Pathoma UTI, Nephrolithiasis, and Chronic Renal Failure Flashcards
What is cystitis and how does it present?
Infection of the bladder. Presents as dysuria, urinary frequency, urgency, and suprapubic pain.
Systemic signs usually absent
Labs for Cystitis
Cloudy urine with > 10WBCs/hpf
Dipstick: Positive leukocyte esterase due to pyuria and nitrites
Culture > 100,000 colony forming units
2 most common bacteria with cystitis
E. Coli = 80%
Staph saprophyticus = increased incidence in young sexually active women
Interesting note, Proteus mirabilis cystitis gives you alkaline urine
If patient presents with sterile pyurian what does that mean and what does it suggest? What bacteria are we working with?
Pyuria (infection of the urine) but negative culture
Suggests urethritis, not cystitis, due to Chlamydia rachomatis or Neissera gonorrhea
Pyelonephritis
Infection of the kidney usually due to ascending infection.
resents with fever, flank pain, WBC casts, and leukocytosis in addition to symptoms of cystitis
Most common pathogens for pyelo?
90% E Coli
Can also be Klebsiella and Enterococcus
Chronic pyelo?
Leads to interstitial fibrosis and atrophy of tubules.
Due to vesicoureteral reflux in children or an obstruction
Scarring from chronic pyelo
Cortical scarring with blunted calyces
Scarring at upper and lower poles is characteristic of VUR
Chronic Pyelo leads to what process histologically?
Thyroidization of the kidney.
Atrophic tubules contain eosinophilic proteinaceous material reminiscent of thyroid follicles
Waxy casts in the urine
Most common type of kidney stone and how we treat it
Calcium oxalate/phosphate.
HCTZ to treat
Second most common stone and how we treat it?
Ammonium magnesium phosphate. Surgery required because it results in a staghorn calculi in renal calyces which act as a node for UTIs.
What causes an ammonium magnesium phosphate stone?
Infection with a urease-positive organism like Vulgaris or Klebsiella, which cause the urine to become alkaline, forming the stone
This stone has a special radiology that instantly tells you what it is
Uric acid stone, third most common, shows a radiolucent stone instead of an opaque one
Treatment for uric acid stone?
Hydration and alkalization of urine (potassium bicarb)
Allopurinol can also be given if the patient has gout
Unlike ammonium magnesium stones, uric acid stones usually result from:
Acidic pH
Rarest type of stone and how it is treated
Cysteine, most commonly seen in kids. May form staghorn calculi. Treatment involves hydration and alkalinization of urine
Staghorn cell I’m thinking what and how do I distinguish?
Ammonium phosphate since it is more common, but if it is a kid, it may be a cysteine stone
Most common causes of Renal failure
DM, HTN, glomerular disease
Common effect of end stage renal failure is uremia. What is it and what does it lead to?
Increased nitrogenous waste products in the blood (azotemia)
Leads to nausea, anorexia, pericarditis, platelet dysfunction, encephalopathy with asterixis, and deposition of urea crystals on the skin
How do we get anemia with CRF?
Erythropoietin is down because it is made by the renal peritubular insterstitial cells
2 causes of hypocalcemia in CRF
- Can’t convert Vitamin D
2. Can’t excrete phosphate = high phosphate, which binds up free Ca
CRF can cause renal osteodystrophy. What is it?
Damage to the bone because of renal failure
It has three parts
1. osteitis fibrosa cystica - Low Ca = High PTH which resorbs bone, which causes fibrosis and cysts
- osteomalacia = can’t mineralize the osteoid made by osteobasts because your Ca levels are low
- Osteoporosis = Obviously. From acidosis, we start using the bone to help reduce the acidity, and this eats the bone away
Why do cysts develop on the kidneys of CRF patients?
Shrunken kidney put on dialysis will develop cysts
Dialysis on an end stage small kidney leads to renal cell carcinoma
