Classic triad seen in nephrotic syndrome
- Low serum albumin
- High urine protein content (>3+ protein on urine dipstick)
- Oedema
Who is nephrotic syndrome common in?
Most common in 2–5-year-olds.
Presentation of nephrotic syndrome
- Frothy urine
- Generalised oedema
- Pallor
Signs of nephrotic syndrome
- Low serum albumin: <30g/L
- High urine protein content: >3g in 24 hours
- Oedema
- Deranged lipid profile – high levels of cholesterol, triglycerides and low density lipoproteins
- High blood pressure
- Hypercoagulability – loss of antithrombin II
Causes of nephrotic syndrome
- Minimal change disease (most common – 90% of cases in children under 10)
- Secondary causes:
a. Focal segmental glomerulosclerosis
b. Membranoproliferative glomerulonephritis
c. Henoch schonlein purpura
d. Diabetes
e. HIV
f. Hepatitis
g. Malaria
What does minimal change disease cause?
- Most common cause of nephrotic syndrome in children
Presentation of minimal change disease
oedema, proteinuria and low albumin
Ix for minimal change disease
urinalysis shows small molecular weight proteins and hyaline casts
Mx of minimal change disease
corticosteroids (prednisolone)
Prognosis of minimal change disease
most children make full recovery but it can
Management of nephrotic syndrome
- High dose steroids e.g. prednisolone
- Low salt diet
- Diuretics to treat oedema
- Albumin infusions in severe hypoalbuminaemia
- Abx prophylaxis
complications of nephrotic syndrome
- Hypovolaemia
o Due to oedema
o Causes low BP - Thrombosis
o Proteins to prevent clotting lost in kidneys: antithrombin II and plasminogen
o Pro-thrombotic proteins produced by liver in response to low albumin - Infection
o Kidney leaks Ig, weakening immune system response
o Steroids weaken immune system - Acute / chronic kidney failure
- Relapse
- Hyperlipidaemia = increased CVD risk
- Hypocalcaemia – vitamin D and binding protein lost in urine
what is prostate specific antigen?
Is a glycoprotein produced by epithelial cells of the prostate. Its secreted into the semen, with a small amount entering the blood. It thins the semen so its has a liquid consistency after ejaculation.
Is specific to the prostate.
What type of cancer is prostate cancer usually?
Adenocarcinoma