Renal: MCD; UTIs Flashcards
Describe the pathophysiology of MCD [3]
Podocyte injury:
- The main histological finding in MCD is diffuse effacement of the podocyte foot processes, which are essential structures for maintaining the integrity of the glomerular filtration barrier.
- This effacement occurs without significant immune complex deposition or thickening of the glomerular basement membrane.
Proteinuria:
- As a result of podocyte injury and dysfunction, the glomerular filtration barrier becomes more permeable to proteins, particularly albumin. This leads to nephrotic-range proteinuria, which is the hallmark clinical feature of MCD.
- The loss of protein in the urine further exacerbates the disease by causing hypoalbuminemia, which in turn leads to oedema, hyperlipidemia, and an increased risk of thrombosis.
Glomerular hyperfiltration:
- The reduction in glomerular filtration barrier selectivity and the compensatory increase in glomerular filtration rate may contribute to glomerular hyperfiltration.
- This hyperfiltration is a maladaptive response that can lead to glomerular injury and, in some cases, progression to chronic kidney disease.
Nephrotic syndrome features a classic triad of: [3]
Triad:
* Low serum albumin
* High urine protein content (>3+ protein on urine dipstick)
* Oedema
There are three other features that occur in patients with nephrotic syndrome:
* Deranged lipid profile, with high levels of cholesterol, triglycerides and low density lipoproteins
* High blood pressure
* Hyper-coagulability, with an increased tendency to form blood clots
What are intrinsic [2] and systemic [3] diseases that cause nephrotic syndrome
Most common cause: MCD
It can be secondary to intrinsic kidney disease:
* Focal segmental glomerulosclerosis
* Membranoproliferative glomerulonephritis
It can also be secondary to an underlying systemic illness:
* Henoch schonlein purpura (HSP)
* Diabetes
* Infection, such as HIV, hepatitis and malaria
TOM TIP: Minimal change disease comes up fairly frequently in exams as the most common cause of nephrotic syndrome in children.
How would a child present [4]
TOM TIP: Minimal change disease comes up fairly frequently in exams as the most common cause of nephrotic syndrome in children.
If you spot a 2 – 5 year old child with oedema, proteinuria and low albumin, you may be asked about the underling cause. The answer is likely to be nephrotic syndrome.
Describe the key features of MCD? [4]
Oedema:
- The hallmark of MCD is oedema, typically manifesting as periorbital puffiness, lower extremity swelling, and, in severe cases, ascites.
- Oedema results from a combination of hypoalbuminemia, which decreases plasma oncotic pressure, and renal sodium retention due to altered glomerular filtration.
Proteinuria:
- MCD is characterized by significant proteinuria, with daily losses of 3.5 grams or more of protein in the urine. This selective proteinuria primarily comprises albumin, leading to hypoalbuminemia.
Hypoalbuminemia:
- Reduced serum albumin levels ( < 2.5 g/dL) are a direct consequence of excessive urinary protein loss, leading to decreased plasma oncotic pressure and the development of edema.
Also:
Hyperlipidemia:
- causes elevated cholesterol and triglyceride levels due to increased hepatic synethesis of lipoproteins due to hypoalbuminaemia
Ix for MCD?
Urinalysis:
- Essential for assessing proteinuria and hematuria. A urine dipstick test can provide a rapid preliminary assessment, followed by a 24-hour urine collection to quantify proteinuria.
Blood tests:
- Include serum creatinine, electrolytes, albumin, and lipid profile to evaluate renal function, electrolyte imbalances, hypoalbuminemia, and hyperlipidemia.
Renal ultrasound:
- Useful in assessing kidney size, cortical echogenicity, and ruling out obstructive uropathy or other structural abnormalities.
Renal biopsy:
- Definitive diagnosis of MCD relies on renal biopsy in adults, with light microscopy typically showing normal glomeruli, and electron microscopy revealing diffuse podocyte foot process effacement. In children, renal biopsy is generally avoided.
Mx for MCD? [2]
-
Prednisolone
- given for 4 weeks, then gradually weaned over 8 weeks - Cyclophosphamide is the next step for steroid-resistant cases
Vulvovaginitis is a common presentation in young girls before puberty. It presents with: [6]
- Soreness
- Itching
- Erythema around the labia
- Vaginal discharge
- Dysuria (burning or stinging on urination)
- Constipation
- A urine dipstick may show leukocytes but no nitrites. This will often result in misdiagnosis as a urinary tract infection.
What may be the only presenting feature of a UTI in a child? [1]
Fever
What are age-specific clinical features of UTI for neonates and infants (< 3 months) [5]
Non-specific symptoms:
* Fever, hypothermia, jaundice, vomiting, diarrhoea, lethargy, poor feeding, or failure to thrive.
* Respiratory distress or apnea
* Abdominal distension
What are age-specific clinical features of UTI for infants and toddlers (3months - 2 years) [5]
Generalized symptoms:
- Fever, irritability, lethargy, poor appetite or vomiting.
Strong-smelling urine or diaper rash
What are age-specific clinical features of UTI for children (2-12) [5]
Lower urinary tract symptoms:
- Dysuria, frequency, urgency, hematuria.
Systemic symptoms:
- Fever with chills (more common in pyelonephritis), abdominal pain.
Need to consider risk of pyeloneophritis in children. What are the presenting features? [5]
- Fever (>38°C) with or without chills
- Flank pain or costovertebral angle tenderness
- Abdominal pain, nausea, and vomiting
- Lethargy or irritability
- Poor feeding or failure to thrive in infants
How do you dx UTIs in children? [4]
What are the main risk factors for utis in children? [5]
Female
Constipation
Neuropathic bladder
Structural abnormalities:
- Posterior urethral valves
- Vesico-ureteric reflux
Describe the mx of UTIs in:
- infants
- children with upper UTI [2]
- children with lower UTI [2]
infants less than 3 months old
- should be referred immediately to a paediatrician
children aged more than 3 months old with an upper UTI
- should be considered for admission to hospital.
- If not admitted oral antibiotics such as cephalosporin or co-amoxiclav should be given for 7-10 days
children aged more than 3 months old with a lower UTI
- should be treated with oral antibiotics for 3 days according to local guidelines, usually trimethoprim, nitrofurantoin, cephalosporin or amoxicillin.
- Parents should be asked to bring the children back if they remain unwell after 24-48 hours
All children under 3 months with a fever should start immediate IV antibiotics (e.g. []) and have a full septic screen, including blood cultures, bloods and lactate. A lumbar puncture should also be considered.
All children under 3 months with a fever should start immediate IV antibiotics (e.g. ceftriaxone) and have a full septic screen, including blood cultures, bloods and lactate. A lumbar puncture should also be considered.
How do you further investigate all children under 6 months [1] recurrent UTIs [1] or atypical UTIs [1]?
Ultrasound Scans:
All children under 6 months with their first UTI should have an abdominal ultrasound within 6 weeks, or during the illness if there are recurrent UTIs or atypical bacteria
Children with recurrent UTIs should have an abdominal ultrasound within 6 weeks
Children with atypical UTIs should have an abdominal ultrasound during the illness
A child has an atypical / recurrent UTI.
Which mode of investigation should be given after 4-6 months? [1]
DMSA (Dimercaptosuccinic Acid) Scan
* DMSA scans should be used 4 – 6 months after the illness to assess for damage from recurrent or atypical UTIs.
* This involves injecting a radioactive material (DMSA) and using a gamma camera to assess how well the material is taken up by the kidneys.
* Where there are patches of kidney that have not taken up the material, this indicates scarring that may be the result of previous infection.
Apart from US and DMSA, what other investigation is used for UTIs in children? [1]
Describe the process [1]
Micturating mystourethrogram:
- Fill bladder w contrast then watch flow in mic.
What is the Vesico-Ureteric Reflux (VUR)? [1]
Why is this significant with regards to UTIs? [1]
How is it diagnosed? [1]
Vesico-ureteric reflux (VUR) is where urine has a tendency to flow from the bladder back into the ureters when the bladder contracts
- This predisposes patients to developing upper urinary tract infections and subsequent renal scarring
- Means that have urine sitting in bladder and back pressure in kidneys
- This is diagnosed using a micturating cystourethrogram (MCUG).
Management of vesico-ureteric reflux depends on the severity. What is the general management plan? [4]
Avoid constipation
Avoid an excessively full bladder
Prophylactic antibiotics
Surgical input from paediatric urology
What are the pre-, renal and post-renal causes of AKI? [3]
Pre-renal
- Hypovolaemia
Renal
- HUS
Post-renal
- Obstruction
Chronic renal failure in children is rare.
What are the 3 most common causes? [3]
Structural abnormalities
HUS
Nephritis
When children need renal replacement, what is the usual pattern of care? [2]
Most start on dialysis then have a transplant
Some with pre-emptive transplant first
What are the two types of dialysis that children have? [2]
Peritoneal dialysis
- 2/3rs of children who need
- Catheter put into peritoneal cavity, dialysis fluid pumped into cavity. Osmosis causes movement of waste products away
- Can occur at home / over night
- Takes 12hrs, then off day
Haemodialysis
- 3 x week at hospital, 4hrs per session
- Need to be 10kg for size of catheter
- Blood pumped out and cleaned
- Needs fistula or vascular access
Compications of PD? [5]
Peritonitis
Catheter blockage
tunnel infections
Ommental blockage
hernia
stress
Compications of haemodialysis? [5]
Hypotension
Haemolyisis
Air embolism
Problems with vascular accesss
For deceased donor transplant, how old is the donor normally? [1]
What other considerations do you need to give? [3]
Aged 5-55
Difficult if donor has had significant hypertension
Avoid if Hx of malignancy of BBV
Z score used to match kidney to recipient based on degree of match
A child has a UTI that is found to be caused by Klebsiella.
Why is this clinically significant? [1]
Atypical causes of infection point towards a structural cause of UTIs (as opposed to typical)
Lecture:
What are the investigations for UTIs for < 6 months, 6months-3yrs and > 3 years [+]
