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二尖瓣脫垂與自律神經疾病

台中榮民總醫院 心血管中心

何鴻鋆醫師

二尖(僧帽)瓣脫垂

解剖位置

僧帽瓣(又稱二尖瓣)位於心臟左心房及左心室間，心舒張期時，血液由左心房流向左心室，心收縮期時，僧帽瓣則關閉。

僧帽瓣脫垂

僧帽瓣瓣膜或相關器官中組織發生病變，致使瓣膜鬆大，鍵索變長等變化。

原因:多為原發的，即先天造成。由於上述之病理變化，致使僧帽瓣在心收縮期時，突向左心房側

正常僧帽瓣 (圖1)僧帽瓣脫垂

(圖2)

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病理解剖

僧帽瓣黏液瘤性(myxomatous)變性造成過多黏多醣囤積，進而使瓣膜與肌腱索拉長. 在左心室正常大小時即可能發生。可能在健康女性脫水時產生，水分補足後消失。在懷孕或體重增加後可能消失. 可能與fibrillin基因異常有關. 引發症狀相關異常：

對腎上腺刺激敏感度增加、增加catecholamines、異常乙型接受器、增加atrial natriuretic factor, renin-aldosterone 調節異常、減少血管內容量、鎂離子缺乏…

發生率

目前僧帽瓣脫垂已是最常見的瓣膜性心臟病。

發生率約為2-5%男女之比為1:2~3。尤好發於身材瘦長或胸廓畸型者。

開始症狀年齡: 10-16歲.很少在青春期以前發生

症狀

大部份是没有症狀的，通常是在醫師為病患聽診時意外發現而診斷。

少部份有症狀，臨床表現則相當多樣，包括了呼吸不順暢、非典型心絞痛、心悸、不整脈、緊張焦慮、疲倦、自律神經失調、昏厥等。

少數病患併發嚴重閉鎖不全及心臟功能變化時，也會產生心臟衰竭的相關症狀。十分罕見的病患，會以猝死或暫時性腦部缺氧來表現。

身體檢查發現瘦細體型、骨骼異常 (如漏斗胸、背直､脊柱後側凸)休息時心緩脈與姿勢性低血壓心臟聽診

收縮期clicks心尖聽到l mid-to-late systolic murmur.Click與心雜音會隨姿勢改變.

僧帽瓣閉鎖不全自律神經失調神經內分泌功能異常Ehlers-Danlos症候群表現(如：關節活動異常, 異常abnormal striae, 淤青, 皮膚炎展能力)骨發生不全Osteogenesis imperfecta 徵象 (如：藍色鞏膜)Marfan症候群徵象： 脊柱側凸､背直､漏斗胸､蜘蛛狀指, 手張開比身高高Stickler症候群徵象： (如：駝背､脊柱側凸､mandibular發育不全､視網膜剝離)

死亡率、罹病率

一般而言是良性疾病。

主要獨發性僧帽瓣閉鎖不全原因(MR)90% chordae tendineae斷裂原因40%年輕型中風10-15% 心內膜炎(endocarditis)有結構異常患者 (如僧帽瓣增厚、變形、過長) 較易有併發症 (如僧帽瓣閉鎖不全惡化、心內膜炎、猝死). 合併有心雜音一般死亡率增加15-20%.

檢查

診斷方法除了聽診之外，心臟超音波為診斷僧帽瓣脫垂症候群最有力及準確的工具。

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處理治療原則為針對症狀處理，無法根治。無症狀者，僧帽瓣脫垂症候群患者應避免熬夜、吸菸、喝酒及咖啡等較刺激性的飲食一般日常生活及運動没有特別限制。對於心悸、胸痛不適、焦慮、交感神經系統亢進或疲倦感較明顯的患者，使用乙型交感神經阻斷劑及鎮定劑的治療效果不錯。少數臨床上懷疑有心律不整的患者可以接受24小時心電圖檢查，如有適應症，之後亦可安排心臟電氣生理檢查。如有心房纖維顫動、暫時性腦部缺氧或中風時，可以使用阿斯匹靈或抗凝血劑來預防栓塞症的再次發生。當極少數病患會產生重度僧帽瓣閉鎖不全，心內膜炎，複雜性心室心律不整及暫時性腦缺血，則應由心臟專科醫師做特別處理。

危險分級臨床表徵處置原則

低度危險:無收縮期心雜音心臟超音波無僧帽瓣逆流女性＜45歲

對病人說明病情，無需使用預防性抗生素心超音波每五年追蹤一次

中度危險:有收縮期心雜音心臟超音波有輕度僧帽瓣逆流

需使用預防性抗生素心臟超音波每二至三年追蹤一次

高度危險:心臟超音波有中重度僧帽瓣逆流需使用預防性抗生素每年追蹤一次心臟超音波如有心衰竭症狀，考慮手術治療

自律神經疾病

自律神經系統 Autonomic Nervous System自律神經系統 (ANS)以協調方式控制體內環境

利用反射機制(reflex action) ，ANS控制心跳、血壓、消化、呼吸、血中酸鹼平衡等等身體功能。

In the ANS there are 2 nerves between the central nervous system (CNS) and the organ. The nerve cell bodies for the second nerve are organized into ganglia:

CNS -> Preganglionic nerve -> Ganglion -> Postganglionic nerve -> Organ

At each junction neurotransmitters are released and carry the signal to the next nerve or organ.

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The ANS has 2 Divisions, Sympathetic and Parasympathetic, Which Differ in Anatomy and Function

The sympathetic nerves come from the thoracic and lumbar regions of the spinal cord. The preganglionic nerves are short and synapse in paired ganglia adjacent to the spinal cord The adrenal medulla, technically an endocrine gland, is functionally a part of the sympathetic nervous system

Adrenal medulla is like a modified autonomic ganglion + postsynaptic nerve (see diagram below)

Parasympathetic nerves come from the cranial and sacral regions of the CNS. They have long preganglionic nerves which synapse at ganglia near or on the organ innervated The 2 branches use the same transmitter, acetylcholine (ACh), in the ganglia. At the organ quite different transmitters are used: Parasympathetic = AChSympathetic = norepinephrine (NE). Note: norepinephrine is the same thing as noradrenaline.

Note: there are a few sympathetic nerves where the transmitter at the organ is AChSympathetic fibers releasing ACh: sweat glands, piloerector muscles, some blood vessels

Comparison of the 2 systems

The Sympathetic is the "Fight or Flight" Branch of the ANS

Emergency situations, where the body needs a sudden burst of energy, are handled by the sympathetic system The sympathetic system increases cardiac output and pulmonary ventilation, routes blood to the muscles, raises blood glucose and slows down digestion, kidney filtration and other functions not needed during emergencies Whole sympathetic system tends to "go off" together In a controlled environment the sympathetic system is not required for life, but it is essential for any stressful situation

The Parasympathetic is the "Rest and Digest" Branch of the ANS

The parasympathetic system promotes normal maintenance of the body- acquiring building blocks and energy from food and getting rid of the wastes It promotes secretions and mobility of different parts of the digestive tract. Also involved in urination, defecation. Does not "go off" together; activities initiated when appropriate The vagus nerve (cranial number 10) is the chief parasympathetic nerve Other cranial parasympathetic nerves are: III (oculomotor), VII (facial) and IX (glossopharyngeal)

The Hypothalamus Has Central Control of the ANS

The hypothalamus is involved in the coordination of ANS responses, One section of the hypothalamus seems to control many of the "fight or flight" responses; another section favors "rest and digest" activities

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The Adrenal Medulla is an Extension of the Sympathetic Nervous System

The adrenal medulla behaves like a combined autonomic ganglion and postsynaptic sympathetic nerve (see diagram above) Releases both norepinephrine and epinephrine in emergency situations

Releases a mixture of epinephrine (E = 80%) and norepinephrine (NE = 20%) Epinephrine = adrenaline

This action is under control of the hypothalamus

Comparison of the Actions if the Sympathetic & Parasympathetic Systems

Usually (but not always) both sympathetic and parasympathetic nerves go to an organ and have opposite effects You can predict about 90% of the sympathetic and parasympatheticresponses using the 2 phrases: "Fight or Flight" and "Rest and Digest". Special cases: Occasionally the 2 systems work together: in sexual intercourse the parasympathetic promotes erection and the sympathetic produces ejaculation Eye: the sympathetic response is dilation and relaxation of the ciliarymuscle for far vision (parasympathetic does the opposite) Urination: the parasympathetic system relaxes the sphincter muscle and promotes contraction of muscles of the bladder wall -> urination (sympathetic blocks urination) Defecation: the parasympathetic system causes relaxation of the anal sphincter and stimulates colon and rectum to contract -> defecation (sympathetic blocks defecation

Autonomic nerve symptoms A

Autonomic neuropathy ... autonomic nervous systemD

Dysautonomia ... autonomic nervous systemG

Gastroparesis ... autonomic nervous systemH

Horner's syndrome ... sympathetic nervous systemN

Neuropathy ... autonomic nervous systemV

Vascular neuropathy ... autonomic nervous system

Autonomic neuropathyDisease of the autonomic (involuntary) nervous system.

Causes of autonomic neuropathyDiabetesHereditary sensory and autonomic neuropathy type 2 Hereditary sensory and autonomic neuropathy type 5 Amyloid polyneuropathy (Portuguese) Fabry's disease Achalasia-addisonian syndrome AmyloidosisBradbury-Eggleston syndrome Paraneoplastic limbic encephalitis

Dysautonomiafailure of the sympathetic or parasympathetic components of the ANS, but dysautonomiainvolving excessive ANS activities also can occur. Causes:

Guillain-Barre Syndrome Diabetes Alcoholism Multiple system atrophy Familial dysautonomiaAutonomic neuropathy

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GastroparesisSlow stomach emptying from stomach nerve damage a disorder in which the stomach takes too long to empty its contents. most often a complication of type 1 diabetes. At least 20% of people with type 1 diabetes develop gastroparesis. It also occurs in people with type 2 diabetes, although less often. Gastroparesis happens when nerves to the stomach are damaged or stop working. If the vagus nerve is damaged, the muscles of the stomach and intestines do not work normally, and the movement of food is slowed or stopped.

Gastroparesis -- causesFunctional gastroparesisType 1 diabetes Type 2 diabetes Gallbladder disease PancreatitisPostviral syndromes Anorexia nervosa Stomach damage Stomach surgery Vagus nerve surgery

Gastroesophageal reflux disease Stomach cancer Smooth muscle disorders AmyloidosisScleroderma Abdominal migraine Parkinson's disease Metabolic disorders Hypothyroidism

Horner's syndromeA syndrome associated with defective sympathetic innervation to one side of the face, including the eye. Clinical features include miosis; mild blepharoptosis; and hemifacial anhidrosis(decreased sweating). lesions of the brain stem; cervical spinal cord; first thoracic nerve root; apex of the lung; carotid artery; carvernous sinus; and apex of the orbit may cause this condition.

From Miller et al., Clinical Neuro-Ophthalmology, 4th ed, pp500-11

Horner's syndromeA syndrome associated with defective sympathetic innervation to one side of the face, including the eye. Clinical features include miosis; mild blepharoptosis; and hemifacial anhidrosis(decreased sweating). lesions of the brain stem; cervical spinal cord; first thoracic nerve root; apex of the lung; carotid artery; carvernous sinus; and apex of the orbit may cause this condition.

From Miller et al., Clinical Neuro-Ophthalmology, 4th ed, pp500-11

Horner's syndrome -- causesAortic aneurysm, thoracic Neurofibromatosis type 1 GoitreDissecting aortic aneurysm Thyroid carcinoma Bronchogenic carcinoma Multiple sclerosis

Cluster headache Carotid artery dissection Klumpke paralysis Cavernous sinus thrombosis SympathectomyPosterior inferior cerebellar artery syndrome Syringomyelia

Neuropathy:Any pathology of the peripheral nerves Causes:

Diabetic peripheral neuropathy Diabetes Type 1 diabetes Type 2 diabetes Charcot-Marie-Tooth syndrome

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Vascular neuropathyVascular neuropathy is Neuropathy of the autonomic nerves that control the blood vessels, leading them not to properly constrict and expand to control BP. Causes:

Diabetic neuropathy ‧Type 1 diabetes ‧Type 2 diabetes

Thanks for your attention