Renal Flashcards
Renal
What are the functions of the kidneys?
Removal of waste products/toxins Balancing of electrolytes Stabilising acid-base status Maintaining fluid balance Activating Vit D Stimulating erythropoiesis Maintaining blood pressure
What is an acute kidney injury?
A rapid reduction of kidney function, leading to an inability to maintain fluid, electrolyte and acid-base homeostasis
What are the 3 types of AKIs?
Pre-renal
Renal
Post-renal
What are the causes of pre-renal AKI?
Hypovolaemia/tension
- Sepsis
- Major haemorrhage
- Vomiting/diarrhoea
- Congestive HF
Renal-specific
-RAS/embolus
Drugs eg ACEi, NSAIDs
What are the signs and symptoms of pre-renal AKI?
Tachycardia
Hypotension
Increased capillary refill time
Clinically dry (decreased turgor, absent JVP, dry mucous membranes)
What are the causes of post-renal AKI?
Urinary tract obstruction
- Stones
- Clots
- Blocked catheter
Mural
- BPH
- Malignancy of urinary tract
- Strictures
Extrinsic compression
- Pelvic malignancy
- Retroperitoneal fibrosis
What are the signs and symptoms of post-renal AKI?
Hx of urgency, frequency, or hesitancy
Flank pain +/- haematuria
Distended, palpable bladder if LUTO
What are the causes of renal AKI?
Acute tubular necrosis 2ary to:
- ischaemia (pre-renal)
- nephrotoxic damage
- rhabdomyolysis
Glomerulonephritis
Acute interstitial nephritis (classically NSAIDs)
Vasculitis
What are the signs and symptoms of renal AKI?
Hx of nephrotoxic drug/long lie/crush injury Rash, petechiae, ecchymoses Nephritic syndrome (oedeoma, proteinuria, microscopic haematuria)
What are the investigations for AKI?
Urinalysis- protein, blood, high specific gravity, cellular casts
U+E- raised creatinine, urea, potassium
VBG- metabolic acidosis
Renal US- unilateral vs bilateral dilated calyces
ECG- signs of hyperkalaemia
What is the management for pre-renal AKI?
Correct volume depletion
Haemofiltration if indicated
What is the management for post-renal AKI?
Urinary catheterisation
Urology referral
Haemofiltration if indicated
What is the management for renal AKI?
Treat underlying course
Supporative care
Haemofiltration if indicated
What is chronic renal failure?
Impaired renal function for >3months, either abnormal structure/function, or GFR <60ml/min
How many stages of chronic renal failure are there?
Stage 1 >90 Stage 2 60-89 Stage 3a 45-59 Stage 3b 30-44 Stage 4 15-29 Stage 5 <15 End stage renal failure
What are some causes of chronic renal failure?
Diabetes mellitus Hypertension Chronic inflammation Glomerulonephritis Vasculitis Myeloma/myeloidosis Pyelonephritis Polycystic kidney disease Renal artery stenosis
What are the signs and symptoms of chronic renal failure?
Uraemia- nausea, vomiting, pruritus, yellow skin
Uraemia in extremis- encephalopathy and pericarditis
Hyperkalaemia- arrhythmia
Metabolic acidosis- tachypnoea, confusion
Oedema- periorbital, peripheral, pulmonary
Vit D def- osteomalacia, hypocalaemia
Anaemia- fatigue, breathlessness, pallor, hypertension
What are the investigations for chronic renal disease?
Urinalysis
-haematuria, proteinuria, microalbuminuria
Bloods
-low Hb, raised creatinine/urea, raised K, dec Ca, raised PO4, raised ALP, raised PTH
Imaging
-USS kidneys, shrunk in CKD (unless ADPKD, amyloidosis, myeloma)
Histology
-Renal biopsy
What is glomerulonephritis?
Diseases characterised by immune mediated inflammatory changes in the glomerular capillaries and basement membrane.
What are the two types of glomerulonephritides?
Nephritic syndrome (aka proliferative GN) Nephrotic syndrome (aka non-proliferative GN)
What is nephritic syndrome?
Inflammation of the glomerulus, causing haematuria
What is nephrotic syndrome?
Proteinuria due to podocyte pathology
What are you looking for in nephritic syndrome?
Haematuria +/- RBC casts
Proteinuria
Hypertension
Decreased GFR
What are you looking for in nephrotic syndrome?
Heavy proteinuria (>3.5g/24h)
Hypoalbuminaemia
Oedema
Hyperlipidaemia
What are the types of proliferative glomerulonephritis?
IgA nephropathy
Post-streptococcal GN
Rapidly progressive GN
What are the types of non-proliferative glomerulonephritis?
Minimal change GN
Focal segmented glomerulosclerosis
Membranous nephropathy
What is IgA nephropathy?
Occurs 1-2 days post-URTI due ot IgA deposition on glomeruli
What is post-streptococcal glomerulonephritis?
Occurs 2-6 weeks post-throat/skin infection
What is rapidly progressive glomerulonephritis?
Any aggressive GN progressing to renal failure over days/weeks, typically from vasculitis, lupus nephritis, or anti-GBM disease
What is minimal change glomerulonephritis?
Classical occurs in children
Electron microscopy shows effacement of podocyte foot processes
Good response to oral prednisolone
What is focal segmental glomerulosclerosis?
Scarring of certain segments of glomerulus
Can be idiopathic, or secondary to HIV, heroin, lithium, lymphoma
What is membranous nephropathy?
Can be idiopathic or due to: Infx (hep B, malaria, syphilis) Autoimmune (SLE, thyroiditis, RhA) Malignancy (lung cancer, lymphoma, leukaemia) Drugs (gold, penicillamine, NSAIDs)
What is polycystic kidney disease?
An ausosomal dominant inherited disease, characterised by renal cysts, extrarenal cysts, and intracranial aneurysms
What are the risk factors for PCKD?
FHx of PCKD
- renal failure
- sub-arachnoid haemorrhage
What are the symptoms of PCKD?
Abdominal/flank pain
Haematuria
What are the signs of PCKD?
Hypertension
Palpable kidneys
Hepatomegaly
What are the investigations for PCKD?
Urinalysis -haematuria -proteinuria Bloods -raised creatinine -genetic screen (PKD1, PKD2) Imaging -Renal US: >2 cysts -CT/MRI abdo if US equivocal -CT/MRA head for aneurysms
What is renal artery stenosis?
Narrowing of the renal arterial lumen due to atherosclerotic disease
Reduction of renal perfusion
What are the risk factors for RAS?
Age >55 Smoking Diabetes Dyslipidaemia Hx of vascular disease
What are the symptoms of RAS?
Symptoms of kidney dysfunction (acute or chronic)
What are the signs of RAS?
Resistant hypertension
Abdominal bruit
Kidney dysfunction
What should you not give to a Pt with bilateral RAS and why?
ACEi/ARB
Stimulates dilation of the efferent arteriole
Reduces the GFR leading to renal failure
What are the investigations for RAS?
Urinalysis- normal
Bloods- raised creatinine if CKD/AKI, low K due to RAAS activation
Imaging:
Duplex ultrasound
CTA
Conventional angiography- diagnostic and therapeutic
What pathogens commonly cause a UTI?
E coli Staph saprophyticus Proteus Klebsiella Pseudomonas
What are the risk factors for UTIs?
Female
Sexual activity
Recurrent UTIs
Urinary catheter
What are the clinical features of lower UTIs?
Dysuria Urinary frequency Urinary urgency Suprapubic pain/tenderness Offensive smell Confusion in elderly
What is pyelonephritis?
Severe infectious inflammatory disease of the renal parenchyma, calices and pelvis
What are the risk factors for pyelonephritis?
Female Hx of UTI Stress incontinence Diabetes mellitus Anatomical/functional urinary tract abnormality
What are the clinical features of pyelonephritis?
Loin pain/costovertebral tenderness Vomiting Fever Rigors LUTI symptoms
What are the investigations for a UTI?
Urine dip -nitrite and leukocyte positive Urine MC+S -confirm organism and antibiotic sensitivity Bloods -raised neutrophils, CRP; blood culture
What is the management of a UTI?
Antibiotic therapy
Oral if the Pt is well (nitrofurantoin/trimethoprim)
IV if the Pt is sick (gentamycin/ceftriaxone)
What is a renal cell carcinoma?
Renal malignancy, often due to a sporadic mutation from the renal parenchyma/cortex
What are the risk factors for RCCs?
Smoking Male >55 Obesity Hypertension FHx of RCC
What are some hereditary causes of RCCs?
Von-Hippel Lindau syndrome
Tuberous sclerosis
What are the clinical features of RCC?
Often asymptomatic Haematuria Flank pain Palpable abdominal mass Left-sided scrotal varicocele Paraneoplastic syndromes (EPO, renin, PTHrp, ACTH) FLAWS/bony pain
What are the investigations for RCCs?
Urinalysis- haematuria
US- to detect renal lesions
CTAP- diagnosis and staging
CXR- cannonball mets
A 75 year old man is admitted with community acquired pneumonia.
On examination, his abdomen is soft and non-tender. The bladder is not palpable. A urinary catheter bag at the bedside contains a small amount of concentrated urine. He has dry mucous membranes, reduced skin turgor and his JVP is not visible.
Bloods: Creatinine 362μmol/L (120μmol/L – 1 month ago)
What is the most appropriate immediate management option?
A. IV fluids B. IV furosemide C. USS kidneys D. Urgent urology referral E. Haemodialysis
A. IV fluids
This is a case of pre-renal acute kidney injury – due to kidney hypo perfusion. Treatment here is intravenous fluid replacement to correct hypovolaemia. Most commonly AKI’s are due to a pre-renal cause.
IV furosemide would worsen AKI, diuretics should be stopped or held in these patients.
Ultrasound of the kidneys may be useful to identify whether this is an acute or chronic picture. This is not appropriate in this case as there is a clear acute deterioration from this patient’s baseline creatinine clearance.
Urology referral may be necessary if post-renal cause of AKI identified.
Though haemodialysis can be used in acute kidney injury, there is nothing in the question which fits the criteria for the commencement of haemodialysis.
A 67 year old man presents with a long history of fatigue, nausea and poor appetite. He has a past medical history of type 2 diabetes mellitus and hypertension. You suspect this patient’s presentation is due to chronic kidney disease.
Which of the following can be used to stage chronic kidney disease?
A. Blood pressure B. Haemoglobin C. Creatinine D. Potassium E. HbA1c
C. Creatinine
CKD symptoms are frequently non-specific. Nausea and anorexia are symptoms of accumulation of waste products. Fatigue may be due to anaemia.
Creatinine is the only marker of clearance listed, and therefore can be used to calculate glomerular filtration rate (GFR). GFR is used to stage CKD severity.
Blood pressure – strong association between CKD and hypertension
Haemoglobin – Patients with CKD may have a normocytic anaemia due to EPO deficiency
Potassium – Hyperkalaemia is a feature of CKD
HbA1c – used to monitor glycaemic control in diabetes mellitus
A 32 year old woman is feeling tired for the past 3 days. Over this time she has noticed that has only passed small amounts of concentrated urine. She is normally fit and well. She was successfully treated with oral antibiotics for a sore throat 2 weeks ago.
Blood pressure: 145/95mmHg
Urine dipstick: protein 1+, blood 2+
What is the most likely diagnosis?
A. Acute tubular necrosis B. Acute interstitial nephritis C. Glomerulonephritis D. Pyelonephritis E. Urinary tract calculus
C. Glomerulonephritis
The triad of hypertension, proteinuria and haematuria suggests glomerulonephritis. The previous throat infection (likely caused by streptococcus) makes this post-streptococcal glomerulonephritis.
A 45 year old woman has noticed that her face and legs have become swollen gradually over the last 6 months. She has no past medical history and takes no regular medications.
Blood pressure: 120/80mmHg
Urine dipstick: protein 3+, blood neg
What is the most likely diagnosis?
A. Acute tubular necrosis B. Acute interstitial nephritis C. Glomerulonephritis D. Pyelonephritis E. Urinary tract calculus
C. Glomerulonephritis
The triad of proteinuria, hypoalbuminaemia and oedema suggest nephrotic syndrome.
Membranous glomerulonephritis (membranous nephropathy) causes predominantly nephrotic syndrome. Inflammation of the basement membrane secondary to immune complex deposition and complement activation.
Proteinuria is more substantial in nephrotic. Pathogenesis of nephrotic syndrome: Glomerulus becomes very leaky -> Proteinuria -> hypoalbuminaemia -> low oncotic pressure -> oedema
A 69 year old man with known coronary artery disease and peripheral vascular disease presents with an acute kidney injury. Ramipril has recently been started for resistant hypertension.
What is the most likely underlying diagnosis?
A. Renal artery stenosis B. Renal cell carcinoma C. Phaeochromocytoma D. Conn’s syndrome E. Cushing’s syndrome
A. Renal artery stenosis
All 5 listed are potential causes of secondary hypertension. The history (AKI after the commence of an ACE inhibitor in a vasculopath) is highly suggestive of renal artery stenosis (bilateral disease).
A 36 year old woman presents with a 2 day history of fever and right-sided back pain. She also describes pain on passing urine. She is normally fit and well.
On examination: Right-sided costovertebral angle tenderness. HR 110bpm, Temp 39.2ºC
Urine dipstick: leukocytes ++, nitrites ++, blood +
What is the most likely diagnosis?
A. Lower urinary tract infection B. Acute pyelonephritis C. Urinary tract calculus D. Glomerulonephritis E. Acute tubular necrosis
B. Acute pyelonephritis
Acute pyelonephritis most likely as dipstick shows infection and abdominal pain with high fevers are classical.
UTI would have dysuria and these dipstick results, but you would not expect abdominal/back pain if uncomplicated.
Urinary tract calculus would present with flank pain (renal colic) and haematuria, without signs of infection.
A 66 year old male smoker presents with a 3 month history of dull left flank pain. No significant past medical history or family history.
On examination: Left-sided palpable abdominal mass.
Urine dipstick: leukocytes neg, nitrites neg, blood +
What is the most likely diagnosis?
A. Acute pyelonephritis B. Urinary tract calculus C. Glomerulonephritis D. Renal cell carcinoma E. Polycystic kidney disease
D. Renal cell carcinoma
