Types of Shock: A Simple Guide

Educational guide · ~6 min read

Shock is a state where the circulation fails to deliver enough oxygen to the tissues. It's a clinical emergency. There are four main types, grouped by why the circulation is failing. Recognising the type points you toward the cause and the treatment.

1. Hypovolaemic shock

Not enough volume in the tank. Caused by bleeding (trauma, GI haemorrhage) or fluid loss (vomiting, diarrhoea, burns). Signs: cold, pale, clammy skin, tachycardia, low blood pressure, low urine output. The core problem is reduced preload.

2. Cardiogenic shock

The pump fails. Caused by a large myocardial infarction, arrhythmia or end-stage heart failure. The heart can't push blood forward, so it backs up — patients are often cold and clammy and congested (e.g. pulmonary oedema).

3. Distributive shock

The pipes dilate, so blood pressure drops even with normal volume. This group includes:

• Septic shock — overwhelming infection causing vasodilation and capillary leak. Patients are often warm and flushed early ("warm shock").
• Anaphylactic shock — severe allergic reaction; treated urgently with intramuscular adrenaline.
• Neurogenic shock — loss of sympathetic tone after spinal cord injury; classically low blood pressure with a slow heart rate.

4. Obstructive shock

Something physically blocks the circulation. Causes include a massive pulmonary embolism, cardiac tamponade, and tension pneumothorax. The heart and vessels may be fine, but flow is mechanically obstructed — these need the obstruction relieved.

The general approach

Whatever the type, the priorities are the same airway-breathing-circulation framework: recognise shock early, give oxygen, gain IV access, treat the cause (fluids for hypovolaemia, adrenaline for anaphylaxis, antibiotics for sepsis, decompression for tamponade/pneumothorax), and escalate to senior help immediately.

Frequently asked questions

What are the four main types of shock?

Hypovolaemic, cardiogenic, distributive (including septic, anaphylactic and neurogenic) and obstructive shock.

Which type of shock causes a slow heart rate?

Neurogenic shock classically causes hypotension with bradycardia due to loss of sympathetic tone, unlike most other shock states which cause tachycardia.

This article is for education only and is not medical advice. Shock is a medical emergency requiring immediate senior clinical input.