Harvey's Garden

Cyanosis

2 min read

  • Pathophysiology & Classification
    • Central Cyanosis: ↓ Arterial O2 saturation (SaO2) or abnormal Hb. Deoxygenated Hb > 5 g/dL. Manifests in lips, tongue, mucous membranes.
    • Peripheral Cyanosis: Normal SaO2, but ↑ tissue O2 extraction due to sluggish capillary flow. Manifests in distal extremities (fingers, toes), nose, earlobes.
  • Epidemiology & Risk Factors
    • Central: Cardiopulmonary dz (COPD, ILD, congenital heart dz), altitude, toxins (dapsone, local anesthetics, nitrates).
    • Peripheral: Cold exposure, low cardiac output states (HF, shock), vasospasm (Raynaud’s), vascular occlusion.

Acrocyanosis

  • Epidemiology & Risk Factors
    • Physiologic: Healthy newborns (resolves in days). c
      • Exaggerated autonomic/sympathetic response to the sudden drop in ambient temperature (womb vs. room air) causes reflex peripheral vasoconstriction.
    • Primary: Young women, low BMI. Triggered by cold/stress.
    • Secondary: Anorexia, POTS, CTDs, sympathomimetics.
  • Clinical Features
    • Persistent, symmetric blue/purple hands & feet.
    • Painless (key identifier).
    • Cool, clammy extremities w/ normal pulses.
  • Diagnosis
    • Initial: Clinical H&P.
    • Key Labs: Pulse ox normal (rules out central cyanosis).
    • Confirmatory: None. Workup (ANA, CBC) only if atypical/secondary suspected.
  • Differential Diagnostics
    • Raynaud Phenomenon: Painful, episodic, triphasic color change (white blue red).
    • Central Cyanosis: Involves mucosa (lips/tongue), ↓ SpO2.
    • Acute Limb Ischemia: Painful, pulseless, pale (6 Ps).
  • Management
    1. First-line: Reassurance.
    2. Conservative: Avoid cold, wear warm clothing.
    3. Refractory: CCBs (rarely needed).
  • Complications
    • Benign. No tissue necrosis or ulcers. Primarily cosmetic.

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