Effects of congenital hydrocephalus on the hypothalamic gonadotrophin-releasing hormone system

Swedish cohort study found that half of the girls with shunted hydrocephalus had precocious or early puberty

AIM

We aimed to evaluate the occurrence of, and risk factors for precocious and early puberty in a retrospective cohort study of girls with shunted infantile hydrocephalus.

METHODS

The study population comprised 82 girls with infantile hydrocephalus, born between 1980 and 2002, and treated with a ventriculoperitoneal shunt. Data were available for 39 girls with myelomeningocele and 34 without. Medical records were analysed regarding clinical data and timing of puberty. Precocious and early puberty was defined as the appearance of pubertal signs before 8 years and 0 months and 8 years and 9 months, respectively.

RESULTS

Median age at last admission was 15.8 years (range 10.0-18.0). In total, 15 girls (21%) had precocious puberty, and another 21 (29%) had early puberty. Three or more shunt revisions had been performed in 26/36 girls with early or precocious puberty and in 3/37 girls without (p = 0.01). The number of shunt revisions correlated negatively with age at the start of puberty in the girls with myelomeningocele (Spearman's correlation coefficient = -0.512, p = 0.001).

CONCLUSION

Girls with shunted infantile hydrocephalus have a high risk of precocious or early puberty. Repeated shunt revisions seemed to be associated with early puberty.

Kaolin-induced hydrocephalus causes acetylcholinesterase activity dysfunction following hypothalamic damage in infant rats

In hydrocephalus, the progressive accumulation of cerebrospinal fluid (CSF) causes dilatation of the lateral ventricles affecting the third ventricle and diencephalic structures such as the hypothalamus. These structures play a key role in the regulation of several neurovegetative functions by the production of the hormones. Since endocrine disturbances are commonly observed in hydrocephalic children, we investigated the impact of progressive ventricular dilation on the hypothalamus of infant rats submitted to kaolin-induced hydrocephalus. Seven-day-old infant rats were submitted to hydrocephalus induction by kaolin 20% injection method. After 14 days, the animals were decapitated and brain was collected to analyze mitochondrial function, neuronal activity by acetylcholinesterase (AChE) enzyme, oxidative damage, glial activation, and, neurotransmission-related proteins and anti-apoptotic processes in the hypothalamus. The hydrocephalic animals showed reduction in respiratory rates in the States of phosphorylation (P < 0.01) and non-phosphorylation (P < 0.05); increase in AChE activity in both the cytosol (P < 0.05) and the membrane (P < 0.01); decrease in synaptophysin (P < 0.05) and Bcl-2 (P < 0.05) contents and; increase in protein carbonyl (P < 0.01), GFAP (P < 0.01) and Iba-1 (P < 0.05) levels. The results demonstrate that ventricular dilation causes hypothalamic damage characterized by cholinergic dysfunction and suggests further investigation of the synthesis and secretion of hormones to generate new approaches and to assist in the treatment of hydrocephalic patients with hormonal alterations.

Does Ventriculoperitoneal Shunting Improve Thyroid Hormone Levels in Hydrocephalic Newborns?

OBJECTIVE/AIM

The aim of this report was to investigate the effect of ventriculoperitoneal shunt insertion for the treatment of hydrocephalus on thyroid hormones in the first 3 months of life.

METHODS

Thyroid-stimulating hormone (TSH), free T3 (fT3), and free T4 (fT4) levels were compared at 7 days (preoperatively) and at 30 and 90 days (postoperatively) after birth between 25 ventriculoperitoneal shunt-inserted hydrocephalic newborns and 20 healthy newborns.

RESULTS

The TSH level at 7 days was higher in the hydrocephalic patient group (6.33 µIU) compared to the control group (3.76 µIU). This value was significantly decreased at 90 days in the ventriculoperitoneal shunt-inserted newborns (2.35 µIU) compared to the control group (3.33 µIU; p < 0.05). There were no significant differences between time points for fT4 and fT3 values in the patient group or for TSH, fT4, and fT3 values in the control group.

CONCLUSION

We propose that a ventriculoperitoneal shunt inserted in the early period of life may have beneficial effects on thyroid hormones.

Evaluation of Hearing Function by Auditory Brainstem Response in Newborn Patients with Hydrocephalus before and after Ventriculoperitoneal Shunt Surgery

BACKGROUND/AIM

There is currently no objective evaluation of hearing in patients with hydrocephalus (HCP), and we could not find any study in the literature comprising a sufficient number of patients with a high level of scientific evidence. In the current study, we used the auditory brainstem response (ABR) test to assess whether hearing function in patients with HCP is altered after ventriculoperitoneal shunt surgery.

METHODS

In total, 20 newborn patients with HCP (13 female, 7 male) were enrolled in this study. For each patient, ABR testing was performed at three time points: 1 day prior to the operation and on days 7 and 90 after the operation. ABRs using click stimuli of 90, 70, 50 and 30 dB nHL (normal hearing level) were achieved for V-wave latency, and I-III and I-IV interpeak latencies for both ears were recorded. Variance analysis for parametric data and Tukey's post hoc honest significant difference test were used to demonstrate the relationship between the results obtained from the different recording periods. Results were considered significant at p < 0.05, and 95% confidence intervals were calculated.

RESULTS

The mean values of the ABR tests were compared between the pre- and postoperative results, which showed an increase (faster transmission) of nerve conduction velocity of 0.2 ms. The results were not statistically significant for 50 and 90 dB (p > 0.05) but were significant for 30 and 70 dB (p < 0.05).

CONCLUSION

Diagnosis in hydrocephalic patients is important not only for the treatment but also for the prevention of HCP-associated complications. Early treatment appears to be promising in terms of auditory benefit. Prompt diagnosis and treatment are therefore essential as soon as possible.

Neuropathology and structural changes in hydrocephalus

In the context of spina bifida, hydrocephalus is usually caused by crowding of the posterior fossa with obstruction to cerebrospinal fluid flow from the forth ventricle, and less often by malformation of the cerebral aqueduct. Enlargement of the cerebral ventricles causes gradual destruction of periventricular white matter axons. Motor, sensory, visual, and memory systems may be disturbed through involvement of the long projection axons, periventricular structures including the corpus callosum, and the fimbria-fornix pathway. Secondary changes occur in neuronal cell bodies and synapses, but there is minimal death of neurons. The clinical syndrome of hydrocephalic brain dysfunction is thus due to subcortical disconnection. Some of the brain dysfunction is reversible by shunting, probably through restoration of cerebral blood flow and normalization of the extracellular environment. However, destroyed axons cannot be restored.