Chylothorax

06/26/13 amr badreldin hamdy MD FCCP 1
Chylothorax
Amr Badreldin Hamdy
MD, FCCP

Definition
A chylothorax is formed
when the thoracic duct is
disrupted and chyle enters
the pleural space.

Drainage from the thoracic duct
is called chyle.
Ductal lymph is clear during
fasting and becomes milky after
a fatty meal.
Principal function of the thoracic
duct is the transport of digestive
fat to the venous system.

Chyle appears grossly as
milky, opal- escent fluid that
usually separates into three
layers upon standing:
> a creamy uppermost layer
containing chylomicrons,
> a milky intermediate layer,
>a dependent layer containing
cellular elements.

The flow rate through the
duct is affected by
the rate of lymph
formation in the
gastrointestinal tract.

Anatomy

The thoracic duct (TD) is constant
only in its variability.
It originates from the cisterna chyli
which overlies the anterior surface
of the second lumbar vertebra,
posterior to and to the right of the
aorta. It passes through the
esophageal hiatus of the
diaphragm into the thoracic cavity.

The TD ascends extrapleurally in
the posterior mediastinum along
the right side of the anterior
surface of the vertebral column
and lies between the azygos
vein and the descending aorta
in close proximity to the
esophagus and pericardium.

At T5 - T7 it crosses to the left
behind the aorta and ascends on
the left side of the esophagus.
Once the TD passes the thoracic
inlet, it arches 3 to 5 cm above the
clavicle and passes anterior to the
sublcavian artery, vertebral artery
and thyrocervical trunk to terminate
in the region of the left jugular and
subclavian veins.

A bicuspid valve prevents
entry of blood into the
lymphatic system.
The right duct is small
( 2cm in length) and drains
lymph from right head and
chest.

Unidirectional flow is
ensured by:
- multiple valves throughout
the duct,
- intrinsic wall contraction,
- thoracic pressure gradient.

Daily between 1,500 and 2,500
mL of chyle normally empties
into the venous system.
Ingestion of fat can increase
the flow of lymph in the TD by
2-10 times the resting level for
several hours.

Ingestion of liquid increases
the chyle flow, whereas the
ingestion of protein or
carbohydrates has little effect
on lymph flow.
The protein content is usually
above 3g/dL, the electrolyte
composition of chyle is similar
to that of serum.

Composition of
Chyle

Lipids
Fat is the main component of
chyle.
Sixty to seventy percent of
ingested fat absorbed by
intestinal lymphatics is
conveyed to the blood by the
thoracic duct.

Lymphatic fat is
transported as chylo-
microns.
Fatty acids with less than
10 carbon atoms are
absorbed directly into the
venous portal system.

Proteins
Lymphatics are the main
pathway for return of extra-
cellular proteins to the
vascular space.
The protein content is half the
concentration of plasma.

Electrolytes
Electrolyte composition
is similar to plasma.

Cells
Lymphocytes are the main cellular
elements.
Ninety percent are T-lymphocytes.
The primary cell in chyle is the
small lymphocyte (400 -
6,800/mm3).
Prolonged drainage of a chylous PE
can result in profound T-
lymphocyte depletion.

Pathophysiology of Chyle

@ it leads to cardiopulmonary
abnormalities and metabolic
immunologic deficiencies.
@ it can compress the lung
resulting in dyspnea and
respiratory distress.
@ empyema is a rare
complication due to the
bacteriostatic nature of lecithin
and fatty acids.

@ loss of proteins and vitamins,
more than fat, leads to
metabolic and nutritional
defects, immunodeficiency,
coagulopathy, malnutrition and
death.
@ because it is bacteriostatic
and non- irritating, it does not
cause fibrothorax.

Etiology
1. Trauma.
2. Tumor.
3. Miscellaneous.
4. Idiopathic.

Surgical Trauma
1. Cardiovascular surgery (coronary
artery by-pass when the internal
mammary artery is harvested; heart
transplant, high lumbar
aortography).
2. Esophageal
surgery( sclerotherapy for
esophageal varices).
3. Pulmonary surgery.
4. Costo-vertebral surgery.

5. Neck surgery (thoracic-lumbar
fusion for correction of
kyphosis).
6. Diaphragm surgery.

Non-surgical Trauma
1. Blunt chest trauma.
2. Hyperextension of the spine or
fracture of a vertebra.
3. External cardiac massage.
4. Aortic angiography.
5. Sub-clavian vein
catheterization.

6. The injury may be less
impressive,and chylothoraces
have been attributed to
coughing, vomiting, and weight
lifting, or vigorous stretching
while yawning.

Chylothorax secondary to closed
trauma is usually on the right
side, and the site of rupture is
most commonly in the region of the
ninth or tenth thoracic vertebra
(e.g. fall from height, motor vehicle
accidents, compression injuries to
the trunk, heavy blows to the back
or stomach, and childbirth).

Tumors

Fifty percent of chylothoraces in
adults are caused by tumors.
Seventy five percent are
lymphomas.
Other forms include chronic
lymphocytic leukemia,
metastatic disease and lung
cancer.

Benign and malignant
tumors may involve the TD
through lymphatic
permeation, direct
invasion or tumor
embolus.

Miscellaneous
1. On rare occasions, a
chylothorax is associated with
heart failure or nephrotic
syndrome and the effusion is a
transudate.
2. Liver cirrhosis.
3. Thrombosis of the SVC or the
subclavian vein.

4. Primary lymphangioleiomatosis
(LAM).
5. Tuberus sclerosis.
6. Lymphangiomatosis.
7. Sarcoidosis.
8. Yellow nail syndrome.
9. Tuberculosis.

10. Amyloidosis.
11. Castleman’s disease (Giant
Lymph Node hyperplasia).
12. Familial lymphedema.
13. Hypothyroidism.
14. Obstruction of the SVC
secondary to Behcet’s
syndrome.

15. Filariasis.
16. Radiation-induced
mediastinal fibrosis.
17. Kaposi sarcoma in AIDS
patients.
18. Gorham’s syndrome.

Congenital Chylothorax
It is the most common cause of
pleural effusion in the newborn
infant.
Is twice as often in males.
Prognosis is good and perinatal
morbidity is between 15-30%.
The infant develops respiratory
distress in the first few days of
life.

In some cases, a
congenital chylothorax
is associated with
Turner’s syndrome,
Noonan’s syndrome, or
Down’s syndrome.

Clinical

The main danger to patients
with chylothorax is that they
become mal- nourished and
immuno-compromised
because of the removal of large
amounts of protein, fat,
electrolytes and lymphocytes
from the body with repeated
thoracentesis and chest tube
drainage.

The loss of chyle might
result in hyponatremia,
hypocalcemia,
acidosis, hypovolemia,
reduction of venous return
to the heart, and
lymphocytic depletion.

With non-traumatic chylothorax,
the onset of symptoms is
usually gradual.
The initial symptoms of
chylothorax are usually related
to the presence of space
occupying fluid in the thoracic
cavity e.g. dyspnea.
Pleural chest pain and fever are
rare.

A latent period of 2-10 days
usually occurs between the
trauma and the onset of the
pleural effusion.
Lymph collects extrapleurally in
the mediastinum after the initial
duct disruption, forms a
CHYLOMA, and produces a
posterior mediastinal mass.

The mediastinal pleura
eventually ruptures, chyle gains
access to the pleural space,
and dyspnea is produced by the
chyle compressing the lung.
At times, hypotension, cyanosis,
and extreme dyspnea occur
when the chyloma ruptures into
the pleural space.

Diagnosis

Lipid measurements
might be indicated in all
patients with pleural
effusion of unknown
etiology in order to rule out
the diagnosis of
chylothorax.

High levels of lipid accumulate
in the pleural space in two
situations:
* When the thoracic duct is
disrupted, chyle can enter
the pleural space to produce
a chylous effusion.

* In long standing pleural
effusions, large amounts of
cholesterol or lecithino-
globulin complexes can
accumulate in the pleural
fluid to produce a chyliform
pleural effusion.

Chyle or Pus?
Chyle may be mistaken for
pus but there is no odor
and the cultures are
negative.
Gram stain reveals
lymphocytes rather than
PMLs with no bacteria.

The milkiness with
empyema is caused by the
suspended white blood
cells, and debris and if
such fluid is centrifuged,
the supernatant is clear.

The best way to establish
the diagnosis of
chylothorax is by
measuring the triglyceride
and cholesterol levels in
the pleural fluids.

If the pleural fluid
triglyceride level is
above 110mg/dL and the
ratio of the pleural fluid to
serum cholesterol is less
than 1.0, the diagnosis of
chylothorax is established.

The cholesterol ratio is used to
exclude pseudochylothorax
because some patients with
chyliform pleural effusion also
have triglyceride levels above
110 mg/dL, but their pleural
fluid to serum cholesterol ratio
will exceed 1.0 .

NB/ the only other situation in
which the pleural fluid
triglyceride is above
110mg /dL is when IV fluid
containing high levels of
triglycerides leaks from a
central vein into the pleural
space.

Chylomicrons
The demonstration of
chylomicrons in the pleural
fluid by lipoprotein analysis
establishes the diagnosis of
chylothorax.

Lipophilic Dye Ingestion
Ingestion of a fatty meal
with a lipophilic dye, followed
by a thoracentesis 30 to 60
min later, to ascertain
whether the pleural fluid has
changed in color.

With congenital
chylothorax, the pleural
fluid is initially serous
and turns chylous only
when milk feedings are
started.

Lympho-scintigraphy
Technetium-99m human
serum albumin is injected
into the dorsum of the foot or
hand and subsequently the
thoracic duct is imaged in
nuclear medicine.

Oral ingestion of iodine
labeled BMIPP, and after
ingestion of this tracer by
approximately 80 minutes
the thoracic duct can be
imaged.

Treatment

The general aims are:
1. Relief of dyspnea by
removal of chyle.
2. Preventing dehydration.
3. Maintenance of nutrition.
4. Reduction in the rate of
chyle formation.

Conservative Treatment
 Tube drainage.
 Medium-chain fatty acid diet.
 NOP and total parenteral
nutrition (TPN) is the most
effective method of decreasing
chyle production.
 Fluid and electrolyte support.

Decrease flow of chyle
The patient’s nutritional status
can be maintained with IV
hyper-alimination. This is
preferred than medium-chain
triglycerides which are
unpalatable and are
recommended when one
wishes to reduce the flow of
chyle.

The flow of chyle is also
decreased if the patient
stays in bed because any
lower extremity movement
increases the flow of
lymph.

Somatostatin
oIt requires continuous IV
infusion.
oUsual starting dose is
3.5mg/kg/hr which can be
increased to 10mg/kg/hr.

Octreotide
o It is given by SC route.
o Usual dose in the adult is 50mg/8
hrs, in children 0.3-1mg/kg/hr.
o Primary side effects include
suppression of GIT motility and
secretion (loose stools,
malabsorption, nausea and
flatulance).

Mechanism of action
They decrease triglyceride
absorption and lymphatic
flow.

One must treat the chylothorax
definitively, such as with
thoracic duct ligation or
pleuroperitoneal shunt
implantation, before the patient
becomes too cachectic to
tolerate the operation.

Pleuroperitoneal Shunt
• The optimal method to remove
chyle.
• Chyle is shunted to the peritoneal
cavity where it is absorbed
without creating significant ascitis.
• It can be inserted with local
anaesthesia as opposed to general
anaesthesia which is required for
thoracic duct ligation.

• The shunt can be removed
30-90 days after its insertion.
• No dietary restriction is
needed.
• Should not be inserted if
chylous ascitis is present.

Percutaneous
Transabdominal Thoracic
Duct Ligation

• Minimally invasive.
• Pedal lymphography is
initially performed to
opacify large
retroperitoneal lymph
channels.

A suitable duct (>2 mm
diameter) is punctured
transabdominally to allow
catheterization and
embolization of the thoracic
duct under fluoroscopic
guidance.

The embolization is
performed using platinum
microcoils or micro
particles.
Glue may be used singly
or in combination with
coils.

Pleurodesis
Pleurodesis through a chest
tube is not generally
recommended for patients with
chylothorax.
Thoracoscopy with talc
insufflation of 2gm talc or with
pleural abrasion or partial
parietal pleurectomy is done
and is effective.

Ligation of Thoracic Duct
Until Lampson initially
described successful ligation
of the thoracic duct in 1948,
the mortality rate from
chylothorax was 50%.
It is the definitive treatment.

Causes no ill defects (because of
the multiple anastamosis among
various lymphatic channels and
direct lymphatico-venous
communications.
If the chylothorax is bilateral, a right
thoracotomy should be performed
because the duct is more readily
approached from that side.

The actual point of leakage
from the duct must be
determined and ligation of the
duct on both sides of the leak is
done.
Preoperative lymphangiogram
should be done.

Chyliform Pleural
Effusion
Is a pleural effusion that is
turbid or milky from high
lipid content not resulting
from disruption of the
thoracic duct.

Pseudochylothoraces may
be seperated into those with
cholesterol crystals
(pseudochylous effusions), and
those without cholesterol
crystals (chyliform pleural
effusions). But no practical
reason exists for making this
distinction.

Most patients with
chyliform pleural effusion
have long standing pleural
effusion (mean >5y), and
have thickened and
sometimes calcified
pleura.

Most of the cholesterol in
chyliform PE is associated
with high-density lipo-
proteins in contrast to the
cholesterol in acute
exudates that is mostly
bound to low-density
lipoproteins.

The origin of cholesterol
and other lipids is not
definitely known, but one
possibility is from
degenerating RBCs and
WBCs in the pleural fluid.

Causes
The two most common
causes of the effusion
initially are rheumatoid
pleuritis and tuberculosis.
Many pleural effusions
secondary to paragnomiasis
contain cholesterol crystals.

Chyliform effusions are usually
unilateral.
Differential diagnosis of
chyliform pleural effusions are
empyema and chylothorax.
In an empyema,
centrifugation results in a
clear supernatant.

Chyliform pleural effusions contain
cholesterol crystals.
Microscopically, the cholesterol
crystals present a typical rhomboid
configuration.
Pleural fluid cholesterol levels >
200 mg/dL strongly suggest a
chyliform effusion. Some have a
high (>250mg/dL ) trigyceride level.

When a patient is diagnosed as
having a chyliform pleural
effusion, the possibility of TB
should always be entertained.
Decortication should be
considered if the patient is
symptomatic and the under-
lying lung is believed to be
functional.

Pleurectomy
If the thoracic duct cannot be
successfully ligated at
thoracotomy, a parietal
pleurectomy should be
performed to obliterate the
pleural space.
One must not delay
thoracotomy too long.

Role of Thoracoscopy
Ligation of the thoracic duct is
done with the
videothoracoscope.
Thoracoscopy permits the entire
pleural space to be visualized,
as well as allowing direct suture
of a lymphatic leak.

References
 Light R.W.: Pleural Diseases. Fifth ed.
Lippincott Williams & Williams ( 2007).
 Miller JI Jr: Diagnosis and management
of chylothorax. Chest Surg Clin North
Am, 6:139 (1996).
 Hillerdal G: Chylothorax and pseudo-
chylothorax. Eur Respir J; 10:1157
(1997).

 Merrigan BA et.: Chylothorax. Br J Surg
84:15 (1997).
 Williams KR, Burford TH: The manage-
ment of chylothorax. Ann Surg 160:131
(1964).
 Roy PH et al.: The problem of chylo-
thorax. Mayo Clin Prod 42:457 (1967).

 Chernick V, Reed MH: Pneumothorax
and chylothorax in the neonatal period.
J Pediatr; 76:624 (1970).
 Hughes RL et al: The management of
chylothorax. Chest; 76:212 (1979).
 Ross JK: A review of the surgery of the
thoracic duct. Thorax; 16:12 (1961).

 Hamdan MA, Gaeta ML: Octreotide and
low-fat breast milk in postoperative
chylothorax. Ann Thorac Surg; 77:2215
(2004).
 Buettiker V et al.: Somatostatin: a new
therapeutic option for the treatment of
chylothorax. Intensive Care Med; 27:
1083 (2001).

 Demos NJ et al.: Somatostatin in the
treatment of chylothorax. Chest; 119: 964
(2001).
 Kalomendis I: Octreotide and chylothorax.
Cur Opin Pul Dis; 12:264 (2006)
 Little AG et al.: Pleuroperitoneal shunting:
alternative therapy for persistent chylothorax.
Ann Thorac Surg; 208:443 (1988).

 Adler RH, Levinsky L: Persistent chylo-
thorax. J Thorac Cardiovasc Surg; 76:
859 (1978).
 Robinson CLN: The management of
chylothorax. Ann Thorac Surg; 39: 90
(1985).
 Perry RE et al.: Pleural effusion in the
neonatal period. J Pediatr 62:838 (1963

THANK YOU

Chylothorax

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (11)

Similar to Chylothorax

Similar to Chylothorax (20)

Chylothorax