Hypertension and Calculi Flashcards
What characteristic changes occur histologically in the renal vessels and infrarenal vasculature over time? (2)
Intimal thickening with reduplication of the elastic lamina, reduction in kidney size and increase in proportion of sclerotic glomeruli.
Associated decrease in renal function (more common in black people)
How can the kidneys cause further increase in blood pressure in a patient with malignant hypertension? (3)
- Malignant hypertension causes development of fibrinoid necrosis in afferent glomerular arterioles and fibrin deposition in the arteriolar walls.
- Rapid rise in blood pressure may trigger these arteriolar lesions…
- Fibrin deposition leads to renal damage, increased renin release, further increased bp.
When is imaging required for renal artery stenosis? (3)
- Evidence of atheromatous vascular disease in patients with hypertension or progressive CKD
- Rise in serum Cr by more than 30% after introduction of an ACEi or ARB
- Abdominal bruits in patient with CKD or hypertension
- Recurrent flash pulmonary oedema without cardiopulmonary disease
- Renal asymmetry of >1.5cm in length on imaging
What options are available for imaging of renal arteries? (2)
eg to look for renal artery stenosis
Renal arteriography (gold standard but requires femoral canalisation.. invasive) MR or CT angiography (contrast avoided if poor renal function) Doppler ultrasonography
What is the management for renal artery stenosis? (3)
Aspirin ACEi Statins BP control Increased exercise and smoking cessation
Transluminal angioplasty is used for patients with fibromuscular hypertrophy but not for atheromatous stenosis.
What is the fancy term for renal stones? (1)
Nephrolithiasis
Name 4 different types of renal stones. (4)
Calcium oxalate* or calcium phosphate*
Uric acid
Struvite (mangesium ammonium phosphate)
Cysteine
Name 3 factors in the development of calcium renal stones. (3)
Primary renal disease: medullary sponge kidney or polycystic renal disease, renal tubular acidosis
Hypercalciuria:
-primary hyperparathyroidism
-excessive calcium intake
-excessive resorption of calcium from bone (immobilisation)
-idiopathic hypercalciuria
Hyperoxaluria:
-dietary (high oxalate or low calcium intake)
-enteric (chronic intestinal malabsorption)
-primary hyperoxaluria (rare autosomal dominant enzyme deficiency)
What co-morbdity is associated with the formation of uric acid stones? (1)
Why are ileostomies associated with uric acid renal stones? (1)
Hyperuricaemia and gout.
Ileostomies - loss of bicarb from gastrointestinal secretions leads to increased acid environment and reduced solubility of uric acid.
Which renal stones are typically stag-horn calculi? (1)
What causes the formation of these stones? (1)
Struvite
Infection with urease producing organisms e.g. Klebsiella and Pseudomonas.
What condition causes the formation of cysteine stones? (1)
Cystinuria (autosomal recessive condition)
What are the clinical feature of urinary tract calculi? (4)
Asymptomatic Pain (loin to groin) Haematuria UTI Urinary tract obstruction
Name 3 causes of ureteric colic? (3)
Urolithiasis
Post renal biopsy can cause blood clots that cause obstruction
Sloughed necrotic renal papillae
[Pain from ectopic pregnancy or leaking AAA may be similar]
What is the management of ureteric stones? (3)
Small: <5mm; analgesia, hydration, will pass spontaneously
Medium; nifedipine or tamsulosin to reduce ureteric spasms
Large: extracorporeal shockwave lithotripsy to fragment stones; Ureteroscopy with YAG laser
Percutaneous nephrolithotomy if very large/unsuitable for other methods.
Name 3 investigations for renal stones. (3)
Urine: dipstick, MC&S, 24 hour collection for cr, ca, po4, oxalate and urate
Blood: U&Es, Ca, PO4, albumin, PTH, vit D, urate, bicarbonate, serum ACE, TFTs
Imaging: Plain KUB xray, IVU, HR spiral CT**, Renal ultrasound
Special: chemical analysis of any passed stones.
** best imaging
