Mediastinum lect

8/7/2019 Mediastinum lect

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Mediastinal diseasesMediastinal diseases::

clinical and surgical aspectsclinical and surgical aspects


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The mediastinumThe mediastinum is a nonis a non--delineated groupdelineated group

of structures in the thorax, surrounded byof structures in the thorax, surrounded byloose connective tissue. It is the centralloose connective tissue. It is the centralcompartment of the thoracic cavity.compartment of the thoracic cavity.

It contains:It contains:

the heart,the heart,

the great vessels of the heart,the great vessels of the heart,

esophagus,esophagus,

trachea,trachea,phrenic nerve, cardiac nerve,phrenic nerve, cardiac nerve,

thoracic duct,thoracic duct,

thymus,thymus,

and lymph nodes of the central chestand lymph nodes of the central chest


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AnatomyAnatomy

The mediastinum liesThe mediastinum lies

between the right andbetween the right and

left pleur in andleft pleur in and

near the mediannear the mediansagittal plane of thesagittal plane of the

chest.chest.


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AnatomyAnatomy

superior mediastinumsuperior mediastinum --

above the upper level ofabove the upper level of

the pericardiumthe pericardium

lower portionlower portion thethe anterior mediastinumanterior mediastinum;;

that containing the pericardiumthat containing the pericardium

and its contentsand its contents

thethe middle mediastinummiddle mediastinum

thethe posterior mediastinumposterior mediastinum


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Superior MediastinumSuperior Mediastinum

It contains:It contains:

the origins of the Sternohyoidei and Sternothyreoidei andthe origins of the Sternohyoidei and Sternothyreoidei andthe lower ends of the Longi colli;the lower ends of the Longi colli;

the aortic arch; the innominate artery and the thoracicthe aortic arch; the innominate artery and the thoracicportions of the left common carotid and the leftportions of the left common carotid and the leftsubclavian arteries; the innominate veins and the uppersubclavian arteries; the innominate veins and the upperhalf of the superior vena cava; the left highest intercostalhalf of the superior vena cava; the left highest intercostalvein;vein;

the vagus, cardiac, phrenic, and left recurrent nerves;the vagus, cardiac, phrenic, and left recurrent nerves;

the trachea,the trachea,esophagus, and thoracic duct;esophagus, and thoracic duct;

the remains of the thymus,the remains of the thymus,

and some lymph glands.and some lymph glands.


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AnatomyAnatomyTheThe Anterior MediastinumAnterior Mediastinum

a quantity of loose areolar tissue,a quantity of loose areolar tissue,

some lymphatic vessels, two or threesome lymphatic vessels, two or threeanterior mediastinal lymph glands,anterior mediastinal lymph glands,

and the small mediastinal branchesand the small mediastinal branchesof the internal mammary arteryof the internal mammary artery

TheThe Middle MediastinumMiddle Mediastinumheart enclosed in the pericardium,heart enclosed in the pericardium,

ascending aorta,ascending aorta,

superior vena cava with the,superior vena cava with the,

the bifurcation of the trachea and thethe bifurcation of the trachea and thetwo bronchi, the pulmonary artery,two bronchi, the pulmonary artery,

the phrenic nerves,the phrenic nerves,TheThe Posterior MediastinumPosterior Mediastinum

descending aorta,descending aorta,

azygos and hemiazygos veins,azygos and hemiazygos veins,

vagus and splanchnic nerves,vagus and splanchnic nerves,

esophagus,esophagus,

thoracic duct, lymph glands.thoracic duct, lymph glands.


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MediastinoscopyMediastinoscopyMediastinoscopy with biopsyMediastinoscopy with biopsyis a procedure in which ais a procedure in which a

lighted instrumentlighted instrument

(mediastinoscope) is inserted(mediastinoscope) is inserted

through the neck to examinethrough the neck to examine

the structures in the top ofthe structures in the top of

the chest cavity, and athe chest cavity, and a

sample of tissue is taken.sample of tissue is taken.


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Anterior mediastinotomyAnterior mediastinotomy


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Posterior mediastinotomyPosterior mediastinotomy


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VideoVideo--assisted thoracoscopyassisted thoracoscopy


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Sternotomy and thoracotomySternotomy and thoracotomy


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Classification of mediastinumClassification of mediastinum

diseasesdiseasesInjury ofInjury of mediastinal organsmediastinal organs

Inflammation ofInflammation of mediastinal organs andmediastinal organs and

tissuetissue

Mediastinal tumorsMediastinal tumors


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75% of chest traumas due to blunt or75% of chest traumas due to blunt or

penetrating injuries are accompanied bypenetrating injuries are accompanied byinjuries of other organ systems.injuries of other organ systems.

Cardiac injuries take place as high as 64%Cardiac injuries take place as high as 64%

in cases of thoracic organ injuriesin cases of thoracic organ injuriesBlunt cardiac injuries are seen in 9 to 38%Blunt cardiac injuries are seen in 9 to 38%

of cases with severe thoracic traumaof cases with severe thoracic trauma

There is a pathological condition seenThere is a pathological condition seen

after blunt cardiac injury which is calledafter blunt cardiac injury which is called

myocardial concussion.myocardial concussion.


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Myocardial injury may appear:Myocardial injury may appear:

lifelife--threatening arrhythmias,threatening arrhythmias,

anomalies of conduction system,anomalies of conduction system,

congestive heart failure,congestive heart failure,

cardiogenic shock,cardiogenic shock,hemopericardium, pericardial tamponade,hemopericardium, pericardial tamponade,

cardiac rupture, valvular rupture,cardiac rupture, valvular rupture,

intraventricular thrombus, thromboemboli,intraventricular thrombus, thromboemboli,

coronary artery occlusion,coronary artery occlusion,ventricular aneurysmventricular aneurysm

and constrictive pericarditis.and constrictive pericarditis.


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Signs and diagnosisSigns and diagnosis

Beck's triadBeck's triad

cardiac tamponadecardiac tamponade

jugular venous distension,jugular venous distension,hypotensionhypotension

faint heart soundsfaint heart sounds

urgent pericardialurgent pericardial

puncture should be carriedpuncture should be carried


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cardiac tamponadecardiac tamponade

If the patient was taken to the operating room

and the pericardium was opened to remove blood,the bleeding sites of myocardium should be

localized and repaired


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Urgent surgeryUrgent surgery

Absolute indications:Absolute indications:cardiac arrest due tocardiac arrest due totamponade or exsanguinationstamponade or exsanguinations

continued haemorrhage:continued haemorrhage:

immediate blood loss fromimmediate blood loss fromchest drain > 1500 ml of totalchest drain > 1500 ml of totalblood volume. Loss > 500 ml inblood volume. Loss > 500 ml infirst hr. or 200 ml/hr thereafterfirst hr. or 200 ml/hr thereafteris also an indication foris also an indication forthoracotomy. Decision tothoracotomy. Decision to

operate should be made earlyoperate should be made earlybefore occurrence of abefore occurrence of adilutional coagulopathydilutional coagulopathy

dangerous predicteddangerous predictedtrack/mediastinal traversingtrack/mediastinal traversing

massive air leakmassive air leak

Relative indications:Relative indications:thoracoabdominal injurythoracoabdominal injury

bullet embolismbullet embolism

highhigh--velocity gunshot woundvelocity gunshot wound

missile retrieval.missile retrieval.

RelativeRelativecontraindications:contraindications:

cardiac contusioncardiac contusion

pulmonary parenchymalpulmonary parenchymalcontusioncontusion

pneumomediastinum (withoutpneumomediastinum (withoutother injury).other injury).


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Central venous pressure (CVP)Central venous pressure (CVP)

If a patient is in shockIf a patient is in shockor preshock conditionor preshock conditionand his/her centraland his/her centralvenous pressurevenous pressure(CVP) is more than(CVP) is more than

12 mm Hg,12 mm Hg,pericardiocentesispericardiocentesis

should be carried outshould be carried out


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Signs and diagnosisSigns and diagnosis

CKCK--MB isoenzymes, Cardiac troponinMB isoenzymes, Cardiac troponin

radioisotope scanning,radioisotope scanning,

continuous ECG monitoring,continuous ECG monitoring,echocardiographyechocardiography

and cardiac catheterizationand cardiac catheterization


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ECG changes:ECG changes:

reveal ST segment elevations and branchreveal ST segment elevations and branchblocks.blocks.

ST segment elevations are thought to be due toST segment elevations are thought to be due to

transient myocardial ischemia or coronarytransient myocardial ischemia or coronaryarterial spasm.arterial spasm.

Any type of arrhythmia and ST segmentAny type of arrhythmia and ST segmentchanges may be seen.changes may be seen.

Sinus tachycardia,Sinus tachycardia,atrial flutter or atrial fibrillation are the mostatrial flutter or atrial fibrillation are the mostcommon ones.common ones.


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EchocardiographyEchocardiography

detecting hemopericardiumdetecting hemopericardium

Echocardiographic view of theEchocardiographic view of the

fresh thrombus surrounding thefresh thrombus surrounding the

heart in a case with right atrialheart in a case with right atrial

rupture due to blunt cardiacrupture due to blunt cardiac

trauma after vehicular accidenttrauma after vehicular accident

View of the acute cardiacView of the acute cardiac

tamponadetamponade


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Esophageal InjuryEsophageal InjuryEsophageal tears are estimatedEsophageal tears are estimatedto occur in 1% of patients withto occur in 1% of patients with

blunt trauma, but they are farblunt trauma, but they are far

more common with penetrating ormore common with penetrating or

iatrogenic trauma.iatrogenic trauma.Esophageal rupture carries a highEsophageal rupture carries a high

mortality rate secondary to rapidlymortality rate secondary to rapidly

developing mediastinitis.developing mediastinitis.

Survival improves dramatically ifSurvival improves dramatically if

the esophageal injury isthe esophageal injury is

recognized and treated within 24recognized and treated within 24

hours of its occurrencehours of its occurrence


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Esophageal InjuryEsophageal Injury

Clinical presentation of esophageal tears/ruptureClinical presentation of esophageal tears/rupture

includes hematemesis, chest pain, dysphagia,includes hematemesis, chest pain, dysphagia,

odynophagia and rapid onset of sepsis, fever,odynophagia and rapid onset of sepsis, fever,

tachycardia, hypotension and shock.tachycardia, hypotension and shock.Patients often complain of sudden, sharpPatients often complain of sudden, sharp

epigastric pain radiating to the interscapularepigastric pain radiating to the interscapular

area. Dyspnea, cyanosis, and shock are latearea. Dyspnea, cyanosis, and shock are late

symptomssymptoms


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Esophageal InjuryEsophageal InjuryDiagnostic ModalityDiagnostic Modality CT findings of esophagealCT findings of esophageal

rupture include focalrupture include focal

extraluminal airextraluminal air

collections at the site ofcollections at the site of

tear and a hematoma oftear and a hematoma ofthe mediastinal orthe mediastinal or

esophageal wallesophageal wall

CT findings in esophagealCT findings in esophageal

perforation can beperforation can be

summarized as follows:summarized as follows:

Extraluminal air in theExtraluminal air in the

mediastinum/surrounding themediastinum/surrounding the

esophagus is the mostesophagus is the most

reliable sign and when takenreliable sign and when taken

in conjunction with the clinicalin conjunction with the clinical

presentation has 92%presentation has 92%accurac .accurac .


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Esophageal perforations that are treatedEsophageal perforations that are treatedsurgically within 24 hours have goodsurgically within 24 hours have goodresults.results.

The outcome obviously depends onThe outcome obviously depends oncomorbidity and to whether postoperativecomorbidity and to whether postoperativepulmonary complications occur.pulmonary complications occur.

Even with prompt therapy, the mortalityEven with prompt therapy, the mortalityrate is high, varying from 30rate is high, varying from 30--50%.50%.


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With delay in diagnosis, the mortality rateWith delay in diagnosis, the mortality rate

exceeds 90%. Mortality rates from perforationexceeds 90%. Mortality rates from perforation

caused by instrumentation are lower than othercaused by instrumentation are lower than other

causes (15causes (15--20%), although clearly still notable.20%), although clearly still notable.Vertebral osteomyelitis has been reported inVertebral osteomyelitis has been reported in

association with penetrating and after bluntassociation with penetrating and after blunt

traumatic esophageal rupture.traumatic esophageal rupture.


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Mediastinitis is inflammation of the tissues inMediastinitis is inflammation of the tissues in

the midthe mid--chest, or mediastinumchest, or mediastinum

Acute mediastinitisAcute mediastinitis is usually bacterial and dueis usually bacterial and dueto rupture of organs in the mediastinum.to rupture of organs in the mediastinum.

Chronic sclerosingChronic sclerosing (or fibrosing)(or fibrosing)

mediastinitismediastinitis, is caused by a long, is caused by a long--standingstandinginflammation of the mediastinum, leading toinflammation of the mediastinum, leading togrowth of acellular collagen and fibrous tissuegrowth of acellular collagen and fibrous tissuewithin the chest and around the central vesselswithin the chest and around the central vesselsand airways.and airways.

It has a different cause, treatment, andIt has a different cause, treatment, andprognosis than acute infectious mediastinitis.prognosis than acute infectious mediastinitis.


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MediastinitisMediastinitis

Acute mediastinitisAcute mediastinitis is usually bacterialis usually bacterialand due to rupture of organs in theand due to rupture of organs in themediastinum.mediastinum.

Chronic sclerosing (or fibrosing)Chronic sclerosing (or fibrosing)mediastinitismediastinitis , is caused by a long, is caused by a long--standing inflammation of the mediastinum,standing inflammation of the mediastinum,leading to growth of acellular collagen andleading to growth of acellular collagen andfibrous tissue within the chest and aroundfibrous tissue within the chest and aroundthe central vessels and airways.the central vessels and airways.


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Acute mediastinitisAcute mediastinitis

causes mediastinitiscauses mediastinitis

cardiovascular orcardiovascular or

endoscopic surgicalendoscopic surgicalproceduresprocedures

A procedure such asA procedure such asendoscopyendoscopy

Forceful or constantForceful or constantvomitingvomiting

TraumaTrauma

Other causes ofOther causes ofmediastinitismediastinitis

CancerCancerHistoplasmosisHistoplasmosis

RadiationRadiation

SarcoidosisSarcoidosis

TuberculosisTuberculosis


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Acute mediastinitisAcute mediastinitis

SymptomsSymptoms

Chest painChest pain

ChillsChills

Coughing up bloodCoughing up bloodFeverFever

MalaiseMalaise

Shortness of breathShortness of breath


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Treatment ofAcuteTreatment ofAcutemediastinitismediastinitis

intravenous antibioticintravenous antibiotic

therapy andtherapy and

hydrationhydration

abscessesabscesses needneed

surgically drain.surgically drain.

Treatment for chronicTreatment for chronicfibrosing mediastinitisfibrosing mediastinitis

include steroids orinclude steroids or

surgicalsurgical

decompression ofdecompression ofaffected vessels.affected vessels.


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Fine needle aspiration biopsyFine needle aspiration biopsy

(FNAB)(FNAB)


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Classification of mediastinal tumorsClassification of mediastinal tumors

EPITHELIAL TUMORSEPITHELIAL TUMORS

LYMPHOPROLIFERATIVELYMPHOPROLIFERATIVE

DISORDERSDISORDERSGERMCELL TUMORSGERMCELL TUMORS

NEURAL TUMORSNEURAL TUMORS


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EPITHELIAL TUMORSEPITHELIAL TUMORS

ThymomaThymoma Type AType A -- proliferation of epithelial cells, usually with scantproliferation of epithelial cells, usually with scant

lymphocytes.lymphocytes.

T

ypeB

T

ypeB

-- a tumor composed of round, dendritic ora tumor composed of round, dendritic orepithelioid cellsepithelioid cells with variable numbers of lymphocytes.with variable numbers of lymphocytes.

Type CType C -- tumors showingtumors showing a combinationa combination of the above wereof the above were

designated as type AB.designated as type AB.

Thymic CarcinomaThymic Carcinoma


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Myasthenia gravisMyasthenia gravis

is a chronicis a chronic

autoimmuneautoimmune

neuromuscularneuromuscular

disease (seedisease (seeautoimmune disease)autoimmune disease)

characterized bycharacterized by

varying degrees ofvarying degrees of

weakness of theweakness of theskeletal (voluntary)skeletal (voluntary)

muscles of the bodymuscles of the body


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ThymectomyThymectomy


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DISORDERSDISORDERS

A.A. Hodgkin LymphomaHodgkin Lymphoma

B.B. Large Cell LymphomaLarge Cell Lymphoma

C.C. Lymphoblastic Lymphoma (LL)Lymphoblastic Lymphoma (LL)


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DISORDERSDISORDERS


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GERMCELL TUMORSGERMCELL TUMORS

A.A. erminoma/SeminomaGerminoma/Seminoma

Mature teratoma is the most common form ofMature teratoma is the most common form ofmediastinal germ cell tumor (GCT).mediastinal germ cell tumor (GCT).

Germinoma/seminoma is the 2nd most frequentGerminoma/seminoma is the 2nd most frequenttype. Men in the 2ndtype. Men in the 2nd -- 4th decade are affected.4th decade are affected.

B.B. NonNon--Seminomatous Germ Cell TumorsSeminomatous Germ Cell Tumors

The major subtypes in this category include yolkThe major subtypes in this category include yolk--

sac tumor, embryonal carcinoma, andsac tumor, embryonal carcinoma, andchoriocarcinoma. Clinical features are similar tochoriocarcinoma. Clinical features are similar tothose for seminomatous GCT.those for seminomatous GCT.


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Germ cell tumorsGerm cell tumors

anterior mediastinal tumor withanterior mediastinal tumor withheterogeneous attenuationheterogeneous attenuationassociated with calcificassociated with calcificintratumoral nodules suggestsintratumoral nodules suggestsa mediastinal teratodermoid.a mediastinal teratodermoid.

ContrastContrast--enhanced axial CTenhanced axial CTscan shows an illscan shows an ill--defineddefined

anterior mediastinal mass withanterior mediastinal mass withirregular borders that isirregular borders that isinfiltrating the mediastinal fat.infiltrating the mediastinal fat.CTCT--guided needle biopsyguided needle biopsyrevealed a mediastinalrevealed a mediastinalseminoma.seminoma.


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A.A. SchwannomaSchwannoma

Neurogenic tumors account for 20Neurogenic tumors account for 20--30% of30% ofmediastinal neoplasms. Schwannoma is themediastinal neoplasms. Schwannoma is the

most common mediastinal neural tumor.most common mediastinal neural tumor.Patients are usually 20Patients are usually 20--40 yrs.40 yrs.

B.B. GanglioneuromaGanglioneuroma

Older female children and young adults areOlder female children and young adults are

affected. Most are paraspinalaffected. Most are paraspinalC.C. Neuroblastoma/GanglioneuroblastomaNeuroblastoma/Ganglioneuroblastoma

The most common childhood tumor in that site.The most common childhood tumor in that site.


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Symptoms of mediastinal tumorsSymptoms of mediastinal tumors ::

Chest painChest pain

ChillsChills

CoughCough

Coughing up blood (hemoptysis)Coughing up blood (hemoptysis)

FeverFever

HoarsenessHoarseness

Night sweatsNight sweats

Shortness of breathShortness of breath


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Signs and tests:Signs and tests:

FeverFever

HighHigh--pitchedpitchedbreathing soundbreathing sound

(stridor )(stridor )Swollen or tenderSwollen or tenderlymph nodeslymph nodes(lymphadenopathy)(lymphadenopathy)

Unintentional weightUnintentional weightlossloss

WheezingWheezing

Chest xChest x--rayray

CTCT--guided needleguided needlebiopsybiopsy

CT scan of the chestCT scan of the chestMRI of the chestMRI of the chest

Mediastinoscopy withMediastinoscopy withbiopsybiopsy


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Treatment for mediastinal tumorsTreatment for mediastinal tumors

For thymic cancersFor thymic cancers, surgery is the treatment of, surgery is the treatment of

choice. It may be followed by radiation orchoice. It may be followed by radiation or

chemotherapy, depending on the stage of thechemotherapy, depending on the stage of the

tumor and the success of the surgery.tumor and the success of the surgery.For lymphomasFor lymphomas, chemotherapy followed by, chemotherapy followed by

radiation is the treatment of choice.radiation is the treatment of choice.

For neurogenic tumorsFor neurogenic tumors of the posteriorof the posterior

mediastinum, surgery is the treatment of choice.mediastinum, surgery is the treatment of choice.

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Mediastinum lect