Urinary Tract Disease in Reptiles and Birds Flashcards

Question

Discuss Avian Renal Disease: Diagnostic Tests with regards to urea and creatinine?

Answer 1

**Urea** •May help assess dehydration but NOT kidney dysfunction **Creatinine** •Not very useful in birds

Answer 2

**Phosphorus** •May be elevated in renal failure (& haemolysis) **Calcium** * May be reduced in renal failure. * Measure ionised and total calcium in conjunction with albumin

Answer 3

**Potassium** •Elevated in acute renal failure (& haemolysis). Normal level in potassium is much lower in birds than mammals **Sodium** * Hypernatraemia in dehydration * Hyponatraemia in renal failure

Answer 4

* Difficult to obtain ‘pure’ sample → try to collect under perch on clean greaseproof paper or similar * Normal urine contains crystals and bacteria * Look for renal casts, abnormal cells, glucose etc * Specific gravity range 1.005-1.020 but is species specific and not very helpful in most cases

Answer 5

* Used to confirm gout * Sample of material (e.g. joint aspirate) is mixed with nitric acid and dried over flame * Add 1 drop concentrated ammonia * If turns mauve = uric acid * In practical terms he does not do this that often

Answer 6

**Radiography** * Two views → ventrodorsal and lateral with wings and legs extended * Normal kidneys difficult to see especially on VD view * Gonad and pelvis may obscure lateral view * Normally a small rim of air dorsal (air sac) to the kidneys on lateral view → absent in renomegaly * Look for changes in size, density & contour. Eggs, cloacaliths, evidence of gout and rest of body

Answer 7

Egg-bound Blue & Gold Macaw Presented with resp disease as it had complete bloackage of GI, repro and URI tract. Has full crop with sour crop causing resp distress. Removed bloackage and gave fluid therapy similar treatment to blocked tom cat

Answer 8

Testicular Tumour (Budgerigar) This testicular tumour was secreting oestrogen and causing secondary sex characteristic changes If it was female probaby think it was pre-ovulatory reduction in bone density

Answer 9

* Useful to look at architecture of kidney but often severely hampered by air sacs in the healthy bird * In sick bird with ascites makes it easier to image kidneys and gonads

Answer 10

* Most useful to visualise and biopsy kidneys * Can assess most other organs at the same time * Requires specific training and experience

Answer 11

•May be useful in selected cases; not routine

Answer 12

* Keep warm = 29-30oC * Quiet, away from predators * Dimmed lighting * Oxygen * Nebulise saline for 20-30 minutes

Answer 13

* Fluid therapy → SC, IV, IO depending on severity of condition and level of dehydration (don’t put IO catheter into femur and humerus as they are pneumatised and you will drown them) * Commence oral fluids once bird is more stable * Crop feed an easily assimilated food once bird tolerates oral fluids * Progress to more substantial feed if bird tolerating so far * Metoclopramide 0.5-1mg/kg IM q 8-12 hrs if ileus * Specific treatment based on diagnosis

Answer 14

−measuring the pcv/ts −skin elasticity −mucous membrane moisture −brightness and position of the eye −ulna vein refill time. Practically speaking it may be safe to assume that most sick birds are 5-10% dehydrated or more at presentation

Answer 15

Maintenance fluid volumes are generally assumed to be 50ml/kg/day. **Usually rehydrate avian patients over 48 hrs:-** −Day one → maintenance fluids (50ml/kg) + half calculated rehydration fluids −Day two → maintenance fluids (50ml/kg) + half calculated rehydration fluids −Day three → maintenance fluids Route of fluid administration depends on the severity of dehydration, bird’s demeanour and whether the gastrointestinal tract is functional.

Answer 16

**Food** −High in fat and carbohydrate, lower in protein −Ensure balanced diet for species −Vitamin supplementation in ‘stubborn’ birds

Answer 17

**Antibiotics:** −Aminoglycosides are nephrotoxic so avoid their use systemically −Trimethoprim/sulpha & amoxycillin/ clavulanic acid can be nephrotoxic if bird is dehydrated so only use in hydrated birds to prevent worsening renal disease

Answer 18

**Allopurinol** −Xanthine oxidase inhibitor −May help reduce hyperuricaemia −May worsen and cause gout in some species especially at higher doses e.g. Red-Tail Hawk.

Answer 19

* Renal portal system similar to birds * Nephrons lack a Loop of Henle (no means of renal concentration of urine) * Urinary bladder in chelonia and some lizards e.g. Iguana, chameleon * Urine may be modified in bladder/colon by refluxing into the copredeum * Electrolyte and fluid exchange can occur across the bladder wall * Nitrogen excreted as uric acid +/- Urea +/- ammonia (proportion varies) * Salt glands in some desert and aquatic species (don’t misdiagnose as resp infection)

Answer 20

•Inadequate Husbandry −Humidity −Temperature −Diet −Supplements → Ca, Phos, Vit A, Vit D * Chronic dehydration (some species only drink from droplets not bowls) * Infection – bacterial, parasitic (giardia) * Neoplasia

Answer 21

* Visceral gout → accumulation of uric acid tophi in soft tissues particularly liver, pericardium and kidney * Articular gout → accumulation of uric acid tophi in and around joints Occurs when uric acid secretion is decreased and/or uric acid production is increased

Answer 22

* Dehydration * Renal tubular disease

Answer 23

* Infection/inflammation * Post-renal obstruction

Answer 24

Excess dietary protein

Answer 25

* Early signs of disease often subtle * Advanced disease → signs are often non-specific → lethargy, anorexia, weight loss, dysecdysis, abnormal thermoregulation * Polyuria and polydypsia are usually not a feature of reptile renal disease because they don’t concentrate urine anyway so never compensate by drinking * Classic sick reptile pose below

Answer 26

* Hindlimb weakness * Constipation (renomegaly in pelvic canal common in older iguanas) * Gout * Oedema

Answer 27

* Assess patient from afar * Assess dangers to you and the patient * Ensure have everything to hand * Inspect cage, droppings, food etc * History → husbandry, diet, supplements, UVB supplementation, heat gradients, previous treatments, other reptiles… * Ensure patient is kept at optimum body temperature

Answer 28

Dysecdysis (Yemen Chameleon)

Answer 29

Metabolic Bone Disease (Bosc Monitor) Malocclusion of jaw

Answer 30

Peripheral Oedema (Marginated Tortoise) Often terminal sign either sepsis, renal or neoplasia

Answer 31

Metabolic Bone Disease and Dysecdysis (Leopard Gecko)

Answer 32

Hemipenal prolapse & femoral Pore impaction (Green Iguana) Due to poor low grade dehydration has prolapsed due to urolith presence

Answer 33

Radiograph of same Iguana from previous flashcard showing the large urolith

Answer 34

Yemen Chameleon - note gouty kidneys (white spots)

Answer 35

* Elevated only when \>70% function lost * Mild to no elevation in dehydration * Post-prandial rise in carnivorous reptiles can occur 24-36hrs after meal → NB most reptiles are presented anorexic!

Answer 36

**Urea** * May be elevated in dehydration or anorexia * Renal disease likely if uric acid also raised * More useful in desert tortoises e.g. Testudo spp.

Answer 37

•Not very useful in reptiles

Answer 38

**Phosphorus** May be elevated → renal failure more likely if phosphorus higher than total calcium (look at the ratios) ensure not haemolysed sample that can skew results.

Answer 39

**Calcium** * May be reduced in chronic renal failure. * Normal or increased in acute renal failure

Answer 40

Potassium •Elevated in acute renal failure (& haemolysis)

Answer 41

**Urinalysis** * Try to avoid faecal contamination * Many tortoises void when handled * Normal urine contains crystals and bacteria * Renal casts, cells, parasites (Hexamita) etc * pH may change from normal alkaline to acidic in anorexic herbivores and post-hibernation * Specific gravity range 1.003-1.014 may elevate slightly in dehydration

Answer 42

**Iohexol Excretion Test:** * Excreted solely by glomerular filtration * Gives good indication of renal function * Inject iohexol intravenously and take blood 4, 8 & 24hrs later. Post on ice * Validated for the Green Iguana only so far * Not used routinely as yet but potentially very useful

Answer 43

**Radiography** * 2 or 3 views → ventrodorsal, horizontal-beam lateral +/- horizontal-beam craniocaudal (chelonia) * Kidneys often difficult to see unless enlarged or increased density * Look for changes in size, density & contour. Eggs, uroliths, gout and bone density

Answer 44

● Juvenile Marginated Tortoise ● Large cloacalith with secondary substrate impaction of the colon ● Bone density is normal ● Has a urolith probs due to poor environment.

Answer 45

* Metabolic bone disease in a juvenile Bosc Monitor * Decreased bone density * Pathological fractures * Constipation secondary to hypocalcaemia * This could be RSHP or NSHP

Answer 46

**Ultrasound** •Very useful to look at architecture of kidney **Endoscopy** * Most useful to visualise and biopsy kidneys * Can assess most other organs at the same time * Requires specific training and experience **MRI/CT** •May be useful in selected cases; not routine

Answer 47

**•Heat** → patients should be kept at preferred body temperature (PBT) **•Fluid** → ensure correct humidity and appropriate access to water e.g. bath, spray **•Light** → appropriate UVB supplementation for the species

Answer 48

−measuring the pcv/ts −skin elasticity −mucous membrane moisture −brightness of the eye −appearance of the urine and urates **Practically speaking it may be safe to assume that most sick reptiles are 5-10% dehydrated or more at presentation**

Answer 49

* **Hartmann’s** → often used for rehydration and maintenance and in cases of metabolic acidosis. In theory, perhaps should be avoided in patients with liver compromise. But generally seems safe and effective * 0.9% Saline/electrolyte and amino acid (e.g. Duphalyte) combined at ration of 4:1 * 2.5% dextrose in 0.45% saline or 4% dextrose in 0.18% saline (should not be given subcutaneously) * Nine parts 5% glucose with 0.9% saline to 1 part sterile water * All fluids should be warmed to the upper level of the POTZ

Answer 50

* Rehydration of reptilian patients may take 10-14 days in severe cases * Overzealous fluid therapy can lead to pulmonary and tissue oedema, hypokalaemia and death

Answer 51

Generally advised to give fluids at the rate 10 - 30ml/kg/ day for maintenance + 25% of the fluid deficit daily always erring on the side of caution The route of fluid administration will depend on the species and severity of dehydration

Answer 52

* **Lizards** → cephalic, jugular, ventral tail vein * **Chelonians** → jugular vein * **Snakes** → jugularvein, intra-cardiac * **All species** → intracoelomic, subcutaneous and oral routes can be employed depending on severity of dehydration * **Intraosseous** (not snakes)

Answer 53

**Bathing:** * Should be performed daily in all inpatients * Encourages drinking, voiding urine/faeces and some can suck fluid into the cloaca/bladder * Close monitoring is essential to prevent drowning even in aquatic species.

Answer 54

* Routine procedure * Local anaesthetic * Sedation or GA * Analgesia important!! * Lizards = 10-20ml/kg * Snakes = 15-30ml/kg * Tortoises = 5-15ml/kg

Answer 55

**Food:** * Appropriate balanced diet for species → generally high in fat and carbohydrate, lower in protein * Omnivores generally treated as herbivores * Vitamin supplementation → care with Vitamin D

Answer 56

**Antibiotics:** * Most infections are caused by gram -ive bacteria * Aminoglycosides are nephrotoxic * Fluoroquinolones and ceftazadime commonly used

Answer 57

* Allopurinol → may help reduce hyperuricaemia * Anabolic steroids * B-vitamins * Phosphate binders