Diabetic Ketoacidosis–Associated Hemichorea–Hemiballismus: Rare Imaging Findings, CT Diagnosis, and Radiology Interpretation in Emergency Neurology
Diabetic Ketoacidosis–Associated Hemichorea–Hemiballismus: A Rare Emergency Radiology Diagnosis
Diabetic ketoacidosis (DKA) is traditionally recognized as a life-threatening endocrine emergency characterized by hyperglycemia, metabolic acidosis, dehydration, and electrolyte imbalance. However, in rare circumstances, DKA may trigger unusual neurologic complications that challenge even experienced clinicians and radiologists.
One such rare imaging entity is hemichorea–hemiballismus (HCHB) occurring after DKA recovery. Although uncommon, this syndrome is increasingly recognized in emergency neuroradiology and medical imaging literature because early CT and MRI diagnosis can dramatically alter patient outcomes.
The disorder is characterized by involuntary unilateral movements caused by dysfunction of the basal ganglia, often associated with metabolic derangements. Radiologists play a central role because imaging findings may be subtle, delayed, or mimic other devastating neurologic emergencies such as stroke, osmotic demyelination syndrome, or toxic-metabolic encephalopathy.
This article presents a clinically important case involving a renal transplant recipient with insulin-dependent diabetes mellitus who developed unilateral involuntary movements after recovery from diabetic ketoacidosis. We will explore the pathophysiology, CT scan diagnosis, radiology interpretation, differential diagnosis, emergency imaging workflow, treatment strategies, and prognosis using globally recognized literature and neuroradiologic insights.
Clinical Case Presentation
A 38-year-old man with insulin-dependent diabetes mellitus and prior renal transplantation presented with delirium secondary to diabetic ketoacidosis.
Key Laboratory Findings
Serum glucose: 528 mg/dL
Calculated serum osmolality: 304 mOsm/L
Initial sodium: 132 mmol/L
Corrected sodium after 18 hours: 139 mmol/L
The patient’s mental status normalized after insulin therapy and intravenous hydration. However, three weeks later, he developed involuntary “fidgety” movements involving the right arm and right leg.
These movements were consistent with:
Hemichorea
Hemiballismus
This delayed neurologic manifestation raised concern for metabolic or osmotic injury involving the basal ganglia.
Understanding Hemichorea–Hemiballismus
What Is Hemichorea?
Hemichorea refers to irregular, abrupt, nonrhythmic involuntary movements affecting one side of the body.
Typical Characteristics
Rapid, unpredictable movements
Distal limb predominance
Continuous motor restlessness
Often worsens with activity
What Is Hemiballismus?
Hemiballismus represents the severe spectrum of choreiform movement disorders.
Features Include
Violent flinging movements
Proximal limb involvement
Basal ganglia dysfunction
Often associated with subthalamic nucleus injury
In metabolic disorders such as DKA or nonketotic hyperglycemia, these syndromes are believed to result from transient dysfunction of the striatum and associated motor pathways.
Epidemiology of DKA-Associated Hemichorea
Hemichorea–hemiballismus related to hyperglycemia is rare.
Most reported cases involve:
Elderly Asian women
Type 2 diabetes mellitus
Nonketotic hyperglycemia
However, DKA-associated cases are substantially rarer and may occur in:
Younger patients
Type 1 diabetes mellitus
Severe osmotic disturbances
Rapid electrolyte correction
Because of its rarity, the condition is frequently misdiagnosed as:
Stroke
Toxic encephalopathy
Seizure disorder
Psychiatric disease
Osmotic demyelination syndrome
Pathophysiology: Why Does DKA Cause Basal Ganglia Dysfunction?
The exact mechanism remains incompletely understood. Current evidence suggests multifactorial metabolic injury involving the basal ganglia.
Proposed Mechanisms
1. Hyperosmolar Injury
Rapid osmotic shifts may disrupt neuronal metabolism within:
Putamen
Caudate nucleus
Globus pallidus
The basal ganglia appear particularly vulnerable to osmotic stress.
2. GABA Depletion
During severe hyperglycemia:
Cerebral metabolism becomes impaired
Gamma-aminobutyric acid (GABA) may become depleted
Inhibitory motor pathways fail
This leads to excessive involuntary motor activity.
3. Microvascular Ischemia
Hyperviscosity and endothelial dysfunction may impair:
Basal ganglia perfusion
Regional oxygen delivery
Neuronal energy metabolism
4. Electrolyte Correction Injury
Rapid sodium correction can precipitate:
Osmotic demyelination syndrome (ODS)
Extrapontine myelinolysis
Basal ganglia injury
This mechanism becomes especially important in patients recovering from DKA.
Imaging Findings in DKA-Associated Hemichorea
Role of CT Scan Diagnosis
CT imaging remains the first-line modality in emergency diagnosis because it is:
Rapid
Widely available
Effective for excluding hemorrhage and stroke
However, subtle metabolic abnormalities may be overlooked.
Figure 1. Axial Brain Imaging
Radiologic Interpretation
Axial imaging demonstrates abnormal involvement of the basal ganglia, particularly within the putaminal region. Hyperattenuation or signal abnormality may be identified contralateral to the symptomatic side.
Diagnostic Importance
This imaging pattern strongly supports metabolic striatal dysfunction associated with hyperglycemia-related movement disorder.
The findings help distinguish this condition from:
Acute ischemic stroke
Intracranial hemorrhage
Infectious encephalitis
Degenerative disorders
Figure 2. Additional Axial Imaging
Radiologic Interpretation
Additional axial imaging demonstrates persistent metabolic abnormalities involving the basal ganglia without significant mass effect or surrounding edema.
Diagnostic Importance
The absence of edema or vascular territory infarction favors a metabolic etiology rather than ischemic stroke.
These findings are highly valuable in emergency radiology interpretation.
Characteristic MRI Findings
MRI is more sensitive than CT for detecting metabolic basal ganglia injury.
Typical MRI Features
T1-Weighted Imaging
Hyperintense basal ganglia lesions
Most commonly within the putamen
T2/FLAIR
Variable signal intensity
Sometimes hypointense or mixed signal
Diffusion Imaging
Usually no true diffusion restriction
Helps exclude acute infarction
Susceptibility Imaging
May demonstrate petechial hemorrhage or mineral deposition
Osmotic Demyelination Syndrome: The Critical Differential Diagnosis
A major diagnostic consideration in this patient is osmotic demyelination syndrome (ODS).
ODS is a severe neurologic disorder caused by rapid correction of electrolyte abnormalities, especially hyponatremia.
Because this patient underwent sodium correction during DKA management, radiologists must carefully evaluate for ODS.
Figure 3. Osmotic Demyelination Syndrome Imaging
Radiologic Interpretation
Axial and sagittal images demonstrate a centrally located low-attenuation lesion within the pons, compatible with osmotic demyelination syndrome.
Key Imaging Findings
Symmetric pontine involvement
Trident-shaped abnormality
Absence of significant mass effect
Relative preservation of corticospinal tracts
Diagnostic Importance
ODS may mimic stroke, encephalitis, or brainstem neoplasm. Early recognition is critical because delayed diagnosis may lead to:
Locked-in syndrome
Quadriplegia
Respiratory failure
Death
Differential Diagnosis
1. Acute Ischemic Stroke
Key Distinguishing Features
Vascular territory distribution
Diffusion restriction
Sudden focal deficit
2. Intracranial Hemorrhage
Important Clues
Hyperdense hemorrhage on CT
Surrounding edema
Mass effect
3. Wilson's Disease
Usually affects younger patients and demonstrates:
Copper metabolism abnormalities
Bilateral basal ganglia changes
4. Huntington's Disease
Typically hereditary with:
Progressive cognitive decline
Caudate atrophy
5. Osmotic Demyelination Syndrome
Important in patients with:
Rapid sodium correction
Alcoholism
Malnutrition
Liver disease
Emergency Diagnosis Workflow
Step 1: Clinical Assessment
Evaluate:
Movement disorder characteristics
Mental status
Electrolyte history
DKA severity
Step 2: Laboratory Testing
Key studies include:
Serum glucose
Sodium
Serum osmolality
Arterial blood gas
Renal function
Step 3: CT Scan Diagnosis
Perform emergency noncontrast CT to exclude:
Hemorrhage
Stroke
Mass lesion
Step 4: MRI Evaluation
MRI helps confirm:
Basal ganglia metabolic injury
Osmotic demyelination
Extrapontine myelinolysis
Step 5: Radiology Interpretation Correlation
Integrate:
Clinical timing
Metabolic correction history
Imaging distribution
Neurologic findings
Treatment Strategies
Immediate Goals
Stabilize glucose
Correct electrolyte imbalance gradually
Prevent osmotic injury
Symptomatic Treatment of Hemichorea
Common medications include:
Haloperidol
Risperidone
Tetrabenazine
Benzodiazepines
Most patients improve over weeks to months.
Management of Osmotic Demyelination Syndrome
Unfortunately, no definitive therapy exists.
Supportive Care Includes
Intensive neurologic monitoring
Respiratory support
Rehabilitation therapy
Prevention of further osmotic shifts
Prevention remains the best strategy.
Prognosis
Hemichorea–Hemiballismus
Generally favorable when:
Hyperglycemia is corrected
Diagnosis is early
Severe structural injury is absent
Most patients recover substantially.
Osmotic Demyelination Syndrome
Prognosis varies widely.
Severe cases may result in:
Permanent neurologic disability
Locked-in syndrome
Death
Early recognition improves outcomes.
Key Takeaways
Critical Clinical Lessons
DKA can produce rare movement disorders involving the basal ganglia.
Hemichorea–hemiballismus should be considered in patients with unilateral involuntary movements after metabolic stabilization.
CT scan diagnosis may reveal subtle basal ganglia abnormalities.
MRI provides superior characterization of metabolic and osmotic injury.
Rapid sodium correction increases risk for osmotic demyelination syndrome.
Radiology interpretation is essential for differentiating metabolic injury from stroke or hemorrhage.
Summary Table
| Feature | Hemichorea–Hemiballismus | Osmotic Demyelination Syndrome |
|---|---|---|
| Main Region | Basal ganglia | Pons ± extrapontine |
| Typical Trigger | Hyperglycemia | Rapid sodium correction |
| Movement Disorder | Common | Possible |
| CT Findings | Putaminal hyperdensity | Pontine hypodensity |
| MRI Findings | T1 basal ganglia hyperintensity | Trident pontine lesion |
| Prognosis | Usually favorable | Variable |
Frequently Asked Questions (FAQ)
Can diabetic ketoacidosis cause neurologic complications?
Yes. Severe metabolic derangements during DKA may lead to cerebral edema, seizures, osmotic injury, and rare movement disorders such as hemichorea–hemiballismus.
Why are the basal ganglia vulnerable in hyperglycemia?
The basal ganglia have high metabolic demand and are particularly sensitive to osmotic stress, ischemia, and neurotransmitter depletion.
Is CT or MRI better for diagnosis?
MRI is more sensitive, but CT remains essential in emergency diagnosis because it rapidly excludes hemorrhage and stroke.
Can osmotic demyelination syndrome be reversed?
Some patients recover partially, but severe cases may cause permanent neurologic deficits.
How fast should sodium be corrected?
Overly rapid correction should be avoided. Controlled gradual normalization is essential to reduce the risk of osmotic demyelination.
Educational Quiz (MCQs)
Question 1
Which brain structure is most commonly involved in diabetic hemichorea–hemiballismus?
Options
A. Hippocampus
B. Cerebellum
C. Basal ganglia
D. Occipital lobe
E. Corpus callosum
Correct Answer
C. Basal ganglia
Explanation
The putamen and striatum are most frequently affected in hyperglycemia-related movement disorders. Dysfunction of these motor control pathways produces involuntary choreiform movements.
Question 2
What is the most important risk factor for osmotic demyelination syndrome?
Options
A. Hypocalcemia
B. Rapid sodium correction
C. Hyperkalemia
D. Hypertension
E. Hypoglycemia
Correct Answer
B. Rapid sodium correction
Explanation
ODS is classically associated with overly rapid correction of chronic hyponatremia, leading to osmotic injury and demyelination.
Question 3
Which imaging modality is most sensitive for early osmotic demyelination syndrome?
Options
A. Skull radiograph
B. Ultrasound
C. CT angiography
D. Diffusion-weighted MRI
E. PET/CT
Correct Answer
D. Diffusion-weighted MRI
Explanation
Diffusion-weighted MRI can detect osmotic demyelination earlier than conventional MRI or CT, sometimes within the first day of symptom onset.
Recommended Reading
Alleman AM. Osmotic demyelination syndrome: central pontine myelinolysis and extrapontine myelinolysis. Semin Ultrasound CT MR. 2014;35(2):153-159. DOI: https://doi.org/10.1053/j.sult.2013.09.009
Howard SA, Barletta JA, Klufas RA, Saad A, De Girolami U. Best cases from the AFIP: osmotic demyelination syndrome. Radiographics. 2009;29(3):933-938. DOI: https://doi.org/10.1148/rg.293085151
Kleinschmidt-Demasters BK, Rojiani AM, Filley CM. Central and extrapontine myelinolysis: then and now. J Neuropathol Exp Neurol. 2006;65(1):1-11. DOI: https://doi.org/10.1097/01.jnen.0000196131.72302.68
Lambeck J, Hieber M, Dreßing A, Niesen WD. Central Pontine Myelinolysis and Osmotic Demyelination Syndrome. Dtsch Arztebl Int. 2019;116(35-36):600-606. DOI: https://doi.org/10.3238/arztebl.2019.0600
Ruzek KA, Campeau NG, Miller GM. Early diagnosis of central pontine myelinolysis with diffusion-weighted imaging. AJNR Am J Neuroradiol. 2004;25(2):210-213.
Yuh WT, Simonson TM, D'Alessandro MP, Smith KS, Hunsicker LG. Temporal changes of MR findings in central pontine myelinolysis. AJNR Am J Neuroradiol. 1995;16(4 Suppl):975-977.
Oh SH, Lee KY, Im JH, Lee MS. Chorea associated with non-ketotic hyperglycemia and hyperintensity basal ganglia lesion on T1-weighted brain MRI study. Arch Neurol. 2002;59(3):448-452. DOI: https://doi.org/10.1001/archneur.59.3.448
Wintermark M, Fischbein NJ, Mukherjee P, et al. Unilateral putaminal CT, MR, and diffusion abnormalities secondary to nonketotic hyperglycemia in the setting of acute neurologic symptoms mimicking stroke. AJNR Am J Neuroradiol. 2004;25(6):975-976.
Image Challenge. N Engl J Med. DOI: https://doi.org/10.1056/NEJMicm0909769
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