Renal Flashcards
Under the age of 1, which gender has more UTIs
Males
More common in uncircumcised boys (2X)
Over the age of two, which gender has more UTIs
Males:females
1:10
Symptoms of UTI
Fever Unwell Lethargic Jaundice Poor feeding
Symptoms of cystitis
Frequency and dysuria but no fever necessarily or generalised feeling unwell
Screening for assumptomatic bacteremia in
Pregnant women
Type 1 and type II e.coli
Type 2 have fimbriae that are mannose resistant and allow bacteria to ascend –> pyelonephritis or septicaemia
(20% will only cause cystitis)
Diagnosis of UTI:
Urine dip stick analysis:
Positive leukocytes
Positive nitrites
Urine culture:
More than 10^5 bacterial/ml
Less than that suggests contaminated sample
Methods of urine collection
Bag urine - lot of false positive bc readily contaminated with skin and gut flora (<30% are true positives)
Approx 100% sensitivity
Useful screening test
Catheter urine
Midstream urine
Suprapubic aspirate (<2% contamination)
Infant <6months
Febrile with first UTI
Treatment?
IV antibiotics
Usually amoxicillin and gentamicin
Oral - very high rate of beta lactamase producing e.coli so ~50% resistant to amoxicillin
Signs of an atypical UTI
Seriously ill Septicaemia Poor urine flow Abdominal mass Raised creatinine Non-e.coli UTI Failure to respond to antibiotics <48 hrs
Recurrent UTI means:
Generates further investigation
2 episodes of pyelonephritis
Or
1 pyelonephritis + 1 cystitis
Or
3 or more episodes of cystitis
Kidneys contribute to body homeostasis by:
Eliminating metabolic waste
Regulating fluid and electrolyte balance
Influencing acid- base balance
The kidneys produce:
Prostaglandins (affect salt and water regulation and influence vascular tone)
EPO
1,25-dihydroxylcholecalciferol (enhances calcium absorption from gut and phosphate resorption by renal tubules)
Renin (acts on angiotensin pathway to increase vascular tone and aldosterone production)
Renal circulation starts with the renal artery and goes to…
Segmental artery --> interlobar artery --> arcuate artery --> Cortical radiate arteries --> Afferent arterioles --> Glomerulus --> Efferent arteriole --> Peritubular capillaries --> Venules --> Interlobular veins --> Arcuate --> Interlobar veins --> Renal vein
What does the juxtaglomerular apparatus release?
Renin
EPO
What is the function of endothelial cells in the glomeruli
- role in charge-dependent filtration barrier
- synthesis, release, and bind coagulation factors
- participate in antigen presentation (express class 2 histocompatibility antigens)
- synthesise and release a relaxing factor
What type of junctions are between the foot processes?
adherens-type junctions (filtration slit diaphragms)
Two types of mesangial cells:
- one type - contractile and contain actin filaments, attach to capillary BM (damage –> reduces strength of capillary –> micro-aneurysm)
- type two - resembles monocyte
both types - synthesise new matrix material and secrete cytokines responsible for cell prolif and attraction of inflam cells
What is the function of the mesangial area being attached to the endothelial cells (BM in between) in the central core area?
allows access of immune complexes and ability of mesangium to probe the capillary lumen
the GFR reflects :
the permeability of the capillary will together with hydrostatic and osmotic gradients
Three mechanisms affecting the GFR:
Involve the JGA
- autoregulation within glomerulus
- tubuloglomerular feedback
- neurohormonal influences
The macular densa
monitor the levels of chloride in the tubular luminal fluid
Reduced GFR leads to:
fall in luminal chloride level –> dilatation of aa and constriction of ea due to renin
What hormones from the adrenal gland are involved in neurohormonal regulation?
angiotensin II - constricts ea more than aa
noradrenalin - constricts
both stimulate prostaglandin synthesis –> reduces arteriolar tone
