Expansion
Anaemia, pregnancy, thyrotoxicosis, sepsis, beriberi, Paget disease and arteriovenous fistula
Expansion
Think APT BAT:
- A - Anaemia
- P - Pregnancy
- T - Thyrotoxicosis
- B - Beriberi (thiamine deficiency)
- A - Arteriovenous fistula, including large haemangiomas
- T - Paget disease of bone (and sepsis, and liver failure)
The common mechanism is either reduced systemic vascular resistance (fistula, sepsis, beriberi, Paget disease, pregnancy) or increased demand (anaemia, thyrotoxicosis).
Cardiac output rises to compensate, and if sustained the heart eventually fails despite an output that is normal or high. The clinical picture is heart failure with warm peripheries, a bounding pulse, a wide pulse pressure and often a flow murmur, in contrast with the cold, vasoconstricted picture of low output failure.
Treatment is directed at the cause, since diuresis and inotropes address the consequence rather than the mechanism.