Acrocyanosis
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Clinic
- Acrocyanosis is persistent blue or cyanotic discoloration of the extremities, most commonly occurring in the hands, although it also occurs in the feet and distal parts of face.
- A medical emergency would ensue if the extremities experience prolonged periods of exposure to the cold, particularly in children and patients with poor general health.
- However, frostbite differs from acrocyanosis because pain (via thermal nociceptors) often accompanies the former condition, while the latter is very rarely associated with pain.
Differential diagnosis
- Raynaud phenomenon,
- Pernio
- Acrorygosis
- Erythromelalgia
- Blue finger syndrome. The diagnosis may be challenging in some cases, especially when these syndromes co-exist.
Acrocyanosis may be a sign of
- Connective tissue diseases
- Diseases associated with central cyanosis
- Infections
- Toxicities
- Antiphospholipid syndrome
- Cryoglobulinemia
- Neoplasms
- In these cases, the observed cutaneous changes are known as "secondary acrocyanosis". They may have a less symmetric distribution and may be associated with pain and tissue loss.
Signs / Symptoms
- Characterized by Peripheral / Persistent cyanosis of the hands, feet, knees, or face.
- The extremities often are cold and clammy and may exhibit some swelling (especially in warmer weather).
- The palms and soles exhibit a wide range of sweating from moderately moist to profuse, but all peripheral pulses should have normal rate, rhythm, and quality.
- Exposure to cold temperatures worsens the cyanosis, while it often improves on warming.
- Aside from the color changes, patients normally are asymptomatic and therefore there is usually no associated pain. The most common sign, discoloration, usually is what prompts patients to seek medical care.
Pathophysiology
- The precise mechanism is not known, possibly vasospasms in the cutaneous arteries and arterioles produce cyanotic discoloration, while compensatory dilatation in the postcapillary venules causes sweating.
- Arteriovenous subpapillary plexus shunting also occurs.
- Persistent vasoconstriction at the precapillary sphincter creates a local hypoxic environment, thus releasing adenosine into the capillary bed. Vasospasms force adenosine to enter the capillary bed, where it vasodilates the postcapillary venules. Such differences in vessel tone create a countercurrent exchange system that attempts to retain heat.
- Profuse sweating would then be caused by an overwhelmed countercurrent exchange system.