Anaphylactic Shock

Case 5.2Mustafa Al AliGroup 1

OBJ.What is the main problem of this case?

Pathophysiology

What is angioedema and urticaria and there indication?

The explanation of the short breath

Why there is hypotension?

What is the effect of dilatation in venous return curve?

The explanation of tachycardia ?

The management?

What is angioedema & urticaria

Angioedema :  is the swelling of deep dermis, subcutaneous, or mucosa due to vascular leakage ( deeper )

Urticataria (hives): is a common skin condition charcterized by acute development of itchy wheals or swelling in the skin due to

leaky dermal vessels ( commonly upper part of dermis)

They usually indicate to allergy

The main problem of this case Anaphylactic shock

Anaphylactic shock : a serious allergic reaction that’s rapid in onset and may cause

death.

Pathophysiology

Sensitized

TPR×BP= COVasodilation

TPR↓BP↓

Why there’s hypotension?

Decrease in BP

Powerful stimulation

of SNS

Vasoconstriction in most tissues

Increase TPR

Veins and venous

reservoir constrict

Maintaining adequate VR

Increase in heart

activity

HR 160-180

beats/min

The explanation of tachycardia?

Why there’s shortness of breath

Histamine causes changes in VR curve

↑vascular capacity because of venous dilation, thus causing a marked ↓ in venous return

dilation of the arterioles, resulting in greatly ↓ arterial pressure

and (3) greatly ↑ capillary permeability, with rapid loss of fluid and protein into the tissue

spaces .

The net effect is a great ↓ in venous return Guyton Ch.24

Arterial dilation

Increase in cardiac output (CO) with a small increase in right atrial

pressure (PRA).

Arterial dilation

Peripheral resistance

Cardiac Out put

Venous dilators

Venous dilation reduce : 1.Venous pressure and 2.therefore cardiac preload.

2.Cardiac output.

3.Arterial pressure.

4.Myocardial O2 demand.

The best treatment is prevention. Avoidance of triggering foods may require almost obsessive self-discipline.

Desensitization has a well-established place in the management of this disorder, especially if exposure is

unpredictable/unavoidable such as insect stings.

Management

Patient education is necessary and many are instructed in self-administration of adrenalin and carry pre-loaded

syringes (needles)

Management

Immediate – Often lifesaving

Kumar & Clark Ch.3

References

Websites

://http . . / /135208-emedicine medscape com article overview