Clinical presentation of 54 patients with endogenous hyperinsulinaemic hypoglycaemia: a neurological chameleon (observational study).

BACKGROUND Important causes of endogenous hyperinsulinaemic hypoglycaemia (EHH) in adult patients are insulinoma and adult nesidioblastosis. Data on main symptoms in EHH are scarce and controversial. We analysed main symptoms of patients with EHH in the framework of two prospective studies investigating glucagon-like peptide-1 receptor imaging. METHODS Patients were referred from secondary European endocrine centres and endocrinologists. Inclusion criteria were biochemically proven EHH (glucose <2.5 mmol/l in the presence of inadequate insulin and C-peptide levels) with neurological hypoglycaemic symptoms. Demographic characteristics and aetiologies of the patients with EHH were retrieved. Main symptoms were categorised into neurological, sympathicoadrenal (sweating, tremor, palpitation, hunger, shivering and pallor) and nonspecific other symptoms (nonspecific asthenia, weight gain, gastrointestinal symptoms and headaches). Neurological symptoms were subdivided into moderately impaired consciousness (confusion, dizziness, somnolence and delirium), visual, speech and sensorimotor impairment, severely impaired consciousness (loss of consciousness and apathy), attention deficit, seizures and personality changes. Biochemical assessment and duration of EHH at the end of a fasting test were recorded. RESULTS Fifty-four patients with full documentation were included in the analysis (74% female; mean age 54 years, range 22–84). Median duration from onset of symptoms to diagnosis of EHH was 12 months (range 0–120). Fifty (92.6%) patients had neurological symptoms, including moderately impaired consciousness (46.3%), visual, speech and sensorimotor function impairment (44.4%), severely impaired consciousness (37%), attention deficit (31.5%), seizures (16.7%) and personality change (13%). Sympathicoadrenal symptoms were present in 33 (61.1%) patients. Nonspecific other symptoms occurred in 36 (66.7%) patients. 43 patients (79.6%) suffered from symptoms of at least two different categories. CONCLUSIONS Clinical symptoms of EHH are characterised by a wide variety of mainly different neurological symptoms (“neurological chameleon”). EHH should be considered as a differential diagnosis in many neurological disorders. Trial registration numbers NCT00937079 & NCT02127541