Isolated Arterial Hypertension as a Rare Early Manifestation of Guillain-Barré Syndrome: A Case Report.

Guillain-Barré syndrome (GBS) is a well-known post-infectious acute polyradiculoneuritis, classically characterized by ascending muscle weakness. While dysautonomia affects up to two-thirds of patients, it almost always follows the onset of motor deficits. Arterial hypertension, when presenting as an isolated premonitory sign occurring weeks before neurological involvement, constitutes an exceptional clinical pitfall that can lead to exhaustive and unnecessary etiological assessments. We report the case of a 9-year-old girl with no prior medical history, initially admitted for persistent headaches, vomiting, and severe arterial hypertension (160/110 mmHg). An extensive initial investigation for secondary hypertension (renal Doppler, echocardiography, catecholamine levels, cortisol, and renin-aldosterone system) was normal. It was only 20 days later, with the onset of facial paralysis and progressive limb weakness (3/5 strength), that the diagnosis was reconsidered. Electromyography confirmed an axonal-demyelinating sensory-motor polyneuropathy, and cerebrospinal fluid analysis revealed classic albuminocytologic dissociation. The patient was treated with intravenous immunoglobulins, leading to favorable motor recovery and complete normalization of blood pressure. This observation illustrates a highly unusual "hypertension-first" presentation of GBS. It serves as an essential reminder for pediatricians: unexplained acute arterial hypertension can be the sole inaugural manifestation of GBS-related dysautonomia. Recognizing this early signal is crucial to avoid diagnostic delays and initiate life-saving treatment before the onset of severe respiratory or motor failure.