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A 73-year-old woman was admitted to our emergency
department due to severe dyspnea and altered consciousness for
one day. She had been noted to have multiple nodular goiter 10
years before this admission and she had ever undergone total
thyroidectomy 4 years later. She was then lost to follow-up
and didn't take thyroid hormone replacement regularly. She
also had a history of hypertension with irregular treatment.
Two weeks prior to this admission, she complained of
progressive weakness, general malaise, bilateral leg edema,
dysuria and urinary urgency. She visited local clinics where
diuretics and vitamine complex were prescribed without
benefit. Progressively drowsy consciousness and dyspnea
developed later, and she was brought to our emergency
department. Throughout the course, there was no fever, chest
pain, visual deficit, headache, joint pain, focal weakness or
paresthesis. She denied a history of smoking, drug abuse,
alcohol consumption, operation and a family history of
endocrine disorders.
On examination, her Glasgow Coma Scale was E2V1M5. There was
generalized non-pitting edema and the skin appeared coarse and
dry. The body temperature was 34.6°C, pulse rate was 56
beats per minute, the respirations were 12 breaths per
minute and the blood pressure was 83/54 mmHg. She had a puffy
face, pale conjunctiva, isocoric pupils with prompt light
reflex, slightly protruding tongue and operative scar at the
neck region. Auscultation of the chest disclosed bilateral
basal rales and distant heart sounds with irregularly slow
heart beats.
Laboratory examinations showed WBC 5600 cells/μL with 92.1%
neutrophils, Hgb 11.4 g/dL, Na 132 mEql/L,K 3.8 mEq/L, plasma
glucose 142 mg/dL, and serum creatine kinase and CK-MB was 289
IU/L and 18 IU/L, respectively. Arterial blood gas showed pH
7.26, PaO2 39.7 mmHg, PaCO2 99.0 mmHg, HCO3 41.6 mmol/L while
she was breathing ambient air. Electrocardiogram disclosed
atrial fibrillation with a slow ventricular rate. Chest
radiography revealed cardiomegaly with bilateral pulmonary
congestion (Figure). Emergent endotracheal intubation was
performed immediately because of impending respiratory failure
and fluid resuscitation was started.
Computed tomography (CT) of the brain showed brain atrophy
without any organic lesions. Thyroid function test disclosed
TSH 75.8 μIU/mL (0.4-4.0) and free T4 <2.0 pg/ml. Other
hormone survey disclosed cortisol 9.96 μg/mL and 22.3 μg/mL 90
minutes before and after rapid ACTH test was performed,
respectively. Urine routine showed pyuria (WBC 2+).
She was admitted to the intensive care unit with
a diagnosis of myxedema coma and urinary tract
infection. Therapy with oral L-thyroxine 200μg/day was
started immediately after the diagnosis was made. Urine culture
grew E. coli. Due to hypothermia on admission, normal saline
was warmed and infused via parenteral route or via
nasogastric tube. Heat lamp was used for external warming with
electrical blanket. The body temperature elevated gradually.
After replacement of thyroid hormone and administration
of hydrocortisone, antibiotics and fluid resuscitation,
she gradually regained her consciousness after one week
of hospitalization. She was weaned off the
ventilator subsequently. During the hospitalization, thyroid
echogram showed small size of bilateral glands; the size of the
right lobe was estimated 0.6 x 0.5 cm and the left lobe 0.7 x
0.4 cm; there was no hypervascularity. Anti-microsomal
antibody and anti-thyroglobulin antibody were negative. She
was subsequently discharged with L-thyroxine 150μg/day. Four
months after treatement, the serum thyoid stimulating hormone
(TSH) and free thyroxine (free T4) levels at the OPD were
within normal ranges.
<Laboratory
data>
1. Results of baseline data
| WBC |
HB |
HCT |
MCV |
PLT |
| K/μL |
g/dL |
％ |
fL |
K/μL |
| 5.6 |
11.4 |
32.7 |
86.4 |
151 |
| LDH |
AST |
ALT |
CK |
CK-MB |
Glucose |
| mg/dL |
U/L |
U/L |
U/L |
U/L |
mg/dL |
| 324 |
51 |
43 |
289 |
18 |
103 |
| BUN |
CRE |
Na |
K |
ALB |
| mg/dL |
mg/dL |
mmol/L |
mmol/L |
g/dL |
| 11.2 |
1.4 |
132 |
3.8 |
3.4 |
2.
Results of the baseline endocrine tests
| hsTSH |
FT4 |
ACTH |
Cortisol before
rapid ACTH test |
Cortisol after rapid
ACTH test |
0.4- 4
μIU/mL |
6.0-17.5 pg/mL |
10-65
pg/mL |
5-25
μg/dL |
>19
μg/dL |
| 75.8 |
<2.0 |
11 |
9.96 |
22.3 |
*** hsTSH, high sensitivity thyroid-stimulating hormone;
FT4, free thyroxine; ACTH, corticotropin
3. Figure
<病例解析>
黏液水腫昏迷是內科的急症，若能及時診斷，及時治療，可以大大降低死亡率。
及時診斷需靠對疾病的了解：其症狀除了一般甲狀腺功能低下表現的大舌頭、皮膚乾粗黃、非壓性水腫(non-pitting
edema)、疲累無力外，由於本身甲狀腺荷爾蒙低下的狀態碰到外來的刺激因素時失去代償，而喪失促進熱能產生、呼吸、心跳，增加基礎代謝率的作用，就會出現體溫過低、心律緩慢、心搏輸出量減少，進而血壓降低，加上呼吸肌肉無力造成換氣不足，很容易造成呼吸衰竭，病人常因此而死亡。另外，甲狀腺功能過低會改變鈉離子的調節，造成低鈉血症，低血鈉會使模糊的意識更惡化。在診斷黏液水腫昏迷方面，病人除了會出現前述的症狀以外，病史的追問、確認是否有甲狀腺功能低下的可能也相當重要，包括：過去是否有過甲狀腺的疾病、是否接受過手術、放射碘或抗甲狀腺藥物治療、是否最近有使用會影響甲狀腺功能的藥，如鋰鹽、干擾素或Amiodarone、是否最近有接受過有顯影劑等等都要詳細追問；其它如自體免疫疾病、腦下垂體手術、是否有產後大出血病史(Sheehan
syndrome)
也都要考慮在內。其次可以詢問是否有較大腦下垂體腫瘤常有的症狀，如頭痛、視覺障礙。另外要找出使甲狀腺功能不足惡化的誘因，如寒流、飲酒、手術、感染、心肌梗塞、消化道心衰竭、出血、使用鎮定劑、麻醉、等等.
在實驗室數據的表現:除了T3、T4下降，TSH上升以外,血糖和血鈉可能會下降，膽固醇、
GOT、LDH、CPK可能會上升(CPK-MM 佔大部分)。
黏液水腫昏迷的治療以大量甲狀腺素靜脈注射治療為優先(T4
500-800μg投予，然後每天再給予100μg劑量)，靜脈注射T4比口服、皮下或肌肉注射好，因為病人在甲狀腺低下的狀態下吸收代謝不良，但臺灣目前沒有T4注射針劑，故本病人於初時治療採口服高劑量的eltroxin。使用甲狀腺素治療的同時，必須同時靜脈注射類固醇(補充劑量為solu-cortef
50 mg
Q6H)，因為甲狀腺功能過低，腎上腺類固醇的產生也會跟著下降，補充甲狀腺素時基礎代謝率回升，相對也會造成腎上腺功能不足。另外基於同樣的道理,
也要小心低血糖的發生，必要時得補充糖水。針對升血壓補充體液而言，不可以給低張的生理食鹽水，因甲狀腺低下時水的排出是有障礙的，如此會加重病況；必要時可以給升壓劑。而升高低體溫患者的體溫也很重要，一般建議用內在的加溫(internal
rewarming)，如用加溫過的生理食鹽水靜脈點滴注射，或經鼻胃管或肛管的溫水灌洗。至於使用外來的熱源體外加溫(external
rewarming)，則容易使週邊血管擴張而導致更嚴重的休克及心律不整，所以需要相當小心。一般而言，若對甲狀腺荷爾蒙的補充有反應，多半在24小時內可以見到體溫的回升。再者，應針對誘發黏液水腫昏迷的原因加以治療，尤其細菌感染，常見肺炎和尿道炎，通常病人體溫過低且白血球也不高，細菌感染很容易被忽略而引起敗血症致死。早期診斷、及時且適切的治療是照顧的重點。
<參考文獻>
- Wartofsky L. Myxedema coma. Endocrinol Metab Clin
North Am 2006;35:687-98
- Pimentel L, Hansen KN. Thyroid disease in the
emergency department: a clinical and laboratory review. J
Emerg Med 2005;28:201-9.
- Kearney T, Dang C. Diabetic and endocrine
emergencies. Postgrad Med J. 2007;83:79-86.
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Case Discussion
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