From the Guidelines
Syncope is a potential complication of ventriculoperitoneal (VP) shunt malfunction, particularly related to overdrainage of cerebrospinal fluid (CSF), and patients experiencing syncope with a VP shunt should be considered a medical emergency as it may indicate serious shunt dysfunction requiring immediate intervention. When a VP shunt drains too much CSF, it can cause a sudden drop in intracranial pressure, especially when a patient changes position from lying to standing, leading to decreased cerebral perfusion and syncope. This is known as orthostatic or postural syncope. Patients with this complication should be evaluated promptly by a neurosurgeon for shunt revision. Management may include adjusting the valve setting if a programmable valve is present, or surgical revision to replace the valve with one that has a higher pressure setting or anti-siphon device, as recommended by the 2016 Infectious Diseases Society of America (IDSA) clinical practice guideline for the treatment of coccidioidomycosis 1.
Causes of Syncope in VP Shunt
Other VP shunt complications that may present with syncope include:
- Shunt obstruction
- Infection
- Overdrainage syndrome with subdural hematoma formation The mechanism involves altered CSF dynamics affecting cerebral blood flow and intracranial pressure regulation. In the interim, patients should be advised to change positions slowly, particularly when getting up from lying down, and maintain adequate hydration.
Evaluation and Management
According to the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope, patients with syncope and ventricular arrhythmias (VA) should receive guideline-directed medical therapy (GDMT) 1. Additionally, the 2024 American Heart Association and American Red Cross guidelines for first aid recommend physical counterpressure maneuvers (PCMs) as a first aid intervention to help prevent syncope in patients with vasovagal or orthostatic syncope 1.
Recommendations
Patients with VP shunt malfunction should have the revision performed in a single procedure, unless the shunt has developed a bacterial or other superinfection, in which case the infected shunt should be removed and a replacement be placed at a subsequent time as a second procedure 1. Patients experiencing syncope with a VP shunt should be evaluated promptly and managed accordingly to prevent further complications and improve quality of life.
From the Research
Complications of VP Shunt
- The complications of VP shunt can be mechanical or non-mechanical, and can include shunt malfunction, infection, or abdominal complications 2.
- Syncopy, or fainting, can be a symptom of VP shunt malfunction, although it is not a direct complication of the shunt itself.
- The diagnosis of VP shunt malfunction can be challenging, and may require the use of imaging modalities such as MRI, CT, or X-ray shunt series 3, 4.
Diagnostic Modalities
- A systematic review and meta-analysis found that MRI had a sensitivity of 57% and specificity of 93% for diagnosing VP shunt malfunction, while CT scan had a sensitivity of 53-100% and specificity of 27-98% 3.
- Low-dose computed tomography (LD-CT) has been shown to have high sensitivity and diagnostic confidence for detecting VP shunt complications, with lower radiation exposure compared to radiographic shunt series 4.
Clinical Presentations
- VP shunt failure can present with a variety of clinical symptoms, including headache, nausea, vomiting, and altered mental status 5.
- Syncopy, or fainting, can be a symptom of VP shunt malfunction, and may require prompt medical attention to prevent further complications.
Management
- Prompt referral for neurosurgical intervention is recommended for patients with suspected VP shunt malfunction, regardless of the results of imaging studies 3.
- Nurses play an important role in caring for patients with VP shunts, and should be aware of the possible complications and nursing care required for these patients 2.