- 1–2% mortality rate reported: Hydrocephalus is a rare cause of death in the population; its mortality rate has been calculated as 0.71/100,000 person-years (12). Among hydrocephalic patients, Paulsen et al. found a 22% mortality rate over a 20-year period in 138 patients with shunts, but only 2.9% of the patients died of identified hydrocephalus-related causes (35). Other authors have determined the rate of shunt-related deaths to be 1% per year (24).
- Myelomeningocele patients at increased risk: Patients with myelomeningocele are especially at risk for a fatal shunt malfunction, because the Chiari malformation predisposes them to a catastrophic evolution (51).
- Risk of sudden death in patients with ETV: Obstruction of an ETV can present as sudden death (17).
- May be under-reported: The true rate of shunt-related mortality might be much higher than reported, because fatal shunt malfunction or infection can be undetected, especially in severely debilitated patients (9). Additionally, hydrocephalus may contribute to a fatal outcome in severely ill patients. Basically, the occurrence of sudden death in a patient treated for hydrocephalus should be considered as treatment related until proven otherwise. This risk for death underscores the need for the education of the patient, his entourage, and the general practitioner about the signs of shunt malfunciton. It also calls for closely observing the patient for precursor signs of dysfunction, such as asymptomatic shunt rupture, atypical headache, and subtle modifications in behavior or intellectual performance.
- Highest risk of failure during the first year: In all study series of shunt survival, the first year of follow-up sees a failure rate of about 25–30%, followed by a steady decline in the rate of shunt survival.
- Plateau in incidence failure after 20 years: In the experience of the author and colleagues (figure below) with patients followed for more than 20 years, 20% had never required a revision during childhood, but several patients had their first shunt malfunction after age 20 years. These data confirm that lifelong follow-up is necessary for all patients with shunts. The fact that the shunt has never been revised sometimes raises suspicion that it has been occluded from the start. Proof of its functionality comes when it fails and requires revision.
- Risk of failure then gradually declines: The cumulative incidence of shunt malfunction shows an initial sharp drop during the first year, then a steady decline, and an almost flat line after 15 years. However, it never falls to zero. Many patients presented with their first episode of shunt malfunction after the age of 20. Thus, even in adulthood, a shunt should always be considered functional unless proved otherwise.
- 41% remain dependent on others: Data on long-term achievement and employment of hydrocephalic patients are scarce. Among 138 adult patients who received shunts in infancy in Norway, 23% were still studying, 33% were employed in the competitive labor market, 23% were employed in a sheltered job, and 21% were “not in contact with the labor market”; overall, even in a generous healthcare system, 41% were dependent (35). Gupta et al. also found that 63% of the adult patients were single (20).
- High incidence of depression: 43% suffered depression (20).
- Patients with early-onset hydrocephalus do worst: The level of achievement seems to be lower in individuals with early-onset hydrocephalus (20).
- Success in school not predictive: School achievement has been found not to be predictive of social outcome (27). The author and colleagues found a discrepancy between the results of IQ tests and’ schooling performance of patients. Furthermore, school achievement did not predict the patients’ eventual social-professional integration; these successive hurdles represent a “funnel of integration” (50).