Renal + urology Flashcards
Gitelman syndrome
Mutations in the thiazide-sensitive Na/Cl symporter
Autosomal recessive
Features:
- Normotensive
- Low Cl-, K+, Mg2+, Ca2+
- Metabolic alkalosis
- Raised urinary Na+ and K+
Investigations:
- Bloods
- 24h urinary Na+ and K+
Management:
- K+ and Mg 2+ supplementation
- Trial of aldosterone antagonists
Conn syndrome
Primary hyperaldosteronism
- Usually due to adrenal adenoma
Features:
- Hypertension
- Normal/raised Na+, low K+
Management:
- Aldosterone antagonists
- Adrenalectomy
Liddle syndrome
Pseudo-hyperaldosteronism due to mutations in the ENaC
- Autosomal dominant
- Increase ENaC activity = increased Na+ reabsorption
Features:
- HTN
- Hypokalaemia
- Metabolic alkalosis
- Low renin + aldosterone
Management:
- Potassium-sparing diuretics e.g. amiloride
Acute interstitial nephritis
Inflammation of the renal tubulointerstitium
Aetiology:
- Drug hypersensitivity
- Rifampicin, allopurinol, antibiotics, NSAIDs
- Autoimmune
- SLE, Sjogrens
- Idiopathic (rare)
- Viral
- Hantavirus
- Bacterial
- Leptospirosis, mycobacteria
Features:
- AKI
- Fever
- Eosinophilia
- Sterile pyuria
- Nephrotic syndrome if NSAID-induced
Management:
- Treat cause
- Steroids
Renal tubular acidosis
Type I - distal
- Failure of distal and collecting tubular cells to secrete H+ and reabsorb K+
- Features:
- Renal stones - due to urinary alkalosis +
increased secretion of Ca2+ in serum
acidosis
- Diabetes insipidus
- Salt wasting
- Severe metabolic acidosis + hypokalaemia
Type II - proximal
- Failure of proximal tubule cells to reabsorb HCO3
- Features:
- Mild metabolic acidosis +/- hypokalaemia
- Osteomalacia
- Rickets
Type III
- Combined type I and type II
Type IV
- Either low serum aldosterone or renal resistance to aldosterone activity
- Features:
- Hyperkalaemia
- CKD
Type 1 renal tubular acidosis
Failure of distal and collecting tubular cells to secrete H+ and reabsorb K+
Aetiology:
- Idiopathic or genetic
- Autoimmune disease
- Nephrocalcinosis
- Drugs incl. lithium
Features:
- Renal stones
- due to urinary alkalosis + increased secretion
of Ca2+ in serum acidosis
- Diabetes insipidus
- Salt wasting
- Severe metabolic acidosis + hypokalaemia
Type 2 renal tubular acidosis
Failure of proximal tubule cells to reabsorb HCO3
Aetiology:
- Idiopathic
- Fanconi syndrome
- Drugs incl. NSAIDs, heavy metals
Features:
- Mild metabolic acidosis +/- hypokalaemia
- Osteomalacia
- Rickets
Fluid requirements
Adult:
25-30 ml/kg/day
50-100g glucose
Child:
- 100ml/kg/day for first 10kg, then 50ml/kg/day for next 10kg, then 20ml/kg/day for the remainder
Central pontine myelinolysis (osmotic demyelination syndrome)
A disorder in which myelin +/- neuronal cells are damaged by rapid correction of hyponatraemia
- A rise of > 1 mmol/hr or >10 mmol/day
- Symptoms start 2-3 days after hyponatraemia
Features:
- Reduced GCS
- Confusion
- Limb weakness, paralysis, paraesthesia
- Dysphagia
- Dysphasia
- Impaired coordination
- Can progress to coma/death
Management:
- Supportive
- May recover over months or be left with permanent disability
Functional parts of kidney
Glomerulus
- Receives 600ml/min
- Filters (GFR) 120ml/min
- Filtration depends on molecular weight and charge of molecule
- Foot processes and BM are -ve charge
- Molecules > 4nm are completely blocked (e.g. cells, protein), 2-4nm partially blocked.
PCT
- 70% of reabsorption - esp. glucose, amino acids
- Completely permeable to water and glucose
- Secretes HCO3 to allow H+ reabsorption
- Can vary amount of isotonic reabsorption to modulate the ECF
- Contains a number of organic ion transporters which affect excretion of hormones, drugs, etc.
Loop of Henle
- Establishes the medullary concentration gradient to allow for later reabsorption
DCT
- Contains K+/H+ antiporters which help to maintain plasma K+ and pH
Collecting duct
- Site of ADH action -> aquaporin insertion allowing for reabsorption down the medullary concentration gradient
Afferent and efferent arterioles
Can be modulated by systemic NA/Adr or by local mechanisms to maintain GFR across a range of cardiac outputs
Afferent
- Constriction -> reduced rate filtration, same amount of filtrate
- Myogenic response
- Constricts when stretched due to stretch-
activated calcium channels
Efferent
- Constriction -> increased rate of filtration
- Dilation -> reduced rate of filtration
Renin-aldosterone-angiotensin system
Renin:
- Proteolytic enzyme
- Secreted by juxtaglomerular cells in the afferent arteriole in response to:
- NA action on beta-1 adrenoceptors
- Fall in afferent arteriole stretch
- Decreased Na+ load at the macula densa
- Catalyses cleavage of angiotensinogen to angiotensin - 1
Angiotensin:
- 2 step production:
- Angiotensinogen + renin -> angiotensin -1
- angiotensin-1 + ACE -> angiotensin-2
- AT1 stimulation
- Vasoconstriction - raises BP and GFR
- Increased Na+ reabsorption
- AT2 stimulation
- Increases thirst + Na+ appetite
- Stimulates aldosterone synthesis
Aldosterone:
- Acts on thick ascending limb + collecting ducts to promote Na+ reabsorption, H+ and K+ secretion
- Slowly increases expression of ENAC
Atrial and brain natriuretic peptides (ANP, BNP)
ANP
- Stored in atrial myocytes
- Released in response to atrial stretch (aka high BP)
- Stimulates Na+ and water loss, inhibits ADH and renin
BNP
- Cleaved from NT-proBNP
- Binds to ANP receptors although with reduced efficacy
- Found in brain and heart
ADH/vasopressin
Synthesised in the SON and PVN, stored in nerve terminals in the posterior pituitary
- Release dependent on osmoreceptors
Effects:
- V1
- Vasoconstriction
- V2
- Aquaporin insertion -> increased water
reabsorption
Hereditary angioedema
Mutation/deficiency in C1INH (C1 esterase inhibitor) leading to excessive bradykinin levels and episodes of painful swelling
- Similar mechanism can lead to angioedema
with ACEi use
Management
- Ecallantide - synthetic C1INH
Hypernatraemia
Aetiology:
- Diabetes insipidus
- HHS
- Dehydration
- ATN - early polyuric phase
- Diuretics
- Steroid excess - Cushing, Conn
- Salt poisoning - iatrogenic (NaCl, sodium bicarb), drowning in salt water, high sodium feed
Features:
- Mild (140-180)
- Can be asymptomatic
- Excessive thirst, confusion
- Severe (> 180)
- Ataxia, tremor, coma, seizures
- Raised ICP
Management:
- Aim reduction no greater than 10 mmol/day otherwise risk cerebral oedema
- Hypovolaemic
- Fluid resus + 5% dex
- Euvolaemic
- 5% dex
- Hypervolaemic
- 5% dex + loop diuretic
Hyponatraemia
Hypertonic
- Serum osmolality > 285
- Hyperglycaemia
- Mannitol infusion
Isotonic
- Serum osmolality 280-285
- Hyperlipidaemia or paraproteinaemia
Hypotonic
- Serum osmolality < 280
- Hypovolaemic
- Urine Na < 20
- Vomiting
- Diarrhoea
- 3rd spacing
- Urine Na > 20
- Diuretics
- Addisons’
- Salt wasting nephropathy
- Euvolaemic
- Urine osmolality > 100
- Primary polydipsia
- Beer potomania
- Ecstasy
- Urine osmolality < 100
- SIADH
- Hypothyroidism
- ACTH deficiency
- Hypervolaemic
- Urine Na < 20
- Heart failure
- Liver failure
- Nephrotic syndrome
- Urine Na > 20
- Kidney failure
Severe hyponatraemia management
aka symptomatic with seizures and drowsiness
Admit to ITU
- Aim initial rise of 1-2 mmol/hr over first 3 hr
- Can raise Na+ > 10mmol/day with care
Calculate sodium deficit:
Fluid [Na] - serum [Na]/1 + total body water
(1L 0.9% NaCl = 154 mmol)
Hypoalbuminaemia
Aetiology:
- Decreased production
- Chronic inflammation
- Severe malnutrition
- Liver cirrhosis
- Increased loss
- Renal - nephrotic syndrome
- GI - erosive (IBD, malignancy, PUD), non-
erosive (coeliac, sprue, SIBO, Whipples),
raised lymphatic pressure (CCF, mesenteric
TB)
- 3rd spacing
- Increased catabolism
- Prolonged severe illness e.g. ITU
Management:
- Mostly supportive + treat underlying cause
- HAS if cirrhosis or haemodynamic instability not responding to crystalloids alone
SIADH
Aetiology:
- Malignancy
- SCLC, pancreatic, prostate
- Infections
- TB
- Neurological
- Stroke, SAH, abscess
- Drugs
- SSRIs, Indomethacin, TCAs, thiazide diuretics,
antipsychotics, cyclophosphamide, vincristine
Investigations:
- Paired urine + serum osmolality
- Paired urine + serum sodium
- Water deprivation testing
Management:
- Fluid restriction
- Demeclocycline
Hyperkalaemia
Aetiology:
- Kidney failure
- Rhabdomyolysis
- Tumour lysis
- Metabolic acidosis
- Hypoglycaemia
Features:
- Muscle weakness
- Paraesthesias
- Palpitations
- Arrhythmia
Investigations:
- Bloods
- ECG - tall tented T waves, broad QRS
Management:
- Calcium gluconate 10ml over 10 mins, repeated
- Insulin/dextrose - 10 units in 250ml 10% dextrose
- Salbutamol nebs 5-10mg
Hypokalaemia
Aetiology
- Vomiting or diarrhoea
- Loop and thiazide diuretics
- Conn’s syndrome
- Laxative abuse
- Metabolic alkalosis
- Insulin therapy
- Refeeding syndrome
Features:
- Muscle weakness + myalgia + cramps
- Tremor
- Palpitations
- Constipation
Investigations:
- Bloods
- ECG - T wave flattening/inversion, U waves, QT prolongation
Management:
- Treat underlying cause
- Sando-K TT TDS
- IV KCl
Hypercalcaemia
Aetiology
- Malignancy
- Hyperparathyroidism
- Multiple myeloma
- Dehydration
- Paget’s disease
- Addison’s disease
- CKD
Features:
- Bone pain
- Fatigue, weight loss
- Constipation
- Kidney stones, kidney impairment
- Depression, psychosis
Investigations
- Routine bloods
- TFTs, PTH level, vitamin D
- ECG - shortened QTc
- Imaging of bones
Management:
- Acute:
- IV fluids
- IV bisphosphonates
Hypocalcaemia
Aetiology:
- Vitamin D deficiency
- Hypoparathyroidism (incl. post-surgical)
Features:
- Muscle cramps, twitching -> tetany
- Paraesthesias
- Carpopedal spasms
- Chvostek’s + Trousseau’s signs
- Risk of laryngeal tetany and asphyxiation
Investigations:
- Routine bloods
- PTH and vitamin D levels
- ECG - prolonged QTc
Management:
- Acute (calcium < 1.9, symptoms)
- IV calcium gluconate
- Chronic:
- Cholecalciferol (if vit D deficient)
- Calcitriol (if PTH deficient)
Calcium homeostasis
Absorption
- GIT
- Renal reabsorption
Storage:
- 99% calcium hydroxyapatite in the bones
- Remainin 1% in cells + serum
- Protein-bound
- Chelated - for transport
- Ionised - used in cellular signalling
PTH:
- Secreted in response to hypocalcaemia, from parathyroid glands (x 4)
- Stimulates bone resorption
- Increases renal calcium reasbsorption
- Increases renal vitamin D activation
Vitamin D
- Increases in response to hypocalcaemia
- Metabolised in two steps into 1,25-dihydroxyvitamin D
- Increased expression of GIT calcium-binding
proteins -> increased absorption
- Stimulates bone resorption
Calcitonin
- Secreted from parafollicular C cells (thyroid) in response to hypercalcaemia
- Inhibits bone resorption
- Inhibits renal reabsorption of calcium
Phosphate
Levels are usually inverse to calcium
High:
- Aetiology - CKD, acidosis, tissue lysis, tertiary hyperparathyroidism
Low:
- Aetiology - primary hyperparathyroidism, refeeding syndrome, ETOH, Cushing’s, alkalosis
- Features - muscle weakness, tremor, infection, confusion, respiratory depression
- Management - PO or IV replacement
Hypomagnesaemia
Aetiology:
- Malnutrition
- Medications - diuretics, PPIs, ciclosporin, cisplatin
- Osmotic loss - diabetes
- Malabsorption
- Prolonged GI suction, stoma, fistula etc.
Features:
- Fatigue
- Weakness
- Muscle cramps
- Spasticity
- Seizures
Investigations:
- U&Es + bone profile
- Leads to hypokalaemia
- ECG - prolonged QTc, tachy
Biochemical patterns:
Adrenal insuff (5)
Hyperaldo(3)
Phaeochromocytoma(1)
Sarcoidosis(2)
Carcinoid syndrome(3)
Refeeding syndrome(4)
Sequelae of parenteral nutrition(3)
Rhabdomyolysis (5)
Tumour lysis syndrome (6)
Toxic alcohols (ethylene glycol as eg)(3)
Lithium toxicity (2)
Salicylate toxicity (3)
Adrenal insufficiency
- Hyponatraemia
- Hyperkalaemia
- Normal anion gap acidosis
- Hypoglycaemia
- Hypercalcaemia
Hyperaldosteronism
- Hypernatraemia
- Hypokalaemia
- Metabolic alkalosis
Phaochromocytoma - beta-2 blockade
- Hypokalaemia
Sarcoidosis - ACE activity
- Hypercalcaemia
- Hypercalciuria
Carcinoid syndrome - secretory diarrhoea
- Hypokalaemia
- Hypomagnesaemia
- Normal anion gap acidosis
Refeeding sybdrome
- Hypophosphataemia
- Hypokalaemia
- Hypomagnesaemia
- Hyperglycaemia
Parenteral nutrition
- Hyperglycaemia
- Hyperlipidaemia
- Normal anion gap acidosis
Rhabdomyolysis
- Hyperkalaemia
- Hyperphosphataemia
- Myoglobinuria
- Raised CK, LDH
Tumour lysis syndrome
- Hyperkalaemia
- Hyperphosphataemia
- Hypocalcaemia
- Hyperuricaemia
- Raised anion gap acidosis
- Raised LDH
Toxic alcohols (e.g. ethylene glycol)
- Hypocalcaemia
- Raised anion gap acidosis
- Raised serum osmolar gap
Lithium toxicity
- Hypernatraemia
- Low anion gap acidosis
Salicylate toxicity
- High anion gap acidosis
- Hypokalaemia
- Hyperkaluria
Nephrotoxic drugs
Membraneous GN
- Pencillamine
- Gold
- Captopril
(Acute) interstitial nephritis
- Penicillins
- Cephalosporins
- NSAIDs
- Allopurinol
- Phenytoin
- PPIs
Renal tubular damage:
- Amphotericin
- Heavy metals - incl. mercury, lithium
- Cisplatin
- Aminoglycosides
- Vancomycin
- NSAIDs
- Aciclovir
Acute tubular necrosis
Renal tubular cell damage (+/- death) which initially causes AKI but can lead to strictural injury
Aetiology:
- Reduce renal perfusion e.g. hypovolaemia, sepsis
- Nephrotoxic medications
Pathology:
- Loss of brush border
- Tubular cell vacuolation and sloughing
- Typically Na+ wasting
Features - three phases:
- Initiation
- Oliguria
- Uraemia
- Maintenance
- Worsening oliguria and uraemia
- Hyperkalaemia
- Acidosis
- Fluid overload
- Recovery
- Polyuria - massive loss of Na+ and K+
- Hypokalaemia
Investigations:
- Urine analysis
- Urine Na+ > 40
- Urine osmolality < 350
- Microscopy - brown epithelial casts + free
epithelial cells
- Fluid balance
- Bloods
- Renal US normal
Acute interstitial nephritis
Aetiology:
- Infection
- Medications e.g. NSAIDs, PPIs, antibiotics
Features:
- AKI
- HTN
- Rash
- Eosinophilia
- Fever
- Flank pain - from swelling and stretch of the renal capsule
Chronic interstitial nephritis
Fibrosis and dysfunction secondary to chronic or repeated insults
Aetiology:
- Heavy metals
- Nephrocalcinosis
- Chronic hyperkalaemia
- Medication e.g. analgesics
Urea:creatinine ratio
Both freely filtered by the tubules but urea should be reabsorbed in a regulated fashion whereas creatinine is not
Normal ratio 40-110:1
Used to define types of AKI:
- > 110:1 = prerenal
- 40-110:1 = post-renal
- < 40:1 = intrinsic
Azotaemia and uraemia
Azotaemia = increased non-nitrogenous waste products in the blood (usually proteinaceous)
Uraemia = increased urea in the blood
Azotaemia will precede uraemia
Features:
- Azotaemia
- Fatigue
- Muscle weakness
- Nausea/vomiting
- Uraemia
- Itching
- Pericardial effusion
- Encephalopathy
- Stomatitis or parotitis
- Tremors
- Peripheral neuropathy
CKD - aetiology and staging
Aetiology:
- Diabetic nephropathy (44%)
- HTN (27%)
- Glomerulonephritis (8%)
- Other
- Cystic disease
- Urological
- Infection - malaria, schistosomiasis
Classification - eGFR + ACR:
G stage:
- Stage 1
- Preserved eGFR + abnormal ACR
- Stage 2
- eGFR 60-89 + abnormal ACR
- Stage 3
- A = eGFR 45-50
- B = eGFR 30-44
- Stage 4
- eGFR 15-29
- Stage 5
- eGFR < 15 or requiring RRT
A stage
- A1 - ACR < 3
- A2 - ACR 3-30
- A3 - ACR > 30
CKD + bone disease
Pathophysiology:
- Reduced vitamin D activation + reduced secretion of phosphate leads to hyperphosphataemia
- High phosphate leaches calcium out of bones causing osteomalacia
- Compensatory response includes PTH secretion
Aim of treatment is to treat high PTH and high phosphate
- Reduced dietary phosphate
- Phosphate binders
- Activated vitamin D supplements e.g. alfacalcidol
Haemodialysis
Usually 4hr sessions, 3x a week
Access:
- AV fistula in the non-dominant hand
- 6-8 weeks to mature
- Ideally formed several (6) months prior to
need
- Tunneled dialysis line
- Only if fistula fails or severe vascular disease
Complications
- Fistula stenosis or thrombosis
- Line infection
- Steal syndrome
- Redirection of blood leading to hand
ischaemia
- Hypotension
- Arrhythmias
- Dialysis disequilibrium syndrome
- Cerebral oedema secondary to rapid fall in
urea
- Headache, confusion, focal neurology
- Anaphylaxis
- Usually to dialysis membrane
- Accelerated cardiovascular disease
Peritoneal dialysis
Utilisation of the peritoneum as a semipermeable membrane to dialyse the blood
Performed daily but can be done at home
- Requires generally good health (no cardiac
comorbities)
- Preferred if have a residual renal function
Complications:
- Exit site infection
- Peritonitis
- Fatigue, headache, cramps, etc.
Continuous RRT
A slower type of dialysis which reduces the haemodynamic shifts associated
Allows removal of both fluid and solutes
Continuous venovenous haemofiltration or haemodialysis
- Dialysis = gradients alone, filtration = pressure
Indications:
- Pulmonary oedema or pericardial effusion resistant to diuresis
- pH < 7.2
- Persistent K+ > 6.5 or other severe eletrolyte abnormalities
- Symptomatic uraemia
Hyperuricaemia aetilogy
- Gout
- Lesch-Nyhan syndrome
- Congenital disorder of purine metabolism - Tumour lysis syndrome
- High purine diet
- Hyperparathyroidism
- Lead posioning
- Downs syndrome
- Exercise
- Starvation
- Medications e.g. thiazides, salicylates, ETOH
Hepatorenal syndrome
Includes both AKI and CKD developed on a background of liver cirrhosis with no other cause for renal impairment
Aetiology:
- Acute - SBP, GI bleed, ETOH, acute liver failure, large volume ascites paracentesis
- Chronic - liver decompensation
Pathophysiology:
- Hypoalbuminaemia + splanchnic vasodilation -> fall in systemic BP -> renal hypoperfusion
- RAAS activates and cannot deactivate leading to worsening renal perfusion and impairment
Management:
- Aim to restore euvolaemia + splachnic vasoconstriction
- HAS + terlipressin
- TIPS
- Liver transplant
Metabloc acidosis
High anion gap (CAT MUDPILES) - > 12
- C - CO, CN
- A - alcoholic and starvation ketoacidosis
- T - toluene
- M - metformin, methanol
- U - uraemia
- D - diabetic ketoacidosis
- P - paracetamol, propylene glycol
- I - iron, isoniazid, IEM
- L - lactic acidosis
- E - ethylene glycol
- S - salicylates
Normal anion gap (CAGE)
- NB hypercholraemic acidosis (Cl - replacing HCO3 - ) or HCO3 loss
- C- chloride excess
- A - acelazolamide, adrenal insufficiency
- G - GI e.g. diarrhoea, vomiting, fistulae
- E - extras e.g. RTA
D-lactic acidosis
A rare cause of raised anion gap acidosis
Aetiology:
- Short bowel syndrome
- SIBO
- Jejuno-ileal bypass
Pathophysiology:
- Malabsorptive state - carbohydrate is taken up and metabolised by abnormal colonic flora, producing D-lactate
- D-lactate competes with pyruvate in the heart and brain (although can be used and metabolised in the liver)
Features:
- Reduced GCS / confusion
- Ataxia
- Coma
- Heart arrhythmias or block
Investigations:
- Serum D-lactate levels - not seen on standard assays
Nephrotic syndrome
Aetiology:
- Membraneous glomerulonephritis
- Minimal change disease
- SLE
- FSGS
- Mesangiocapillary glomerulonephritis
- Amyloidosis
- IgA glomerulonephritis
Features:
- Hypoalbuminaemia (< 35)
- Proteinuria (> 3.5g/day)
- Oedema
- Hypercoagulability
- Hyperlipidaemia
- High cholesterole + LDL, normal HDL
- Immunodeficiency
- esp. pneumococcal infections, loss of IgG
- Hypothyroidism
- loss of thyroid-binding protein
- Vitamin D deficiency
- loss of vitamin D binding protein
- Abdominal pain
- from splanchnic ischaemia
Investigations:
- Urine
- Dipstick
- Protein-creatinine ratio
- 24h protein collection
- Bloods:
- Routine
- Lipid profile
- Serology - syphilis, HIV, hepatitis,
autoimmune
- Myeloma screening
- Increased alpha- and beta-globulin fractions
- Renal biopsy
Management:
- Treat underlying cause
- Fluid + salt restriction
- Diuresis - furosemide, ACEi (anti-proteinuric)
- Anticoagulation
Membraneous glomerulonephritis
Aetiology:
- Idiopathic (up to 85%)
- SLE
- Infection - malaria, HBV/HCV
- Drugs - pencillamine, NSAIDs, gold
- Malignancy (10%)
Pathology:
- Generalised thickening of the glomerular basement membrane
- Subepithelial deposition of IgG and C3
Management:
- Diuretics + fluid restriction
- Anticoagulation + aspirin
- ACEi/ARBs
- Immunosuppression if no improvement after 6 months
- cyclophosphamide, tacrolimus, biologics
Prognosis:
- 25% spontaneous remission
- 25% partial remission
- 50% progressive renal impairment
Renal vein thrombosis
Aetiology:
- Severe dehydration
- e.g. neonate in NICU with insufficient feed
- Hypercoagulability
- Cancer, nephrotic syndrome, polycythaemia,
protein C deficiency
Features:
- Flank pain
- Renal enlargement
- Haematuria
- Worsening renal function
Investigations:
- Renal USS
- CT angio
Management:
- Hydration
- Anticoagulation
Nephritic syndrome
A syndrome of worsening renal failure associated with haematuria, non-nephrotic proteinuria, and hypertension
Aetiology:
- Paeds:
- IgA nephropathy
- PSGN
- HSP
- HUS
- Adults
- Above causes
- Autoimmune e.g. SLE, Goodpasture’s,
vasculitis
- RPGN
- MPGN
- Infective endocarditis
- Cryoglobulinaemia
Features:
- Hypertension
- Renal impairment
- Haematuria
- Flank pain
Investigations
- Urinalysis
- Bloods
- Renal biopsy
- Commonly crescenteric appearance
- Immunofixation
IgA nephropathy
The most common type of glomerulonephritis in adults
- 20-40% progress to CKD
Aetiology:
- 1-2 days following URTI, pneumonia, tonsillitis or gastroenteritis
- Post-immunisation
- Some association with coeliac disease and cirrhosis
Pathology:
- Hypercellular mesangium + crescenteric appearance
- Granular IgA + C3 deposition
Features:
- HTN
- Visible haematuria
- May worsen with exercise
- AKI or CKD
- High serum IgA (in 50%)
Management:
- Immunosuppression - steroids
- Consider tonsillectomy if tonsillitis is a trigger
Post-infectious glomerulonephritis
Aetiology:
- Most commonly post-streptococcal
- Typically children, 1-2 weeks after infection
- Can be viral, fungal, etc.
Pathology:
- Type III hypersensitivity reaction
- Hypercellular mesangium
- IgG + C3 deposition
Features:
- Haematuria
- AKI
- HTN
- Can also present with proteinuria + oedema
Investigations:
- Urine MCS
- Haematuria with RBC casts
- Streptolysin-O titre
- Complement levels
- low C3
Management:
- Usually self-limiting with only supportive care required
Mesangiocapillary glomerulonephritis
Epidemiology:
- 8-30 yrs
- M > F
Aetiology:
- Idiopathic
- Infection
- Viral - HIV, HBV/HCV
- Bacterial - TB, infective endocarditis
- Autoimmune - any immune complex deposition disease
- Cryoglobulinaemia, SLE, scleroderma
- Malignancy
- Leukaemia and lymphoma
Pathology:
- BM splitting allows mesangial cell cytoplasm to spread between the endothelium and basement membrane
- Appears as mesangial cell proliferation + subendothelial thickening
Features:
- Can present as nephrotic syndrome, nephritic syndrome, or more subtle progressive renal failure
Investigations:
- Low complement levels
Prognosis
- 50% progress to ESRF at 10 yrs
- Fluctuant disease severity
Minimal change disease
Aetiology:
- Associated with atopy, infection, malignancy, and drugs (NSAIDs)
Pathology:
- No obvious change on standard microscopy
- Effacement of the podocyte foot processes
Features:
- Massive oedema
- Foamy urine
- Nephrotic syndrome
Management:
- Steroids should induce rapid remission
Focal segmental glomerulosclerosis
Aetiology:
- Idiopathic
- M > F, African ethinicity
- Drugs
- Heroin
- Lithium, steroids, doxorubicin
- Infection
- HepB/C, HIV, CMV
- Other
- Obesity, diabetes
Pathology:
- Focal and segmental sclerosis
- IgM + C3 positive
- Foot process effacement
Features:
- Paeds - nephrotic syndrome
- Adults - spectrum of nephrotic and pre-nephrotic syndromes
Investigations:
- Urine MCS
- Casts + protein
- Renal biospy
Management:
- 1st line - steroids
- 2nd line - calcineurin, mycophenolate, rituximab
Prognosis:
- Usually leads to progressive renal dysfunction
- Prognosis worse in idiopathic cases
Henoch-Schonlein purpura (HSP)
Epidemiology:
- Peaks at 4-6yr
- 90% of cases are in under-10s
- Rare in both adults and infants
Pathophysiology
- IgA vasculitis, usually triggered by preceding illness or vaccination
Features:
- Low-grade fever
- Lower limb purpura
- Abdominal pain
- Arthralgia
- Bloody diarrhoea
- Renal dysfunction (IgA nephropathy, nephrotic picture)
Management:
- Usually self-limiting, within 4 weeks
- Supportive
Prognosis:
- Rarely leads to permanent kidney damage (<1%)
Haemolytic uraemic syndrome
Secondary to shiga toxin or shiga-like toxin, predominantly produced by gastrointestinal pathogens
- Usually 5 days after onset of diarrhoea
Features:
- Preceding profuse diarrhoea, turning bloody after 1-3 days
- Haemolytic anaemia
- Thrombocytopenia
- AKI with uraemia
- (Also abdo pain, confusion, lethargy)
Investigations:
- Blood film
- Schistocytes, thrombocytopenia
- DAT+
Management:
- Supportive care +/- dialysis
- Avoid antibiotics where possible
Complications:
- Abdominal pain
- Perforation or strictures
- Pancreatitis
- Myocarditis or cardiomyopathy
- Retinal haemorrhage
- Kidney failure
Goodpasture’s
Anti-GBM disease affecting both kidneys and lungs - antibodies against type IV collagen
Risk factors:
- HLA-DR15
- Cocaine use
- Smoking
- Infection (esp. influenza)
Pathology:
- Crescenteric glomerulonephritis
- Linear IgG deposition along basement membrane
Features:
- Renal disease
- Nephritic syndrome with acute renal failure
- Pulmonary disease
- Haemoptysis + alveolar haemorrhage
Management:
- Many (esp. younger patients) may present in acute respiratory failure + AKI
- Induction = Prednisolone + cyclophosphamide + plasmapheresis
Causes of combined renal + neurological disease (11)
Wilson’s disease
- Fanconi syndrome -> type II RTA
- Basal ganglia dysfunction
- Peripheral neuropathy
Hypertension
- CKD
- Hypertensive encephalopathy
Haemolytic uraemic syndrome
- AKI
- Uraemic encephalopathy
SLE
- Lupus nephritis - typically diffuse sclerosis + crescenteric glomerulonephritis
- Encephalitis, neuropathies, seizures
Alport syndrome
- FSGS with micro- and macroscopic haematuria
- Sensorineural deafness
APCKD
- Renal cysts + CKD
- Berry aneurysms, SAH
Sickle cell anaemia
- Nephropathy with varying appearances
- renal papillary necrosis, FSGS
- Renal medullary carcinoma
- Stroke
Lead poisoning
- Fanconi syndrome -> type II RTA
- Raised ICP
Tuberous sclerosis
- Renal cysts
- Angiomyolipoma can cause HTN and AKI
- Seizures
- Intellectual impairment
Neurofibromatosis
- Renal artery stenosis
- Learning difficulties
Posterior reversible encephalopathy syndrome (PRES)
- HTN with AKI/CKD
- Seizures, delirium, visual changes
Haematuria
Aetiology:
- Kidney
- e.g. cancer, stone, infarction, cysts, GN
- Bladder
- e.g. cancer, cystitis, stones, tear
- often terminal +/- pain
- Prostate
- e.g. BPH, varices, post-RT
- painless, can be initial or terminal
- Urethra
- dribbling
Also several transient causes - UTI, period, beetroot, exercise, rifampicin, anticoagulants
Investigations:
- Urine dip +/- MCS
- Bloods incl. clotting
- Renal USS or CT renal w/ contrast
- Flexi-cystoscopy
Management:
- Exclude transient causes
- 2ww - if > 45 with VH or > 60 with non-VH
Renal stones
Risk factors:
- Male
- testosterone increases liver oxalate
production
- women have higher urinary citrate
- Family history
- Dehydration
- esp. urate and cysteine stones
- High oxalate diet
- meat, spinach
- Hypercalciuria
- RTA, hyperparathyroidism
Types:
- 80-85% calcium oxalate
- 10% mixed calcium oxalate/phosphate
- 5-10% urate
- 2-20% struvite
- 1% cysteine
Investigations:
- Urine dip
- Microscopic haematuria
- r/o possible UTI -> struvite stones
- CT KUB
- Radio-opaque: Ca phos > ca oxalate > cysteine
> struvite > uric acid
Management:
- Analgesia - PR diclofenac, tamsulosin
- < 5mm
- Watch and wait
- < 2cm
- Lithotripsy, or ureteroscopy if pregnant
- > 2cm, obstructive, staghorn
- Percutaneous nephrolithotomy +/-
nephrostomy
Cystinuria
Autosomal recessive disorder
- Impaired renal and GI transport of dibasic
amino acids (cysteine, ornithine, arginine,
lysine)
Features:
- Up to 3% will produce cysteine renal stones (radio-translucent)
- Yellow/brown hexagonal crystals on MCS
- Postive urinary cyanide nitroprusside test
Management:
- High fluid intake
- Urinary alkalisation - bicarbonate/citrate
ADPCKD
Epidemiology:
- Autosomal dominant mutations in PKD 1/2
- Presents between 30-50 yr
Pathophysiology:
- Polycystin-1/2 mutations lead to dysfunction of cilia and cell junctions
- Form large fluid-filled cysts which cause ischaemic atrophy of surrounding parenchyma as well as obstruction of tubules
Features:
- Polycystic kidneys
- Prone to infection, haemorrhage, etc
- Progressive renal dysfunction - HTN, oedema,
stones
- Liver cysts (33%)
- Berry aneurysms (30%)
- Aortic root dilatation
- With associated MR, TR, etc.
- Increased risk of renal adenomas
Investigations:
- Urinalysis + bloods
- Imaging
- Renal US, CT, MRI
- Genetic testing
Management:
- Early
- Monitoring
- Antihypertensives
- Hydration
- Late
- Requires RRT - dialysis or transplant
Sterile pyuria - aetiology
Infectious:
- Renal TB
- Perinephric abscesses
- Chronic prostatitis
- Fungal UTIs
Non-infectious:
- Drugs - lithium, heavy metal toxicity
- Renal stones
- Sarcoidosis
- Interstitial cystitis
- Polycystic kidney disease
- Urinary tract malignancies
- Renal transplant rejection
Urinary casts
Hyaline
- Not pathological if occurring in isolation
Red cell casts
- Always pathological, usually an underlying glomerulonephritis
White cell casts
- Acute pyelonephritis or interstitial nephritis
Granular casts
- Tubular or interstitial disease, although finely granular casts can be normal in paeds
Renal tumours
Benign:
- Adenoma - symptomless
Malignant:
- Renal cell carcinoma (80% of adult)
- M > F
- Asytmpomatic, haematuria (50%), loin ache
(40%), loin mass (25%), unilateral varicocele
(1%)
- Paraneoplastic manifestations possible - HTN
(renin), hypercalcaemia (PTH), polycythaemia
(EPO)
- Nephroblastoma
- Most common paediatric renal cancer
Metastases:
- Generally rare but can be from breast, lung, or haematological malignancies
Bladder tumours
Epidemiology:
- 90% urothelial carcinoma
- Middle-aged
- Risks - smoking, long-term catheterisation,
beta-naphthylamine exposure
- Squamous cell carcinoma
- Associated with schistosomiasis
Features:
- Painless haematuria
- LUTS - frequency, urgency, dysuria
- Possible spread to other pelvic viscera
Investigations:
- Urine dip
- Bloods
- Flexi-cystoscopy +/- CT KUB for staging
Management:
- Superficial = resection + BCG + mitomycin C
- Muscle-invasive = platinum chemotherapy + cystectomy
-
Bladder stones
Similar types and causes as renal stones, many will be formed in kidney and pass into bladder
Bladder-unique causes include foreign body (catheter) or stasis (stricture, BPH, atony)
Features:
- Pain
- Suprapubic, perineal, or tip of penis
- Worse at end of micturition (bladder
contracted)
- Urinary frequency
- Worse during the day as upright position
allows stone to irritate the trigone
- Terminal haematuria
Pneumaturia
Air or bubbles in the urine, or a history of sputturing passage of urine
Aetiology:
- Colovesical fistula
- Diverticular disease (80%), IBD, colorectal or
bladder cancer
- Often also have faecuria
- Air-forming UTIs
Investigations:
- Urine dip + culture
- Renal US
- CT +/- PR contrast
- Colonoscopy
Testicular torsion
Epidemiology:
- Mostly boys aged 10-15 yr
- Uncommon in over-30s
Features:
- Sudden unilateral testicular pain
- Although may have non-specific abdo pain
- Nausea and vomiting
- Tender swollen testis
- High in scrotum
- Oedematous + erythema
Management:
- Urgent surgical exploration +/- fixation or orchidectomy
- Must happen within 1hr
- Ischaemia occurs within 4hr but testis can be
salveagable up to 8hr after pain
Differentials:
- Torted hydatid cyst or epididymal appendix
Acute epididymo-orchitis
Aetiology:
- Bacterial infection:
- Younger men = chlamydia, Older men = E.
coli
- Viral infection incl. mumps
Features:
- Gradual onset unilateral pain and swelling
- Initially epididymis thickened + tender, then
hemiscrotum becomes oedematous and
erythematous
- Fever
- Dysuria
- Lymphadenopathy
Management:
- IV fluids
- Antibiotics - 2-6 weeks
- May form abscesses requiring IV gentamicin + surgical drainage
Fournier’s gangrene
Necrotising fasciitis of the scrotum, perineum, and/or perianal region
- Often spread from a urinary or anorectal
infection
Management:
- Urgent surgical debirdement
- Catheterisation if penile involvement
- IV antibiotics
Autonomic dysreflexia
Seen in patients with spinal cord injury above the level of T6
Symptoms most commonly triggered by bladder problems e.g. calculi, UTI, instrumentation
Symptoms:
- Hypertension
- Bradycardia
- Flushing + diaphoresis
- Palpitations
- Blurred vision
Balanitis
Aetiology:
- Infection
- Bacterial - STIs
- Fungal - candida
- Increased risk with diabetes or HIV
Features:
- Penile soreness + itch
- Bleeding + odour from foreskin
- Dysuria + dyspareunia
- Redness, swelling, and exudate over glans
- Tightening or phimosis of the foreskin
Investigations:
- Urine dip
- Foreskin swab - for candida and STIs
Management:
- Avoid triggers
- Clean daily with water
- Topical hydrocortisone + imidazole cream
- Flucloxacillin if confirmed bacterial infection
Prostate cancer
Epidemiology:
- Over-50s
- Most common cancer in men
Investigations:
- DRE - hard, craggy surface
- PSA - >20 ng/ml suggestive of disseminated disease
- Imaging:
- Multiparametric MRI
- Transrectal USS for biopsy
- Bone scan if PSA > 20 or bony pain
Gleeson scoring:
- Based on the tissue architecture
- Scores <= 6 suggest low risk, 7 is intermediate, >= 8 is high risk
Management:
- Watch and wait
- If low risk, well-differentiated, no mets, life-
expectancy < 10yr
- Radial prostatectomy and/or radiotherapy
- removal of prostate, seminal vesicles, pelvic
lymph nodes
- GnRH antagonists
- symptom relief in metastatic disease
Testicular cancers
Germ cell tumours
- Risk factors - undescended testis, dysgenesis, genetics
- Seminoma (50%)
- Less aggressive, usually curable with
orchidectomy
- NSGCT
- Teratoma
- Yolk sac
- Most common testicular cancer in children
- Testicular much less aggressive than
ovarian
- AFP secretion
- Choriocarcinoma
- Highly aggressive
- bHCG secretion
- Embryonal
Non-germ cell tumours
- Lymphoma
Nutcracker syndrome
A vascular compression disorder - compression of the L renal vein
- Usually between SMA and aorta
Can be anatomical but can also be secondary to retroperitoneal or pancreatic cancers or AAA
Features:
- Renal venous hypertension
- Flank pain
- Haematuria
- Increased risk of renal vein thrombosis
Investigations:
- Urine dip
- CT abdomen
Retroperitoneal fibrosis
Aetiology
- Idiopathic (70%)
- Drugs - methylsergide, etanercept
- Malignancy
- AAA
Features:
- Malaise
- Back pain
- Normocytic anaemia
- Uraemia
- Raised ESR
Investigations:
- Bloods
- Anaemia, uraemia, raised ESR
- CT/MRI
- Bilateral ureteric obstruction at level of pelvic
brim +/- periaortic mass
Management:
- Surgery with biopsy + ureteric stenting
- Trial of long-term steroids or steroid-sparing agents
Chronic reflux disease
Features:
- Recurrent UTIs
- HTN
- Premature renal impairment
- Renal atrophy
Investigations:
- Urinalysis - proteinuria
- Imaging - VCUG
Management:
- Intermittent antibiotic therapy
- Surgical correction of any anatomical abnormalities
Hyperoxaluria
Aetiology:
- Enteric - short bowel syndrome
- Dietary - meat, spinach
- Male sex - testosterone
Features:
- Recurrent oxalate stones
Management:
- Hydration
- Calcium supplementation (binds excess free oxalate to enhance excretion)
- Low oxalate diet
Renal transplant rejection
Hyperacute
- Presence of recipient antibodies against the donor kidney
- Features:
- Within minutes of revascularisation
- Kidney swelling + discolouration
- RBC clumping + haemorrhage, fibrin
deposition
- Management:
- Transplant nephrectomy
Acute
- Within 4 weeks of transplant
- Either cell-mediated or antibody-mediated
- Management:
- Increased immunosuppressive therapy
Chronic
- > 3 months after transplant
- Gradual worsening of kidney function
- HTN, proteinuria are key markers
- Usually due to transplant vasculopathy
Xanthogranulomatous pyelonephritis (XGP)
A rare and aggressive form of chronic pyelonephritis
Histology:
- Enlarged kidney
- Destruction and replacement of renal and peri-renal tissue with granulomas and lipid-rich macrophages
Features:
- Weight loss
- Flank pain and mass
- Fevers
- Anorexia
Investigations:
- CT abdomen
- Replacement of renal parenchyma with
rounded, low-density areas surrounded by a
ring of enhancement
Management:
- Antibiotics in acute phase, nephrectomy in chronic phase
Lupus nephritis - staging
The spectrum of SLE-associated renal disease characterised by diffuse immune complex deposition
- Immune deposits along tubular and
glomerular basement membranes
- Subendothelial, subepithelial, and mesangial
deposits
- Tubular reticular structures on EM
- Systemic depletion of complement
Class I
- Minimal mesangial lupus nephritis
Class II
- Mesangial proliferative lupus nephritis
Class III
- Focal lupus nephritis
Class IV
- Diffuse lupus nephritis
Class V
- Membraneous lupus nephritis
Class VI
- Advanced sclerotic lupus nephritis
Renal artery fibromuscular hyperplasia
A cause of renovascular HTN - 5% of all HTN
Features:
- Occult HTN with hypertensive eye disease
- Periodic pulmonary oedema
- Mild hypokalaemia
- Worsening renal function post-ACEi
- RAAS overactivation
Investigations:
- Urine
- Bloods
- Renal US - normal
- Renal angiography - arterial stenosis, often in a rosary bead appearance
Management
- HTN control - ACEi / ARBs
- Angioplasty
Prognosis:
- Variable course and may not progress (vs atherosclerotic disease)
Renal tract TB
Initial formation of glomerular granulomas which eventually rupture and lead to medullary disease
Features:
- Sterile pyuria
- Haematuria
- Dysuria
- Refractory HTN
- Renal calcification
Management:
- Anti-mycobacterial agents
Pollakuria
aka benign urinary frequency
Aetiology:
- Idiopathic - esp paeds
- Drugs - risperidone
Features:
- Increased daytime urinary frequency
- Enuresis
- Urinary incontinence
