Risk factors, comorbidities, quality of life, and complications after surgery in idiopathic normal pressure hydrocephalus: review of the INPH-CRasH study

Abstract

OBJECTIVEIdiopathic normal pressure hydrocephalus (INPH) is a dementia treatable by insertion of a shunt that drains CSF. The cause of the disease is unknown, but a vascular pathway has been suggested. The INPH-CRasH (Comorbidities and Risk Factors Associated with Hydrocephalus) study was a modern epidemiological case-control study designed to prospectively assess parameters regarding comorbidities and vascular risk factors (VRFs) for INPH, quality of life (QOL), and adverse events in patients with shunted INPH. The objective of this review was to summarize the findings of the INPH-CRasH study.METHODSVRFs, comorbidities, QOL, and adverse events were analyzed in consecutive patients with INPH who underwent shunt placement between 2008 and 2010 in 5 of 6 neurosurgical centers in Sweden. Patients (n = 176, within the age span of 60–85 years and not having dementia) were compared to population-based age- and gender-matched controls (n = 368, same inclusion criteria as for the patients with INPH). Assessed parameters were as follows: hypertension; diabetes; obesity; hyperlipidemia; psychosocial factors (stress and depression); smoking status; alcohol intake; physical activity; dietary pattern; cerebrovascular, cardiovascular, or peripheral vascular disease; epilepsy; abdominal pain; headache; and clinical parameters before and after surgery. Parameters were assessed through questionnaires, clinical examinations, measurements, ECG studies, and blood samples.RESULTSFour VRFs were independently associated with INPH: hyperlipidemia, diabetes, obesity, and psychosocial factors. Physical inactivity and hypertension were also associated with INPH, although not independently from the other risk factors. The population attributable risk percent for a model containing all of the VRFs associated with INPH was 24%. Depression was overrepresented in patients with INPH treated with shunts compared to the controls (46% vs 13%, p < 0.001) and the main predictor for low QOL was a coexisting depression (p < 0.001). Shunting improved QOL on a long-term basis. Epilepsy, headache, and abdominal pain remained common for a mean follow-up time of 21 months in INPH patients who received shunts.CONCLUSIONSThe results of the INPH-CRasH study are consistent with a vascular pathophysiological component of INPH. In clinical care and research, a complete risk factor analysis as well as screening for depression and a measurement for QOL should probably be included in the workup of patients with INPH. The effect of targeted interventions against modifiable VRFs and antidepressant treatment in INPH patients should be evaluated. Seizures, headache, and abdominal pain should be inquired about at postoperative follow-up examinations.

Medication‐free remission with shunt surgery for depression induced by normal pressure hydrocephalus

“…Also, apathy and cognitive deficits caused by iNPH can mask depression, psychosis and behavioural problems. 6 Previous studies have shown that the psychiatric symptoms of patients with a diagnosis of depression who were later diagnosed with NPH significantly improved after shunt surgery. 7 It is thought that enlargement of the ventricular system may prepare the groundwork for the development of psychiatric disorders, such as mania, psychosis and depression, by causing ischaemic and degenerative changes in neighbouring structures and projections by causing a mass effect.…”

“…Psychomotor retardation, apathy and anxiety symptoms that may also present at the same time with iNPH can mimic major depression. Also, apathy and cognitive deficits caused by iNPH can mask depression, psychosis and behavioural problems 6 …”

“…On the other hand, since our patient did not receive medical treatment for her psychiatric symptoms, it is likely that her clinical recovery was directly related to the shunt surgery itself. The presence of similar vascular pathologies and similar symptoms in the aetiology of depression and iNPH suggest that these two different diseases affect the same regions of the brain 6,7 . The relationship between iNPH and cerebrovascular disease is well known.…”

“…2 The frequency of probable depression in patients with iNPH who have undergone shunt surgery is four times higher in the elderly population. 6 In our literature review, we found that psychiatric disorders, such as depression, mania, obsessive compulsive disorder, psychosis, and dementia, were often reported in iNPH. We aimed to present a case of an iNPH patient with recurrent depressive episodes who recovered following shunt surgery.…”

“…One of the most frequently used methods to decide whether shunt therapy is appropriate is to perform a lumbar puncture (LBP) in patients with suspected iNPH and wait to observe improvement in the patient's clinical condition 2 . The frequency of probable depression in patients with iNPH who have undergone shunt surgery is four times higher in the elderly population 6 …”