Abnormalities of the urogenital tract Flashcards
What are some common causes of umbilical swellings?
Defect in umbilical wall → Failure of umbilical ring closure → Herniation
Infection of umbilical structures → Involves internal abdominal components
Persistent Urachus → Communication remains between bladder & umbilicus
What are the main causes of umbilical hernias?
Mostly congenital (potential hereditary link), some acquired but usually present at birth
How can umbilical hernias be classified?
Simple vs. Strangulated (strangulated requires emergency intervention)
Reducible vs. Irreducible (irreducible can lead to complications)
When can simple umbilical hernias be repaired?
Often corrected during routine neutering if they don’t resolve on their own
What are the signs of a strangulated hernia?
Failure to suckle, vocalisation, sepsis markers, severe pain
What are the main characteristics of umbilical hernias?
Soft tissue swellings, typically consistent in size, some may self-resolve, others require intervention
How does hernia size impact treatment decisions?
Small: Likely to resolve naturally, monitor
Medium: Highest strangulation risk, careful monitoring needed
Large: Unlikely to resolve, often requires surgery
What diagnostic tool can help assess umbilical hernias?
Ultrasound – useful for evaluating contents and severity
What are the treatment options for umbilical hernias?
Monitor small hernias.
Constriction bands (e.g. lamb rings) for fibrosis & closure
Surgery for persistent, large, or strangulated hernias
What is the key surgical approach for umbilical hernias?
Dissect down to hernia ring, return peritoneum to abdomen, & securely close defect
What is a patent urachus?
Failure of fetal urachus (connection between bladder & umbilicus) to close at birth, leading to urine leakage
What is the most obvious clinical sign of a patent urachus?
Dribbling urine from umbilicus
Posturing to urinate but failing
Pain & infection due to persistently wet environment
What complications can arise from a patent urachus?
Infection spreading to nearby tissues
Urachal cysts at bladder apex
Urethral diverticula
Uroperitoneum (if bladder drains into abdomen)
What is the primary surgical treatment for a patent urachus?
Resection back to bladder, inversion of bladder tissue & closure
What are the conservative treatment options for a patent urachus?
Astringents (iodine, silver nitrate) to induce fibrosis
Broad-spectrum antibiotics for infection
Clamps to encourage closure via scarring
What is Meckel’s diverticulum?
Remnant of vitelline duct, can cause intestinal strangulation, requiring surgical resection
What are the three key structures associated with umbilical infections?
Umbilical vein (to liver), umbilical arteries (to aorta), urachus (to bladder)
Define omphalophlebitis.
Infection of umbilical vein, leading to potential liver involvement
Define omphaloarteritis.
Infection of 1 or both umbilical arteries, connecting to aorta
What is urachal sepsis, and why is it concerning?
Infection of urachus, potentially leading to bladder infections & sepsis
Why is it important to differentiate types of umbilical infections?
Each type affects different structures, requiring specific treatment approaches to prevent systemic sepsis
What are the key clinical signs of an umbilical infection?
Localised swelling, pain, pus discharge & potential systemic illness (sepsis signs)
How can ultrasound aid in diagnosing umbilical infections?
Helps identify which umbilical structures are involved (vein, artery, urachus)
What systemic complications can arise from umbilical infection?
Septicaemia & joint ill (synovial sepsis) from bacterial spread
What is the first step in preventing umbilical infections in neonates?
Applying antiseptic solutions to umbilicus immediately after birth
What are the key treatment options for umbilical infections?
Antibiotics for systemic infection
Drainage of abscesses
Marsupialisation or surgical resection for severe cases
Define renal failure
Loss or urine concentrating ability
What is the earliest functional loss seen in renal failure?
Loss of urine concentrating ability occurs first, leading to polyuria
> 66% functional nephron loss
What is the USG threshold indicating renal failure?
Dogs: USG < 1.030
Cats: USG < 1.035
At what nephron loss percentage do waste products start accumulating in the blood?
> 75% nephron loss leads to persistent renal azotaemia (high urea & creatinine)
Both kidneys must be affected
What is SDMA, and why is it useful in renal failure?
Early marker of renal failure
Increases when >25% nephron loss has occurred, making it more sensitive than urea:creatinine
What defines chronic kidney disease (CKD)?
Functional or structural changes in one or both kidneys persisting for >3 months
Why is CKD often diagnosed late?
It is clinically silent until 66-75% of nephrons are lost, making early detection difficult
Is CKD more common in younger or older animals?
More common in older animals, especially cats
(30-50% of cats >15 years have CKD)
What happens initially when CKD develops?
Nephrons are destroyed & remaining nephrons hypertrophy to compensate
Is CKD progression the same in cats and dogs?
No, cats tend to have stable disease for longer, while dogs progress more rapidly
What happens in the end stage of CKD, regardless of the initial cause?
Fibrosis (scar tissue) replaces functional nephrons, leading to irreversible kidney damage
tubulointerstitial nephritis (seen on histology)
What is acute kidney injury (AKI)?
Sudden kidney damage that may be reversible, progressive, or fatal
How can AKI lead to chronic kidney disease (CKD)?
Progressive loss of nephrons in AKI can cause permanent damage, leading to CKD
What is “acute on chronic kidney disease”?
AKI occurring in patient with pre-existing CKD, worsening kidney function
Why is early diagnosis of AKI crucial?
Helps limit disease progression & improves chance of reversibility
Why is AKI prevention important in emergency and critical care patients?
Many critical patients are hypovolaemic or hypotensive, reducing kidney perfusion
Preventing renal hypoperfusion is key to avoiding AKI
When should we suspect AKI in a sick patient?
Any increase in creatinine, even within normal range, can indicate early AKI
What conditions can lead to poor renal perfusion and AKI?
Cardiovascular disease
Severe hypoxia
Critical illness/emergency cases
What are common nephrotoxins that cause AKI?
Ethylene glycol (antifreeze) → More common in cats
Lily toxicity → Cats only
Grape/raisin toxicity → Dogs only
Vitamin D supplements/human psoriasis creams
NSAIDs → High doses, esp. in dehydrated patients
Why is ethylene glycol (antifreeze) a key nephrotoxin?
It metabolises into toxic compounds, leading to severe kidney damage—often fatal if untreated
Why is dehydration a risk factor for NSAID-induced AKI?
NSAIDs reduce renal prostaglandin production, impairing blood flow to kidneys, worsening dehydration effects
How does obstructive disease cause AKI and what are the 2 types?
Blockage of urine flow increases pressure, leading to kidney damage
Urethral obstruction → Both kidneys affected
Ureteric obstruction → One kidney affected (usually)
What are common causes of urinary obstruction leading to AKI?
Calculi (stones)
Blood clots
Neoplasia (tumours blocking urine flow)
How can infections lead to AKI?
Localised infection → Ascending UTI infects renal pelvis (pyelonephritis)
Systemic infections → Cause direct kidney damage (e.g. leptospirosis in dogs, FIP in cats)
How does hypercalcemia cause AKI?
Excess calcium deposits in kidneys, leading to nephron damage & impaired function
What is “Alabama rot,” and how does it relate to AKI?
Cutaneous & renal glomerular vasculopathy
Unknown cause
Affects dogs → causes skin lesions + severe AKI (often fatal)
Why is there often no definitive diagnosis (underlying cause) for CKD?
CKD is end-stage result of multiple disease pathways, with no clear initial cause in many cases
What are some familial renal diseases that cause CKD?
Juvenile nephropathy → Boxer dogs
Renal dysplasia → Shih Tzu, Lhasa Apso, Golden Retriever
Amyloidosis → Shar Pei, Abyssinian cats
Polycystic kidney disease (PKD) → Persian & related breeds (autosomal dominant trait)
How can immune-mediated disease cause CKD?
Glomerulonephritis (Type III hypersensitivity) leads to immune complex deposition in glomerulus, causing glomerular damage & protein loss (protein losing nephropathy)
What vascular issues can cause CKD?
Ischaemia (restricted blood flow)
Renal infarcts (areas of dead tissue due to blood supply loss)
Vascular injury (damaged blood vessels lead to hypoxic damage in kidneys)
How is CKD typically managed?
Managing consequences (e.g. controlling blood pressure, proteinuria) rather than treating (usually unknown) primary cause
What factors in signalment and history increase suspicion of renal disease?
Young animal → Possible familial renal disease
Old cat → Increased risk of CKD
History of toxin exposure (e.g. ethylene glycol)
Use of nephrotoxic drugs (e.g. NSAIDs in dehydrated animals)
What systemic illnesses can target the kidneys and cause failure?
FIP or lymphoma (cats)
Leptospirosis (dogs) → Also causes hepatitis
Severe illness causing hypovolemia/hypotension (e.g. pancreatitis, trauma, post-RTA)
How does hypovolaemia contribute to renal failure?
Low blood volume reduces renal perfusion, leading to ischaemic kidney damage
Which blood parameters increase in both AKI and CKD?
Urea, creatinine, SDMA & phosphorus
How should azotaemia (high urea and creatinine) be interpreted?
Check urine SG
High USG → Dehydration likely
Low USG + azotaemia → Intrinsic renal disease (AKI or CKD)
How does potassium change in AKI vs CKD?
AKI → ↑ Potassium (hyperkalaemia) (due to decreased renal clearance)
CKD → ↓ Potassium (hypokalaemia) (due to polyuria & decreased intake (poor appetite))
Why is hypocalcaemia significant in AKI?
Key marker for ethylene glycol toxicity, especially in cats
What does USG <1.035 in cats or <1.030 in dogs with azotaemia suggest?
oor concentrating ability + azotaemia → Renal disease (CKD or AKI)
What does USG >1.040 suggest in an azotaemic patient?
Non-renal cause of azotaemia, e.g. dehydration
What does +ve dipstick for glucose indicate if blood glucose is normal?
Possible tubular damage → Consider AKI
What should be done if a +ve dipstick for protein is found?
Run urine protein:creatinine ratio
Increased levels indicate protein-losing nephropathy or tubular damage
What does +ve dipstick for blood suggest?
Damage anywhere in urinary tract
Describe normal ureters
Fibromuscular tubes with peristaltic activity carrying urine from renal pelvis to bladder neck
Retroperitoneal structures for most of their length until they become peritoneal near bladder insertion site
What is an ectopic ureter?
Ureter that doesn’t insert at correct location in bladder but instead inserts into urethra, vestibule, vagina (females), or ductus deferens (males)
Can be unilateral or bilateral
What are the two types of ectopic ureters?
Extramural: Directly inserts abnormally
Intramural: Appears to insert at correct site but tunnels along urethral wall & opens distally
Which sex is more likely to have clinical problems caused by ectopic ureters and why?
Females because they have shorter urethra, making them more prone to incontinence
(Males have longer urethra providing some compensation to maintain continence)
What are the clinical signs of ectopic ureters?
Can be asymptomatic
Incontinence (esp. female)
Urine scalding, dermatitis & pyoderma in perivulvar region
Increased risk of UTIs due to abnormal ureter position
Risk of ascending infections leading to pyelonephritis
What surgical complication can lead to ureteric injury?
Spaying, if ureter is accidentally included in ligature for ovarian pedicle or cervical stump
What non-surgical event can cause ureteric avulsion or partial tearing?
Road Traffic Accidents (RTA)
How can urine leakage from a damaged ureter be assessed?
Using ultrasound to identify location of fluid accumulation
retroperitoneal fluid if proximal injury
peritoneal fluid if distal injury close to bladder
What are the three main types of ureteric obstruction?
Intraluminal, Intramural & Extramural
What can cause intraluminal ureteric obstruction?
Calculi (esp. calcium oxalate in cats)
Blood clots
Inflammatory debris (mucus, inflammatory cells)
What can cause intramural ureteric obstruction?
Stricture (e.g. fibrosis from previous calculi damage)
Neoplasia (rare)
What can cause extramural ureteric obstruction?
e.g. post-op complications with ligated ureter
Why can unilateral ureteral obstruction be easily missed?
Clinical signs are non-specific (e.g. pain) & renal failure signs only appear if >66-75% of nephrons are lost
What happens to ureteric pressure in unilateral ureteral obstruction?
Increased ureteric pressure proximal to obstruction → Increased renal tubular pressure → Decreased GFR
What is the consequence of complete unilateral ureteral obstruction?
Hydronephrosis (fluid accumulation in kidney)
Fibrosis (leading to small kidney)
What is compensatory hypertrophy in unilateral ureteral obstruction?
Normal kidney enlarges (big kidney) to compensate for affected kidney’s loss of function
Why are animals with unilateral ureteral obstruction not azotaemic?
If second kidney is healthy, it maintains renal function, preventing azotaemia
Why is a second ureteral obstruction in “big kidney/little kidney” cats serious and life-threatening?
Cat relies on big kidney for renal function, as small kidney is likely non-functional or severely reduced in function
Clinical signs:
- Renal pain
- Azotaemia (signs of renal failure)
- Acute Kidney Injury (AKI)
Can the renal function be restored after a second ureteral obstruction?
Yes, AKI can be reversible, but only with prompt diagnosis & treatment
