Nephrology

Question 1

What are common symptoms of urinary tract and/or renal disease?

Answer 1

• haematuria
• proteinuria
• hypertension
• oedema
• renal masses

Question 2

In regards to urological imaging, what is ultrasound used for?

Answer 2

• non-invasive anatomical assessment of the entire urinary tract
• provides info about renal size
• can identify most congenital abnormalities, renal calculi, hydonephrosis
• indicates presence of obstruction or severe reflux

Question 3

What is the DMSA scan?

Answer 3

• isotope used in static nuclear medicine scans
• particularly good (gold std) for detecting renal parenchyma defects + scars

Question 4

What is the MAG3 scan?

Answer 4

• isotope used in dynamic nuclear medicine scans
• it is exerted in the glomerular filtrate + gives information about blood flow, renal function + drainage
• good for detecting structural abnormalities
• in older children who can stop and start voiding it can be used to detect vesicoureteric reflux

Question 5

What is the MCUG scan?

Answer 5

• micturating cystourethrography
• the bladder is filled w/ contrast via a urethral catheter
• contrast lines the bladder to show any vesicoureteric reflux (gold std)
• uretheral obstruction can also be demonstrated if catheter removed + pt voids
• invasive + requires catheterisation
• prophylactic antibiotics are given to prevent iatrogenic infection

Question 6

How common are urinary tract infections (UTIs) in children?

Answer 6

by age 7:

• 7% of girls
• 2% of boys

Evidently more common in girls, except in the first 6 months of life

Question 7

What are the bacterial causes of UTI?

Answer 7

• commonest → E. coli, from bowel flora
• psueodomonas
• proteus - splits urea into ammonia making the urine alkaline, which encourages the formation of phosphate stones
• in the newborn, infection is most likely to be from haematogenous spread

Question 8

Urinary stasis predisposes to UTIs as well as bacterial infections. What are the causes for this?

Answer 8

• habitual infrequent voiding; vulvitis; constipation; obstructive uropathy eg. urethral valves; neuropathic bladder
• vesicoureteric reflux:
  
  • some children are predisposed to this bc their ureters enter the bladder directly rather than at an angle, and the segment of ureter within the bladder is abnormally short
  • reflux into the kidneys can cause distension of ureter and renal pelvis and clubbed calyces
  • reflux increases the risk of renal scarring when a UTI is present
  • the reflux decreases as child gets older

Question 9

How does the clinical presentation of UTI vary in children, depending on age?

Answer 9

• often child is non-specifically ill
• infants → fever, D+V, poor feeding, failure to thrive, collapse/septicaemia, neonatal jaundice, febrile convulsion (>6months), rarely any urine symptoms <2 y/o
• childhood → LUTS: dysuria, frequency, wetting, haematuria, lower abdo pain
• upper urinary tract symptoms → loin pain, fever, rigors, malaise
• urinary tract is usually normal, byt 35% have vesico-ureteric reflux, 14% have renal scars (most having reflux too), 5% have stones, 3% develop hypertension

[*dysuria without a fever is often due to vulvitis or balanitis]

Question 10

For all children present with a fever, it is important to measure: temp, HR, RR + CRT.

Acute pyelonephritis/upper UTI should be suspected in children with what features?

Answer 10

• temp of 38^oC or higher + bacteriuria
• temp < 38^oC + loin pain/tenderness + bacteriuria

If no systemic symptoms but bacteruria is present then → cystitis/lower UTI considered

Question 11

It is rare but healthcare professionals should be aware that urinary symptoms could be due to child abuse. Consider if a child has dysuria or ano-genital discomfort that is persistent or recurrent and has no medical explanation.

What investigations should be done for UTI in children?

Answer 11

• Urine Sample → all infants w/ unexplained temp of 38^oC or higher should have urine sent for M+C within 24hrs
  
  1. clean catch urine sample ⇒ ready w/ pot for baby to pee into
  2. urine collection pads (+ not cotton, gauze, sanitary towels)
  3. catheter or suprapubic aspiration
• Urine dipstick → leukocyte + nitrites +ve? → M+C
  
  • E.Coli ⇒ gram negative rods

Question 12

What are features of an atypical UTI?

Answer 12

• poor urine flow
• abdominal or bladder mass
• raised creatinine
• sepsis
• failure to respond to treatment within 48 hrs
• non-E.coli organism

Question 13

What is the definition of recurrent UTI?

Answer 13

• two or more episodes of upper UTI (pyelonephritis)
• one episode of upper UTI + one episode of lower UTI
• three episodes of lower UTI

Question 14

What is the role of imaging for UTI in infants under 6 months?

Answer 14

Question 15

What is the role of imaging for UTI in childreen between 6 months and 3 years?

Answer 15

Question 16

What is the role of imaging for UTI in children over 3 years?

Answer 16

Question 17

What is the management of UTI in children?

Answer 17

1. All infants < 3 months w/ suspected UTI → refer immediately to care of a paediatric specialist for urine analysis + treatment w/ parenteral antibiotics
2. For all infants + children 3 months or older w/ cystitis/lower UTI →
   
   • treat w/ oral antibiotics for 3 days ⇒ trimethoprim, nitrofurantoin, a cephalosporin or amoxicillin may be suitable (refer to guidelines + results of urine culture)
   • advise parents + carers to bring child back to GP if still unwell 24-48hrs later
3. For infants + children 3 months or older w/ acute pyelonephritis or upper UTI →
   
   • consider referral to paed specialist ?(age, vomming, fluids, carer)
   • if referral not appt ⇒ treat w/ oral abx ⇒ ciprofloxacin or co-amoxiclav 7-10 days

Question 18

What is the use of prophylactic antibiotics for UTI?

Answer 18

• consider if recurrent UTI or significant GU anomaly/renal damage
• eg. trimethoprim prophylaxis (2mg/kg at night, max 100mg)
• eg. while awaiting imaging - and sometimes indefinitiely (optimum duration is unknown, but may be after 2 negative cystograms, if indication is reflux)
• consider screening siblings for reflux
• prophylaxis can be ruled out if there is no scarring
• recurrence of UTIs are more likely in:
  
  • younger children - <6months
  • girls over boys
  • VUR grade 3-5
  • voiding abnormalities

Question 19

AKI/acute renal failure can be defined as a sudden decrease in renal function; elevated urea is followed by an elevated creatinine and a resulting decreasing GFR. There are often associated difficulties in fluid + electrolyte regulation as well as with BP control.

What are pre-renal (hypoperfusion of kidney) causes of acute renal failure?

Answer 19

• hypovolaemic shock (eg. gastroenteritis, burns, nephrotic syndrome)
• septic shock
• cardiogenic shock

Important to replace intravascular fluid in these pts, but if more severe -> specialist input

Question 20

What are renal (intrinsic renal pathology) causes of acute renal failure?

Answer 20

• vasculitis
• renal vein thrombosis
• glomerulonephritis
• acute tubular necrosis
• interstitial nephritis
• pyelonephritis
• acute-on-chronic renal failure

Management complex requiring specialist input, fluid restriction may be necessary to avoid overload and a renal biopsy may be required

Question 21

What are the post-renal (outflow tract obstruction) causes of acute renal failure?

Answer 21

• congenital eg. posterior urethral valves
• acquired eg. abdominal mass obstructing ureter

Treatment requires identification of site of obstruction + targeted therapy, this may mean a urinary catheter is required or a nephrostomy

Question 22

What is haemolytic uraemic syndrome (HUS)?

Answer 22

• thought to be due to the activation of neutrophils which damage endothelium
• normally secondary to gastrointestinal infection w/ verocytotoxin-producing E.Coli or shigella
• the syndroem follows a bout of bloody diarrhoea
• other involved organs: pancreas, brain, heart
• characterised by presence of acute renal failure, microangiographic haemolytic anaemia + thrombocytopenia
• management is with supportive therapy

Question 23

Acute renal failure can present non-specifically, particularly in neonates w/ symptoms such as unexplained crying, restlessness, lethargy, vomiting or poor feeding. Other features may include reduced urine output and pallor.

What features can more severe AKI present with?

Answer 23

• haematuria
• rash → may be purpuric as found in HUS + HSP
• bloody diarrhoea → only found if AKI is caused by HUS
• confusion → normally due to uraemia
• abdo pain
• oliguria
• oedema → particularly in periorbital region
• abdo mass → may be due to PKD or urinary retention
• hypertension
• arrhythmia → usually secondary to hyperkalaemia

Question 24

What investigations can be done for those who have a very mild AKI with a known cause such as sepsis or dehydration?

Answer 24

• U+Es → quantify renal dysfunction + identify electrolyte disturbance
• venous blood gas → allow rapid assessment of acid-base balance
• urine dipstick → identify proteinuria + haematuria
• MC+S → to exclude infection + to look for red cells in context of glomerulonephritis

Question 25

What **additional investigations** can be done in those with more **severe** AKI or where the cause is unknown?

Answer 25

* **FBC + blood film** → anaemia if renal dysfunction longstanding, anaemia part of HUS * **early morning urine protein:creatinine** → look for proteinuria, more sensitive * **urinary sodium** → look for IV fluid depletion * **blood + stool cultures** → identify infective causes * **throat swab** → post-streptococcal glomerulonephritis * **urate** → identify urate nephropathy * **CXR** → pulmonary oedema secondary to AKI * **renal USS** → identify a cause for renal failure eg. hydronephrosis

Question 26

**Treatment** of acute renal failure depends on the underlying cause. What might treatment include?

Answer 26

* hospitalisation * administration of IV **fluids** in large volumes * **diuretic** therapy or medications to inc urine output * close monitoring of important **electrolytes** such as potassium, sodium + calcium * **anti-hypertensives** * specific diet requirements * **dialysis** if above fails or severe electrolyte imbalances or pulmonary/multisystem failure

Question 27

**Nephrotic syndrome** is a glomerular disorder which presents as a _classic triad_ of what?

Answer 27

* generalised **oedema** * heavy **proteinuria** (\>200mg/mmol or 3+ on dipstix) * **hypoalbuminaemia** (\<25g/L)

Question 28

What is the **pathophysiology** of **nephrotic** syndrome?

Answer 28

* **nephrosis** is the process of **leaking protein** from a **damaged glomerulus** * distinguishing it from **nephritis**, which is _inflammation_ that can involve _any part of the nephron or interstitium_ * the glomerular basement membane is made of specialised epithelial cells ⇒ **podocytes** * they normally fuse together + prevent proteins albumin-sized or larger from being filtered * in nephrotic syndrome, they become **flattened** + start to allow the _leaking_ of these proteins * the most common cause of nephrotic syndrome in children is **minimal change disease**, so-named bc on biopsy there is little change to see * other, rarer causes include **congenital nephrotic syndromes**, **focal segmental glomerulosclerosis** + **mesangiocapillary glomerulonephritis**

Question 29

Symptoms of nephrotic syndrome vary depending on the underlying aetiology and severity of the condition. What might patients present with?

Answer 29

* **periorbital oedema** (often earliest sign) * discomfort relating to swelling or skin breakdown * weight gain * abdo distension * tiredness * foamy urine * increased infections * poor growth + development

Question 30

First line investigations aim to confirm the diagnosis of nephrotic syndrome and to rule out any atypical features. What **investigations** should be done for children presenting for the first time with typical nephrotic syndrome?

Answer 30

* urine dip * urinary protein:creatinine ratio * U+Es * FBC * serum albumin * varicella zoster + hepatitis serology * complement levels * anti-streptolysin O Titre (ASOT) * autoimmune → ANA, ANCA + anti-dsDNA

Question 31

Children with _typical_ nephrotic syndrome are usually managed with **steroids**, without the need for a diagnostic renal biopsy. There are some **atypical** features which would prompt discussion with a nephrologist and consideration of renal biopsy. What are said atypical features?

Answer 31

* age \<1yr or \>12yrs * hypertension * impaired renal function * frank haematuria * steroid resistant nephrotic syndrome

Question 32

What is the **management** of nephrotic syndrome?

Answer 32

1. **high-dose steroids** → majority of children w/ minimal change disease will respond (steroid-sensitive nephrotic syndrome) but most will have a **relapse** ⇒ if they respond to further course of steroids + enter remission then prognosis favourable * some will have _frequent relapse_ or _steroid-resistant_ ⇒ **low-dose maintenance steroid** therapy or **immunomodulatory** drugs (eg. levamisole, cyclophosphamide, ciclosporin or tacrolimus) 2. **low salt diet** → to avoid worsening oedema 3. **prophylactic antibiotics** → these children leak immunoglobulins through their kidneys + therefore at high risk of infection, so also consider vaccination against pneumococcal + varicella

Question 33

What is characteristic of **nephritic** syndrome?

Answer 33

* **_microscopic haematuria_** is the main feature * also may be **proteinuria**, **oedema** and **hypertension** * caused by fluid retention due to **oliguria** * nephritic syndrome is not a diagnosis but a clinical _syndrome_ * several underlying causes

Question 34

What are the differentials for **haematuria** in children?

Answer 34

* **infecton** → cystitis, TB, infective endocarditis, schistosomiasis * **tumours** → renal or bladder * **trauma** * **inflammation** → glomerulonephritis, IgA vasculitis, Alport syndrome * **haematological** → sickle cell anaemia * **medications** → NSAIDs, sulphonamides

Question 35

What is **post-infectious glomerulonephritis**?

Answer 35

* **commonest** cause of nephritic syndrome * mixed nephritic-nephrotic * often caused by **group A streptococcus** * typically present 1-2 weeks after a streptococcal throat infection * diagnosis is based on clinical history, positive antistreptolysin O antibody titre (ASOT) and anti-DNase B titres, plus reduced complement C3 + C4

Question 36

What is **IgA nephropathy**?

Answer 36

* usually presents as **macroscopic haematuria** in association w/ URTI when IgA levels may be elevated * only definitive way to diagnose is via **percutaneous renal biopsy**, but rarely required * prognosis in children is better than in adults

Question 37

What are the relevant **investigations** for nephritic syndrome?

Answer 37

* **urine** → dipstick, MC+S (red cell _casts_), early morning urine albumin:creat ratio * **U+Es, LFTs, albumin** → identify AKI, electrolyte imbalance * **ASOT** → specific streptococcal exposure * **FBC** → anaemia? thrombocytopaenia? * **ESR** → SLE? infection? * **auto-antibody tests** → inc ANA and dsDNA may suggest autoimmune disorders eg SLE, anti-glomerular basement membrane (GMB) antibodies are +ve in Goodpasture syndrome * **throat swabs** → strep infections * **renal USS** → identify parenchymal abnormalities

Question 38

Management of **nephritic** syndrome should be tailored to the likely cause, but is generally supportive therapy, including fluid + electrolyte monitoring. It may be **rapidly progessive glomerulonephritis**, which is characterised by rapid deterioration of GFR rate and usually associated w/ crescent formation (fibrin deposition in the shape of crescents) on percutaneous renal biopsy. What would be the treatment?

Answer 38

* requires immunosuppression → **corticosteroids w/ IV methylprednisolone** * may require **dialysis** and/or **plasmapheresis**

Question 39

Cryptorchidism is a **congenital absence of one or both testes in the scrotum** due to a failure of the testes to descend during development. It's found in **6% of newborns**, but drops to 1.5-3.5% of males at 3 months. What 3 broad groups can crytoporchidsm be divided into?

Answer 39

* **true undescended testis:** where testis is absent from scrotum but lies along the line of testicular descent * **ectopic testis:** where testis is found away from the normal path of decent * **ascending testis:** where testis previously identified in the scrotum undergoes a secondary ascent out of the scrotum

Question 40

What are the stages of **testicular descent** in foetal **development**?

Answer 40

1. **trans-abdominal phase:** occurs in **1^st trimester** and is dependent on mullerian-inhibiting substances (**MIS**) + insulin related growth factor (**IRGF**), descent occurs from kidneys down to the _inguinal ring_ 2. **inguino-scrota stage**: occurs in **3^rd trimester** + depends on **testosterone**, this in turn depends on a functional HPA, descent occurs through inguinal canal down to bottom of _scrotum_ ## Footnote *Risk factors for undescended testes include: prematurity, low birth weight, having other genitalia abnormalities + first degree relative w/ cryptorchidsm*

Question 41

What is the difference between **palpable** and **impalpable** undescended testis?

Answer 41

* key element in history is to clarify **if testis has ever been seen or palpated within scrotum** (such as @ newborn check) * initial inspection may reveal testes within scrotum, therefore a dx of **retractile** or **normal descended testis** can be made * **around 80% of undescended testis are _palpable_** * imperfectly descended → external inguinal ring, superficial inguinal pouch, gliding testis * ectopic → lateral abdo wall, femoral, base of penis, perineal * **around 20% of undescended testis are _impalpable_** * absent → primary failure, vascular injury * high location → intra-abdominal * ectopic

Question 42

How do you **examine** for undescended testis?

Answer 42

* have infant/child lay flat on bed * aim to keep child **relaxed** + comfortable * w/ **warm** hands, palpate **laterally** w/ left hand from inguinal ring + work **along** inguinal canal to pubic symphysis * from there, use **other** hand to palpate testis in scrotum * if found, one should attempt to see if testes can be gently milked down to base of scrotum, if so → **retractile testis** * if it is pulled down but under tension in base → **high scrotal/testis** * sometimes found in groin along inguinal canal but won't move further → **inguinal undescended testis** * if having difficulties finding testis during examination, add a little soap to finger tips to remove friction, it will _feel_ like an enlarged lymph node

Question 43

What should you do if **disorder of sexual development (DSD), undescended testis assocatied w/ ambiguous genitalia** or **hypospadias or bilateral undescended testis** are suspected?

Answer 43

* **urgent referral to senior paeditrician within 24hrs** * ideally w/ access to paed endocrinology + urology services * this may be a presentation of **congenital adrenal hyperplasia** * therefore at **risk of salt-losing crisis** * requiring high dose sodium chloride therapy + careful glucose monitoring followed by steroid replacement

Question 44

For undescended testis in the newborn, what would you do (in terms of **time-scale** and when to review)?

Answer 44

* **at birth** → review @ 6-8wks of age * at **6-8wks** → if fully descended ⇒ no further action, if unilateral ⇒ re-examine @ 3 months * **at 3 months** → if testis is retractile then advise annual follow up (due to risk of ascending testis), if undescended ⇒ refer to paed surg/urology for _definitive intervention_, ideally occurring 6-12months of age

Question 45

What is the **intervention** for undescended testes?

Answer 45

Intervention is **dependent on clinical findings** + suspected position of undescended testis. If unable to find testis on examination it is important to identify if the testis is **absent** or **intra-abdominal**. Therefore, an examination under **anaesthesia** followed by laparoscopy remains the mainstay of intervention in order to locate an impalpable testis. * if testis **palpable** → open **orchidopexy** * if testis **intra-abdominal** → a single or 2-stage procedure (**Fowler-Stephens**) can be adopted * alternative findings at laparoscopy may be an **atrophic testis**, which should be removed or an absent testis → groin exploration