<Case
Presentation>
A 56-year-old female was admitted due to an episode of
syncope one day prior to admission.
The patient did not have hypertension, diabetes mellitus or
other systemic diseases. Occasional chest discomfort and
dyspnea on exertion have been noted for two days and she was
treated at a local hospital. One day before admission, a spell
of syncope occurred with a duration of less than 5 minutes and
right cheek hematoma on account of falling to the ground at
home. There was no aura, incontinence, convulsion,
nausea/vomiting or limb weakness. Then she was sent to our
emergency department for further evaluation.
On arrival, the patient looked weak
and irritable. Consciousness was clear. The body temperature
was 35.5°C, the pulse rate was 103 beats per minute, and the
respiration rate was 22 per minute. Blood pressure was 148/85
mmHg. Jugular venous pressure with estimated 8
cmH2
O, clear breathing sounds
and regular heart beats without murmurs were found on physical
examination. Liver was palpable 3 finger breath below right
subcostal margin along right midclavicle line. There was no
leg pitting edema.
Sinus tachycardia with non-specific
ST-T change was noted on EKG. CXR showed borderline
cardiomegaly. Blood gas analysis under FiO2: 30% showed: PH:
7.38, PO2: 94.7, PCO2: 31.5,
HCO3: 18, BE: -5.5 and O2 saturation:
97.2%. Because neurogenic syncope could not be ruled
out, brain CT scan was arranged and it showed negative finding.
Holter EKG study disclosed sinus rhythm from 56 to 140
beats per minute and no significant ST change. Pulmonary embolism
was highly suspected. D-D dimer test was 349 μg/L (normal
range: <250 μg/L). Echocardiography revealed dilated right
ventrcile, adequate left ventricular performance and moderate
tricuspid regurgitation. Thereafter lung perfusion study was
performed and it was suggestive of high probability of
pulmonary embolism. Computed tomography (CT) showed pulmonary
embolism in both-side pulmonary arteries at the hilar region
and bilateral lower lobes (figure
1
).
Table 1. Hematologic Laboratory
Values:
RBC |
Hb |
Hct |
MCV |
PLT |
WBC |
D-D dimmer test |
M/L |
g/dL |
% |
fL |
K/L |
K/L |
ug/L |
3.77 |
11.8 |
34.9 |
92.4 |
257 |
6.6 |
349 |
Protein S |
Protein C |
Antithrombin III |
%(70-140) |
%(77-158) |
%(78-151) |
43.3 |
69 |
108 |
Table 2. Biochemistry Values:
BUN |
Cr |
Na |
K |
Sugar |
GOT |
GPT |
mg/dL |
mg/dL |
mEq/L |
mEq/L |
mg/dL |
IU/L |
IU/L |
28.8 |
1.12 |
144 |
4.00 |
120.7 |
59.0 |
92.5 |
Intravenous heparin was administered upon a high
index of suspicion of pulmonary embolism and warfarin was also
given simultaneously after the documentation of pulmonary
embolism. rt-PA was infused after the finding of massive
pulmonary embolism on chest CT. Finally the patient was
discharged under stable condition after 2-week treatment.
Figure
1. Image from CT pulmonary
angiogram. Large clot (arrows) is present at the left and
right pulmonary arteries.
<個案分析>
本病人是pulmonary embolism的病例, 臨床上以昏厥來表現,但大部分pulmonary
embolism的病人是以喘來表現, pulmonary embolism的病人有其危險因子,包括surgery,
trauma, immobilization, obesity, old age, 服用contraceptives,
pregnancy, cancer, cancer therapy, previous stroke or spinal
cord injury, indwelling central venous catheter,
obesity及immobilization是導致venous
stasis及thromboembolism的重要機轉。另外重要的risk
factors包括antithrombin-III deficiency, protein C or S
deficiency, factors V Leiden mutation等,在無明確risk
factors情形下,值得進一步評估。
病人呼吸沒有明顯囉音或哮喘音,給O2,PaO2不高,同時hyperventilation造成PaCO2下降。EKG多半是
sinus tachycardia,典型有S1Q3T3, 但不多見. 病人D-D dimer > 500
μg/L,可以高度懷疑pulmonary embolism。D-D dimer
data若<500μg/L,可以用來rule out pulmonary embolism,有 > 90%
negative predictive value。若 > 500μg/L,則建議進一步做venous
thromboembolism的診斷評估。而D-D dimer
data由於infection,tumor等疾病都會引起D-D dimer上升,D-D dimer <
500μg/L, pulmonary embolism的比率 <
10%,因此對診斷幫助較少,但也不能完全排除pulmonary
embolism的可能性,這個病人就是這樣的狀況。Venous echo在acute pulmonary
embolism診斷陽性率只有50%,如果是陽性則支持acute pulmonary
embolism的診斷。如果陰性則不排除acute pulmonary embolism的診斷。
Pulmonary embolism的治療以抗凝血劑為主,包括heparin (LMWH or
unfractionated heparin) and warfarin
(coumadin),合併使用,待warfarin效應出現後,可停用heparin, warfarin則維持PT(INR):
2-3. 至於thrombolytic agents則使用於 RV failure or unstable
hemodynamics,至於massive pulmonary embolism則沒有規定一定非使用不可.
如何預防再發生acute pulmonary embolism: 1.改善acute pulmonary
embolism 的 risk factors,增加活動量,減少體重, 2. 使用口服凝血劑warfarin,追蹤PT
(INR) 維持在 2 – 3,持續半年或以上, 3. 如果病人 risk factors
是永久性的話,或反覆發生acute pulmonary embolism,則warfarin終生使用. 目前在NEJM
2003有關於預防recurrent venous
thromboembolism的研究,發現warfarin使用半年後,在持續使用低劑量warfarin,INR 1.5 ~
2.0,可以有效且安全減少venous
thromboembolism的復發。穿彈性襪也是一個可行的方法。
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