Ventriculitis

What ventriculitis is

The brain contains four ventricles that make and circulate cerebrospinal fluid (CSF), the clear fluid that cushions the brain and spinal cord. In ventriculitis, bacteria or, rarely, fungi infect the fluid inside the ventricles and inflame their lining. Pus and debris can collect, clog the narrow channels between ventricles and cause hydrocephalus, a buildup of fluid under pressure.

Doctors use the term "healthcare-associated ventriculitis and meningitis" for infections linked to neurosurgery and devices. These now account for most cases seen in hospitals.

Causes and risk factors

Device and surgery related (most common)

• External ventricular drains (EVDs): temporary tubes placed to relieve pressure after bleeding, trauma or tumors. A small percentage become infected, and the risk rises the longer the drain stays in, with frequent sampling and with CSF leaks.
• Shunts: ventriculoperitoneal (VP) and other shunts for hydrocephalus. Most shunt infections appear within weeks to months of surgery.
• Brain or spine surgery, especially when there is a CSF leak.
• Penetrating head trauma or skull base fractures with fluid leaking from the nose or ears.
• Intraventricular bleeding, such as after a subarachnoid hemorrhage, which often needs an EVD.

Community acquired

• Severe bacterial meningitis, where infection spreads into the ventricles
• A brain abscess that ruptures into a ventricle, a serious complication
• In newborns, meningitis from group B streptococcus or gram-negative bacteria, especially in premature babies

Common germs

Skin bacteria (coagulase-negative staphylococci, Staphylococcus aureus and Cutibacterium acnes) cause most device infections. Gram-negative bacteria such as Acinetobacter, Pseudomonas, Klebsiella and E. coli cause a significant share, particularly in intensive care units, and are often resistant to many antibiotics.

Symptoms

• Fever, sometimes the only sign
• Headache
• Reduced alertness, confusion or new drowsiness
• Neck stiffness and light sensitivity (less common than in typical meningitis)
• Nausea and vomiting
• Seizures
• Cloudy, discolored fluid in an EVD drainage bag
• Signs of shunt failure: returning headache, vomiting and sleepiness (see shunt malfunction)
• Redness or swelling along a shunt tract, or belly pain from infection at the shunt's end
• In babies: irritability, poor feeding, a bulging soft spot, a rapidly growing head

In ICU patients who are already sedated or have brain injuries, symptoms can be subtle. That is why clinicians monitor CSF from drains closely.

Diagnosis

• CSF analysis from the drain, shunt or lumbar puncture (if safe): a raised white cell count, low glucose and high protein suggest infection. Results are harder to read after bleeding or surgery, which also change CSF.
• CSF Gram stain and culture, ideally before antibiotics, held for up to 10 days to catch slow-growing Cutibacterium.
• Repeated CSF samples to show whether infection is clearing.
• Blood cultures and blood tests.
• MRI with contrast: shows debris layering in the ventricles, enhancement of the ventricle lining and hydrocephalus. MRI is the most sensitive imaging test.
• CT scan for hydrocephalus or abscess when MRI is not possible.
• Shunt tap: sampling fluid directly from a shunt reservoir.

Treatment

Treatment follows the IDSA guideline for healthcare-associated ventriculitis and meningitis, guided by an infectious disease specialist and neurosurgeon.

Antibiotics

• Empiric treatment: intravenous vancomycin plus an antibiotic active against Pseudomonas, such as cefepime, ceftazidime or meropenem, started as soon as cultures are taken.
• Targeted treatment once the germ and its sensitivities are known.
• Intraventricular antibiotics: antibiotics such as vancomycin, gentamicin or colistin given directly into the ventricles through a drain, when infections respond poorly to IV treatment or involve resistant bacteria.
• Duration: commonly 10 to 14 days, sometimes extended to about 21 days for gram-negative bacteria, depending on the organism, how inflamed the CSF is and how quickly cultures clear.

Managing the device

• Infected shunts and drains are usually removed, and a temporary external drain is placed.
• A new shunt is placed only after repeated CSF cultures are negative, typically after a period of days that depends on the organism.
• Infected EVDs are replaced or removed.

Surgery and supportive care

• Endoscopic washing out of pus from the ventricles in some severe cases
• Drainage of an associated brain abscess
• Treatment of hydrocephalus, seizures and raised pressure
• Intensive care support

Complications and outlook

Ventriculitis is serious. Possible complications include:

• Hydrocephalus needing a permanent shunt
• Loculated (walled-off) fluid pockets
• Brain abscess and seizures
• Stroke from inflamed blood vessels
• Long-term problems with thinking, movement and development in children
• Death, with higher risk in infections caused by resistant gram-negative bacteria, in very ill ICU patients and in ruptured brain abscess

Early diagnosis, prompt device removal and adequate antibiotic treatment improve outcomes.

Prevention

Hospitals reduce drain and shunt infections with careful sterile technique, antibiotic-impregnated catheters, tunneling the drain under the skin, limiting how often CSF is sampled, removing drains as soon as possible, and antibiotics given just before surgery. Families of children with shunts should learn the signs of infection and malfunction.

Frequently asked questions

What is ventriculitis?

Ventriculitis is an infection of the brain's ventricles, the internal fluid-filled spaces, and their lining. It usually happens after brain surgery, an external drain or a shunt, or as a complication of bacterial meningitis or a burst brain abscess. It needs urgent treatment with antibiotics and often surgery.

What are the symptoms of a shunt infection affecting the ventricles?

Fever, headache, vomiting, unusual sleepiness, irritability and confusion are common. There may be redness or swelling along the shunt tubing or belly pain. In babies, a bulging soft spot and poor feeding are warning signs. Any of these after shunt surgery needs emergency assessment.

How is ventriculitis diagnosed?

Doctors test cerebrospinal fluid taken from a drain, shunt or spinal tap for white cells, glucose, protein and bacteria, and culture it. MRI with contrast shows inflammation of the ventricle lining and debris in the ventricles. Blood tests and cultures are also done.

How long is treatment for ventriculitis?

Antibiotics are usually given intravenously for about 10 to 14 days, and some specialists extend treatment to around 21 days for gram-negative bacteria. The exact length depends on the germ and how quickly the fluid clears. Infected shunts are typically removed and replaced only after the fluid has been clear of infection.

Can ventriculitis be cured?

Yes, many people recover with prompt antibiotics and removal of infected devices. However, it can cause lasting problems such as hydrocephalus requiring a permanent shunt, seizures or difficulties with thinking, and it can be fatal, especially with resistant bacteria or in very ill patients.