Nephrology Flashcards
Enuresis, haematuria, HSP, nephrotic syndrome, UTIs, VUR, AKI, CKD, tract abnormalities
Daytime enuresis
Lack of bladder control in a child over 3-5y, usually also nocturnal
Causes: lack of attention to full bladder (developmental/psychogenic/preoccupied child), detrusor instability, bladder neck weakness, neuropathic bladder e.g. spina bifida, UTI, constipation, ectopic ureter
Ix: urine for MCS, US if indicated, exclude neurological cause (different management)
M: look for underlying cause, adv on fluid intake/diet/toileting, reward systems e.g. star chart (for agreed behaviours e.g. using toilet when get up), enuresis alarm (if <7 is first line), desmopressin (may be first line for >7 esp if need short term relief like for a sleepover, this is an anti-diuretic for overnight), daytime may need antimuscarinics like oxybutynin or TCA like imipramine (2ndary care)
Causes of haematuria
Non-glomerular: infection, trauma to renal tract, stones, tumours, sickle cell, bleeding disorders, renal vein thrombosis, hypercalciuria
Glomerular: acute glomerulonephritis, IgA nephropathy, familial nephritis (eg Alport syndrome-X linked, progress to end stage RF by early adult life in males, a/w sensorineural deafness + eye abnormalities), thin basement membrane disease
Acute glomerulonephritis
Causes: post-infectious (e.g. strep throat/skin), vasculitis (HSP, SLE etc), IgA nephropathy, mesangiocapilary glomerulonephritis, anti-GBM disease (Goodpasture syndrome)
CF: reduced urine output, volume overload, HTN, seizures, periorbital oedema, haematuria + proteinuria
M: water + electrolyte balance (diuretics if needed). If rapidly progressive need renal biopsy + immunosuppression +/- plasma exchange
Henoch-Schonlein purpura
IgA-mediated vasculitis that affects the kidney, peaks in winter, often preceded by URTI but cause unknown
CF:
- Rash: symmetrical over buttocks, extensor surfaces (trunk usually spared). May progress from urticarial - maculopapular - purpuric, usually palpable
- Joint pain: in 2/3 joints esp knees + ankles, peri-articular oedema, doesn’t cause long term issues
- Colicky abdomen pain: common
- Renal involvement: majority get micro/macroscopic haematuria, or mild proteinuria
M: should follow up all for a year to detect persisting haematuria/proteinuria. Give steroids if severe CF
Comps: haematemesis/melaena/intussusception, nephrotic syndrome, progressive CKD (more likely if lots of proteinuria, oedema, HTN and deteriorating renal function)
Causes of proteinuria
Transient from febrile illness/exercise Orthostatic: only when stand up Increased glomerular filtration pressure Reduced renal mass in CKD HTN Tubular proteinuria Glomerular abnormalities: minimal change disease, glomerulonephritis, abnormal GBM
What is nephrotic syndrome?
Heavy proteinuria of unknown cause - leads to low plasma albumin + oedema
(sometimes secondary to systemic disease like HSP, SLE, infections)
CF of nephrotic syndrome
Periorbital oedema esp on waking
Scrotal/vulval/leg oedema
Ascites
Breathlessness from pleural effusions/abdo distension
Infection due to loss of protective immunoglobulins in urine
What are the types of nephrotic syndrome?
Steroid-sensitive: most common group + don’t progress to CKD. A/w atopy, often URTI precipitates, mostly in 1-10y.
- CF: no macroscopic haematuria, normal BP, normal complement + renal function
- Causes: minimal change disease (commonest), focal segmental glomerulosclerosis (more likely to cause ESRD), mesangiocapillary glomerulonephritis (more in older kids, low complement, decline in renal function over many years), membranous nephropathy (a/w Hep B, may precede SLE, most resolves within 5y)
- M: oral corticosteroids (unless atypical), taper after 4w and end after 6w
Steroid-resistant: refer to nephrology. M: diuretics, salt restriction, ACEi, sometimes NSAIDs
Congenital: rare, in first 3m, most common in Finnish people. High mortality cos of low albumin, may need nephrectomy + dialysis + transplant
Complications of nephrotic syndrome
Hypovolaemia: volume depletion of intravascular compartment, CF abdo pain/faint feeling/peripheral vasoconstriction/shock (need IV fluids before shocked)
Thrombosis: hyper coagulable state as lose anti-thrombin III, exacerbated by steroids. In any circulation tbh
Infection: encapsulated bacteria e.g. Pneumococcus. E.g. spontaneous bacterial peritonitis.
Hypercholesterolaemia
RF for UTI in children?
- Congenital renal tract abnormality: in up to half
- Vesicoureteric reflux (35%)
- Incomplete voiding: e.g. obstructed from loaded rectum, neuropathic bladder, VUR, hurried micturition, infrequent voiding
- Poor hygiene
UTI presentation + Ix
CF:
- infants: usually non-specific like fever, vomiting, lethargy, poor feeding, jaundice, sepsis, offensive urine, febrile convulsion
- children: dysuria/frequency/urgency [these alone usually cystitis, or vulvitis/balanitis], abdo pain/loin tenderness, fever +/- riggers, lethargy, anorexia, D+V, haematuria, offensive/cloudy urine, febrile seizure, enuresis – basically so many so commonly need to check kids urine
- Pyelo suggested when bacteria + fever >38, or bacteria + loin pain/tenderness
Ix: clean catch urine sample if poss (e.g. when nappy removed), catheter if urgent, in older children MSU
- Nitrite pos likely a true UTI, but some UTI are nitrite neg
- leucocytes may be there or not and are common in any febrile illness
- L+N+ = UTI, L-N+ = start Abx if CF of UTI + send culture, L+ N- = only Abx if convincing CF, L- N- = UTI unlikely
Management of UTIs
<3m old with suspected UTI: immediately refer for IV Abx e.g. co-amoxiclav for 5-7d, then oral
> 3m + children with acute pyelonephritis: oral Abs e.g. TMP for 7d, or if severe IV co-amox then oral
Cystitis/lower UTI (no systemic CF): oral TMP/nitrofurantoin for 3d
Adv high fluid + regular voiding to completion to wash out aggressive organisms (they enter from perineum/stool etc), treat/prevent constipation, hygiene, probiotic to encourage gut colonisation. Abx prophylaxis is controversial
Vesicoureteric reflux
Developmental abnormality of the VUJ - ureters displaced and have shortened intramural course
Causes: familial, from bladder pathology like neuropathic bladder or temporary after UTI
Severe cases cause gross dilation of ureter + RP + calyces - predisposes to intra-renal reflux (back flow into the collecting ducts) + renal scarring if a UTI occurs; infection may destroy renal tissue causing a shrunken poorly-formed section of kidney (reflux nephropathy); if B/L can cause CKD
M: lower grades tend to resolve with age
Acute kidney injury
Sudden, potentially reversible reduction in renal function, usually p/w oliguria
Causes:
- pre renal: commonest in kids, due to hypovolaemia (gastro, burns, sepsis, haemorrhage, nephrotic syndrome) or circulatory failure
- renal: salt + water retention, blood/protein/casts in urine. may be due to HUS, ATN, ischaemia, glomerulonephritis, interstitial nephritis
- post-renal: obstruction, either congenital e.g. posterior urethral valves or acquired e.g. a blocked catheter
- acute on chronic RF: suggested in a child with growth failure, anaemia + disordered bone mineralisation
M:
- pre-reanl: fluids!
- Renal: diuretic/fluid restriction if overloaded, high calorie normal protein feed to reduce catabolism/uraemia/hyperkalaemia
- post-renal: relieve obstruction
Chronic kidney disease
Progressive loss of renal function, in 5 stages, stage 5 eGFR <15
CF (apparently in stage 4-5): anorexia, lethargy, polydipsia+uria, faltering growth, renal osteodystrophy, HTN, acute on chronic renal failure, proteinuria, normochromic normocytic anaemia
M: supplements (as anorexia/vomiting common), prevent renal osteodystrophy (calcium + vid D), salt + bicarb supplements, SC EPO for anaemia, may need GH treatment. May need dialysis or transplant
