Overview of Acquired Hydrocephalus

Acquired hydrocephalus develops after birth and can be caused by a variety of factors, such as head injury, meningitis, and brain tumors. The basic nature of this condition is that the circulation of cerebrospinal fluid (CSF) is blocked, causing the brain’s ventricles so that they become enlarged.  As a result, pressure develops in the brain, which can result in significant swelling. Surgical treatments, such as shunting, are effective in alleviating the symptoms and providing proper circulation of CSF (1).

Typology

Hydrocephalus can be either communicating, in which CSF can still flow between the ventricles (flow is blocked after it exits the ventricles), or non-communicating, in which CSF is blocked along the passages connecting the ventricles. Hydrocephalus ex-vacuo occurs when a stroke or injury damages the brain matter, causing the brain to shrink. This eventually leads to an increase in CSF, which fills the extra space within the skull. Another type of communicating hydrocephalus known as normal pressure hydrocephalus (NPH), occurs from the gradual blockage of the CSF draining. Over time, the ventricles enlarge in order to accommodate the increased volume of CSF. In contrast to hydrocephalus ex-vacuo, CSF pressure fluctuates from high to low in NPH (2).

Symptoms of Acquired Hydrocephalus

NPH is characterized by a triad of symptoms (2). Gait disturbance is usually the first sign, followed by cognitive impairment and then urinary dysfunction. Gait disturbance can range from unsteadiness and shortened stride length, to perceived weakness (although no paresis or ataxia are found upon examination). Gait difficulties may resemble those seen in Parkinson’s disease, but there is no shuffling (at least not in the early stages), rigidity, slowness, or tremor. In terms of mental changes, apathy, slowed thinking, and inattention may be present. Impairment may also occur in memory, visuospatial skills, and executive functions (higher-order abilities such as planning, organizing, and problem solving) (3). Urinary symptoms appear relatively later in the course of the disorder, consisting of increased urgency and frequency, which may lead to incontinence. Other symptoms include headaches, nausea, double vision, leg and arm weakness, sudden falls, mood irritability, drowsiness, seizures, and personality and behavior changes. In severe cases, patients may have trouble sitting and positioning their heads (2).

Prevalence

Hydrocephalus can occur at any age, although it most frequently occurs in older adults. There are no differences in terms of gender or ethnicity. According to the National Institute of Neurological Disorders and Stroke (4), there is an estimated 375,000 older Americans who have NPH.

Course

Patients who have hydrocephalus generally worsen over time. Hydrocephalus is an ongoing condition that requires long-term care from a doctor, as there is no cure. Many people believe that their symptoms are part of the aging process, and their cases go unrecognized. It is not uncommon for hydrocephalus diagnoses to be missed, or for patients to be misdiagnosed (such as for Alzheimer’s disease). Death can result from the direct symptoms produced or from hydrocephalus itself (1).

Treatments for Acquired Hydrocephalus

There are two ways of treating hydrocephalus. The disorder may be treated either directly, by removing the cause of CSF obstruction, or indirectly via shunting to divert the fluid to another body cavity. The indirect method may still require another surgery later to remove the cause of the obstruction. Side effects from treatment include redness, tenderness, pain or swelling of the skin, irritability, drowsiness, nausea, fever, and abdominal pain (2).

 

References

  1. Edgar, S, White, K, Cummings, J (2002). Neuropsychiatric Aspects of Alzheimer’s Disease and Other Dementing illnesses. In S Yudofsky & R Hales (Eds.),Textbook of neuropsychiatry and clinical neurosciences (pp. 977-1000). Washington, DC: American Psychiatric Publishing.
  2. Rooper, H, Samuels, A, & Klein, P (2014). Disturbances of Cerebrospinal Fluid, including hydrocephalus, pseudotumor, cerebri, and low pressure syndromes. In A Ropper & R Brown (Eds.), Adams and Victor's principles of neurology (pp. 632-640). NY: McGraw-Hill.
  3. Devito, E, Pickard, J, Salmond, C, Iddon, J, Loveday, C, & Sahakian, B (2005). The neuropsychology of normal pressure hydrocephalus (NPH). British journal of neurosurgery19(3), 217-224.
  4. National Institute of Neurological Disorders and Stroke (2013). Hydrocephalus Fact Sheet. Retrieved from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Hydrocephalus-Fact-Sheet.