Overdraining and Underdraining with Hydrocephalus: Key Causes, Symptoms, and Solutions

Treatments like shunt systems and endoscopic third ventriculostomy (ETV) help manage the flow of cerebrospinal fluid (CSF) in the brain. While these treatments are essential for people living with hydrocephalus, they don’t always work perfectly.

Sometimes, they remove too much fluid (overdrainage), and other times they don’t remove enough (underdrainage). Both problems can lead to serious symptoms and health challenges, so it’s important to understand how they happen, what they feel like, and how to fix them.

Overdrainage: Causes, Symptoms, and Risks

Overdraining happens when CSF is removed too quickly or in excessive amounts, creating an effect that lowers intracranial pressure (ICP). This condition can occur due to:

• Malfunctioning Shunts: Shunts can remove more CSF than necessary.  Programmable valves may be set to drain too aggressively or the need for more CSF drainage may change over time.  Non-programmable valves can malfunction, resulting in more CSF drainage than intended.
• Common Symptoms of Overdraining:
  • Positional Headaches: Severe headaches that worsen when sitting or standing and improve when lying down.
  • Dizziness and Fatigue: Low CSF levels can affect balance and energy levels.
  • Visual Disturbances: Blurred vision or double vision.
• Potential Complications:
  • Intracranial Hypotension: Persistent low intracranial pressure (ICP) can cause debilitating symptoms and even impact daily activities.
  • Subdural Hematomas: When the brain pulls away from the skull due to pressure changes, blood vessels can tear, leading to bleeding in the subdural space.

Underdrainage: Causes, Symptoms, and Risks

Underdrainage occurs when CSF is not removed appropriately, leading to fluid buildup and/or increased intracranial pressure (ICP). This can happen due to:

• Shunt Blockages: Partial or complete obstructions in the shunt tubing or valves prevent proper CSF flow.  Sometimes fluid can collect in a cyst at the end of a peritoneal shunt and cause poor shunt function and underdrainage.
• Inadequate Shunt Function: Programmable shunts may be on a setting that drains less CSF than needed.  Non-programmable shunts may have too high a resistance to spinal fluid flow, and can lead to CSF accumulation.
• ETV Stoma Closure: Scar tissue or other factors can partially or completely close the stoma, reducing drainage.  In some cases, the stoma remains open but there is not enough absorption of the CSF to control the pressure.
• Common Symptoms of Underdrainage:
  • Persistent Headaches: Often described as a feeling of intense pressure, especially in the morning or after lying down; some people will say the headache is in the front of their head or directly inside their head.
  • Cognitive Impairments: Difficulty concentrating, memory problems, or confusion.
  • Nausea and Vomiting: Common signs of increased ICP.
  • Papilledema: Not a symptom but a finding on examination of the eyes; The optic nerve at the back of the eye can show signs of intracranial pressure.
• Potential Complications from prolonged underdrainage include:
  • Ventricular Enlargement: worsening hydrocephalus with enlargement of the ventricles and possibly permanent brain damage.
  • Functional Decline: patients may experience physical and cognitive impairments, affecting their independence.
  • Vision changes or loss of vision:  increased pressure can result in vision changes or permanent loss of vision

Diagnosis: How Medical Teams Identify the Problem

Both overdrainage and underdrainage require prompt evaluation to prevent long-term problems. Diagnostic methods include:

• Symptom Review: A detailed history of symptoms can guide adjustments to treatment settings and indicate whether additional testing is needed.
• Imaging Studies: CT scans or MRIs help assess ventricular size and detect structural changes; these are indirect measures of intracranial pressure.
• Pressure Monitoring: Measuring intracranial pressure (ICP) through invasive methods, such as inserting an external ventricular drain or intracranial pressure (ICP) monitor, can provide precise readings. Non-invasive methods may also be used but are less accurate.
• Shunt Flow Studies: Tests like a “shuntogram” (shunt patency study) check whether the shunt is open and functioning. Some methods inject a contrast dye or nuclear tracer then image the flow in the shunt; other methods use temperature to show fluid flow in the shunt.
• X-rays: These are used to visualize the shunt system and tubing, looking to see if it is intact and properly positioned in the body.

Treatment Options: Restoring Balance

Managing overdrainage and underdrainage often involves adjustments to treatment plans. Key interventions include:

1. Symptom Management: Medications, hydration, and lifestyle adjustments can help alleviate associated symptoms while treatment is optimized.
2. Shunt Adjustments: Programmable shunts allow healthcare providers to adjust the flow of cerebrospinal fluid (CSF) without requiring surgery. Adjustments can address both overdrainage and underdrainage.
3. Shunt Revisions: If the shunt system is malfunctioning or not functioning adequately, surgical replacement or repair may be necessary.
4. Endoscopic Third Ventriculostomy (ETV) Modifications: For ETV patients, re-evaluating the stoma’s patency through imaging or revision surgery can restore effective drainage.

Living with Shunts and ETV: Practical Tips for Patients

For individuals managing hydrocephalus, maintaining a proactive approach to health is critical. Here are some practical tips:

• Track Symptoms: Keep a daily log of symptoms and activities to identify patterns or changes over time. Consider using tools like the HydroAssist® app, which helps track symptoms, shunt settings, and treatments, providing valuable data to share with your healthcare team. Regularly update your log with details such as headaches, nausea, or changes in vision.
• Recognize Emergency Signs: Learn to identify symptoms that require immediate attention, such as sudden severe headaches, seizures, confusion, or loss of consciousness. Seek immediate medical help if these occur.
• Attend Regular Check-Ups:
• Stay Educated: Understanding your condition and treatment options empowers you to make informed decisions.
• Seek Community Support: Joining hydrocephalus support groups can provide valuable advice and emotional encouragement.

Managing the Delicate Balance of CSF Drainage

Overdrainage and underdrainage highlight the delicate balance required in managing hydrocephalus. While these complications can be challenging, advances in medical technology and personalized care strategies have made it possible to address them effectively. By maintaining open communication with healthcare providers and staying vigilant about symptoms, patients can lead fulfilling lives despite these hurdles. For additional resources and support, reach out to the Hydrocephalus Association.

Information you can trust! This article was produced by the Hydrocephalus Association, copyright 2025. We would like to thank Bruce A. Kaufman, MD for his valuable contribution and expert input.