Seminar: Approach to
Abdul Waris Khan
4th Year (Medicine)
• Shock is the term used to describe acute circulatory
failure with inadequate or inappropriately
distributed tissue perfusion resulting in generalized
cellular hypoxia and/or an in ability of the cells to
Causes of shock
Abnormalities of tissue perfusion may result from:
failure of the heart to act as an effective pump
mechanical impediments to forward flow
loss of circulatory volume
abnormalities of the peripheral circulation.
CLINICAL FEATURES OF SHOCK
Inadequate tissue perfusion:
(a) Skin – cold, pale, slate-grey, slow capillary refill, ‘clammy’
(b) Kidneys – oliguria, anuria
(c) Brain – drowsiness, confusion and irritability.
Increased sympathetic tone:
(a) Tachycardia, narrowed pulse pressure, ‘weak’ or ‘thready’ pulse
(c) Blood pressure – may be maintained initially (despite up to a 25%
reduction in circulating volume if the patient is young and fit), but
later hypotension supervenes.
Metabolic acidosis – compensatory tachypnoea.
• Elevated JVP.
• Pulsus paradoxus and muffled heart sounds in
• Signs of pulmonary embolism
Signs of profound vasodilatation:
(a) Warm peripheries
(b) Low blood pressure
■ Erythema, urticaria, pallor, cyanosis.
■ Bronchospasm, rhinitis.
■ Oedema of the face, pharynx and larynx.
■ Hypovolaemia due to capillary leak.
■ Nausea, vomiting, abdominal cramps, diarrhoea.
• Sepsis, severe sepsis and septic shock
■ Pyrexia and rigors, or hypothermia (unusual).
■ Nausea, vomiting.
■ Vasodilatation, warm peripheries.
■ Bounding pulse.
■ Rapid capillary refill.
■ Hypotension (septic shock).
■ Occasionally signs of cutaneous vasoconstriction.
■ Other signs:
(b) Coma, stupor
(c) Bleeding due to coagulopathy (e.g. from vascular puncture
sites, GI tract and surgical wounds)
(d) Rash and meningism
(c) Hyper-, and in more severe cases hypoglycaemia
Assessment of tissue perfusion
■ Pale, cold skin, delayed capillary refill and the
visible veins in the hands and feet indicate poor
■ Metabolic acidosis with raised lactate
concentration may suggest that tissue perfusion is
sufficiently compromised to cause cellular hypoxia
and anaerobic glycolysis. dysfunction.
■ Urinary flow is a sensitive indicator of renal perfusion
and haemodynamic performance
• Kumar & Clark’s Clinical Medicine 7th edition