Respiratory.ppt Pathology of the respiratory system
Reza cyanosis
1. Presented by
Dr. S. M. Monir hossain
Intern doctor
Khulna Medical College Hospital
2. Definition
It is a clinical condition characterized
by bluish or purple discoloration of
skin and mucous membrane due to
increased amount of reduced or
deoxygenated hemoglobin (Hb) in
the blood.
• Cyanosis is not seen until the
amount of deoxygenated Hb is >5
g%
4. Peripheral cyanosis
It occurs due to localised reduction of
blood flow on exposure to
cold, causing capillary
vasoconstriction. Also occurs in
reduced cardiac output i.e. Heart
failure or Shock. Peripheral cyanosis
is also seen in peripheral vascular
disease like Raynaud’s disease.
Tongue is spared in peripheral
cyanosis.
5. Central cyanosis
This is either due to imperfect oxygenation
of blood in lung or admixture of venous
and arterial blood. It is evident when O2
saturation falls below 80% to 85%.
Central cyanosis is best evident in tongue.
Tongue is not involved because tongue is
always warm and circulation is good in
tongue.
10. Causes of Central Cyanosis
• In newborn:
Birth asphyxia
Intracranial hypertension, hemorrhage
Oversedation (direct or through maternal
route)
Seizures
Respiratory distress syndrome
Meconium aspiration
Pneumonia (sepsis)
Pneumothorax
Congenital diaphragmatic hernia
Pulmonary hypoplasia
11. Causes of Central Cyanosis
• Defect in oxygenation of blood in lungs.
Fibrosing alveolitis
Severe pneumonia
COPD
Severe acute bronchial asthma
Pulmonary infarction
• Shunt anomaly in heart (right to left)
Transposition of great vessels
Total anomalous pulmonary venous return
Truncus arteriosus
Tetralogy of Fallot
Ebstein malformation of the tricuspid valve
Tricuspid atresia
12. Causes of Central Cyanosis
• Heart failure/Cardiogenic Shock
• Polycythemia
• Methemoglobinemia
• High altitude (physiological)
13. Differences between central and peripheral cyanosis
Points Central Peripheral
1. Cyanosis Generalised Localised
2. Affected part Warm Cold
3. Application of
warm
Does not disappear Disappears
4. Oxygen Cyanosis may disappear in pulmonary case (Except
in right to left shunt)
Disappears
5. Tongue Always involved Never involved
14. There is no cyanosis in Severe anemia
because Hb is low and fully saturated,
leaving no excess deoxygenated Hb.
Similarly in Polycythemia cyanosis may
occur even in mild hypoxia.
15. • When cyanosis is present only in the
toes but not in the fingers, it is called
Differential cyanosis. It is seen in
PDA. In newborns, it can also occur in
pre-ductal coarctation of aorta along
with PDA.