Nephrology and Urology Flashcards
Apart from vascular, traumatic and toxic, what other classification of disease is often responsible for acute injury?
Inflammatory
What is the characteristic of azotaemia?
Increase urea with/without increased creatinine in the blood
Define uraemia.
The clinical syndrome arising from azotaemia
What is pre-renal azotaemia?
Reduction in renal blood flow or increase protein catabolism/GI haemorrhage (bleeds means delivering a huge amount of protein to the kidney that normally functioning kidneys wouldn’t be able to deal with it).
What is the USG of pre-renal azotaemia?
The kidney will be doing everything they can do to conserve water = azotaemia with concentrated urine
> 1.030 in dogs
1.035 in cats
What is renal azotaemia?
Fewer functional nephrons. The kidneys are unable to conserve water so azotaemia with dilute urine
What is the USG of renal azotaemia?
< 1.030 in dogs
< 1.035 in cats
What are 2 examples of post-renal azotaemia?
Urinary tract obstruction > back-pressure
Urinary tract rupture > urine leakage > reabsorption of waste products
How is post-renal azotaemia diagnosed?
- Identify with history, imaging with/without effusion analysis. Uroabdomen: [creatinine]fluid > [creatinine]serum
- Free abdominal fluid
You are presented with a 9 year old cat for a dental treatment. Pre-operative bloods identified increased urea and creatinine. You collect a urine sample – specific gravity is 1.018. What classification of azotaemia does this cat have?
Renal
Define acute kidney injury.
Sudden organ damage and association dysfunction, usually severe clinical signs. Causes fatal injury, complete recovery, partial recovery to chronic disease. Acute nephron damage/dysfunction
What is chronic kidney disease?
Chronic nephron loss > gradual decline in renal function
Why are the kidneys so susceptible to toxic and ischaemic injury?
As they weight 0.5% of body weight but get 20% of cardiovascular output so are very sensitive to CVS changes/lesions or toxic lesions
What is the effect of severe acute kidney injury on urine output? How does this effect prognosis?
Most commonly = anuria/oliguria
Less commonly = polyuria
Polyuric has better prognosis as at least they are able to excrete the waste products with lots of water, anuric/oliguric cannot and so this is what is fatal progressively
What are the physiological consequences of acute kidney injury?
- Failure of excretion of nitrogenous waste products
- Acid base disturbances
- Electrolyte disturbances
- Fluid balance disturbances
What is the effect of failing to excrete nitrogenous waste due to acute kidney injury?
- Azotaemia = increased serum urea, creatinine
- Increased phosphate
What is the effect of electrolyte disturbances due to acute kidney injury?
- Hyperkalaemia with an/oliguria
- Various with polyuria
What is the presentation of acute kidney injury?
- Often uraemic – lethargic, inappetant, nauseous/vomiting, diarrhoea
- With/without dehydrated/hypovolaemic
- Increased or decreased temperature
- With/without renomegaly – symmetry? Cats may get asymmetry from AKI
- With/without renal/abdominal pain
- With/without concurrent signs due to other affected organ systems
What are the possible concurrent signs from other organ systems with presentation of acute kidney injury?
- Hypocalcaemia – tremors, seizures (ethylene glycol)
- Icterus, petechiae – leptospirosis causes acute kidney and liver injury
- Cutaneous lesions
What are the possible aetiologies of acute kidney injury?
- Toxic – toxins, drugs
- Ischaemic – hypoperfusion
- Infectious – leptospirosis, pyelonephritis, CRGV
- Metabolic – elevated Ca:P product or condition causing high calcium and phosphate that may cause kidneys to mineralise
- Uncorrected pre/post renal progressing to renal azotaemia
What is CRGV?
Cutaneous and renal glomerular vasculopathy – Alabama rot
What is the presentation of CRGV?
Skin lesions are rare with other causes of AKI – clots in blood vessels causing ischaemic skin lesions
How is CRGV diagnosed?
- Acute azotaemia with exclusion of pre-renal and post-renal causes – non-azotaemic AKI is possible
- Often hyperphosphataemic
- Potassium variable – increased if anuric/oliguric, decreased if polyuric
- Metabolic acidosis
- With/without changes related to underlying cause
- Rule out addison’s – can look like AKI
What are the specific urinalysis findings with CRGV?
- Submaximally concentrated urine with/without proteinuria/glucosuria due to tubular damage
- Casts, crystals
- Inflammatory cells/bacteriuria
- Bacterial culture and sensitivity (ideally cystocentesis sample) - polynephritis
- Calcium oxalate dihydrate may be found in normal cats and dogs
- Calcium oxalate monohydrate = ethylene glycol toxicity
How can imaging exclude post-renal causes in acute kidney injury diagnosis?
Ureteric obstruction > pelvic dilation
Urinary tract rupture > free fluid
What can be seen of acute kidney injury on ultrasound?
- Renal size normal to renomegaly
- Pyelonephritis may lead to pyelectasia
- With/without cortices, peri-nephric fluid
What can be seen of acute kidney injury on radiography?
With/without renomegaly and radio-opaque uroliths
When may renal cytology FNA be indicated?
Rarely. Use if suspect renal lymphoma – black band around the kidney. Thrombocytopathia?
Which infectious disease may cause acute kidney injury? How is this tested?
Leptospirosis
Serology, PCR (blood first 5-7 days of illness, urine thereafter)
What other specific test can you do in acute kidney injury?
Specific tests for toxins such as ethylene glycol. Potentially toxicology for owner peace of mind if there is concern someone has poisoned the cat in the neighbourhood
How is acute kidney injury managed?
- Remove underlying cause - stop known nephrotoxic drugs, f recent ingestion of substance – gastric decontamination/adsorption
- Supportive management, pending renal recovery. Manage fluid balance, electrolytes, uraemic toxins, nausea, pain
- Specific treatment where available
How is initial fluid therapy done in acute kidney injury?
- Correct any hypovolaemia (pre-renal component) within 1-2 hours
- Once euvolaemic, correct any dehydration
- Replace over 6 hours
What are the potential contraindications for initial fluid therapy in acute kidney disease?
- Overhydration - kidneys made oedematous are work more poorly
- Clinically significant cardiac disease
What are the risks of anuria/oliguria?
- Progressive azotaemia
- Metabolic derangements
- Life threatening potassium increase
- Volume overload > worse outcome
What are the risks of polyuria?
Dehydration, hypovolaemia, potassium wasting, hypokalaemia
Easier to manage, better prognosis because can excrete uraemic toxins
How is ongoing fluid therapy for acute kidney injury done?
- Hartmann’s
- 2ml/kg/h maintenance obsolete in patients with increased or decreased urine output
- Match ins with out
- Re-evaluate every 1-4 hours
What are the consequences of hyperkalaemia caused by acute kidney injury?
- Reduced pacemaker activity – may be bradycardic
- Can lead to ventricular fibrillation and cardiac arrest - wide QRS, spiked T, flattened P
How is hyperkalaemia by acute kidney injury managed?
- Restore renal perfusion
- Calcium gluconate IV – does not address hyperkalaemia but stabilised cardiomyocyte membranes
- Redistribute potassium intracellularly
How is potassium redistributed intracellularly to manage hyperkalaemia caused by acute kidney injury?
- Glucose in hartmann’s – stimulate endogenous insulin release which will cause cells to uptake with potassium
- With/without exogenous insulin (neutral) – requires regular BG monitoring
- Sodium bicarbonate is rarely indicated even in referral, requires acid base monitoring
How are acute kidney injuries managed?
- Fluid balance – post AKI polyuria may be profound
- Renal perfusion – systemic blood pressure, avoid hypertension
- Electrolytes – supplement as necessary
- Azotaemia
What is the antidote for NSAID induced acute kidney injury?
Misoprostol
What is the specific antidote for pyelonephritis causing acute kidney injury?
Antibiotics. Clavulanate potentiated amoxicillin = reasonable choice pending culture
What is the specific antidote for leptospirosis induced acute kidney injury?
Clavulanate potentiated amoxicillin IV (pending results/if too sick for oral doxy.) Doxycycline (2 weeks, orally) to eliminate carrier state
What is the specific antidote for ethylene glycol toxicity induced acute kidney injury?
Ethanol (or 4-methylpyrazole) within 8 hours ingestion
What is the adjunctive management for acute kidney injury?
- Consider dose reductions for renally metabolised drugs
- Manage nausea – maropitant, metoclopramide
- Manage GI haemorrhage (may > nausea) – omeprazole (reduce 50%), sucralfate
- Analgesia (opioids) if required
What are the other considerations for acute kidney injury management?
- If feeding liquid food incorporate into fluids ins calculation
- Manage hypertension with amlodipine
What is done if there is persistent anuria?
- Double check – euvolaemic, euhydrated
- No post-renal disease – obstruction, rupture
- Frusemide single dose, expect response 20-60 minutes, may repeat
- Still a anuric, indication for renal replacement, prognosis guarded if cannot respond to single dose
What is the prognosis of acute kidney injury?
- Approximately half of survivors have CKD
- All survivors should be considered as CKD IRIS stage 1 at minimum
What is chronic kidney disease?
- Functional and/or structural disease of over 3 months duration
- Gradual, progressive, irreversible, nephron loss
- Management aimed at protecting remaining nephrons and managing clinical consequences
Why is evidence of chronic kidney disease not seen until late in the disease?
- Loss 50% nephrons = 1 kidney loss or 50% function in each, still subclinical
- Loss 67% = lose concentrating ability
- Loss 75% = become azotaemic
- Loss 100% nephrons = decreasing quality of life
What are the possible aetiologies of chronic kidney disease?
- Chronic interstitial nephritis (CIN) – end stage of many pathological processes. Original inciting cause of the injury is not possible to tell
- Glomerulonephropathy
- Undiagnosed/untreated infections
- Chronic obstructive disease
- Congenital – PKD, renal dysplasia
- Lymphoma
What is the genetic test for polycystic kidney disease?
- Cheek swab or EDTA blood sample
- Negative cats > ICC PKD register
What is the pathogenesis of chronic kidney disease?
- Asymptomatic/undiagnosed initial insult > decreased GFR
- Compensatory hypertrophy of remaining nephrons
- Leads to progressive nephron loss, progressive decreased GFR
- Loss of electrolyte/water regulation
- Loss acid/base regulation
- Failed excretion of organic solutes
- Impaired renal hormone synthesis – calcitriol (vitamin D), erythropoeitin (EPO)
- Hypertension; cause vs. consequence
What are the findings from the history of a clinical presentation of chronic kidney disease?
- PUPD – in cats, major differentials are diabetes mellitus ad hyperthyroidism
- Weight loss
- Lethargy, weakness
- Inappetance
- Vomiting with/without diarrhoea with/without haematemesis/melaena. May see constipation secondary to dehydration
- With/without signs associated with hypertension - blindness, neurological
What are the findings from the examination of a clinical presentation of chronic kidney disease?
- Catabolic state
- Typically dehydrated
- With/without weakness – hypokalaemic myopathy > neck ventroflexion
- With/without uraemic ulcers, with/without uraemic halitosis
- With/without hypertensive retinopathy
- Kidneys typically small and irregular on palpation – may be large if lymphoma
- ‘Rubber jaw’
What is the pathogenesis of renal secondary hyperparathyroidism/rubber jaw?
- Decreased GFR > decreased phosphate excretion
- Increased serum phosphate
- Parathyroid secretion
- Decreased phosphate and increased calcium – ineffective as inadequate renal function to excrete increased phosphate
- Progressive increased phosphate
- Persistent parathyroid hormone release
- Bone resorption resulting from increased parathyroid hormone activity
- Rubber jaw – R2PTH. Clinically most recognised in renal dysplasia
What diagnostic test is needed to confirm a renal azotaemia in a cat?
Urine specific gravity less than 1.035
How is chronic kidney disease diagnosed?
- Azotaemia is increased urea and creatinine, not until 75% GFR loss
- With inadequately concentrated urine not until 67% GFR loss
- GFR = gold standard measure of renal filtration
- SDMA = benefits and limitations, equally prone to limitations of creatinine (increases with pre, renal and post renal azotaemias)
How might chronic kidney disease appear on urinalysis?
- Submaxillary concentrated urine
- Evaluate for proteinuria
- Sediment examination for casts and crystalluria
- Cytological examination – EDTA sample for inflammatory sediment or atypical cells
- Culture and sensitivity – cystocentesis, plain sample
How may chronic kidney disease be diagnosed from bloods?
Haematology – anaemia (normocytic, normochromic)
Serum biochemistry
- Azotaemia
- With/without increased phosphorous
- With/without increased/decreased calcium
- With/without decreased potassium – very end stage causes increase
What other diagnostic tests might be done for chronic kidney disease?
- FIV (/FeLV)
- Systolic blood pressure
What might be assessed from radiography about chronic kidney disease?
- Renal size and architecture
- Ureteroliths
- Ureteric obstruction
- Pyelonephritis
- Lymphoma
How is IRIS staged?
- Creatinine
- Substage by proteinuria
- Substage by blood pressure
How is fluid balance managed for chronic kidney disease?
- Encourage oral intake
- Subcutaneous fluids
- Oesophageal tube – nutrition, fluid, medication
How is the progression of chronic kidney disease delayed?
- Renal diet
- Control hypertension, proteinuria, hyperphosphatemia, hypokalaemia
- Avoid further insults
Which nutrients are restricted in renal diets?
Protein
Phosphorus
Sodium
Which nutrients are supplemented in renal diets?
Omega-3 PUFAs
Vitamin E
Synergistic with PUFAs
B vitamins
Potassium in cats
Soluble fibre
How is calorific intake managed in chronic kidney disease?
- Important to avoid protein calorie malnutrition
- Avoid introducing prescription diets in the hospital or syringe feeding
What are the possible causes of inappetence in chronic kidney disease?
- Dehydration
- Hypokalaemia
- Nausea, mirtazepine, maropitant
- Uraemic gastropathy, omeprazole, sucralfate
How is hyperphosphataemia from chronic kidney disease managed?
Phosphate restriction slows progression and so prolongs survival
- Renal diet
- If inadequate decreased phosphorous > phosphate binder
What are the contributors to hypokalaemia caused by chronic kidney disease?
Inadequate dietary intake
Renal potassium wasting
What are the clinical signs of hypokalaemia caused by chronic kidney disease?
Inappetence, lethargy, weakness, PUPD
How is hypokalaemia caused by chronic kidney disease managed?
Renal diet with/without potassium supplementation
How is hypertension caused by chronic kidney disease assessed?
Do a retinal exam
Target = SBP <140mmHg
Describe the anaemia caused by chronic kidney disease.
- Anaemia of chronic disease is common/expected in CKD
- Usually mild and does not need specific treatment
- Exacerbated by gastrointestinal haemorrhage and reduced RBC lifespan
- Reduce GI losses (omeprazole, sucralfate)
- If PCV <20% and symptomatic for anaemia
What is systemic hypertension due to?
- Increased SNS > increased RAAS > vasoconstriction
- RAAS > sodium ion retention
- Volume expansion
What are the causes of secondary hypertension?
- Kidney disease
- Endocrinopathies
- Situational hypertension – stress associated
- Increase intracranial pressure (with bradycardia = Cushing’s reflex)
What are the consequences of systemic hypertension?
- Ocular – hypertensive retinopathy, acute blindness
- Renal - increased risk of progression of CKD
- Cardiac – pressure overload causes left ventricular concentric hypertrophy
- Neurological
What is the normal systemic blood pressure?
- SBP 120-140mmHg
- Sight/deerhounds 10-20mmHg higher – this appears to be in-hospital situational hypertension
Define the values for hypertension.
Pre-hypertensive = 140-159 mmHg, low risk of future target organ damage/TOD
Hypertensive = 160-179mmHg, moderate risk of future TOD
Severely hypertensive = over 180mmHg, high risk of future TOD
How is cuff for blood pressure measurement selected?
Cuff width is 40% the circumference of the limb and placed as close to cardiac height as possible
When should hypertension be treated?
- SBP ≥180mmHg = treat
- SBP ≥160mmHg with evidence of target organ damage = treat
- Sustained (>1 visit) SBP ≥160mmHg
What are the signs of hypotension the owner should be made aware of?
Lethargy, weakness, ataxia/syncope – and reassess immediately
Which medications can be used to manage reduce renal blood flow for hypertension management?
- Amlodipine is 1st choice in cats – calcium blocker that causes vasodilation in peripheral arteries
- Benazepril is first choice in dogs – ace inhibitor
- Telmisartan – angiotensin receptor blocker
What is proteinuric kidney disease?
- Proteinuric kidney disease is the most common type of CKD in dogs, rare in feline renal disease
- Proteinuria accelerates progression of renal disease
How is proteinuria diagnosed?
Dipstix – qualitative
Urine protein:creatinine ration – quantitative
How is proteinuria diagnosed from protein:creatinine ratio?
- Normal < 0.2
- Borderline 0.2-0.4/0.5
- Proteinuric – > 0.4 in cat, > 0.6 in dog
- Severely proteinuric >2
What are the pre-renal causes of increased urine protein?
- Increased blood proteins – hyperglobulinaemia, haemo/myoglobinaemia
- Functional – pyrexia, post-exercise, seizure
What are the renal causes of increased urine protein?
Intrinsic renal disease
- PLN
- Glomerular disease - increased permeability to albumin > proteinuria
- Tubular disease
What are the post-renal causes of increased urine protein?
- Urinary tract (ureteric, bladder, prostatic, urethral) - inflammatory or neoplastic disease, urinary tract haemorrhage
- Reproductive tract disease
Does glomerular disease result in azotaemia?
They are not necessarily azotaemic and may retain urine concentrating ability – it is glomerular, not tubular disease
What are the consequences of nephrotic syndrome?
- Progressive proteinuria > hypoalbuminaemia > effusions/oedema
- Hypercoagulability > exacerbates/accelerates glomerular nephropathy
- Hypercholesterolaemia
What are some causes of primary glomerular disease?
- Inherited/familial glomerular disease – developmental collagen defects
- Idiosyncratic disease
- Autoimmunity
What are some causes of secondary glomerular disease?
Secondary > Immune complex formation/deposition or amyloid deposition
- Inflammatory (sterile, infectious)
- Neoplastic disease
- Drug/toxin exposure
What is amyloidosis?
- Chronic inflammatory disease (elsewhere in the body) > production of serum amyloid A (SAA)
- AA is deposited in tissue – kidneys, liver, other organs
- Polymerises and forms β-pleated sheet – insoluble
What is renal amyloidosis?
- Causes marked proteinuria
- Typically glomerular deposition
- Familial Shar-pei Fever (FSF) believed to be the inflammatory trigger – treat FSF episodes with NSAIDs
How do I find out what type of glomerular disease a patient has?
- Evaluating for a possible underlying trigger of the glomerulonephritis/amyloidosis. Primary vs. secondary/reactive glomerular pathology
- Renal biopsy
- Histopathology alone inadequate
When is renal biopsy used?
- Not appropriate disease if secondary disease or end-stage
- Use in primary cases (no trigger), without familial cause, not responding to ‘standard’ therapy
How is proteinuria treated?
- Angiotensin receptor blocker (first line therapy)
- Angiotensin converting enzyme inhibitor (second line therapy)
- Significantly decreases proteinuria and delays onset and progression of azotaemia
- Monitor every 2 weeks (3 months once stable) - aim UPC < 0.5 or <50% from baseline, creatinine, albumin, sodium, potassium, Blood pressure
What might be the adverse events of treating proteinuria?
Worsening azotaemia, hypotension, hyperkalaemia
What are the adjunctive therapies used in all glomerular patients?
- Renal diet
- Omega-3 PUFAs
- Anti-platelet therapy (e.g. clopidogrel or aspirin)
- Oedema management; light exercise
- Manage hypertension
- Monitor/manage otherwise as per IRIS guidelines (glomerular disease is a form of CKD)
What is the prognosis of glomerular disease?
- Highly variable, depending on subtype – poor in those presenting with azotaemia and nephrotic syndrome, <2 months
- Slow progression with survivals of a number of years
- Spontaneous resolution/remission also reported
What are the features of nephrotic syndrome?
Proteinuria, hypalbuminaemia, effusions, hypercholesterolaemia
What is the class of the first line drug for treating proteinuria?
Angiotensin receptor blocker
What are 2 tubular disorders?
Glucosuria in the absence of hyperglycaemia > osmotic diuresis > PUPD. If normal in blood, is not DM
Fanconi syndrome - hereditary or acquired (copper hepatopathy, leptospirosis, Chinese jerky treats)
What are the clinical signs of lower urinary tract disease?
Similar regardless of aetiology:
- Dysuria
- Stranguria
- Vocalisation, licking prepuce, inappetence, lethargy
- Haematuria
- Pollakirua – increased pollakiuria
- Periuria – voiding in inappropriate places
What are the differential diagnoses for lower urinary tract disease in cats?
- Urethral plus
- Urethral spasm
- Behavioural
- Urolithiasis
- Bacterial UTI
- Stricture (congenital)
Rare - neurological, neoplasia, prostatic
What are the differential diagnoses for lower urinary tract disease in dogs?
- Bacterial UTI – prone to ascending infections due to short wide urethra
- Prostatic disease
- Urolithiasis
- Transitional cell carcinoma
Rare:
- Urethritis
- Cyclophosphamide induced sterile haemorrhagic cystitis
- Stricture (congenital)
- Neurological
When is a neurological examination indicated for lower urinary tract disease?
If hindlimb ataxia, difficulty posturing, dribbling urine
What is the presentation of urinary obstruction?
- Unproductive urination attempts
- Tense, usually large painful bladder
- Not palpable? Ruptured? AFAST
- Associated complications
- Bradydysrhythmias – life-threatening hyperkalaemia
How is urinary obstruction diagnosed from basic urinalysis?
- Submaximally concentrated – appropriate vs. pathological
- Dipstix analysis
- Urine biochemistry – expect some proteinuria due to LUT inflammation
- Crystals – true vs. storage artefact. normal vs. abnormal (plain tube). Can be normal alone, abnormal if with stones
- Bacteria – asymptomatic bacteriuria vs. urinary tract infection
- Cytology – inflammatory, neoplastic cells
- Culture
How is urinary obstruction diagnosed from ultrasounds?
- For cystocentesis
- Bladder wall morphology
- Prostatic parenchyma
- Uroliths
How is urinary obstruction diagnosed from radiography?
Plain – uroliths (radio-opaque), prostato/lymphadenomegaly
Contrast, double contrast – uroliths (radiolucent), masses, polyps, strictures
What further diagnostics could be used to diagnose urinary obstruction?
- Haematology, serum biochemistry – underlying systemic disease?
- Free abdominal fluid? – analyse
- Prostatic wash/suction
- Bladder suction biopsy
- Cystoscopy
How might urine samples be collected?
- Cystocentesis – preferred method for culture
- Catheterisation - can culture, although less sterile than cystocentesis
- Analyse fresh from free catch or litter trays – appropriate for USG, biochemistry, UPC, sediment exam, cytology
What are the predisposing factors for UTIs?
- Indwelling urinary catheter – risk for infection, do not treat while catheter is in situ, will only create resistant infection
- Structural urinary tract disease
- Abnormal voiding
- Sub-maximally concentrated urine
- Immunosuppression/systemic disease
How are UTIs treated in dogs?
Ideally treat based on culture and sensitivity. Ideally NSAIDs only pending results. Amoxicillin or trimethoprim sulphonamide. 3-5 day course
What are the considerations for UTI management?
- Fresh water access
- Enable frequent voiding
- Keep vulva, prepuce clean and free from urine scald – UTIs are typically due to ascending infections if alkaline pH, consider evaluating for struvite uroliths
What are the possible complications of UTIs?
- Struvite uroliths – urease producing bacteria (Staphylococcus, Proteus)
- Pyelonephritis
- Polypoid cystitis
- Emphysematous cystitis
When might UTIs be complicated?
Recurrent bacterial cystitis, cats?, male dogs?, predisposing factors
How are complicated UTIs managed?
- Evaluate for and treat underlying cause
- Base treatment on culture and sensitivity
- Prostatic – only TMPS, fluoroquinolones and doxycycline will penetrate, 3-6 weeks. Neuter entire male dogs 1-2 weeks into treatment
- Pyelonephritis – treat pending c&s – Quinolone, 7-14 days
- Re-culture - 1 week into treatment to demonstrate control and1-2 weeks after stopping treatment
Which cats are susceptible to feline idiopathic cystitis?
- Neuroendocrine modulation – adjusted sensory nerve function, abnormalities of the CNS stress response
- GAG layer hypofunction
- Environmental stress manifests as FLUTD
What is the presentation of non-obstructed feline idiopathic cystitis?
- Signs of LUTD
- Still able to void
- Often self-limiting
- May experience recurrent episodes
What is the presentation of obstructed feline idiopathic cystitis?
- Urethral spasm or plug
- Unproductive attempts to urinate
- Emergency
- More common in males (non-obstructive equi-prevalent)
- High recurrence rates
- > 40% experience a recurrence within 6 12 months
What should never be done in feline idiopathic cystitis?
Never attempt to express their bladder
How is feline idiopathic cystitis managed?
- FLUTD signs, young cat, first episode, non-obstructed – manage medically
- Obstructed – alleviate obstruction then manage medically
What is the presentation of urethral obstruction?
- Back pressure on kidneys > post renal azotaemia
- Hyperkalaemia
- Painful bladder
- Agitated/painful vs. depressed
What is the emergency management for hyperkalaemia as the result of obstruction?
- Definitive correction requires alleviation of obstruction – urinary catheterisation
- Hyperkalaemia needs addressing first
- Bladder decompression rarely required in the interim
- Analgesia (opioids) during stabilisation, pending GA
How is urinary catheterisation done?
- Rectal examination
- Use a drape
- Examine penis for plugs, stones, trauma
- Straighten penis and advance the catheter using flushing
- Do not force, if not advancing easily, flush to alleviate obstruction
- Leave it in situ for 24-48 hours to provide sufficient analgesia and drugs to alleviate spasm – stitch in
- Submit urine for full analysis
- Flush bladder until clear
How do you care for a urinary catheter post catheterisation?
- Closed, clean system – wear gloves for handling, keep bag off the floor
- Change bag daily
- Avoid antibiotics
- Tape collection system to tail to avoid pulling
- Buster collar
What should be monitored post catheterisation?
- Monitor urine output
- Monitor hydration/volaemic status
- Monitor electrolytes – post obstruction diuresis > hypokalaemia
- Urine sediment/cytology daily for evidence of infection
Which analgesics are used for cats with lower urinary disease?
- Opioids – buprenorphine
- NSAIDs – consider contraindications
- Gabapentin – useful in severely affected cases, anxiolytic
How is feline idiopathic cystitis managed by environmental modification?
- Alleviate predisposing stressor
- Address negative cat-cat interactions
- Plentiful clean/varied toileting stations
- Feliway
How is urinary health promoted in feline urinary cystitis?
- Encourage water intake – dilute inflammatory mediators/noxious substances in urine
- Wet diets
- Urinary diets
- Avoid obesity
- GAG supplementation - GAG protects against noxious substances in urine
What are the antispasmodics used in feline idiopathic cystitis, commonly used in post-obstruction?
Prazosin – α1 blocker, smooth muscle relaxant, may cause hypotension
Dantrolene – skeletal muscle relaxant, (external urethral sphincter)
What are the functions of the kidney?
- Homeostasis – acid-base balance, water and electrolyte balance
- Endocrine – renin-aldosterone, erythropoietin, vitamin D activation
- Formational of urine – elimination of metabolic waste
How are pig kidneys different to dog kidneys?
Pig kidney also similar but has papillae rather than a renal crest
How is the cat kidney different from a dog’s?
Cat has a single papillae but looks like a renal crest. In some cats, the cortex is pale tan-cream owing to lipid storage – normal, looks paler than you might expect. Cats also have stellate veins
How are bovine kidneys different to dog kidneys?
- Multiple lobes
- No renal pelvis
- After passing through the renal hilus, the ureter branches and forms a funnel-shaped calyx around each of the renal papillae