Features of central cyanosis are the following
1. Central cyanosis sites affected are
- Tongue (mainly the margins as well as the undersurface).
- Inner aspect of lips.
- Mucous membrane of gum. soft palate, cheeks.
- Lower palpebral conjunctiva.
2. Due to increased blood flow, on shaking hands the hand feels warm.
3. No change in cyanosis is noted on application of warmth
4. Cyanosis may improve on application of 100 % oxygen for 10 minutes
5. Clubbing and polycythemia is usually present in association with central cyanosis.
6. Pulse volume may be high if there is arteriovenous shunt
7. Patient is often breathless in central cyanosis
Following are the features of peripheral cyanosis
1. The sites affected in peripheral cyanosis are
- Tip of the nose.
- Ear lobules.
- Outer aspect of lips, chin and cheek.
- Tip of fingers and toes.
- Nail-bed of fingers and toes.
- Palms and soles.
2. Due to decreased blood flow, on shaking hands the hand feels cold.
3. Improvement in cyanosis is noted on application of warmth.
4. Cyanosis shows no change on application of 100 % oxygen for 10 minutes
5. Clubbing and polycythemia is usually absent in peripheral cyanosis.
6. Pulse volume is low
7. Patient doesnot have breathlessness
