Book of Medical Disorders in Pregnancy - Tintash

First stage:
In this stage thromboplastin is formed
and activated. Thromboplastin which is
derived from blood platelets or
endothelial wall is activated by anti
hemophilic globulin Factor (VIII),
Christmas factor (Factor IX), and Factor
V. When thromboplastin is derived from
damaged tissues (Extrinsic system) it is
activated by Factor V, Factor VII and
Factor X.
Second stage - In this stage thrombin
formation occurs and prothrombin
(Factors 11) is converted into thrombin.
Both calcium ions (Factor IV) and the
activated thromboplastin (Factor III) are
needed for this reaction to take place.
Third stage - In this stage thrombin
reacts with fibrinogen (Factor I) and
forms fibrin monomer.
Fourth stage - In this stage
polymerization of fibrin monomer
occurs. Thus strands of fibrin are formed
which trap platelets and clot is formed.
Clinical features - Majority of patients
with thrombosis remain silent. The
symptoms manifest by its complications.
Fig10.3: Shows thrombo phlebitis and
clot in the vain due to trauma
Thrombophlebitis:
138
This complication when present usually
presents with edema, Pain and
tenderness over the involved area.
Homan's sign mayor may not be positive.
Lisker's sign i.e. tenderness on tibial
percussion is usually present if leg veins
are involved. Pratt's sign i.e. failure of
superficial veins to collapse when the leg
is raised to 45 degree may be present.
Sometime one may be able to palpate the
thrombosed vein. The patient may be
pyrexial. In Phlegmasia Alba dolens or
white leg one may see a pale, puffy,
pulseless, limb which is quite painful. O
edema, pain and deep tenderness when
present provide sufficient evidence to
support the dia-gnosis of deep vein
thrombosis. Thrombophlebitis of the
pelvic or leg veins usually starts between
the fourth and tenth days of the
puerperium. It is often associated with
anaemia and anaerobic streptococcal
infection in the pelvis. Increase of skin
temperature may be noticed when a hand
is placed on the affected calf. With the
deep veins blocked, more blood must
pass through the superficial venous
plexus. Arterial spasm is responsible for
the pain and is a marked feature in this
condition. In the puerperium pelvic
thrombophlebitis is relatively more
common. Thrombosis starts in the veins
of the uterus and later extends to the
ovarian and thence to the iliac veins or
even into the inferior vena cava.
Diagnosis - Physical signs in the vast
majority of cases are absent, therefore
other methods of diagnosis have to be
employed.
Phlebography - This is quite an
accurate method and can provide useful
information in doubtful cases.