Page 426 - Textbook of Pathology, 6th Edition

410 Systemic effects are more severe and occur due to embolic layer of endothelium have thin muscle in their walls than in
phenomena, pulmonary thromboembolism being the most veins of the same size and the valves are more numerous.
common and most important. Other systemic manifestations Lymphatic capillaries and lymphatics form plexuses around
include bacteraemia and septic embolisation to brain, tissues and organs. The walls of lymphatic capillaries are
meninges, liver etc. permeable to tissue fluid, proteins and particulate matter.

Special Types of Phlebothrombosis LYMPHANGITIS
A few special variants of phlebothrombosis are considered Inflammation of the lymphatics or lymphangitis may be acute
below: or chronic.
1. THROMBOPHLEBITIS MIGRANS. Thrombophlebitis Acute lymphangitis occurs in the course of many bacterial
migrans or migratory thrombophlebitis or Trousseau’s infections. The most common organisms are (β-haemolytic
syndrome is the term used for multiple venous thrombi that streptococci and staphylococci). Acute lymphangitis is often
disappear from one site so as to appear at another site. The associated with lymphadenitis.
condition is not a morphologic entity but a clinical one, seen
most often in disseminated visceral cancers (e.g. cancer of Grossly, the affected lymphatics are dilated and appear
lungs, prostate, female reproductive tract, breast, pancreas as cutaneous streaks.
and gastrointestinal tract) as part of paraneoplastic syndrome Microscopically, the dilated lumen contains acute
and is also found in nonbacterial thrombotic endocarditis. inflammatory exudate, cell debris and clotted lymph.
There is inflammatory infiltration into the perilymphatic
2. PHLEGMASIA ALBA DOLENS. This term meaning tissues alongwith hyperaemia and oedema. Acute
‘painful white leg’ refers to extensive swelling of the leg, lymphangitis generally heals completely.
occurring most frequently due to iliofemoral venous
thrombosis. It occurs most often in women during late Chronic lymphangitis occurs due to persistent and recurrent
pregnancy or following delivery when the pregnant uterus acute lymphangitis or from chronic infections like
causes pressure on the iliofemoral veins, or after extensive tuberculosis, syphilis and actinomycosis.
pelvic surgery. Development of pulmonary embolism may
occur due to involvement of inferior vena cava. Histologically, there is permanent obstruction due to
fibrosis of affected lymphatics called chronic
3. PHLEGMASIA CERULEA DOLENS. This term lymphoedema.
SECTION III
meaning ‘painful blue leg’ refers to markedly swollen bluish
skin with superficial gangrene. It is a serious complication LYMPHOEDEMA
of massive iliofemoral venous thrombosis and decreased
arterial blood flow. Lymphoedema is swelling of soft tissues due to localised
increase in the quantity of lymph (page 97). It may be primary
4. SUPERIOR VENA CAVAL SYNDROME. Superior (idiopathic) or secondary (obstructive).
vena caval syndrome refers to obstruction of the superior
vena cava. The obstruction results most often from external I. PRIMARY (IDIOPATHIC) LYMPHOEDEMA. Lymph-
compression or from thrombosis. Some of the common oedema occurring without underlying secondary cause is
causes of superior vena caval syndrome are malignancy called primary or idiopathic lymphoedema. Its various types
(especially lung cancer and lymphoma), syphilitic aortic are as under:
aneurysm and tuberculous mediastinitis. Clinical features 1. Congenital lymphoedema. Congenital lymphoedema
Systemic Pathology
include dilated veins of neck and thorax, oedema of the face, has further 2 subtypes—familial hereditary form (Milroy’s
neck and upper chest, visual disturbances and disturbed disease) and non-familial (simple) form.
sensorium. i) Milroy’s disease is a form of congenital and familial
5. INFERIOR VENA CAVAL SYNDROME. Inferior vena oedema generally affecting one limb but at times may be
caval syndrome is the obstruction of the inferior vena cava. more extensive and involve the eyelids and lips. The disease
Most often, obstruction results from thrombosis by extension is inherited as an autosomal dominant trait and is often
from iliofemoral veins. Other causes of obstruction are associated with other congenital anomalies. The condition
external compression and neoplastic invasion. Clinical results from developmental defect of lymphatic channels so
features are oedema of lower extremities, dilated leg veins that the affected tissue shows abnormally dilated lymphatics
and collateral venous channels in the lower abdomen and the area shows honey-combed appearance. Recurrent
infection of the tissue causes cellulitis and fibrosis of
LYMPHATICS lymphatic vessels.
ii) Simple congenital lymphoedema is non-familial form with
NORMAL STRUCTURE unknown etiology. It is often associated with Turner’s
syndrome and affects one member of the family. The
Lymphatic capillaries, lymphatic vessels and lymph nodes
comprise the lymphatic system. Lymphatic capillaries pathologic changes are similar to those of Milroy’s disease.
resemble blood capillaries, and larger lymphatics are 2. Lymphoedema praecox. This is a rare form of lymph-
identical to veins. However, lymphatics lined by a single oedema affecting chiefly young females. The oedema usually