Flashcards in Urethral Obstruction Deck (35)
What sex of dogs and cats are most commonly affected by urethral obstruction?
Why are males more prone to urethral obstruction than females?
Complicated path and narrow lumen of male urethra
What are physical obstructions that can occur in the urethra?
Urolith, neoplasia, stricture, mucosal plug
What kind of mechanical obstruction occurs in the urethra?
Severe urethral spasma
What is the most important life-threatening e-lyte imbalance assoc. w/urethral obstruction?
Why does urethral obstruction cause hyperkalemia?
Decreased renal potassium excretion and extracellular shift d/t acidosis
How does hyperkalemia affect cardiac myocytes?
Affects resting membrane potential and eventually disables depolarization of cells
What ECG changes are assoc. w/hyperkalemia?
Bradycardia, tall/narrow T waves, wide QRS, decreased/absent P waves
How does 0.9% NaCl IVFT help treat hyperkalemia?
Dilutes serum potassium
How does IV Ca gluconate help treat hyperkalemia?
Restores membrane potential and re-establishes normal depolarization
Does IV Ca gluconate lower K+ levels?
How does IV dextrose and regular insulin help treat hyperkalemia?
Moves potassium back into cells
Why should you never give insulin alone to a hyperkalemic patient?
Can result in hypoglycemia and seizures
How does sodium bicarb help treat hyperkalemia?
Shifts potassium back into cells as pH increases
How does metabolic acidosis result from urethral obstruction?
Kidneys unable to excrete H+ ions
How does the body compensate for metabolic acidosis caused by urethral obstruction?
Resp compensation w/incr. RR/tidal volume
What does metabolic acidosis predispose the patient to?
Cardiac arrhythmias, CNS depression, decr. catecholamine responsiveness
How do you treat metabolic acidosis?
Relieve obstruction, IVFT, Na bicarb if severe
How does azotemia/hyperphosphatemia result from urethral obstruction?
Occurs d/t decr renal excretion of urea/other waste products
How do you treat azotemia/hyperphosphatemia?
Relieve obstruction, IV fluid diuresis
When will you see hypoCa with urethral obstruction?
2* to hyperphosphatemia
How does hypoCa further compromise a urethral obstruction?
Compromises neuromuscular excitation and cardiac contractility (can cause seizures)
How do you treat hypoCa?
IV Ca gluconate
How do you diagnose a urethral obstruction?
Straining, decompression, and a distended/turgid bladder
What fluids are needed to rehydrate a urethral obstruction?
Potassium free fluids (best choice is NaCl)
How can you relive a urethral obstruction?
Urinary catheter retropulsion
How do you prevent re-obstruction?
Place indwelling catheter
How long is an indwelling catheter left in place for a urethral obstruction?
Until azotemia, e-lyte imbalances resolve (12-24h after)
Are male or female cats more likely to become obstructed?