Urinary Obstruction & Prazosin for Cats
Urinary obstruction in the cat is a very common presentation for male cats with urinary signs (straining, vomiting, licking, vocalizing). Listed is a general protocol for managing these cases.
On intake, place IV catheter and collect full blood work. Administer pain medication immediately. Buprenex 0.015-0.2 mg/kg, Hydromorphone 0.1-0.2 mg/kg, Methadone 0.1-0.2 mg/kg.
Usual protocol for urinary obstructed cats in the hospital is 24-36 hours, with potential urinary catheter pull based on labwork and urine appearance in line.
Start with fluid bolus 50-100mL depending on if underlying heart disease concern (murmur, gallop, age). Smaller bolus if concerns for heart disease.
Sedation for unblocking:
- If no concern for heart disease: Ketamine 2 mg/kg IV, then repeat during unblock if needed- total of 4 mg/kg Midazolam 0.2 mg/kg IV, then repeat during unblock, usually needed- total of 0.4 mg/kg Butorphanol 0.2 mg/kg IV if not given above +/- Dexdomitor 1-2 units per cat IV +/- Alfaxalone 0.2mL increments PRN, not to exceed >1mL within 5m +/- Propofol 5 mg/kg titrated, and GA if needed.
- If concern for heart disease: Midazolam 0.2 mg/kg IV, repeat during unblock, usually needed- total of 0.4 mg/kg Butorphanol 0.2 mg/kg IV, if not given above +/- Alfaxalone 0.2mL increments PRN, not to exceed >1mL within 5m +/- Propofol 5 mg/kg titrated, and GA if needed.
Clip and sterile prep of prepuce and scrotum, including about 2cm of surround area. Avoid alcohol.
Sterile unblock, 3.5 Fr open ended TomCat with retropulsion to unblock. Once advanced into bladder, empty bladder, save sample for in house urinalysis. Remove and replace with 3.5 or 5 Fr red rubber. After placement, flush and retrieve copious amounts of sterile saline (120-200mL, 30mL at a time, be sure not to over inflate the bladder). General good placement is achieved with retrieving saline and gently pulling out red rubber until negative pressure. At this placement, advance about 2cm and usually this will place end of red rubber at center of bladder.
If possible, ultrasound bladder to observe sediment, if free fluid around bladder, urinary catheter placement, bladder wall thickness when distended with urine/saline and for any stones.
Obtain post procedure lateral abdominal x-ray. Once urinary catheter placement confirmed, place butterfly tape at base of exposed urinary catheter. Place stay sutures on both sides of prepuce, being careful not to take deep bites that may incorporate the penis. Leave about 1cm loop. Place additional stay sutures on both sides of butterfly tape. This leaves about 1-1.5cm of room between tape and preputial opening, to avoid irritation from the tape. Tape red rubber to tail. Attach closed collection system. Place e-collar.
Review urine strip and sediment in house.
Monitor ins and outs q4h. Flush and retrieve 20mLs sterile saline q4hr to help keep urinary catheter clear. Be sure not to flush at a distal port where concern for any debris in line getting flushed back into bladder. IV fluids >5kg: ~30-40mL/hr to start, increase if post obstruction diuresis seen. <5kg: ~ 20-30mL/hr to start, increase if post obstruction diuresis seen. 90-100mL/kg/d, can do higher amounts in the beginning for severe azotemia, or to match post obstruction diuresis, however high volume rates over entire stay are not necessary. If heart murmur, conservative fluid rates around 60-70 mL/kg/d with respiratory watch.
Pain management post obstruction:
- Buprenex 0.01-0.015 mg/kg IV, SL q8-12h PRN for pain Gabapentin 50-100mg PO q8-12h PRN.
- Start Prazosin 0.5 (<10lb) – 1mg (>10lb) PO BID once non-azotemic. Monitor kidney values daily if azotemic. Cerenia 1 mg/kg IV q24h Wet urinary diet only- S/D, C/D, SO.
After 24-36 hours with no azotemia and clear urine in line, remove urinary catheter. Wait 2-4 hours and obtain cystocentesis UA/UCS to lab. Start oral antibiotics if concern for bacteriuria. Can look at sediment in house, while waiting on culture to make determination. Recommended Clavaxmox 13.75 mg/kg PO BID to start. If owner cannot medicate orally, consider Convenia 8 mg/kg SQ.
Remove stay sutures prior to leaving.
DC instructions: Information on urinary obstruction for owners can be found at www.veterinarypartner.com, type in Feline Idiopathic Cystitis, or Feline Lower Urinary Tract Disease into search engine.
Advise on monitoring for re-obstruction, lifestyle changes, increase water intake and prescription diet only. If cat will not eat prescription diet, wet diet only for life, no more commercial dry foods.
If bladder stones present, recommend cystotomy, as stones may lead to re-obstruction prior to dissolution.
Written by Jessica Summers, DVM