Hydrocephalus-induced central hypothalamic-pituitary-thyroid axis dysfunction: a conceptual framework linking ventricular distension to behavioral deficit

Background

Despite successful CSF diversion for pediatric obstructive hydrocephalus, up to 40% of children in Sub-Saharan Africa develop persistent neurodevelopmental delay, growth arrest, and executive dysfunction. Models based on axonal injury or ischemia alone do not fully explain this burden. Hypothesis: We propose the Hypothalamic Compression-Endocrine-Glymphatic Dysfunction Theory. Third ventricular expansion compresses and shears periventricular hypothalamic neurons, particularly TRH-secreting cells of the paraventricular nucleus. This disrupts pulsatile TRH release and impairs TSH glycosylation. The resulting biologically inactive TSH is detected on routine immunoassays but fails to stimulate the thyroid, causing cryptic central hypothyroidism that standard screening misses. Mechanism: Thyroid hormone deficiency downregulates and mislocalizes Aquaporin-4 (AQP4) at the neurovascular unit, causing glymphatic stasis and impaired waste clearance. This creates a cycle: ventricular distension suppresses hypothalamic output, inducing central hypothyroidism that compromises microstructural clearance and intracranial compliance, driving neurocognitive deficits despite pressure normalization. Lmic relevance: In low-resource settings, CT surrogates can stratify risk. Third ventricular width >8 mm plus Evans' Index >0.30 identifies patients needing targeted free T4 testing. Automated deep-learning CSF segmentation offers scalable diagnosis.