FLUTD glossary: feline urinary terms, defined plainly

A

Alert email n. site term: The email this site sends each time the camera sees Nigel enter the litter box. A time and a link. Diagnoses nothing. A timestamp, not a diagnosis.
Azotemia n.: Nitrogen waste building up in the blood, measured as BUN and creatinine. Pre-renal (too little blood reaching the kidneys), renal (the kidneys themselves), or post-renal (urine can’t leave, as in a blocked cat). Post-renal often improves fast once the blockage clears. “Post-renal,” she said. Not the kidneys. The plumbing. See also: BUN, Creatinine, Obstruction, urethral.

B

Bilirubin n.: A yellow pigment from broken-down red cells, processed by the liver. A trace can be normal in dog urine. In cat urine it is never normal; it prompts questions about the liver or red-cell destruction. One line on a feline lab report that doesn’t say “it depends.”
Bladder, distended adj. + n.: A bladder stretched by urine that can’t leave. In a blocked cat: large, firm, painful, usually recognizable by touch in seconds. Owners shouldn’t press on it; it can be damaged. Diagnosed faster than the paperwork.
BUN n. abbr. blood urea nitrogen: A blood test for urea, a waste product the kidneys clear. Rises when they can’t — including when urine can’t leave. Ranges vary by lab; healthy cats sit under about 30. Nigel’s was over 130. A number that rearranges a week. See also: Creatinine, Azotemia.

C

Calcium oxalate n.: A mineral that forms crystals and stones, more readily in acidic urine. The stones can’t be dissolved by diet; they usually come out, and diet then aims to prevent more. Not dissolvable by diet. See also: Struvite, Urolith.
Catheter, urinary n.: A thin tube passed up the urethra under sedation or anesthesia to clear a blockage and drain the bladder. Often left in a day or two, with a collection bag, so the urethra can settle and output can be measured. See also: Obstruction, urethral.
Creatinine n.: A waste product of muscle activity, cleared by the kidneys and measured alongside BUN. Also used as the reference in the urine protein-to-creatinine ratio. BUN’s more serious colleague. See also: BUN, UPC ratio.
Crystalluria n.: Crystals in the urine. Not stones, and not necessarily disease: healthy cats can have them, they can form in a sample after collection (especially refrigerated), and stones can form without them. Overrated, mostly. See also: Struvite, Calcium oxalate.
Cystitis n.: Bladder inflammation, from any cause. In cats, by far the most common form is idiopathic. From Greek kystis, bladder, and -itis, inflammation. See also: FIC.
Cystocentesis n.: Urine collected by passing a fine needle through the belly wall into the bladder, often with ultrasound. The cleanest sample, and the preferred one for culture. Sounds worse than it is. See also: Urinalysis.

D

Diuresis, post-obstructive n.: Very large volumes of dilute urine after a blockage is cleared, as stressed kidneys overcorrect. A cat can dehydrate while seeming to urinate well — hence measuring every milliliter in hospital. See also: Obstruction, urethral.
Dysuria n.: Painful or difficult urination: straining, crying, visible discomfort. Often audible. Rarely early. See also: Stranguria.

E

Eyeshine n.: The glow of an animal’s eyes in light, from a reflective layer behind the retina, the tapetum lucidum. Infrared makes it strong in cats — hence fig. 1 and the drawing. The only lit part of the brand.

F

FIC n. abbr. feline idiopathic cystitis: Bladder inflammation with no identifiable cause. The most common form of FLUTD, roughly 55 to 67 percent of cases in reviews. Understood as a stress-response disorder expressed in the bladder; managed at home more than cured. See also: MEMO, Idiopathic.
Fig. 1 n. site term: The live infrared feed on the front page. Durational cinema. Mostly an empty box, which is the good news.
FLUTD n. abbr. feline lower urinary tract disease: An umbrella for conditions of the bladder and urethra with similar signs: straining, frequent small urinations, blood, going outside the box. Main causes: idiopathic cystitis, stones, infection, and obstruction. A drawer, not a diagnosis. See also: FIC, Obstruction, urethral.

G

GAG layer n. glycosaminoglycan layer: A protective coating on the bladder’s inner surface. Defects are thought to play a part in idiopathic cystitis. Supplements meant to restore it are widely sold; evidence in cats is weak.

H

Hematuria n. also haematuria: Blood in the urine: a pink, red, rust or brown tint, or only detectable by test. Common in every form of FLUTD. Pale, unscented litter shows it. Why this house switched to the most boring litter on the market.
Hermeneutic circle n.: In philosophy: a part is understood only through the whole, and the whole only through its parts. On this site: one clump means nothing without the cat’s baseline. Two centuries of German philosophy, finally applied to litter.
Hyperkalemia n.: High blood potassium. In a blocked cat, potassium that should leave in urine accumulates and can disturb the heart’s rhythm — one of the most immediately dangerous effects. Treated urgently, often before the blockage itself. See also: Potassium.

I

Idiopathic adj.: Of unknown cause, after investigation. Medicine’s most honest word, and its least satisfying.
Indeterminate adj. site term: The permanent answer, on the front page, to the question in the name. Pending observation of fig. 1. With apologies to physics. See also: Schrödinger’s cat.

L

Lower urinary tract n.: The bladder and urethra. The upper tract is the kidneys and ureters. FLUTD is the lower.

M

MEMO n. abbr. multimodal environmental modification: A package of changes — more water, more and better boxes, places to hide and climb, play, routine, less conflict between cats — for managing idiopathic cystitis. A 2006 study reported fewer recurrences; it had no untreated control group. See also: FIC.

O

Obstruction, urethral n. also “blocked cat”: A blocked urethra — usually a plug of crystals, mucus and debris, or a small stone — so urine can’t leave the bladder. Far more common in males. A medical emergency: untreated, it can kill within days, sometimes within 24 to 48 hours. See also: Catheter, urinary, PU.

P

Panopticon n.: Jeremy Bentham’s 18th-century prison design: one inspector in a central tower sees every cell, so inmates behave as if always watched. Here: the same architecture, without the purpose.
Periuria n.: Urinating outside the litter box. Often a sign of urinary pain, especially on cool smooth surfaces — tile, tubs, sinks. Rule out medical causes before calling it behavior. Treat it as a symptom first.
pH, urine n.: How acidic or alkaline urine is. Matters mainly for stones: struvite likes alkaline, calcium oxalate acidic. Varies with meals and sample age; trends beat snapshots. Not something to adjust at home.
Plain text n. site term: The label on emergency instructions: plain type, plain words, no jokes. The voice stops where the danger starts.
Pollakiuria n.: Frequent small urinations. The classic early sign of an irritated lower tract; in the box, many small clumps. From Greek pollakis, often.
Polyuria n.: More urine than normal, usually with more drinking. Bigger or more clumps. More often kidney disease, diabetes or thyroid than FLUTD — a reason for a vet visit soon.
Potassium n.: An electrolyte vital to nerves and muscles, including the heart; normally excreted in urine. Element 19. Unexpectedly central to the worst night of your year. See also: Hyperkalemia.
Prazosin n.: A smooth-muscle relaxant long prescribed after unblocking to prevent re-obstruction. A randomized trial and a large retrospective study haven’t supported that; one found higher recurrence. A question for the prescribing vet.
Proteinuria n.: Protein in the urine, from lower-tract inflammation or bleeding, or from the kidneys. Dipstick false positives are common in cats; kidney loss is checked with a UPC ratio. See also: UPC ratio.
PU n. abbr. perineal urethrostomy: Surgery that makes a wider, shorter urethral opening in a male cat so debris passes. Largely removes the risk of fatal obstruction; doesn’t treat the bladder disease; has its own complications. Usually for repeat blockers. See also: Obstruction, urethral.

R

Refractometer n.: A small optical instrument that measures urine specific gravity by how a sample bends light. Ideally calibrated for cat urine; human ones read it high. The dipstick SG pad isn’t valid in animals. See also: Specific gravity, urine.

S

Schrödinger’s cat n.: Erwin Schrödinger’s 1935 thought experiment: a cat in a sealed box, by a literal reading of quantum mechanics, alive and dead until observed. Meant as a critique, not a recipe. The box on this site is observed continuously. The cat is fine. See also: Indeterminate.
Sediment, urine n.: What settles when a urine sample is spun: examined under a microscope for blood cells, bacteria, crystals, cells and casts. Where the urinalysis stops skimming.
Specific gravity, urine n. USG: Urine concentration compared with water (1.000). For cats with cystitis or stones the goal is usually lower — commonly below about 1.030 to 1.040 — because dilute urine is protective. The only scoreboard the water project has. See also: Refractometer.
Stranguria n.: Straining to urinate, slow and unproductive. In a male cat with little or no urine produced: the key sign of possible obstruction. Often mistaken for constipation. The most important word in this dictionary. Learn it. See also: Obstruction, urethral.
Struvite n.: Magnesium ammonium phosphate. Forms crystals and stones, more readily in alkaline urine. In cats, struvite stones can form without infection and can often be dissolved by a therapeutic diet over weeks. Often dissolvable by diet. See also: Calcium oxalate.

T

Tractatus Litterarius n. site term: The numbered propositions on the front page, numbered after Wittgenstein’s Tractatus. 7. What cannot be settled at home is settled by a veterinarian.

U

UPC ratio n. abbr. urine protein-to-creatinine ratio: Protein lost in urine, corrected for concentration. In cats, under about 0.4 is generally normal, over 1 abnormal, borderline between. See also: Proteinuria.
Urethra n.: The tube from bladder to outside. In male cats long, narrow and tapering — why they block far more often. A design flaw, from the cat’s point of view.
Urinalysis n.: Lab examination of urine: appearance, specific gravity, dipstick chemistry and microscopic sediment, often with a culture. A short text that repays a long reading. See also: Specific gravity, urine, Sediment, urine.
Urolith n.: A stone anywhere in the urinary tract. In cats, mostly struvite or calcium oxalate. Most show on X-ray; ultrasound finds smaller ones. Greek for “urine stone.” No poetry here.
UTI n. abbr. urinary tract infection: Bacterial infection of the urinary tract. Uncommon in young and middle-aged cats with urinary signs; likelier in older cats and those with kidney disease, hyperthyroidism or diabetes. Confirmed by culture. The cause everyone assumes. Usually wrong. See also: Cystocentesis.

W

Wet food n.: Canned or pouched food, roughly 70 to 80 percent moisture against dry’s 6 to 10. The single most effective way to dilute a cat’s urine. The change with the most evidence behind it. See also: Specific gravity, urine.