ANSWER 94
One diagnosis of the abdominal pain which would explain her condition and fit with her
predisposing situation is ischaemic bowelcaused by an embolus from the heart. The patient
is likely to become very ill without markedly abnormal physical signs. Atrial fibrillation
increases the likelihood of such an event. She has been on aspirin which will reduce slightly
the risk of embolic events, but not on anticoagulants which would have decreased the risk
further. In the presence of pre-existing cardiovascular problems, shown by the hypertension
and angina, anticoagulation would normally be started if there are no contraindications. The
risk of cerebrovascular accidents caused by emboli from the heart has been shown to be
reduced. In lone atrial fibrillation with no underlying cardiac disease the risks of emboli and
the benefits of anticoagulation are less. There are alternative diagnoses such as perforation
or pancreatitis, and it is not possible to be sure of the cause of the abdominal problem from
the information given here.
The chart of the observations (Fig. 94.1) covers 10 h. After the first hour or two the cen-
tral venous pressure drops, the blood pressure falls and the pulse rate rises in association
with the fall in urine output.
These findings show that she is developing shock with inadequate perfusion of vital organs.
Types of shock ExampleHypovolaemic shock Blood loss
Cardiogenic shock Myocardial infarction
Extracardiac obstructive shock Pulmonary embolism
Vasodilatory (distributive) shock Sepsis! Possible causes for shock
All these causes are possible in this woman with abdominal problems and a history of
ischaemic heart disease. The fact that the cardiac output is high makes blood loss and
cardiogenic shock unlikely. The most likely cause is septic shock where peripheral vasodi-
latation would lead to a high cardiac output but a falling blood pressure and rising pulse
rate. Vasoconstriction and reduced blood flow occurs in certain organs, such as the kid-
neys, leading to the term ‘distributive shock’ with maintained overall cardiac output but
inappropriate distribution of blood flow. The rise in central temperature and the lack of a
marked fall in peripheral temperature would fit with this cause of the shock.
The patient was stabilized with fluid replacement and antibiotics before going to theatre
where the diagnosis of ischaemic bowel from an embolus was confirmed. Arteriography
can confirm the diagnosis but confirmation is often at laparotomy which is usually
required to remove the necrotic bowel.
- Aspirin and anticoagulation should be considered in patients with atrial fibrillation.
- Septic shock may be present with warm peripheries through vasodilatation.
- A drop in the central venous pressure may be the first sign of developing shock.