Makindo Medical Notes

Assess stroke risk before doing CSM and consider a carotid ultrasound

About

• Carotid sinus hypersensitivity (CSH) is a condition primarily seen in elderly patients, characterized by an exaggerated response to external pressure on the carotid sinus.
• This hypersensitivity can lead to episodes of reflex bradycardia and syncope, contributing to unexplained falls in susceptible individuals.
• Rare and accounts for less than 1% of TLOC and unexplained syncope

Aetiology

• CSH results from an abnormal sensitivity of the carotid sinus, where light external pressure is misinterpreted by the artery as a significant internal stimulus.
• This misinterpretation triggers a severe reflex response, leading to a marked reduction in heart rate and/or a drop in blood pressure.
• Studies indicate that up to 56% of cases of unexplained syncope in the elderly may be attributed to carotid sinus hypersensitivity.

Clinical Presentation

• Patients may experience syncope or near-syncope associated with activities that involve pressure on the neck, such as wearing a tight collar, turning the head, or looking upward.
• Carotid sinus massage (CSM) can reproduce symptoms, confirming the diagnosis.
• Unexplained falls in elderly patients are common and may be a manifestation of this condition.

Differential Diagnosis

• Vasovagal syncope
• Heart block or other conduction abnormalities
• Other causes of orthostatic hypotension

Investigations

• Carotid sinus massage is performed in a controlled setting with resuscitation equipment and atropine available. A positive test is defined as a pause in the heartbeat of 3 or more seconds (cardioinhibitory response) or a drop in blood pressure of 50 mm Hg or more (vasodepressor response), as demonstrated on ECG and blood pressure monitoring.
• Prior to CSM, significant carotid artery disease should be excluded by ultrasonography to reduce the risk of embolic complications.

Monitoring during CSM may show a pause...

Management

• Immediate Management: In cases of syncope or presyncope, the patient should be laid down with their legs elevated to improve cerebral perfusion.
• Preventive Measures: Advise patients to avoid tight collars or any external pressure on the neck that may trigger an episode.
• Cardioinhibitory Response: For patients exhibiting a predominantly cardioinhibitory pattern, pacemaker implantation may be considered.
• Vasodepressor Response: In cases with a significant vasodepressor component, ensure the patient is well hydrated and consider interventions to maintain blood pressure.
• Monitoring and Follow-Up: Continuous monitoring of heart rate and blood pressure, as well as periodic reassessment, is crucial in managing and adjusting treatment for these patients.

References

• For detailed pharmacological and clinical guidelines, please refer to the BNF and other relevant clinical resources.

Revisions

• Last updated: [Insert Revision Date]