Renal Flashcards
What does a DMSA scan detect?
Static scan of the renal cortex
Detects functional defects e.g. scars
What do you need to remember when ordering a DMSA post UTI?
○ Very sensitive so need to wait at least 2 months after a UTI to avoid diagnosing false ‘scars’
What happens in an MCUG?
Contrast introduced into bladder through urethral catheter
What can an MCUG tell you?
Can visualise bladder and urethral anatomy
Detects vesicoureteric reflux and urethral obstruction
What’s the downside of an MCUG?
High radiation dose
What happens in a MAG3?
○ Dynamic scan
MAG3 (isotope labelled substance) is excreted from the blood into the urine
What can a MAG3 tell you?
Measures drainage, best performed with high urine flow
In children old enough to cooperate (>4 years), scan during micturition is used to identify VUR
What is a duplex kidney?
Two ureters drain from two separate pelvicalyceal systems
What are the common complications of a duplex kidney?
Obstructed hydronephrotic upper moiety and ureter, associated with bladder ureterocele
Ectopically inserted upper pole ureter entering urethra or vaginal, causing true continual incontinence
VUR into lower pole ureter, sometimes causing infection and scarring
What is a horseshoe kidney?
Two renal segments fused across midline, usually at lower poles
What is horseshoe kidney associated with?
Turner and Laurence-Moon-Biedl syndromes
What are the clinical features of horseshoe kidney?
Usually asymptomatic but increased incidence of PUJ obstruction and VUR so can develop UTI
What is the main defect in Potter syndrome?
Bilateral renal agenesis or bilateral multicystic dysplastic kidneys
Reduced fetal urine excretion leads to oligohydramnios, which causes fetal compression
What are the classical facies of Potter syndrome?
Low set ears
Beaked nose
Prominent epicanthic folds
Downward slant to eyes
What are the non-renal features of Potter syndrome?
○ Pulmonary hypoplasia causing respiratory failure
Limb deformities e.g. severe talipes
What’s the prognosis for Potter syndrome?
Fatal if not stillborn
What causes multi cystic dysplastic kidney disease?
failure of union of the ureteric bud with the nephrogenic mesenchyme
What is the resulting kidney like in multi cystic dysplastic kidney?
Non-functioning structure with large fluid-filled cysts with no renal tissue and no connection with the bladder
How is multi cystic dysplastic kidney managed?
Only needs nephrectomy if it remains very large or if hypertension develops
What are the features of AR polycystic kidney disease?
Diffuse bilateral enlargement of both kidneys
What are the features of AD polycystic kidney disease?
Separate cysts of varying size between normal renal parenchyma
Kidneys are enlarged
Causes hypertension and haematuria in childhood, and renal failure in late adulthood
Associated with cerebral aneurysms and subarachnoid haemorrhage
What are the cardinal features of Alport syndrome?
Hereditary nephritis with sensorineural deafness and anterior lenticonus (conical deformity of lens of eye seen with slit lamp)
What is the main defect in Alport syndrome?
Type IV collagen
How is Alport syndrome inherited?
X linked or AR
How does Alport syndrome present and progress?
Incidental microscopic haematuria or episode of macroscopic haematuria Deafness around 10 years Hypertension in mid teens Eye signs in mid-late teens Average age for ESRF is 21 years
What are the features of testicular torsion?
Acute abrupt onset of often severe pain Early puberty Swelling of testis and hemiscrotum often with erythema/discolouration Negative urinaylsis Needs urgent surgery
What are the features of torsion of the appendix of the epididymus?
More common than testicular tosion Subacute onset of pain over hours Pre pubertal Localised pain at upper pole of testis Can be managed conservatively but difficult to distinguish from torsion of testicle
What are the features of epididymitis?
Gradual insidious onset of discomfort or pain
Adolescence
Epididymal tenderness
Urinalysis often positive
What is the defect in cystinuria?
Defect in reabsorption of, and hence excessive excretion of, cystine, ornithine, arginine and lysine
How is cystinura inherited?
AR
What is the consequence of cystinuria?
Recurrent urinary stone formation which are extremely hard and densely radio opaque
How is cystinuria treated?
high fluid intake and alkalinisation or urine with oral potassium citrate
What is the mutation in x linked hypophosphataemic rickets?
PEX gene on the X chromosome
What is the defect in x linked hypophosphataemic rickets?
Isolated defect in phosphate reabsorption
What are the clinical features of x-linked hypophosphaaemic rickets?
ALP rises before phosphate becomes low
Causes delayed growth, rickets, delayed dentition and dental abscesses
How are X linked hypophosphataemic rickets treated?
Supplementation
What is the defect in proximal RTA?
Failure to reabsorb filtered HCO3 but can still acidify urine
What are the symptoms in proximal RTA?
Faltering growth
Vomiting
Short stature
How is proximal RTA treated?
High doses of alkali
What is the defect in cystinosis?
AR defect in transport of cystine out of lysosomes
What are the early clinical features of cystinosis?
Fanconi syndrome
Photophobia
Hypothyroidism
What are the late features of cystinosis?
Renal failure at 8-10 years Pancreatic involvement with DM Liver involvement with hepatomegaly Reduced fertility Neurological deterioration and cerebral atrophy
How is cystinosis diagnosed?
○ Cystine crystals in cornea on slit lamp
Peripheral blood white cell cystine level
Antenatal diagnosis possible
How is cystinosis treated?
Supportive - supplements, high fluid intake
Cysteamine, which increases cystine transport out of lysosome
Indometacin reduces GFR and hence helps with severe polyuria and secondary polydipsia, and electrolyte wasting
What is glomerulonephritis??
Inflammation of the glomeruli leading to:
- Haematuria and/or proteinuria
- Nephrotic syndrome
- Acute nephritic syndrome
- Rapidly progressive crescentic glomerulonephritis
What are the main causes of glomerulonephritis
Normal complement:
- FSGS
- IgA nephropathy
- HSP
Reduced complement
- Acute post-streptococcal
- Mesangiocapillary GN
- SLE
- Shunt nephritis
What is the defect in Bartter syndrome?
Inborn AR defect in the sodium/potassium/chloride co transporter in the thick ascending limb, leading to sodium chloride and water wasting
What are the symptoms of Bartter syndrome?
Polyuria Polydipsia Episodes of dehydration Faltering growth Constipation Maternal polyhydramnios
How is Bartter syndrome diagnosed?
Hypochloraemic hypokalaemic alkalosis
Inappropriately high levels of urinary chloride and sodium
Normal or high urinary calcium
How is Bartter syndrome treated?
Potassium supplementation and indometacin
What is pseudo-Batter syndrome?
Same plasma biochemistry with low chloride and potassium but inappropriately low levels of urine chloride and sodium
What are the causes of pseudo Bartter syndrome?
Cystic fibrosis
Congenital chloride diarrhoea
Laxative abuse
Cyclical vomiting
What is the triad of nephrotic syndrome?
Oedema
Proteinuria
Hypoalbuminaemia
What are the causes of nephrotic syndrome?
Minimal change disease FSGS Mesangial proliferative glomerulonephritis Membranous nephropathy SLE
What are the possible complications of nephrotic syndrome?
Infections with encapsulated bacteria
Thrombosis
Hypovolaemia
Drug toxicity
How is nephrotic syndrome managed?
Steroids for initial presentation Steroids for first relapse For frequent relapses -Cyclophosphamide -Tacrolimus -Cyclosporin -Mycophenolate mofetil -Levamisole Refer to renal service if steroid resistant
What is the defect in Gitelman syndrome?
Inborn AR defect in the distal tubule sodium and chloride cotransporter
What are the symptoms of Gitelman syndrome?
Often asymptomatic
Or, transient episodes of tetany and weakness with abdominal pain and vomiting
What are the biochemical features of Gitelman syndrome?
Hypokalaemic metabolic alkalosis
Raised renin and aldosterone
Hypomaynesaemia
Hypocalciuria (distinguishes from Bartter, where there is normal or high urinary calcium)
Where are the ureters placed in VUR?
Ureters are displaced laterally and enter directly into the bladder rather than at an angle, with a shortened or absent intramural course
What defines severe VUR?
reflux during bladder filling and voiding with distended ureter, renal pelvis, and clubbed calyces
High risk of renal scarring
What are the important consequences of VUR?
Urine returning to the bladder from the ureters after voiding results in incomplete bladder emptying, which encourages infection
Kidneys may become infected with intrarenal reflux especially
Bladder voiding pressure is transmitted to the renal papillae, which may contribute to renal damage if voiding pressures are high
What is Fanconi syndrome?
Generalised proximal tubular dysfunction
How does Fanconi syndrome present?
Polydipsia and polyuria Salt depletion and dehydration Hyperchloraemic metabolic acidosis Rickets Failure to thrive/poor growth
Which substances are lost in the urine in Fanconi syndrome?
Amino acids Glucose Phosphate Bicarbonate Sodium Calcium Potassium Urate
What are the causes of secondary Fanconi syndrome?
Cystinosis Glycogen storage disorders Lowe syndrome (oculocerebrorenal dystrophy) Galactosaemia Fructose intolerance Tyrosinaemia Wilson disease
What are the acquired causes of Fanconi syndrome?
Heavy metals
Drugs and toxins
Vitamin D deficiency
What is the raid of haemolytic uraemic syndrome?
Acute renal failure
Microangiopathic haemolytic anaemia
Thrombocytopenia
