Eventration of the Diaphragm
Diseases of The Diaphragm

 

·         Eventration of the Diaphragm

o       Congenitally thin muscular portion of hemidiaphragm

o       Appearance, however, still seems to increase with age

o       Anteromedial on right

§         R:L  5:1

• When on left, usually involves whole hemidiaphragm

Frontal and lateral chest x-ray shows smooth elevation of right hemidiaphragm
medially and anteriorly consistent with an eventration of the hemidiaphragm 

·         Anatomy of the Diaphragm

o       Muscle slips attach to 7-12th ribs   

o       Innervated by phrenic nerve (C4, C3 and C5)

o       Central portion is tendinous; outer portion muscular

o       Right is 1/2 interspace higher than left in 90%

o       Mean diaphragmatic excursion = 0.8-8.0cm

 

·         Elevation of the Hemidiaphragm

o       Causes

§         Subpulmonic effusion

·         Dome is laterally displaced

·         Straight edge of  anterior “diaphragm” seen on lateral at major fissure

§         Decreased lung volume

·         Atelectasis

§         Hypoplastic lung

·         Small pulmonary artery, dextrocardia, scimitar vein

§         Poor inspiration

§         Phrenic Nerve Paralysis

·         BrCa

·         Mets

·         Iatrogenic-post CABG

§         Idiopathic

§         Abdominal Disease

§         Subphrenic abscess

·         Right=subhepatic-appendicitis

·         Left 2° ulcer perforation

§         Liver mass

§         Interposition of the colon

§         Distended stomach

§         Congenital Diaphragmatic Hernia

§         Traumatic Rupture of the Diaphragm

§         Eventration of the Diaphragm

 

·         Congenital Diaphragmatic Hernia

o       General

§         Absence of closure of pleuroperitoneal fold

§         9th gestational week

§         Male to female ratio of 2:1

§         1:2,000 live births

§         Left > right  9:1

o       Associated Anomalies

§         CNS–neural tube defects

§         GI–malrotation, omphalocoeles

§         CV

§         GU

§         IUGR

 

o       Bochdalek Hernia

§         90% of congenital hernias

§         Posterolateral defect    

§         Abnormality of cephalic fold of pleuroperitoneal membrane

§         Left (80%), right (15%), B/L (5%)

§         Babies–large

§         Adults–small

§         Organs Involved

·         Bowel

·         Spleen

·         Fat

·         Liver (left lobe)

·         Kidney, pancreas

·         Stomach

§         The “B’s”

·         Babies

·         Back

·         Big

o       Morgagni Hernia

§         Anteromedial parasternal defect (Space of Larrey)

§         Maldevelopment of septum transversum

§         Overweight, middle-aged, women

§         Right > left (heart protects)

§         Associated with

·         Pericardial defects

·         Omental fat in pericardial space

§         Organs Involved

·         Liver

·         Bowel

§         The “M’s”

·         Middle (anterior and central)

·         Mature (older children)

·         Miniscule

 

·         Congenital Absence of Diaphragm

o       Delayed onset of hernia may occur following streptococcal infection

o       Imaging Findings

§         Initially, hemithorax may appear opaque because loops are fluid-filled

§         Paucity of bowel loops beneath diaphragm

§         Once air swallowing begins, multiple lucencies contained within bowel are seen in chest

·         Respiratory distress may increase as intestine occupies more of thorax

§         Some loops may remain fluid-filled

§         Mediastinal shift to the opposite side

§         Relative paucity of gas in abdomen

§         If stomach remains in abdomen, it is more centrally located than normal

o       Prognosis

§         Intrathoracic stomach             60%

§         Intra-abdominal stomach        6%

§         Polyhydramnios                      89%

§         Operative mortality                 40-50%

o       DDX

§         Cystic adenomatoid malformation

§         Staphylococcal pneumonia

§         Mediastinal cyst

 

·         Diaphragmatic Rupture

o       Blunt trauma (5–50%)

o       2° increased intra-abdominal pressure

§         MVA

§         Fall from height

o       Penetrating trauma (50%)

§         Knife, bullet

o       General   

§         5% of all diaphragmatic hernias

§         Most (90%) are left-sided

§         Central and posterior >10cm in length

§         Contain stomach, colon, small bowel, omentum, spleen

§         Half have no initial abnormal radiographic findings

§         Half are missed clinically

§        Associated with

·         Fx ribs

·         Pneumoperitoneum

·         Ruptured spleen

§         Delayed diagnosis = higher mortality

§         MRI most useful in showing site of tear

o       Imaging Findings

§         Air/fluid levels in left hemithorax   

§         Contralateral shift of heart and mediastinal structures

§         Absence of bowel in abdomen

§         NGT in left hemithorax

§         “Pinch-cock” “hourglass” configuration of bowel through rent in diaphragm

§         MRI shows diaphragm in all planes

o       Complications

§         Strangulation of bowel

§         Hydrothorax/hemothorax 2° strangulation

 

·         Hiatal Hernia

o       Most common form of diaphragmatic hernia in adult

o       Air/fluid level(s) in “mass” posterior to heart

o       May contain entire stomach

o       Can lead to volvulus

o       Usually projects to left of spine

 

·         Paralysis of the Hemidiaphragm

o       Most often from phrenic nerve involvement

§         Neoplasms, CABG surgery (2° ice)

§         Idiopathic

o       Males, right hemidiaphragm

o       Sniff test

• Paradoxical upward motion on affected side

§         Normal excursion of 1-2 ribs

·         Breathe in, diaphragm down

·         Breathe out, diaphragm up

§         Paralyzed – paradoxical motion

·         Breathe in, diaphragm up

·         Breath out, diaphragm down

§         Useless with large effusion

o       Paralysis of the hemidiaphragm versus eventration

§         Diaphragmatic motion is paradoxical in paralysis but not with Eventration

·         Bilateral Paralysis of the Diaphragm

o       Less common than unilateral

o       Occurs in neurologic disease, syrinx, MS

o       Most develop respiratory failure and hypercapnea

·         Tumors of the Diaphragm

o       Very rare

o       Benign vs. malignant 50:50

o       Lipoma (most common benign)

o       Fibrosarcoma (most common malignant)

o       Mets occur via direct extension from pleura or lung