Session 7 - Urinary Stones + UTIs Flashcards
What are the main effects of PTH on calcium levels in the body?
- Increases serum calcium by increasing:
- Osteoclastic resorption of bone
- Intestinal absorption of calcium
- Kidney reabsorption
- Excretion of phosphate
What are the main action of Calcitonin in terms of serum calcium levels?
- Causes a fall in serum calcium levels by:
- Inhibiting osteoclastic activity
- Increasing renal excretion of calcium
What are the three main general reasons why urinary stones may form?
- Decreasing water content
- Increasing mineral content
- Decreasing solubility of salutes in urine
Overly alkaline urine favours the formation of which types of stones?
Calcium phosphate stones
What is the most common cause of Hypercalciuria?
Hypercalcaemia
Give some pathologies which may cause hypersecretion of PTH
- Primary tumour - Parathyroid hyperplasia or tumour
- Secondary to renal failure (retention of phosphate -> hypocalcaemia -> Lots of PTH released)
- Ectopic secretion of PTHrp by malignant tumour
Which malignant cancer is the one which most commonly produces PTHrp?
Squamous cell carcinoma of the lungs
For what reasons may bone be excessively destroyed?
- Primary tumour of bone marrow
- Diffuse skeletal metastases
- Paget’s disease of bone
- Immobilisation
What is the classical presentation of hypercalcaemia?
- Painful bones
- Stones
- Groans
- Moans
How do renal stones present?
- Most are asymptomatic and only picked up on radiography
- Renal colic
- Dull ache in loins
- Recurrent UTIs
- Haematuria
What investigations would we make if we suspected a patient had urinary stones?
- Mid-stream urine analysis (RBCs, urinary crystals)
- Serum (Us+Es, creatinine, Calcium)
- Ab X-Ray
- Best radiography is CT of kidney, ureter and bladder
What treatment options are there for patients with urinary stones?
- Analgesia
- Warmth to site of pain and bed rest
- Ureteroscopy (if stones are in lower ureter or below)
- Percutaneous Nephrolithotomy
- Extracorporeal shock wave lithotripsy
What host factors may make us susceptible to a UTI?
- Females having a shorter urethra
- Potential obstruction (pregnancy, tumours, prostate, stones)
- Neurological issues (incomplete emptying)
- Ureteric reflux (allows UTI to ascend from bladder)
What bacterial factors are important in their pathogenesis of UTIs?
- Faecal flora are potential urinary pathogens
- Fimbrae + adhesins allow attachment to epithelium
- Urease, enzyme that breaks down urea for energy
- Haemolysins: damage membranes
- K antigens: E.coli has these and allow capsule formation
What is the most common UTI?
Cystitis of the lower tract
