內科網路繼續教育試題解析-BN9001101

☆ 網路內科繼續教育 ☆
有效期間：民國 90年11月01日至 90年11月15日止

Case Discussion

A 43-year-old woman visited the outpatient clinic of a teaching hospital in December 2000 because of progressive exertional dyspnea for 5 years. She began to have occasional ventricular premature contractions (VPCs) when she was a young girl, but she did not pay attention to it. One episode of chest tightness with palpitation during exercise occurred 5 years ago, and her exertional dyspnea got worse thereafter.

She is a doctor of family medicine and the past medical history was otherwise not significant. The drug and family histories were non-contributory.

Physical examination showed normal blood pressure (120/80 mm Hg), regular heart beats (80 beats/min) without audible murmur and jugular vein engorgement was also noted. The chest radiograph showed normal heart size with bulging of pulmonary conus and enlarged bilateral pulmonary arteries (Figure 1 ). Chest CT showed dilatation of the central pulmonary artery and abrupt tapering of the distal branches of the pulmonary arteries . The electrocardiography revealed normal sinus rhythm, right ventricular (RV) strain pattern, S1Q3T3 and RV hypertrophy (RVH). The echocardiography showed dilated right atrium (RA) and RV. There were also moderate tricuspid regurgitation (TR) with a pressure gradient of 74 mm Hg and moderate pulmonary regurgitation (PR), suggesting severe pulmonary hypertension. The cardiac catheterization confirmed severe pulmonary hypertension which could be relieved by aerosolized prostacyclin (PGI₂) and oxygen. Serial examinations (see laboratory data below) did not find evidence of autoimmune disease or significant pulmonary thromboembolism. She was listed as a candidate for lung transplantation and continuous infusion of prostacyclin through a Hickmann catheter was started in June 2001.

Laboratory data:

1. CBC/DC:

	WBC	RBC	Hb	Hct	MCV	PLT
	K/uL	M/uL	G/dL	%	fL	K/uL
900402	5.44	3.69	12.7	36.9	100	165
900611	5.75	3.65	12.2	36.1	98.9	184

2. Coagulation:

	PT	PT Cont	INR	PTT	PTT Cont
	Sec	Sec		Sec	Sec
900402	12.5	11.7	1.0	34.4	33.8

3. Autoimmune Profile

	ANA	C3	C4
		mg/dl	mg/dl
900403	1:40 (-)	93.5	13.2

4. Biochemistry

	BUN	Cre	Na	K	T-Bil	D-Bil	GOT	GPT
	mg/dl	mg/dl	mmole/l	mmole/l	mg/dl	mg/dl	U/l	U/l
900402	17.1	0.8	139	4.0	1.0	0.3	18	14

5. ABG

	pH	PCO₂	PO₂	HCO_3-	BE	Condition
	*	mmHg	mmHg	mEq/l	mEq/l
900613	7.47	35.2	86.1	25.1	2.0	O2 cannula 3L/min

6. Cardiac echocardiography: LVEF 76%, Dilated RA & RV moderate TR (PG 74 mm Hg), moderate PR, pulmonary hypertension Dilated MPA (diameter 38 mm)

7. Lung function test

	Observed	Predicted	%Predicted
FVC(L):	3.21	2.86	112.39
FEV1.0(L):	2.53	2.49	101.69
% FEV1.0(%):	78.82	86.71
D^LCO:	17.30	20.37	84.94
V^A:	4.84	3.92	123.38
D^LCO/V^A	3.57	5.08	70.29

8. Lower legs venous duplex: normal

9. Tc99M MAA lung perfusion scan
Heterogeneous pulmonary uptake, without segmental perfusion defects

10. Cardiac catheterization:

Pressure	Before	O2	After PGI2 inhalation 20min	After pure O2 inhalation
RPAW	22	65%
RPA	88/32, 55
MPA	90/34, 54	65%	70/40	85/
RV	84/10	67%
RA	8	64%
SVC	4	63%

Cardiac output

Before

PGI2 inhalation

immediate

5min later

C.O. 3.52 L/min → 4.35 L/min → 3.78 L/min

病例分析
本病例為一原本看似身體健康的中年女性。過去曾有過幾次心律不整的情形，在五年前開始在戶外運動時有胸悶、心悸之情形，且上述症狀逐漸嚴重。她也發現在運動時會有頸靜脈怒張的情形，並產生呼吸困難的感覺。就醫後胸部X光顯示兩側肺動脈較大，心電圖上也顯示了右心擴大，心臟超音波上有肺動脈高壓的現象，可診斷有肺動脈高壓症。可能原因有心臟疾患、慢性肺栓塞、肺實質疾患、結締組織疾患、肝硬化合併肺動脈高壓，以及減肥藥的使用等等。而在經過一系列檢查後，並未發現明顯造成肺高壓的原因，所以應為原發性肺動脈高壓症 (PPH)。在治療上本病例在實施心導管時其肺動脈高壓及心輸出量對prostacyclin反應不錯，因此先接受由Hickman導管連續靜脈輸注此藥來降低肺動脈壓及增加心輸出量，待有機會再接受肺移植。Prostacyclin為目前唯一可改善PPH病人生活品質及存活率之藥物。但其在血中半生期甚短(只有數分鐘)。故需連續由中心靜脈輸注，使用相當不方便。副作用包括顏面潮紅、拉肚子、血壓下降、心跳速率變慢等。且萬一消毒不慎可能形成菌血症或敗血性休克。

繼續教育考題

1.
(A) Which of the following parameters is typically impaired in PPH EXCEPT

A FEV₁

B Pulmonary diffusion capacity (DLco)

C O₂ saturation on exercise

D Cardiac output

2.
(D) Which of the following features is common in advanced PPH?

A Chest pain

B Syncope

C Sudden death

D All of above

3.
(D) Which of the following tests is not helpful to screen the pulmonary hypertension?

A Standard chest radiography

B Electrocardiography

C Transthoracic Doppler echocardiography

D Spironmetry (FEV1 and FVC)

4.
(B) Which of the following descriptions about PPH is WRONG?

A The CxR frequently shows enlarged hilar structures (main pulmonary arteries)

B The ECG abnormalities often reflect LV and left atrial enlargement.

C Physical examination often reveals jugular venous distention and RV heave

D A systolic murmur along the left sternal border that increases in intensity during inspiration (tricuspid regurgitation) is common in these patients

5.
(D) Which of the following conditions may lead to pulmonary hypertension?

A Connective tissue disorder

B Obstructive sleep apnea

C Chronic pulmonary embolism;

D All of the above

6.
(D) Which of the following ECG patterns is NOT typical of PPH?

A A tall R wave and small S wave in lead V1

B A tall S wave with small R wave in lead V5 or V6 (R/S ratio <1),

C P waves greater than 2.5 mm in leads II, III, and aVF.

D ST-segment depressions and T-wave inversions in V5, V6 and aVL

7.
(D) Which of the following descriptions about PPH is correct?

A The pulmonary arterial pathology in PPH include medial hypertrophy, intimal proliferation, in situ thrombosis, fibrosis, and "plexogenic" changes

B Definitive diagnosis requires direct pulmonary artery pressure measurements via right heart catheterization

C A mean pulmonary artery pressure greater than 25 mmHg at rest (>30 mmHg with exercise) represents the standard for the diagnosis of PH.

D All of the above

8.
(B) Which statement about PPH is WRONG? (based on data from NIH)

A The mean age was 45 years (age range, 15-66 years);

B The incidence in male patients is higher than that in the female patients

C The median survival was 5-8 years after diagnosis

D Survival was associated with 3 factors: right atrial pressure, mean pulmonary artery pressure, and cardiac index

9.
(D) Which kind of treatment is recommended for primary pulmonary hypertension?

A Lung transplantation (single lung, bilateral lung, or heart-bilateral lung)

B The mainstay of pharmacological therapy is a combination of vasodilatation and anticoagulation for patients without other treatable secondary conditions

C IV prostacyclin (epoprostenol) has been approved by the FDA for PPH

D All of above

10.
(D) Which statement below is WRONG about the intravenous prostacyclin for the treatment of PPH?

A Is associated with short-term improvement in pulmonary hemodynamics, including reducing PA pressure and PVRI and increasing cardiac output

B Must be administered into a central vein via a 24-hour continuous infusion pump because of its extremely short half-life of 2 to 3 minutes.

C Also has anti-platelet aggregating effects and may cause diarrhea

D This drug can lead to long-term survival in most patients with PPH

答案解說

答案解說:

(A) PPH is a condition in which pulmonary vasculature is involved. Pulmonary gas exchange is impaired, especially during exercise when the demand of cardiac output is greatly increased. The FEV1 is a parameter for airway patency and therefore not often reduced in these patients.

(D) All descriptions are correct. PPH can result in right-sided heart failure and death. Advanced PH, regardless of the cause, can be associated with chest pain, syncope, and sudden death

(D)Spirometry (FEV1) is not useful in the screening of PPH. See Question 1 for the reasons.

(B) ECG: the rhythm is usually sinus; electrical abnormalities reflect RV and right atrial enlargement.

(D) Conditions that may leads lead to pulmonary hypertension include primary cardiac abnormalities, obstructive sleep apnea, chronic pulmonary embolism, pulmonary parenchymal problems, connective tissue disorders, cirrhosis with portal hypertension, and use of appetite suppressants

(D) Criteria for RV hypertrophy include a tall R wave and small S wave in lead V1 (R >7 mm, S <2 mm, and R/S ratio >1), a tall S wave with small R wave in lead V5 or V6 (R/S ratio <1), and right axis deviation (QRS axis > 90°). ST-segment depressions and T-wave inversions in the anterior leads (V1 through V4) suggest severe right-sided heart strain. Right atrial enlargement is suggested by P waves greater than 2.5 mm in leads II, III, and aVF.

(D) All descriptions are correct

(B) A National Institutes of Health Registry (N=187) for primary PH resulted in several published summaries. The mean age was 45 years (age range, 15-66 years); 62% were females. With use of regression analysis, survival was associated with 3 factors: right atrial pressure, mean pulmonary artery pressure, and cardiac index (cardiac output adjusted for body surface area). The median survival was 2.5 years after diagnosis.

(D) All descriptions are correct.

(D) Intravenous prostacyclin (epoprostenol) may be effective in selected patients with PPH. In addition to being a pulmonary vasodilator, it has antiplatelet aggregating effects and may facilitate pulmonary vascular remodeling of occluded arterial beds. This medication is administered into a central vein through a Hickman catheter via a 24-hour continuous infusion pump because of its extremely short half-life of 2 to 3 minutes. Epoprostenol has been associated with improvements in pulmonary hemodynamics. In some patients with PPH, survival has increased with long-term use of epoprostenol.

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