E035

Testosterone Replacement Therapy and Raised Intracranial Pressure: A Complex Interplay in a Patient with Congenital Hydrocephalus and Obesity.

D Mariannis¹, I Karanika¹, A Dimakopoulou¹, S Ahsan², M Wilson², M Martineau¹

1. West Middlesex University Hospital, Chelsea and Westminster Hospital NHS Foundation Trust.

2. St Mary’s Hospital, Imperial College Healthcare NHS Trust.

Abstract

Background
Testosterone therapy has been infrequently associated with raised intracranial pressure (ICP), although the association remains rare and not fully understood. Proposed mechanisms include androgen-mediated alterations in cerebrospinal fluid (CSF) production or absorption. This relationship is particularly unclear in patients with pre-existing structural brain abnormalities such as congenital hydrocephalus and cerebral palsy.

Case Presentation
A 47-year-old man with congenital cerebral palsy and obesity class III presented with reduced frequency of erections, fatigue and difficulty concentrating. He was diagnosed with hypogonadotrophic hypogonadism (testosterone 10.6 nmol/L [RR 10–30], SHBG 21.3 nmol/L [RR 15–55], free testosterone 0.246 nmol/L). He was initially commenced on testosterone gel for one year and subsequently switched to testosterone undecanoate (Nebido) injections due to persistent symptoms of hypoandrogenism.

To achieve stable symptom control, the Nebido dosing interval was gradually shortened, resulting in improvement in hypogonadal symptoms over two years. After transfer of care to our Trust, an MRI pituitary was arranged to evaluate for structural causes of central hypogonadism beyond metabolic contributors. The patient additionally reported a two-year history of worsening headaches and memory difficulties.

MRI demonstrated no pituitary adenoma but revealed marked enlargement of the third and lateral ventricles secondary to aqueductal stenosis, without features of acute CSF obstruction. Within two months of his MRI pituitary been performed, the patient presented acutely following a holiday, with severe headache, vomiting, diplopia and abducens nerve palsy. CT venogram and repeat MRI confirmed stable triventricular hydrocephalus with porencephalic dilatation of the right lateral ventricle, and old perinatal venous haemorrhage.

He was referred to neurosurgery and underwent endoscopic third ventriculostomy, which significantly improved his headaches. The  endocrine plan is to gradually wean testosterone therapy and support weight reduction in an effort to assess for recovery of endogenous gonadal function.

Discussion
While testosterone therapy is not known to cause acute hydrocephalus or aqueductal obstruction, androgen-related increases in intracranial pressure may unmask or exacerbate symptoms in patients with pre-existing CSF flow abnormalities. In this case, chronic aqueductal stenosis was already present, and testosterone replacement therapy may have contributed to decompensation of previously compensated hydrocephalus.

This case highlights the rare but important interplay between testosterone therapy, raised ICP and hypogonadotrophic hypogonadism in an obese patient with congenital hydrocephalus. It underscores the importance of clinical vigilance when prescribing testosterone in individuals with underlying neurological abnormalities or risk factors such as obesity. A multidisciplinary and individualised approach is essential to ensure safe hormonal optimisation while preserving neurological stability.