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Polycystic kidney disease
This is a genetic condition which leads to the development of multiple cysts on the kidneys.
It exists as both autosomal dominant and recessive forms:
Autosomal dominant
This occurs due to a mutation in the genes PKD1 (Chr 16), or PKD2 (Chr 4)
Symptoms
Clinically silent initially but gives symptoms in early adulthood
Hypertension (due to renin release), hematuria, cyst infection and kidney failure
Associations
Liver cysts (most common extra-renal manifestation)
Berry aneurysms in the brain
Cardiovascular abnormalities (mitral valve prolapse, valve issues, aortic dissection)
Key tests
Abdominal ultrasound is used to detect cysts
Management
Tolvaptan can be used to slow progression to CKD
Transplantation is required once patient has CKD
Autosomal recessive
This occurs due to a mutation in PKHD1-fibrocystin (chromosome 6) which is needed for renal tubule development.
Symptoms
Presents in infants with renal cysts causing renal failure and hypertension
Associated with hepatic fibrosis leading to portal hypertension and hepatic cysts
Horseshoe kidney
This is a renal anatomical anomaly which occurs when the kidneys are conjoined.
Rather than being on the two flanks, the single kidney is situated in the lower part of the abdomen near the origin of the inferior mesenteric artery.
Symptoms
Often asymptomatic, but can develop UTIs and stones more frequently
Management
Symptomatic management of complications
Neurocutaneous syndromes
This refers to a group of conditions that involve structures from the embryonic ectoderm, which gives rise to the nervous system, eyes, teeth and skin.
However, they can also involve organs from other germ layers, including the kidney.
Tuberous Sclerosis complex
An autosomal dominant multisystem disorder due to mutations in the TSC1 or TSC2 gene.
It causes hamartoma formation in the skin, eyes and brain leading to epilepsy.
In the kidney, it causes benign tumours with risk of aneurysm and cystic disease.
Von Hippel-Lindau syndrome
This is due to an autosomal dominant mutation in the VHL gene which regulated a protein known as hypoxia inducible factor 1α.
This mutation leads to transcription of a number of genes and growth factors which leads to the development of cysts and tumours in many organs at early ages.
Cysteine Diseases
Cystinosis
This is an autosomal recessive Lysosomal storage disorder with accumulation of cysteine crystals in various organs of the body.
It builds up in kidney causing PCT dysfunction, Fanconi syndrome and progressive renal failure.
Can also build up in eyes (visual impairment), muscles and brain.
Management
Oral cysteamine decreases cysteine accumulation
Cystinuria
This is an autosomal recessive conditions stopping cysteine reabsorption in the PCT
Leads to cysteine in the urine and cysteine urinary tract stones, often seen in children
Management
Increase fluid intake and urine alkalization
