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Hypoadrenocorticism(Addison's Dz) (Signalment (uncommon in dogs>>…
Hypoadrenocorticism(Addison's Dz)
구분
Primary
typical>atypical(10%)
대부분 자가면역에 의한 부신 파괴
GC와 MC 모두 결핍
가장 흔함.
MC 결핍 → crisis
Secondary
atypical
뇌하수체 문제로 ACTH 결핍
GC 결핍 only(MC는 hyperkalemia, RAAS에 의해 분비)
임상증상 mild
MC만 결핍 ← very rare
Signalment
uncommon in dogs>>>>cats
mixed breed>>Poodles, Great Danes, Westie
female>male
young~middle aged
C/S : anorexia, lethargy, vomiting, diarrhea, bradycardia ← 임상증상이 특징적이지 않음.
Lab findings
lack of stress leukogram, lymphocytosis, hyperkalemia, hyponatremia
Na+-K+ ratio
<28(or 24 or 21) ← 숫자가 낮아질수록 민감도는 떨어지지만 특이도는 올라감.
감소하는 경우 → ACTH stimulation test로 확진
Na-K ratio와 lymphocyte count를 같이 보면 좋음.
Ancillary tests : BP, blood gas, ECG(loss P, tent T, wide QRS, brady), thoracic radiographs, US, fecal
진단
Screening tests : resting cortisol ← r/o only
Diagnosing tests
GC 결핍 : ACTH stimulation ← 의인성 쿠싱과 비슷한 양상
MC 결핍 : Na & K ← 다른 내분비 검사 필요x
Differentiating test : eACTH
Management
ER patients
Hyperkalemia
crystalloids
IV regular insulin : shifts K+ into cells, dextrose 함께 투여(dextrose만 주기도)
sodium bicarbonate : shifts K+ into cells, 산증과 고칼륨혈증에 효과
calcium gluconate : 막전위를 안정화, 포타슘 수치를 떨어뜨리지는 않음.
Hypovolemia : crystalloids, IV
Cortisol deficiency : dexamethasone
Aggressive fluid therapy
Steroid replacement(Mineralocorticoids)
Desoxycorticosterone pivalate(DOCP) : every 21~28 days, no glucocorticoid effects, PDS도 소량으로 같이 투여, expensive
Fludrocortisone : PO only, glucocorticoid effects ← 요즘은 안 씀.
Long-term monitoring
첫 1~2개월이 매우 중요, 전해질 검사 자주해야
4~6개월 간격으로 모니터링
ACTH 자극 검사 필요x
Thyroid Dz
Hypothyroidism
middle-aged dogs, very rare in cats
most inappropriately diagnosed endocrinopathy in vet md
Golden retrievers, Doberan pinschers, Boxers 등에서 호발
Etiology
generally primary(thyroid gland) resulting from destruction of the thyroid gland : autoimmune lymphocytic thyroditis, idiopathic thyroid gland atrophy
rarely secondary(pituitary) resulting from loss of TSH secretion : tumor, cyst, trauma
tertiary(↓TRH secretion) ← exceptionally reported in dogs
iatrogenic : anti-thyroid medications(methimazole in cats), bilateral thyroidectomy, or 131 radioiodine therapy
C/S
Behavior signs : aggression, cold intolerance(15%), exercise intolerance, lethargy, metal dullness(20~70%), prolonged anestrus(4~40%), weight gain(41~60%)
Non-behavior sings : alopecia(26~65%), dry or dull hair coat(60%), seborrhea(39%), hyperkeratosis(15~33%), hyperpigmentation(15~33%), pyoderma(11~12%), bradycardia(10~14%)
피부 증상 흔함(60~80%) : 'rat tail', seborrhea, alopecia, pyoderma, recurrent otitis externa, myxedema(tragic face)
Metabolic signs : lethargy, exercise intolerance, weight gain, mental dullness, hypothermia(cold intolerance)
Neuro(7.5%) : peripheral neuropathy/myopathy(weakness, ataxia, quadriparesis), laryngeal paralysis(stridor), cranial nerve(facial drooping, head tilt/circling)
Minimum database
75~80% hypercholesterolemia or hypertriglyceridemia
30% mild, non-regenerative anemia
total T4, free T4, TSH
Thyroid tests
avoid testing during non-thyroidal dz or w/ certain medications
Almost all dz and many medications result in decreased production TSH(euthyroid sick syndrome=ESS) and decreased TT4. ← ESS가 갑기저보다 더 흔함.
fT4ED is less likely to be decreased by nonthyroidal illness.
Total T4
free(<1%) & protein-bound(>99%) T4
특이도가 낮아서 갑기저 r/o에만 사용(normal=갑기저x)
low TT4 : normal, hypothyroid, or ESS
일부 종(Sight hounds, Chinese Sharpei)은 정상적으로 낮은 TT4 가짐.
Free T4 by equilibrium dialysis(fT4ED)
measures unbound, biologically active fraction
less subject to nonthyroidal influence → 더 나은 민감도&특이도
TSH
TSH should be high during hypothyroidism(primary).
high rate of false negative test results in dogs ← lack of sensitivity
Thyroglobulin autoantibodies
Thyroglobulin : major storage form of T4 & T3 in thyroid
Only 60% of hypothyroidism are positive for TgAA.
Lymphocytic thyroiditis doesn't always lead to hypothyroidism.
Treatment
Levothyroxine(no need for T3)
Monitoring
Evaluate T4
4~6 hours post-pill
4~6 weeks after initiating therapy
every 6~12 months after optimum does is estabilished
Goal : T4 in the upper 50% of the RI, but not greater!
no indication to evaluate TSH
Hyperthyroidism
common in older cats(>7yr), very rare in dogs
benign adenomatous hyperplasia(adenoma)가 원인의 대부분
Associated dz : concentric HCM, systemic hypertension, CKD(갑상샘기능항진증이 CKD를 가릴 수 있음)
C/S : PU/PD/PP, vomiting, diarrhea, weight loss w/ increased appetite, hypertension, etc.
진단
TT4로 충분(high TT4=hyperthyroidism)
일부 고양이에서는 fT4ED 필요(high fT4ED=hyperthyroidism)
Even a small increase counts.
screening tests → 종종 질병 조기 진단
TT4 참고 범위(고양이) : 1~4μg/dl ← 4μg/dl 이상이면 진단
7살 이상의 노령묘가 TT4>3μg/dl인 경우 hyperthyroidism 강하게 의심(fT4ED or thyroid scintigraphy 고려)
Treatment
131 Iodine therapy ← 최근에는 먹는 약으로 잘 관리
Thiourylene antithyroid drugs : methimazole, carbimazole ← 갑상샘 호르몬 합성 억제
Hyperthyroid diet(Hill's y/d) : severely iodine restricted diet ← 임상적인 유용성 아직 검증x, 우리나라에 없음.
Other considerations
hyperthyroidism은 renal blood flow를 증진시켜 pre-existing renal failure를 가릴 수 있음. → hyperthyroidism의 치료로 신부전이 드러날 수 있음. 치료가 신부전을 유발한 것이 아님!!
Cardiovascular manifications
치료하면 예후 좋음.
*aldosterone(collecting tubule) : +3Na+, -2K+, +Cl-(or -H+)
*Addison병과 임상증상 유사 : renal failure, renal obstruction, diarrhea, GI parasites
*설사를 하면 소듐만 많이 감소(장액에 소듐 多)
*uncommon thyroid tests : thyroid scintigraphy, TSH stimulation, etc.