Non-ketotic hyperglycaemic hemichorea (NHH), also known as diabetic striatopathy or chorea, hyperglycaemia, basal ganglia (C-H-BG) syndrome, is a rare neurological complication of non-ketotic hyperglycaemia, along with non-ketotic hyperosmolar coma and non-ketotic hyperglycaemic seizures. It is a cause of hemichorea-hemiballismus syndrome.
On this page:
Epidemiology
Non-ketotic hyperglycaemic hemichorea is most frequently reported in elderly patients, typically of Asian ethnicity, who have type 2 diabetes mellitus, although this may represent publication bias 2. The majority of cases published involved female patients 4.
Clinical presentation
Chorea and ballismus develops rapidly and can be either unilateral or bilateral and is seen during episodes of non-ketotic hyperglycaemia. Symptoms usually resolve upon normalisation of glucose levels.
Pathology
The exact underlying pathophysiology of changes seen on imaging of patients with non-ketotic hyperglycaemic hemichorea is not fully understood 1,2.
Some hypothesised mechanisms include 5:
hyperviscosity secondary to hyperglycaemia, leading to regional blood-brain barrier disruption and metabolic damage
the augmented sensitivity of dopaminergic receptors in a postmenopausal period (possibly explaining the female predominance in reported case series)
decreased gamma-aminobutyric acid (GABA) availability in the striatum secondary to the non-ketotic state
Radiographic features
CT
CT of the brain initially is normal, but later it can demonstrate hyperdensity in the striatal region (caudate nuclei and putamen) 2,7. Findings tend to be contralateral to the body side affected by hemiballistic/hemichoreic movements.
MRI
MRI of the brain is the modality of choice for assessing possible non-ketotic hyperglycaemic hemichorea and typically demonstrates signal changes, particularly in the putamen and/or caudate 1-3. If the changes are unilateral, then they are contralateral to the symptomatic side 2.
T1: hyperintense
T2/FLAIR: variable but generally hypointense
SWI: increased susceptibility
DWI: high diffusion signal
Overall, the T1 hyperintensity is the most consistent finding of the disease. The increase in T1 signal is hypothesised to be due to increased protein hydration within gemistocytes 8. Other associated findings do not present to the same frequency and tend to vary 6.
Imaging findings gradually resolve after hyperglycaemia correction. However, they tend to return to baseline more slowly than the clinical findings 3.
Treatment and prognosis
Symptoms and imaging findings usually gradually resolve upon normalisation of glucose levels 7, and there is no need for specific management.
Differential diagnosis
The main MRI differentials are that of other causes of increased T1 signal in the basal ganglia (including Wilson disease) and of a striatocapsular infarct 6.
Some causes of striatal hyperdensity on CT include 6:
Unable to process the form. Check for errors and try again.