Endocrine Diseases Flashcards
(485 cards)
1
Q
what is the most common endocrine condition in cats?
A
hyperthyroidism
2
Q
where in the world is hyperthyroidism seen?
A
everywhere
3
Q
why is feline hyperthyroidism being recognised much more commonly now?
A
awareness is better
older cats that are living longer
may be becoming more common
4
Q
is there evidence that feline hyperthyroidism is auto-immune?
A
no, unlike in humans
5
Q
what are 95% of feline hyperthyroidism cases caused by?
A
benign adenomatous hyperplasia
adenoma pf thyroid tissues
6
Q
what does benign adenomatous hyperplasia / adenoma of thyroid tissues cause?
A
spontaneous secretion of thyroid hormones
escaping control of hypothalamus and pituitary gland
7
Q
what are <5% of feline hyperthyroidism cases caused by?
A
adenocarcinoma (malignant)
8
Q
is feline hyperthyroidism more commonly bilateral or unilateral?
A
2/3 bilateral
1/3 unilateral
9
Q
where is ectopic thyroid tissue most commonly seen?
A
mediasteinum
10
Q
how many cases of feline hyperthyroidism have ectopic thyroid tissue?
A
5%
11
Q
what are the potential causes of feline hyperthyroidism?
A
nutritional factors
environmental factors
genetic factors
circulating factors
12
Q
what are the nutritional factors which cause feline hyperthyroidism?
A
high levels of iodine in diet
presence of goitrogens
13
Q
what cats are much less likely to have feline hyperthyroidism?
A
siamese or himalayan (10x less likely)
14
Q
what circulating factors can increase the risk of feline hyperthyroidism?
A
thyroid growth stimulating immunoglobulins in the blood stream
15
Q
what are the risk factors for feline hyperthyroidism?
A
regular use of flea sprays or powders
indoor cats
reported exposure to lawn herbicides, fertilisers and pesticides
cats fed mainly canned foods
16
Q
what is the signalment of feline hyperthyroidism?
A
middle aged to elderly cats (10-13 years)
no sex predeliction
17
Q
what does the severity of signs of feline hyperthyroidism depend on?
A
duration of disease
presence of concurrent diseases
18
Q
what are the effects on the body of raised thyroid hormones?
A
increased: metabolic rate cardiac output HR BP GI motility CNS activity
decreased:
sleep
body weight
19
Q
what does increased GI motility due to increased thyroid hormone mean for feline hyperthyroidism patients?
A
may have vomiting and diarrhoea
20
Q
what are the major clinical signs of feline hyperthyroidism?
A
palpable enlarged lymph nodes weight loss polyphagia hyperactive for their age PUPD tachycardia
21
Q
what are the minor clinical signs of feline hyperthyroidism?
A
lethargy intermittent anorexia voice changes muscle weakness / tremors CHF heat intolerance mild pyrexia dyspnoea / tachypnoea
22
Q
what is apathetic feline hyperthyroidism?
A
type of hyperthyroidism seen in a small number of patients (<10%) who likely have underlying comorbidity
23
Q
in how may patients is apathetic feline hyperthyroidism seen?
A
<10%%
24
Q
what are the signs of apathetic feline hyperthyroidism?
A
lethargy
inappetance
weight loss
obtundation
25
what is apathetic feline hyperthyroidism likely reflecting?
underlying comorbidity
26
what abnormalities are often present in patients with apathetic feline hyperthyroidism?
cardiac
27
what effect can thyroid hormones have on cardiac disease?
often worsen
28
how should feline hyperthyroidism patients be handled?
cat friendly
hands off
should be allowed to acclimatise and settle
29
what parameters should be closely monitored in feline hyperthyroidism patients?
RR
30
what may be provided to feline hyperthyroidism patients on arrival to veterinary practice?
O2 therapy if tachypnoeic
31
why are feline hyperthyroidism patients often stressed?
high thyroid hormones cause agitation
32
what can feline hyperthyroidism patients be given before travel to calm them?
50mg Gabapentin 2 hours before travel
33
how is feline hyperthyroidism diagnosed?
compatible clinical signs
screening tests
confirmatory diagnostic tests
34
how can thyroid glands be palpated?
lift head with one hand and extend neck
| use other hand thumb and index finger to feel all the way from the larynx to the thoracic inlet
35
what are screening tests used for when diagnosing feline hyperthyroidism?
baseline health
36
what screening tests are used during feline hyperthyroidism diagnosis?
haematology
biochemistry
urinalysis
BP
37
what is often seen on biochemistry in a cat with feline hyperthyroidism?
elevated liver enzymes (mild to moderate)
38
what can be shown by biochemistry when testing for feline hyperthyroidism?
CKD
39
what will urinalysis show in a feline hyperthyroidism patient?
if concurrent CKD
40
what sudden issue can severe feline hyperthyroidism patients get?
sudden blindness due to hypertension
41
what is the gold standard confirmatory diagnostic test for feline hyperthyroidism?
serum total thyroxine (T4) - TT4
42
how elevated is total T4 in most hyperthyroid cases?
>50-60 nmol/L
43
what total T4 level may be seen in some feline hyperthyroidism patients?
fluctuating
| high normal
44
why may high normal total T4 levels be seen in some feline hyperthyroidism patients?
early disease
| presence of non-thyroidal illness that lowers T4 prodution
45
what are the 4 main treatment options for feline hyperthyroidism?
medical management with antithyroid drugs
iodine restricted diet
thyroidectomy
radioactive iodine treatment
46
which of the treatment options for feline hyperthyroidism are curative?
thyroidectomy
| radioactive iodine treatment
47
what should be tried first to treat feline hyperthyroidism?
medical management
48
what should be assessed before undertaking any irreversible feline hyperthyroidism treatment?
renal function when patient is euthyroid
49
what must be done before any surgery/GA if the patient has feline hyperthyroidism?
patient should be stabilised
50
what is the purpose of anti-thyroid drugs?
block thyroid production
51
what is the main drug used to treat feline hyperthyroidism?
methimazole
52
how often should Methimazole be given?
BID
53
in what form can Methimazole be given?
tablets
transdermal gel
oral liquid
54
where is transdermal Methimazole applied?
pinna
55
what tablets are available to treat feline hyperthyroidism that can be given once a day?
slow-release carbimazole tablets
56
what is the role of slow release anti-thyroid tablets?
converted in the body to methimazole which is then utilised
57
who should be careful when handling anti-thyroid drugs?
pregnant women
58
when is a feline hyperthyroidism patient normally euthyroid after anti-thyroid drugs?
<2-3 weeks
59
when should total T4 be checked following anti-thyroid treatment?
2-3 weeks
60
what tests should be run in the first 1-3 months following anti-thyroid drugs?
CBC and biochem
61
what is the purpose of CBC and biochem tests in the first 3 months after beginning treatment for feline hyperthyroidism?
monitor for side effects
62
what may anti-thyroid drugs be used for in the short term?
stabilisation prior to more curative therapy
63
what are the advantages of anti-thyroid drugs?
```
readily available
rapidly effective
inexpensive
practical
no GA or hospitalisation
```
64
what are the disadvantages of anti-thyroid drugs?
lifelong
long term resistance
compliance is crucial
side-effects
65
what are the minor, common, transient side effects of anti-thyroid drugs?
vomiting
anorexia
lethargy
66
what are the major, rare and persistent side effects of anti-thyroid drugs?
```
persistent GI signs
blood dyscrasias (leukopenia, anaemia and thrombocytopenia)
dermatitis
hepatopathy
lymphadenomegaly
myasthenia gravis
```
67
what sort of dermatitis is commonly seen as a major side effect of anti-thyroid drugs?
facial excoriation
68
what is lymphadenomegaly?
enlarged lymph nodes
69
what should happen if major side effects of anti-thyroid drugs are seen?
stop treatment
70
how can diet be used to control feline hyperthyroidism?
iodine restricted diet fed to reduce T4 production
71
what iodine restricted food is available?
Hills y/d
72
what can be fed alongside and iodine restricted diet?
must be fed as sole food - no treats
73
how quickly can feline hyperthyroidism patients be euthyroid when fed an iodine restricted diet?
within 3 weeks
74
how long must be feline hyperthyroidism patient be on the iodine restricted diet for?
lifelong
75
when is an iodine restricted diet less effective / unsuitable?
for severe hyperthyroid cats
76
what are the main pre-surgical considerations for treatment of feline hyperthyroidism?
systemic effects of feline hyperthyroidism
cardiac disease
hypertension
other diseases
77
what should happen to a feline hyperthyroidism patient prior to surgery?
stabilisation
78
what is removed during thyroidectomy?
one or both of the thyroid glands
79
what must be preserved during a thyroidectomy?
parathyroid tissue
80
why must the parathyroid tissue be preserved in thyroidectomy?
to avoid post op complications such as hypocalcaemia
81
why could hypocalcaemia occur following thyroidectomy?
PTH is essential for calcium homeostasis
82
in what % of patients does thyroidectomy achieve euthyroidism?
>90%
83
when is euthyroidism achieved following thyroidectomy?
24-48 hours
84
what structures must you be careful of when performing thyroidectomy?
parathyroid
| vagus nerves
85
is is possible to save the parathyroid gland if feline hyperthyroidism is advanced?
not usually due to enlargement of glands
86
what are the advantages of thyroidectomy?
curative
rapidly effective
short hospitalisation period
87
what are the disadvantages of thyroidectomy?
```
GA
skill required to save parathyroid
location
recurrance
cost
complications
```
88
what are the complications associated with thyroidectomy?
damage or removal of parathyroid tissue leading to post op hypoparathyroidism
damage to recurrent laryngeal nerve
damage to sympathetic trunk
possible recurrence of feline hyperthyroidism if only unilateral thyroidectomy
89
is laryngeal paralysis a common complication of thyroidectomy?
no
90
what is a condition that can be caused by damage to the sympathetic trunk during thyroidectomy?
Horner's syndrome - nictating membrane prolapse and myosis
91
when does iatrogenic hypoparathyroidism occur?
usually after bilateral thyroidectomy
92
how long does iatrogenic hypoparathyroidism last for?
usually transient
93
when does iatrogenic hypoparathyroidism resolve?
recovery of glands/restored function of ectopic tissues
94
how long does it take to recover from iatrogenic hypoparathyroidism?
weks to months
95
when are clinical signs of iatrogenic hypoparathyroidism seen?
withi 2-3 days
96
what are the signs of iatrogenic hypoparathyroidism?
```
due to hypocalcaemia
inappetance
weakness
tremors
ptyalism
pawing at face
progression to tetany
seizures
coma
death
```
97
what should be monitored if concerned about iatrogenic hypoparathyroidism or there has been bilateral thyroidectomy?
serum calcium twice a day
98
how should iatrogenic hypoparathyroidism be treated?
IV 10% calcium gluconate slowly (10-20 mins)
99
what is the initial bolus of calcium gluconate to treat iatrogenic hypoparathyroidism followed by?
CRI
100
what fluids should be avoided when giving calcium gluconate?
bicarbonate, lactate or phosphate containing fluids as will precipitate calcium
not Hartmann's
101
can calcium gluconate be given SC?
no
102
why can calcium gluconate not be given SC?
skin sloughs
103
what should patients receiving calcium gluconate be monitored for?
ECG for arrhythmia and bradycardia
104
what should happen once the patient with iatrogenic hypoparathyroidism is stabilised on IV calcium gluconate?
oral therapy ASAP of calcium and vitamin D
105
how is the patient switched from IV calcium gluconate to oral therapy?
elemental calcium in divided doses to wean off IV
106
how are iatrogenic hypoparathyroidism cats managed orally once IV calcium gluconate has stopped?
oral vitamin D only
107
can iatrogenic hypoparathyroidism patients be weaned off all treatment?
yes - eventually
108
how long does oral therapy for iatrogenic hypoparathyroidism take to work?
1-3 days
109
what is the gold standard treatment for feline hyperthyroidism?
radioiodine treatment
110
how is radioiodine treatment administered?
systemically
111
where does radioiodine therapy target?
excessive T4 producing cells in the thyroid
112
what do beta particles of radioiodine cause?
cell death
113
how long must the cat be isolated for following radioiodine treatment?
1-2 weeks post injection
114
why does the cat need to be isolated for 1-2 weeks following radioiodine injection?
gamma rays they emit are dangerous
115
how many centres are available for radioiodine treatment in the UK?
15 (including Bris)
116
what are he advantages of radioactive iodine treatment for feline hyperthyroidism?
```
gold standard
curative
simple procedure
higher dose to treat adrenocarcinoma
no GA
cost
```
117
what are the disadvantages of radioactive iodine treatment?
```
limited availability
isolation period
irreversible
may take some time to achieve euthyroid
very rarely iatrogenic hypothyroidism
cost
```
118
what is the risk associated with feline hyperthyroidism and CKD?
hyperthyroidism may mask CKD and so treatment may unmask it
119
how much can treatment of feline hyperthyroidism change CKD level?
maximum of one IRIS stage
120
what must be considered about feline hyperthyroidism and CKD?
medical management of feline hyperthyroidism before curative treatment to see effect on kidneys
reassess once euthyroid
121
what may not prevent definitive feline hyperthyroidism treatment relating to CKD?
unmasking of mild azotemia through thyroid medical management
122
when should feline hyperthyroidism patients be monitored irrespective of treatment regime?
6 monthly check ups if stable
| soone if not
123
what are you monitoring for when having feline hyperthyroidism check ups?
recurrence
hypertension
CKD (urea, creatinine, BP, urinalysis)
124
what is the prognosis of feline hyperthyroidism dependent on?
severity / presence of concurrent disease (especially heart disease)
125
what cats have excellent feline hyperthyroidism prognosis?
uncomplicated with curative treatment
126
what are the main types of canine thyroid neoplasia?
carcinomas more common
| adenomas usually incidental
127
what sort of masses are canine thyroid neoplasia?
large, solid, palapabel
128
what type of tumor is canine thyroid neoplasia?
locally invasive
| some metastatic
129
what are most canine thyroid neoplasia patients thyroid levels like?
most euthyroid or hypothyroid
130
what percentage of canine thyroid neoplasia patients are hyperthyroid?
10%
131
what is the signalment of canine thyroid neoplasia?
10 years
132
what are the signs of canine thyroid neoplasia?
mass in ventral neck
| may have cough or dyspnoea due to pressure on trachea
133
how is canine thyroid neoplasia diagnosed?
histopathology of mass
FNA
surgery usually needed to confirm
134
why must care be taken when gaining histopathology of a mass to diagnose canine thyroid neoplasia?
very vasular area
135
what is the issue with FNA of canine thyroid neoplasia?
often blood contaminated sample
136
how is canine thyroid neoplasia treated?
surgical removal
| chemotherapy or radiation to follow
137
why is radioactive iodine treatment for canine thyroid neoplasia not often performed?
high doses required
138
what does the prognosis of canine thyroid neoplasia depend on?
size
local invasion
functional status
histological diagnosis of carcinoma or adenoma
139
what is the prognosis for dogs with large, invasive canine thyroid neoplasia masses?
guarded to poor
| 6-24 months if aggressive treatment
140
when is the prognosis for canine thyroid neoplasia excellent?
surgical removal of adenomas
141
when is the prognosis for canine thyroid neoplasia good?
removal of small, well circumcised carcinomas
142
what is the most common endocrine disorder in dogs?
canine hypothyroidism
143
why is canine hypothyroidism likely to be over-diagnosed?
due to tests used
144
where are the thyroid glands located?
lateral to the proximal tracheal rings
145
what hormones are produced by the thyroid?
thyroxine - T4
| triiodythyronine - T3
146
what are thyroid hormones produced from?
tyrosine amino acids
147
what enzyme causes the oxidation of iodine?
thyroid peroxidase
148
what is the main thyroid hormone that is secreted?
T4
149
where is 99% of T4 found in circulation?
bound to proteins
150
what is the role of unbound T4 (fT4)?
biologically active and exerts a negative feedback on TSH production
151
what happens to fT4 within the cell?
diodinated to form either T3 or reverse T3
152
what does T3 bind to in the cell?
nuclear receptor
153
how does the HPA control T4 and T3 release?
hypothalamus releases TRH
causes pituitary gland to release TSH
this stimulates the thyroid glands to release T4, T3 and rT3
154
how is T4, T3 release controlled?
T4 and T3 negatively feedback on hypothalamus and pituitary to stop TRH and TSH release
155
where does primary hypothyroidism occur?
at the level of the thyroid gland
156
what is the most common type of canine hypothyroidism?
primary
157
what are the 2 causes of primary canine hypothyroidism?
lymphocytic thyroiditis
| thyroid atrophy
158
what is lymphocytic thyroiditis caused by?
immune mediated destructive process
infiltration of lymphocytes and other WBC
thyroid tissue is replaced by fibrous connective tissue
159
when do clinical signs of lymphocytic thyroiditis occur?
when 75% of gland is destroyed
160
what causes thyroid atrophy?
degenerative process
progressive replacement of thyroid tissue with adipose and connective tissue
possibly due to end stage lymphocytic thyroiditis
161
what are the causes of secondary hypothyroidism?
pituitary hypoplasia - congenital (disproportionate dwarfism) or dysfunction (neoplasia)
162
is secondary canine hypothyroidism common?
rare
163
what is the most common cause of secondary hypothyroidism?
suppression of TSH secretion by exogenous glucocorticoid administration (steroids) and hyperadrenocorticism (cushings)
164
what is the mean age of diagnosis of canine hypothyroidism?
7 years
165
what animals tend to develop canine hypothyroidism sooner?
those breeds predisposed to lymphocytic thyroiditis
166
what breeds are predisposed to lymphocytic thyroiditis?
english setter
golden retriever
cocker spaniel
boxer
167
what are the areas of the body which may exhibit signs of canine hypothyroidism?
```
decreased metabolic rate
dermatologic
repro
cardiac
neuromuscular
occular
GI
```
168
what are the clinical signs of canine hypothyroidism linked to decreased metabolic rate?
weight gain
lethargy
inactivity
169
what are the clinical signs of canine hypothyroidism linked to dermatologic signs?
endocrine alopecia
rat tail
tragic facial expression hair in telogen phase
mixoedema
170
what is endocrine alopecia?
symmetrical hair loss
| non puretic
171
what is mixodema?
thickened skin
172
what are the clinical signs of canine hypothyroidism linked to the reproductive system?
```
persistent anoestrus
weak/silent oestrus
prolonged oestral bleeding
inappropriate lactation
no effect on males
```
173
what are the clinical signs of canine hypothyroidism linked to the CVS?
bradycardia
association with atrial fibrilation
some reports of atrial thromboembolysm
174
what cardiac condition may canine hypothyroidism be linked to?
DCM
175
what is the mechanism of neuromuscular disease linked to canine hypothyroidism?
accumulation of mucopolysaccharides leading to impaired transport along axons and arthrosclerosis
176
what are the clinical signs of canine hypothyroidism linked to neuromuscular diseases?
megaoesophagus
laryngeal paralysis
peripheral vestibular syndrome (head tilt)
facial nerve paralysis
177
are neuromuscular diseases usually linked to canine hypothyroidism?
more likely concurrent disorders than causal effect of hypothyroidism
178
what is myxoedema coma?
life threatening potential consequence of hypothyroidism
179
what are the signs of myxoedema coma?
```
profound mental dullness
weakness
hypothermia
bradycardia
hypotension
```
180
what usually leads to a hypothyroid patient developing myxoedema coma?
precipitating factor e.g. surgery, heart failure or sepsis
181
what are the clinical signs of canine hypothyroidism linked to the eyes?
corneal lipid deposits due do hyperlipidaemia
ulcreation
uveitis
182
what are the clinical signs of canine hypothyroidism linked to the GI tract?
diarrhoea due to bacterial overgrowth
| constipation due to reduced peristalsis
183
how is canine hypothyroidism diagnosed?
appropriate history and clinical signs
haematology and biochemistry
specific thyroid testing
184
what signs are typically seen on the biochemistry and haematology of a canine hypothyroidism patient?
mild non-regenerative anaemia (normocytic and normochromic)
hypercholesterolaemia
hypertriglycerideaemia
185
what effect do thyroid hormones have on lipids?
stimulate synthesis, mobilisation and degradation (no T4 no degradation of lipids)
186
what thyroid abnormalities do you expect in a canine hypothyroidism patient?
```
low T4
high TSH (no inhibition)
```
187
what is total T4 useful for in canine hypothyroidism?
initial screeing test
188
why is total T4 not used as a definitive canine hypothyroidism diagnosis?
thyroglobulin antibodies can falsely increase TT4
| TT4 decreases with age, breed, non thyroidal illnesses and drug therapy (steroids)
189
when are thyroglobulin antibodies produced?
in lymphocytic thyroiditis
190
what other tests apart from TT4 can be used to diagnose canine hypothyroidism?
canine TSH
| anti-thyroglobulin antibodies
191
why is TSH increased in canine hypothyroidism cases?
lack of negative feedback
192
why does the canine TSH test have moderate sensitivity?
low TSH in central hypothyroidism (pituitary cause)
| low TSH if there is corticosteroid therapy
193
what is canine TSH level not affected by?
largely unaffected by non-thyroidial illness or drugs
194
when may TSH be elevated in euthyroid dogs?
if recovering from NTI
195
what is a positive anti-thyroglobulin antibody test indicative of?
lymphocytic thyroiditis
196
what does anti-thyroglobulin antibodies give no information about?
thyroid function
197
when can anti-thyroglobulin antibodies be present?
long before hypothyroidism
198
how us canine hypothyroidism treated?
synthetic T4 - prohormone for active T3
199
what is the main drug given for canine hypothyroidism?
sodium levothyroxine
200
how often is sodium levothyroxine given?
SID or divided BID
201
what effect does food have on bioavailability of sodium levothyroxine?
halves bioavailability
202
what is crucial when giving sodium levothyroxine to treat hypothyroidism?
consistency with dosing times and monitoring times
203
how should dogs with cardiac disease, DM or hypoadrenocorticism be dosed with sodium levothyroxine?
start with 25% of dose and titrate up
204
when should sodium levothyroxine effect on hypothyroidism be evaluated?
6-8 weeks after first administration
205
when is peak sodium levothyroxine concentration?
3-5 hours post pill
206
what is the half life of sodium levothyroxine?
9-15 hours
207
why does dose and timing need to be tailored to the dog when giving sodium levothyroxine?
absorption and metabolism vary between dogs
208
what are the formulations of sodium levothyroxine available?
Soloxine - tablets
Thyroforon - flavored tablets
Leventa - liquid
209
what should be observed when monitoring the canine hypothyroid patient?
clinical response
TT4
fT4
cTSH
210
when should monitoring blood tests for canine hypothyroidism be carried out
6-8 weeks after starting treatment
| 2-4 weeks after dose altered
211
when should TT4 be measured when monitoring canine hypothyroidism that is being treated?
6 hours post pill SID
| 4-6 hours BID
212
when should fT4 be measured during canine hypothyroidism monitoring?
if chronic prednisolone admin
213
what is the aim for T4 and TSH values in canine hypothyroidism patients when receiving treatment
TT4 upper half of reference
| TSH normal
214
does hyperthyroidism often occur after treatment for canine hypothyroidism?
rare
215
what are the complications of canine hypothyroidism treatment?
thyrotoxicosis
| myxoedema coma
216
what is thyrotoxicosis secondary to?
drug overdose
217
what are the clinical signs of thyrotoxicosis?
```
panting
anxiety/aggression
PUPD
weight loss
polyphagia
(signs of hyperthyroidism)
```
218
how is myxoedema coma treated?
```
supportive care of other conditions
IV levothyroxine (hard to get hold of)
```
219
what is the prognosis for canine hypothyroidism?
good - adult dogs with primary
| guarded if seocndary
220
what are the 3 areas of the adrenal cortex?
zona glomerulosa
zone fasiculata
zona reticularis
221
what is produced in the zona glomerulosa?
mineralocorticoids
222
what is produced in the zona fasiculata and zone reticularis?
glucocorticoids and sex hormones
223
what is produced in the adrenal medulla?
catecholamines
224
what is the main mineralocorticoid produced?
aldosterone
225
where is the major site of aldosterone action?
cells in distal convoluted tubule and collecting duct (renal tubules)
226
what is the action of aldosterone?
resorption of H2O and NaCl
| secretion of K+ and H+
227
what electrolyte is aldosterone more important for regulating?
K+ more than Na+
228
what is the most important stimuli of aldosterone production?
hyperkalaemia
| increased angiotensin II
229
how does the HPA axis stimulate secretion of cortisol and aldosterone?
hypothalamus produces CRH
pituitary gland is then stimulated to produce ACTH
stimulates adrenal glands to produce cortisol and aldosterone
230
what organ is affected by primary hypoadrenocorticism?
adrenal glands
231
what is caused by primary hypoadrenocorticism?
addison's disease
| lack of cortisol and aldosterone
232
what is caused by secondary hypoadrenocorticism?
lack of cortisol
233
what organ is affected by secondary hypoadrenocorticism?
pituitary gland
234
what is the most common type of hypoadrenocorticism?
primary
235
what happens as a result of primary hypoadrenocorticism?
lack of glucocorticoids and minuralocorticoids
236
what happens in atypical hypoadrenocorticism?
lack of glucocorticoids but normal mineralocorticoids
237
what is the suspected cause of primary hypoadrenocorticism?
immune mediated destruction of the adrenal cortex
238
what is the cause of secondary hypoadrenocorticism?
pituitary gland is cause
| neoplasia, inflammation, infection, infarct, iatrogenic (hypophysectomy)
239
what deficiency does secondary hypoadrenocorticism cause?
glucocorticoid as aldosterone is regulated by RAAS as well
240
why may there be neurological signs with secondary hypoadrenocorticism?
brain lesion present
241
what are the typical dogs that get hypoadrenocorticism?
young/middle aged
| female
242
what breeds are predisposed to hypoadrenocorticism?
standard poodles
bearded collie
novia scotia duck toller
great dane
243
what are the clinical signs of hypoadrenocorticism?
vague waxing and waning history
244
what are the signs caused by lack of cortisol?
weakness
vomiting
diarrhoea
anorexia
245
when are signs of lack of cortisol due to hypoadrenocorticism exacerbated?
at times of stress
246
what are the signs of lack of aldosterone?
PUPD to to low Na
| not in atypical hypoadrenocorticism
247
what is a severe complication of hypoadrenocorticism?
Addisonian crisis - emergancy
248
what are the signs of Addisonian crisis?
```
collapse
severe dehydration
hypovolaemia (low sodium)
pre-renal azotemia (dehydration)
cardiac arrhythmias (hyperkalaemia - bradycardia)
```
249
how is hypoadrenocorticism diagnosed?
```
compatible history and clinical signs
haematology
biochemistry
urinalysis
basal cortisol
```
250
what is found on the haematology results of a patient with hypoadrenocorticism?
non-regenerative anaemia
| absence of stress leukogram (which should be seen in a sick patient)
251
what will the leukogram of a hypoadrenocorticism patient show?
decreased neutrophils
increased lymphocytes
increased eosinophils
252
what is seen on the biochemistry results of hypoadrenocorticism patients?
```
hyperkalaemia and hypernatraemia
hypercalcaemia
pre-renal azotemia
acidaemia (vomiting)
hypoglycaemia
increased liver enzymes
decreased albumin and cholesterol
```
253
what sodium / potassium ratio indicates hypoadrenocorticism?
<27 - due to lack of mineralocorticoids
254
what is pre-renal azotemia in hypoadrenocorticism due to?
hypovolaemia and dehydration
255
what is hypoglycaemia in hypoadrenocorticism due to?
lack of glucocorticoids
256
why does hypoadrenocorticism lead to increased liver enzymes?
poor perfusion
257
why is decreased albumin and cholesterol seen in hypoadrenocorticism?
GI insult from lack of glucocorticoids affecting vascular flow to tract
258
what are the urinalysis findings of a patient with hypoadrenocorticism?
variable USG due to low Na and high Ca2+
| could be dilute due to low Na or concentrated due to dehydration
259
what is basal cortisol used to test?
exclusion of hypoadrenocorticism
260
what basal cortisol level indicates hypoadrenocorticism is unlikely?
>55 nmol/L - cortisol is being stored
261
what basal cortisol level indicates an ACTH stim is necessary?
<55 nmol/L
262
what is used to confirm the hypoadrenocorticism diagnosis?
ACTH stim
263
what are the levels of pre and post ACTH cortisol in hypoadrenocorticism patients?
both below 20 nmol/L
264
what can affect the results of ACTH stim?
exogenous glucocorticoid will cross react and be measured
| previous glucocorticoid treatment will suppress adrenal cortisol production
265
how is an ACTH stim performed?
cortisol level tested before and 1hr after ACTH administration
collect serum for basal cortisol level
inject 5 mg/kg of ACTH IV
collect second sample 1 hr later
266
when is cortisol measured in an ACTH stim?
before and 1 hour after ACTH admin
267
what will the results of an ACTH stim be in a hypoadrenocorticism patient?
pre and post ACTH cortisol will be the same rather than increasing
268
how is an Addisonian crisis treated?
IV 0.9% NaCl at shock dose (60-90ml/kg)
hydrocortisone or dexmathasone IV (or CRI)
correction of hypernatraemia
treatment of hypoglycaemia and hyperkalaemia as needed
269
what si the shock does of 0.9% NaCl required for Addisonian crisis?
60-90 ml/kg
270
what are hydrocortisone and dexmathasone used for?
replacement glucocorticoids and mineralocorticoids
271
why must hypernatraemia be treated?
can cause brain oedema
272
how should hyponatraemia be treated?
slowly
273
how can hypoglycaemia and hyperkalaemia be treated?
glucose and/or insulin
| calcium gluconate to protect myocytes
274
what is the most commonly used long term glucocorticoid therapy for hypoadrenocorticism?
prednisolone
275
what is the dose of prednisolone required to treat hypoadrenocorticism?
0.5 mg/kg PO q12hrs initially
| then 0.1 or 0.2 mg/kg PO q12-24hr
276
what must the dose of prednisolone be tailored to do?
limit clinical signs of polyphagia, PUPD and weight gain
277
when should glucocorticoid dose be increased?
if signs of lethargy, vomiting and diarrhoea
| double dose if stressful event expected
278
what drug is used as mineralocorticoid long term therapy?
desoxycortone pivalate
279
what is the benefit of Zycortal mineralocorticoid therapy?
able to manage GC need separately from MC
280
what is the starting dose for Zycortal (MC)?
1.5 mg/kg SQ
281
how can glucocorticoid levels be monitored?
ask for evidence of lethargy, vomiting, diarrhoea which would prompt increase in dose as indicate low levels
282
how are mineralocorticoid levels tested?
blood test to measure Na/K ration 10-14 days after DOCP admin to see peak effect
then measure Na/K 25/30 days after DOCP admin to see duration of
DOCP
283
what will the measurement of peak DOCP effect determine?
next mg/kg dose
284
what Na/K ratio will lead to dose increase of mineralocorticoids?
>32 or K below reference range = 10% dose increase
285
what should happen if Na/K ratio is below 32 or K is in the lower half of the reference ranges 25-30 days after DOCP administration?
delay injection by 5 days and repeat the same process
286
what was the drug used preciously to treat hypoadrenocorticism?
fludrocortisone
287
why is fludrocortisone less commonly used?
required check of Na/K weekly initially
| dose requirements would often increase
288
what is the prognosis of hypoadrenocorticism?
good if well managed on lifelong medication
289
what should dogs with atypical Addison's be monitored for?
development of mineralocorticoid deficiency which may develop in the future
290
what is canine hyperadrenocorticism also known as?
Cushing's disease
291
what does hyperadrenocorticism occur due to?
excessive production of cortisol as a consequence of pituitary or adrenal tumors
292
how is cortisol produced?
hypothalamus releases CRH
pituitary releases ACTH
adrenal glands release cortisol
cortisol provides negative feedback to hypothalamus and pituitary
293
what are the 3 types of hyperadrenocorticism?
pituitary dependent
adrenal dependent
iatrogenic- admin of glucocorticoids
294
what is the most common type of hyperadrenocorticism?
pituitary dependant
295
what is caused by pituitary dependent hyperadrenocorticism (PDH)?
overproduction of ACTH due to adenoma of pars distalis
loss of negative feedback from cortisol leading to bilateral adrenal hyperplasia
macroadenoma in some leading to CNS signs
296
what animals are predisposed to hyperadrenocorticism?
daschunds, poodles, small terriers
no sex predisposition
middle/old aged dogs
297
what is adrenal dependent hyperadrenocorticism caused by?
adenomas / carcinomas leading to the production of excess cortisol which suppresses ACTH production
leads to atrophy of other gland
298
in what breed / type is adrenal dependent hyperadrenocorticism more common?
female
| large breeds
299
what is iatrogenic hyperadrenocorticism caused by?
suppression of CRH and ACTH production due to excessive glucocorticoids
bilateral adrenal atrophy
300
what are the major clinical signs of hyperadrenocorticism?
```
abdominal distension
hepatomegaly
lethargy and exercise intolerance
panting
PUPD (nocturia and incontinence as a result)
polyphagia
skin changes (thinning and erythema)
alopecia (symmetrical and non-pruretic)
```
301
how is polydipsia defined in dogs?
>100ml/kg/day
302
how is polyuria defined in dogs?
>50 ml/kg/day
303
what are the complications associated with hyperadrenocorticism?
progression of major signs
DM from insulin resistance due to excess cortisol
pulmonary thromboembolism
neurologic signs - obtunded, blindness and seizure
pancreatitis due to poor fat management
secondary infections as immune system suppressed
hypertension
glomerulopathy and proteinuria - direct effect of cortisol in kidney
304
what are the main initial general screening tests used for hyperadrenocorticism?
haematology
biochemistry
urinalysis
305
what are the screening tests used for the HPA axis?
ACTH stim
low-dose dexamethasone suppression test
urine cortisol:creatinine ratio
306
is there a single test for hyperadrenocorticism that is 100% accurate?
no
307
define test sensitivity
probability of positive result if patient is affected (if high sensitivity and negative result it can be ruled out)
308
define test specificity
probability of a negative result if the patient is not affected (high specificity, positive result, rule in)
309
what is seen on the haematology of a patient with hyperadrenocorticism?
mid erthyrocytosis and thrombocytosis - effect of cortisol on bone marrow
stress/steroid leukogram (increased neutrophils and/or monocytes, decreased eosinophils and/or lymphocytes) - opposite of Addison's
310
what is seen on the biochemistry screening tests of a patient with hyperadrenocorticism?
increased ALKP (5-40x upper end of reference)
increased ALT
hypercholesterolaemia and hypertriglyceraemia due to lipolysis
hyperglycaemia due to insulin antagonism (resistance)
increased bile acids
311
what urine specific gravity is seen in patients with hyperadrenocorticism?
variable - <1.015
312
what is found on urinalysis of patients with hyperadrenocorticism?
```
dilute urine
+/- proteinuria
+/- glycosuria
possible UTI
calcium oxalate crystals due to over excretion of calcium
```
313
what is essential before pursuing diagnosis of hyperadrenocorticism?
some historical and clinical signs are apparent
| no recent steroid administration
314
what will the ACTH stimulation test of a patient with PDH show?
excessive response to administration of ACTH
315
what will the ACTH stimulation show in a normal dog?
small cortisol increase
316
what is shown post ACTH stimulation in a patient with iatrogenic hyperadrenocorticism?
cortisol remains at pre-admin levels as they are unable to stimulate cortisol release
317
what are the advantages of ACTH stimulation tests to diagnose hyperadrenocorticism?
more specific than LDDST and less affected by non-adrenal illness
good first line test (if positive can be confident of illness)
useful for iatrogenic disease
used to monitor treatment response
318
what are the disadvantages of ACTH stimulation tests to diagnose hyperadrenocorticism?
less sensitive than LDDST
| doesn't distinguish PDH from ADH
319
how is low dose dexamathasone suppression test (LDDST) performed?
collect serum for basal cortisol
inject low dose (may need to dilute for small patients) IV dexamathasone
collect serum sample 4 and 8 hours after injection
320
what is the LDDST result of a patient with ADH and 40% of those with PDH?
flat line - no response and cortisol remains high
321
what is the LDDST result in 30% of PDH patients?
escape V pattern - cortisol drops at 4 hours but has climbed again by 8
322
what is the response of a normal dog to LDDST?
smooth drop in cortisol - lowest at 8 hours
323
what is the advantage of LDDST to test for hyperadrenocorticism?
more sensitive that ACTH (excellent sensitivity)
| can distinguish PDH from ADH (escape V)
324
what is the disadvantage of LDDST for diagnosis of hyperadrenocorticism?
care with false positives
affected by non-adrenal illnesses
should not be used as sole diagnostic test
not useful for iatrogenic disease
325
how is urine cortisol:creatinine ratio test for hyperadrenocorticism performed?
urine sample collected at home
2 pooled morning samples
several days following a stressful event
326
what are the advantages of urine cortisol:creatinine ratio to diagnose hyperadrenocorticism?
high sensitivity
| useful to exclude hyperadrenocorticism (if normal Cushing's is very unlikely)
327
what is the disadvantage of urine cortisol:creatinine ratio to diagnose hyperadrenocorticism?
not very specific - false positives common
328
what tests can be used to differentiate PDH from ADH (adrenal tumors)?
LDDST
high dose dexamethasone suppression test (HDDST)
imaging
endogenous ACTH conc
329
what dose of dexamethasone is given for HDDST?
0.1mg
330
what will HDDST results look like for a patient with PDH?
escape V
331
what will the HDDST results look like for a patient with ADH and 15% with PDH?
no suppression of cortisol (flat line)
332
what will HDDST look like in a normal dog?
drop smoothly - lowest 8hrs after dex injection
333
what can an abdominal ultrasound be used for in hyperadrenocorticism diagnosis?
looking st symmetry and enlargement of adrenal glands
334
what will be seen on abdominal ultrasound of a patient with PDH?
symmetrical adrenal glands
| enlarged or normal
335
what will be seen on abdominal ultrasound of ADH / AT?
asymmetrical adrenal glands
336
what is MRI used for in hyperadrenocorticism diagnosis?
evaluation of pituitary gland and adrenal glands
337
what is found in 90% of PD patients?
brain mass
338
what types of adenoma can be seen with PDH?
microadenoma
| macroadenoma
339
what are endogenous ACTH levels like in PDH patients?
high (>45 pm/ml)
340
what is endogenous ACTH like in ADH patients?
undetectable / low
341
what is the issue with using endogenous ACTH to diagnose whether hyperadrenocorticism is PDH or ADH?
concentrations of ACTH between 10-45 pg/ml are unhelpful
| lab may not be able to manage sample
342
what are the considerations for treatment of hyperadrenocorticism?
difficult to diagnose in some cases
progressive disease so could wait and retest if uncertain
treatment is expensive
343
when should hyperadrenocorticism only be treated?
if there is a high index of suspicion from history and clinical signs, haematology and biochem and specific tests
344
how is PDH treated?
medically with trilostane (Vetoryl)
surgically - hypophesectomy or bilateral adrenalectomy
radiation therapy
345
what does trilostane do?
blocks adrenal cortisol production
346
how is trilostane administered?
PO with food
SID or dose split to BID
lower dose than formulary suggests given first
347
how is response of patient to trilostane treatment for hyperadrenocorticism monitored?
clinical signs and ACTH stim or pre-pill cortisol
348
what are the side effects of trilostane?
uncommon but life threatening
GI signs
hypoadrenocorticism
bilateral adrenal necrosis
349
what is involved with hypophysectomy?
complete surgical removal of the pituitary gland accessed via the soft palate
350
what is the only potential curative (~75%) option for dogs with PDH?
hypophysectomy
351
what is the long term outcome of successful hypophysectomy?
3 year survival in 70%
352
what is needed after hypophysectomy?
lifelong hormonal supplementation
- glucocoticoids
- thyroxine
transient diabetes may insipidus may be seen post op but DDAVP treatment for this can usually be discontinued
353
where is radiation therapy for PDH available?
refurral only
354
what is the benefit of radiation therapy for PDH treatment?
linear accellerator photon irradiation may be effective in reducing the size of macroadenomas or eliminating neurological signs
355
what concurrent treatment is often required with radiation to treat PDH?
trilostane as reduction in ACTH secretion is variable and often not marked
356
what is radiation treatment of PDH particularly useful for?
large pituitary macroadenomas where surgery would be contraindicated
357
what is the mean survival time for dogs with PDH treated with radiation therapy?
25 months
358
how is ADH treated?
adrenalectomy - gold standard
| medical therapy
359
what is required before adrenalectomy to treat ADH?
work up before operation (assess location/size/infiltration of tumor)
360
what are complications associated with adrenalectomy to treat hyperadrenocorticism?
```
haemorrhage
hypertension
acute hypocortisolaemia
hypoaldosteronism
wound breakdown
(needs refurral treatment)
```
361
how effective is trilostane for treatment of ADH?
ADH generally more resistant
| used pre-surgery to stabilise
362
what are the general considerations when treating any hyperadrenocorticism?
may unmask other underlying diseases that have been hidden by high cortisol
reduced cortisol can make pituitary lesions expand leading to CNS signs
363
what is the prognosis of PDH?
depends on age, overall health and owner commitment
| ~30 months survival post diagnosis
364
what is the prognosis of ADH?
following successful surgery mean survival is 36 months
| metastatic disease leads to death/euthanasia within 12 months
365
is hyperadrenocorticism common in cats?
less os
366
what concurrent disease is seen in 80% of cats with hyperadrenocorticism?
insulin resistant DM
367
what signs are seen in cats with hyperadrenocorticism?
insulin resistant DM
cachexia
fragile skin syndrome (skin may slough off during routine handling so care needed)
alopecia (ventral, symmetrical)
368
what biochemistry signs seen in dogs with hyperadrenocorticism is not seen in cats?
increase in ALP
369
how is hyperadrenocorticism in cats diagnosed?
HDDST
| ACTH stim with post sample at 60 and 90 mins
370
how is hyperadrenocorticism in cats treated?
difficult
adrenalectomy if adrenal mass
no reliable medication for PDH - can use trilostane and hypophysectomy is possible
371
what is the prognosis of hyperadrenocorticism in cats?
guarded to poor
| worse than dogs
372
what type of diabetes mellitus is seen more commonly in dogs?
insulin dependent (type 1)
373
what are the possible causes of diabetes mellitus in dogs?
destruction of pancreatic beta cells
| insulin resistance leading to beta cell exhaustion
374
what causes destruction of pancreatic beta cells?
genetics
immune mediate pancreatic damage
pancreatitis
idiopathic
375
what causes insulin resistance leading to beta cell exhaustion?
obesity
concurrent disease (e.g. pancreatitis or endocrinopathy)
dioestrus
drugs
376
what is the signalment for canine diabetes mellitus?
middle aged/older dogs
female more than male
breed predisposition
377
what are the top 3 dog breeds predisposed to diabetes mellitus?
Australian terrier
schnauzer
bichon
378
what are the clinical findings in a dog with diabetes mellitus?
```
PUPD
polyphagia
weight loss
cataracts
DK
concurrent disease
```
379
what causes PUPD in diabetes mellitus patients?
kidney is unable to process the excess glucose so glycosuria occurs
due to the osmotic pressure of the glucose in the urine more water is drawn out
380
why are polyphagia and weight loss seen in diabetes mellitus?
decreased glucose utilisation due to lack of insulin there is a negative calorie balance
381
what are cataracts caused by in diabetes mellitus?
altered osmotic relationship in the lens
| accumulation of sugars in the lens causing swelling and rupture of lens fibres
382
what are the main signs of diabetic ketoacidosis?
vomiting
collapse
dehydration
383
what is necessary to confirm a diabetes mellitus diagnosis?
glycosuria
| persistent hyperglycaemia
384
what is shown by fructosamine?
average of glycaemia over the past 2-3 weeks so give an impression of blood sugar levels over time
385
how does fructosamine measure glycaemia over weeks?
glucose binds to proteins (glycated proteins) in an irreversible reaction between glucose and plasma proteins
386
what should fructosamine results be interpreted alongside?
clinical signs
387
how is diabetes mellitus treated in dogs?
```
insulin (in almost all cases)
diet
exercise
consistency
owner commitment
```
388
what varies between types of insulin?
time of onset
time of maximum effect
duration of action
389
what is the most commonly used insulin for dogs?
Lente (Caninsulin) - intermediate acting
390
what insulin type is needed to treat DKA?
neutral / short acting insulin
391
are oral hypoglycaemic drugs of any use in dogs?
no
392
what are the 2 types of long acting insulin?
PZI
| glargine
393
what is a Caninsulin VetPen used for?
small doses
| makes administration easy for owners
394
what syringe colour is used for Caninsulin (canine product)?
red syringe
395
how many insulin units are within Caninsulin?
40 IU/mL
396
how should insulin be handled?
```
store in fridge / avoid extremes of temperature
replace bottles after 4 weeks
invert to mix gently
use appropriate syringe
vary site of injection
```
397
how should intact females with diabetes mellitus be managed?
spayed 1-3 days after starting insulin especially in dioestrus
398
why do intact females with diabetes mellitus need to be spayed?
progesterone is a cause of insulin resistance so makes DM harder to treat as insulin is needed in larger volumes
399
what should be used if it is not possible to spay intact females who have diabetes mellitus?
aglepristone
400
what diet should diabetes mellitus patients be fed?
diabetic specific food
| no simple sugars (reduce glucose spike)
401
in a diabetic diet what should the calories be supplied by?
complex carbohydrates and proteins
| increased fibre content for overweight dogs
402
what should thin diabetic dogs be fed?
calorie dense, low fibre maintenance diet
403
what should picky diabetic dogs be fed?
whatever they are used to
404
what is important about the feeding schedule of a diabetes mellitus patient?
consistent timing, quantity and type of diet
405
how should patients receiving BID insulin be fed?
half daily requirement at time of each injection
406
how should patients receiving SID insulin be fed?
1/3-1/2 at time of injection and remainder 8 hours later
407
how long can stabilisation of diabetic patient take?
weeks to months
408
how should the first day of insulin administration be managed?
start with low dose
avoid hypoglycaemia
check BG several times (q2-3 hours) in the day in practice
409
what are the most important clinical signs to monitor for in the healthy newly diagnosed diabetes dog?
PUPD
polyphagia
weight loss
410
what should be checked for if the diabetes patient on insulin no longer has diabetes signs?
are there signs of hypoglycaemia
411
what are the signs of hypoglycaemia?
lethargy
reluctant to exercise
collapse
seizure
412
when should diabetic dogs on insulin have their first recheck?
7-10 days after first dose
413
when should follow up appointments be scheduled for the newly diagnosed diabetic dog?
7-10 days post first insulin
14 days later
1 month
then every 3 months if well controlled
414
when is a blood glucose curve important?
if there is poor glycaemic control so adjustments can be made to insulin therapy
415
what should a glucose curve be used in conjunction with to make management / insulin changes?
clinical signs
416
how is a blood glucose curve performed?
serial blood glucose with a glucometer
| continuous glucose monitoring
417
how is serial blood glucose taken?
in the ear every 2 hours and then every hour close to the nadir
418
how is continuous glucose monitoring performed?
measured interstitial blood glucose - device placed on scruff and glucose levels monitored constantly
419
what is the nadir?
lowest blood glucose value
420
what parameters should be assessed when doing a blood glucose curve?
nadir
| duration of action of insulin
421
what is the renal threshold for glucose?
point at which glucose will be secreted in the urine as kidneys are no longer able to prevent glucose spilling into urine so PUPD is caused
422
how much glucose will be seen in the urine of a patient with insulin controlled diabetes melitus?
mild amount in urine especially before glucose administration
423
what may no glucose in the urine of a patient with insulin controlled diabetes melitus for more than 24 hours indicate?
insulin overdose
424
what would ketones in the urine of insulin controlled diabetes melitus patients indicate?
poor glycaemic control - not enough insulin
425
what can one off blood glucose monitoring show?
good glycaemic control if prior to insulin administration but curve is more useful
426
what are the complications of insulin therapy?
hypoglycaemia
| somogyi overswing
427
what are the clinical signs of hypoglycaemia?
lethargy
weakness
collapse
seizure
428
what blood glucose level indicates hypoglycaemia?
<3 mmol/L
429
how should hypoglycaemia be treated?
small meal
| glucose / sugar solution PO or IV
430
what is somogyi overswing?
rebound hyperglycaemia response from other hormones in the body due to physiologic response to hypoglycaemia
431
when may somogyi overswing occur?
when blood glucose is <3.6 mmol/L
| or quick drop in glucose following insulin
432
how long does lente (caninsulin) work for?
8-12 hours
433
how are issues with insulin therapy diagnosed?
glucose curve
434
when may short duration of inslin occur?
using Lente if duration of action is less than 8 hours
435
how can you tell if patients insulin is too short acting?
PUPD between injections
436
how can short duration of insulin be managed?
switch to long acting insulin BID
437
when does prolonged duration of insulin occur?
when nadir is >10 hours post injection
438
what is the risk of prolonged action of insulin?
risk of hypoglycaemia and Somogyi overswing
439
how can prolonged duration of action of insulin be managed?
if long acting give SID or switch to short acting
440
what should you do if insulin is having inadequate action?
make sure owner is administering the insulin correctly
441
what are the long term complications of diabetes?
```
hypoglycaemia
cataract formation (inevitable in dogs)
diabetic neuropathy (uncommon in dogs)
diabetic nephropathy (uncommon in dogs)
hypertension
DKA
```
442
what causes diabetic neuropathy?
distal neuropathy due to segmental demylination and axonal degredation
443
what is the prognosis of dogs with diabetes melitus?
good if well managed with committed owners (MST - 3 to 5 years)
444
what type of diabetes melitus do cats most often get?
non-insulin dependent - type 2
445
what are the risk factors for diabetes melitus in cats?
old age
obesity
male
indoor
446
what cat breeds are predisposed to diabetes melitus?
burmese
main coon
russian blue
siamese
447
what are the 2 main causes of diabetes melitus in cats?
insulin resistance
| reduced insulin secretion
448
what can cause insulin resistance in cats?
genetically determined
| obsetity (antagonises effect of insulin)
449
what element of diabetes can further damage the pancreas in cats?
hyperglycaemia
450
how is reduced insulin secretion caused in cats?
chronically increased glucose and free fatty acids
amylin is co-secreted with insulin by beta cells
toxic amyloid polypeptide deposition leads to inflammation and cell death
beta cell damage (some function remains)
451
what can cause insulin resistance?
obesity
inflammatory / infectious diseases
endocrinopathies
452
what inflammatory / infectious diseases can cause insulin resistance in cats?
```
pancreatitis
UTI
CKD
dental disease
enteropathy
```
453
what endocrinopathies can cause insulin resistance in cats?
hyperthyroidism
acromegaly
hypercorticism (iatrogenic steroid use)
454
what are the signs of pre-diabetes melitus in cats?
impaired fasting glucose (rarely seen due to stress hyperglycaemia)
BG constantly above >6.5 mmol/L (elevated but not in diabetic range)
455
what is the blood glucose level in subclinical DM in cats?
>10mmol/L and <16mmol/L (renal threshold) persitantly
456
what can be done to manage cats with subclinical DM?
low carbohydrate diet
weight loss
insulin sensitisers (glipizide)
try to avoid overt DM
457
what is the BG of a patient with overt DM?
>16 mmol/L
| renal threshold is exceeded
458
what are the signs on biochemistry and urinalysis of overt DM cat?
hyperglycaemia
increases fructosamine (unaffected by stress hyperglycaemia)
glycosuria
459
what are the clinical signs of DM in cats?
as for dogs - weight loss, polyphagia, DKA
peripheral neuropathy
cataracts (rare)
460
how is DM diagnosed in cats?
hyperglycaemia and glycosuria
461
what should you be aware of when screening cats for DM?
stress hyperglycaemia altering results
462
what does fructosamine show in cats?
mean BG in the last week
463
what can be used to differentiate between stress hyperglycaemia and DM?
combine fructosamine with history and clinical signs
464
how is DM in cats treated?
```
insulin
diet
exercise
commitment from owner
consistantcy
```
465
what insulin is used in cats?
longer acting
466
what is the first insulin type that will be tried in cats with DM?
Prozinc
467
can Caninsulin be used in cats?
yes but response is very unpredictable
468
what is the other insulin type that can be used if prozinc and caninsulin have not worked?
Glargine - on cascade as not licenced
469
what do oral hypoglycaemic drugs do?
increase insulin secretion to decrease IR
470
when are oral hypoglycaemic drugs useful in cats?
if owner declines insulin
with diabetic diet and weight loss
as long as no comorbidities
471
what is a key benefit for management and prevention of DM in cats?
diet
472
what should the composition of feline diabetic diets be?
```
wet
high protein
low carbohydrate
reliable intake
fibre less key than in dogs
```
473
what can be the result of dietary management and associated weight loss in cats?
resolution of DM in 30% of cats
| reduction in insulin dose for 50% of cats
474
what is a serious complication of DM?
DKA
475
what often caused DKA?
DM with serious concurrent disease (e.g. heart failure, pancreatitis or sepsis)
476
how is DKA caused?
increased production of glucoregulatory hormones (glucagon, adrenaline, cortisol)
lack of insulin in DM allows the glucogenic effects of the stress hormones to be unopposed in liver, muscle and adipose tissue
leads to excessive breakdown of fatty acids, excessive ketone formation (e.g. acetone) leading to a build up in the body
477
what are the clinical signs of DKA?
PUPD
polyphagia
weight loss
systemic signs such as lethargy, anorexia and vomiting which worsen
additional signs of concurrent disease
strong odour of pear drops on breath (acetone) - not everyone can smell it
severe dehydration and hypovolaemia
478
what is the aim of treatment of DKA?
restore water and electrolyte balance
provide adequate insulin to 'switch off' ketone production
correct acidosis
identify any underlying disease
479
what electrolytes may be altered by DKA?
sodium
potassium
phosphorus
480
what insulin is needed to treat DKA?
neutral - CRI or IM every hour
481
what supportive therapy is needed for the DKA patient?
analgesia (if pancreatitis etc)
feeding to avoid hypoglycaemia (appetite stimulants, mariopitant, feeding tube)
careful monitoring
482
how long does it take for hypoglycaemia to improve?
12-24 hours
483
how long does it take for ketosis to improve?
48-72 hours
484
what is the prognosis of DKA?
challenging to treat
often underlying disease
25% will die or be euthanised
485
what can happen to cats after DKA?
DM remission in some cases
