Lactology Foundation

ABDOMINAL PULSATION

A pulsatile swelling in the abdomen may be due to:
• A prominent aorta – normal or arteriosclerotic
• An abdominal aortic aneurysm
• Transmission of aortic pulsations through an abdominal mass
• A pulsatile, enlarged liver

PROMINENT AORTA
The pulsations of the normal aorta may be felt in perfectly normal but thin subjects along a line extending from the xiphoid to the bifurcation of the aorta at the level of the fourth lumbar vertebra. This is on a line joining the iliac crests, about 2 cm below and a little to the left of the umbilicus. In the arteriosclerotic and hypertensive subject, it may be difficult to decide whether or not the aorta is merely thickened and tortuous, or whether it is aneurysmal. If the two index fingers are placed parallel, one on either side of the aorta, the distance between the fingers can be measured.
According to the size of the patient, a gap of 2–3 cm between the fingertips may be considered normal, but any measurement above this is suspicious of aneurysmal dilatation.
If in doubt, visualization of the aorta by means of ultrasound or computed tomography enables accurate measurement of the aorta to be made.

ABDOMINAL AORTIC ANEURYSM
There is no doubt that arteriosclerotic abdominal aneurysms are becoming more frequently encountered, as is the serious emergency of leakage or rupture of such an aneurysm. The majority of patients are aged more than 60 years, and the great majority are men. The aneurysm may be entirely symptomless or the patient may complain of epigastric or central abdominal discomfort that frequently radiates into the lumbar region.
Patients themselves may actually detect the pulsating mass in the abdomen.
The pulsation may be visible in the upper abdomen, above the umbilicus, and – if large enough – may actually appear as a pulsating mass. On palpation, the aneurysm is a midline swelling that bulges over to the left side, away from the adjacent inferior vena cava. If the mass extends below the level of the umbilicus, it suggests involvement of the iliac arteries.
The characteristic physical sign is that the mass has an expansive pulsation. The index fingers are placed on either side of the mass, which enables the diameter to be assessed. If the diameter is more than 3 cm, this certainly suggests aneurysmal dilatation of the aorta; if the diameter is above 5 cm, the clinical diagnosis is
all but certain. Typically, the fingers are pushed apart with each pulse, and not up and down. The latter sign suggests transmission of the pulsation.
Usually, the aneurysm is resonant to percussion due to overlying loops of intestine. However, an extremely large aneurysm will displace the bowel laterally to reach the anterior abdominal wall and will then give a dull percussion note. Auscultation may reveal bruits over the lower extremity of the aneurysm. This suggests turbulent flow of blood caused by relative stenosis at the aortoiliac junctions.
Rectal examination may reveal a pulsatile mass when one or both of the internal iliac arteries are involved in the aneurysmal process.
Leakage or rupture of the aneurysm is an acute
abdominal emergency. The patient presents with
the features of massive blood loss (pale, sweating,
clammy skin, a rapid pulse and low blood pressure)
together with severe abdominal pain, lumbar pain
and marked abdominal tenderness and guarding.
Because of the low blood pressure and the associated
peri-aneurysmal haematoma, as well as the overlying one guarding, the aneurysm may be quite difficult to
palpate and, unless sought carefully, is easy enough
to miss.
The diagnosis of aortic aneurysm is often readily confirmed by means of a plain abdominal X-ray, which frequently delineates the aneurysm because of the associated calcification in its wall.
Typically, the aneurysm is seen to bulge over to the left side of the abdomen. More accurately, an ultrasound or computed tomogram of the abdomen visualizes the aneurysm and enables its length and diameter to be measured accurately.

Plain X-ray of the abdomen, showing a large calcified aortic aneurysm (arrowed).

Coronal computed tomography image of an infrarenal aortic aneurysm with a calcified wall (blue arrow) and intraluminal thrombus (red arrow). The arteries have been enhanced by an intravenous injection of contrast.

TRANSMISSION OF AORTIC PULSATIONS THROUGH AN ABDOMINAL MASS
A large intra-abdominal or retroperitoneal solid mass, pressing against the aorta, may exhibit transmitted aortic pulsation. Typical examples are a large carcinoma of the body of the stomach, a carcinoma or cyst of the pancreas, and a large ovarian cyst. Indeed, when the entire abdomen is filled by a cystic mass, it may be quite difficult to distinguish between such a mass and extensive ascites. Percussion, of course, is helpful since ascites gives dullness in the flanks as compared with the central dullness of a large intra-abdominal mass. The two index fingers, when placed on the mass, will perceive that the pulsation is transmitted directly forwards from the aorta and is not expansive, as would be found in an aneurysm.

PULSATILE LIVER
It is unlikely that an enlarged pulsatile liver will be mistaken for any other kind of pulsatile tumor.
It occurs in cases of chronic failure of cardiac compensation, generally from mitral stenosis or tricuspid stenosis. There is associated cyanosis, edema of the legs and ascites. It is not, however, every liver which seems to pulsate that really presents expansive pulsation. An impression of pulsation may be given by the movements transmitted directly to the liver by the hypertrophied right heart.