Acute Ataxias

Vascular Disorders

• Cerebellar Ischemia: Reduced blood flow to the cerebellum leading to infarction.
• Cerebellar Hemorrhage: Bleeding within the cerebellum, often associated with hypertension or anticoagulation therapy.

Medications and Toxins

• Antiepileptic Drugs:

  • Phenytoin
  • Carbamazepine
  • Oxcarbazepine
  • Lacosamide
  • Lamotrigine
  • Zonisamide
  • Rufinamide
    (Particularly in the setting of hyperammonemia, with valproic acid, benzodiazepines, phenobarbital, and felbamate.)

• Chemotherapy Agents:

  • Cytarabine
  • Fluorouracil
  • Capecitabine
  • Hexamethylmelamine
  • Procarbazine
  • Vincristine
  • Cisplatin
  • Oxaliplatin

• Antiarrhythmic Drugs:

  • Amiodarone
  • Procainamide

• Antibiotics:

  • Metronidazole
  • Polymyxins

• Toxins and Poisons:

  • Alcohol
  • Carbon tetrachloride
  • Heavy metals (e.g., lead, mercury)
  • Phencyclidine
  • Toluene
  • Pesticides

• Other Drugs:

  • Lithium

Infections

• Viral Causes:

  • Epstein-Barr virus (EBV)
  • Varicella-zoster virus (VZV)
  • Herpes simplex virus 1 (HSV-1)
  • Human herpesvirus 6 (HHV-6)
  • Influenza A and B
  • Mumps
  • Coxsackie virus
  • Rotavirus
  • Echovirus
  • SARS-CoV-2
  • Enterovirus
  • Hepatitis A
  • Measles
  • Parvovirus B19

• Bacterial Causes:

  • Mycoplasma pneumoniae
  • Listeria monocytogenes
  • Streptococcus pneumoniae
  • Neisseria meningitidis
  • Tuberculosis

• Other Infections:

  • Typhoid fever
  • Malaria

Subacute Ataxias

Subacute ataxias develop over weeks to months and are often caused by autoimmune, infectious, structural, or systemic disorders. 

Autoimmune Disorders

• Central Nervous System Disorders:

  • Multiple Sclerosis (MS): Demyelination affecting the cerebellum or its pathways.
  • Acute Disseminated Encephalomyelitis (ADEM): Post-infectious or vaccine-related inflammatory demyelination.
  • Paraneoplastic Cerebellar Degeneration: Associated with malignancies (e.g., lung, breast, ovarian), often presenting with specific autoantibodies.

• Cerebellar-Specific Autoimmune Disorders:

  • Celiac Disease/Gluten Ataxia
  • Glutamic Acid Decarboxylase (GAD) Antibody-Associated Ataxia
  • Anti-NMDA Receptor Antibody Syndromes
  • Anti-P/Q Voltage-Gated Calcium Channel Antibodies
  • Homer-3 Autoantibodies
  • Contactin-Associated Protein-Like 2 Antibodies
  • Anti-M-Phase Phosphoprotein-1 Antibodies

• Thyroid-Associated Disorders:

  • Hashimoto Thyroiditis/Encephalopathy

• Other Autoimmune Disorders:

  • Histiocytosis X
  • Anti-GQ1b Antibody Syndromes (e.g., Miller Fisher Syndrome, Bickerstaff Brainstem Encephalitis)
  • Neurosarcoidosis
  • Postinfectious Cerebellitis
  • Behçet Syndrome
  • Polyarteritis Nodosa
  • Systemic Lupus Erythematosus (SLE)
  • Sjögren Syndrome

Infectious Causes

• Bacterial Infections:

  • Lyme Disease
  • Whipple Disease
  • Syphilis
  • Tuberculosis

• Viral Infections:

  • JC Virus (Progressive Multifocal Leukoencephalopathy)
  • HIV

• Prion Diseases:

  • Creutzfeldt-Jakob Disease (CJD) and other transmissible spongiform encephalopathies.

Structural Causes

• Tumors:

  • Primary cerebellar tumors (e.g., medulloblastoma, astrocytoma)
  • Metastatic tumors to the cerebellum

• Abscess:

  • Infectious collections in the cerebellum causing localized inflammation and pressure effects.

Systemic Causes

• Liver Failure:
  • Hepatocerebral Degeneration: Resulting from chronic liver dysfunction leading to toxic effects on the cerebellum.

Chronic Ataxias:

Chronic ataxias develop over months to years and often reflect underlying systemic, degenerative, or structural issues.

Vitamin and Hormone Deficiencies

• Vitamin Deficiencies:

  • Vitamin B1 (Thiamine): Wernicke Encephalopathy (associated with malnutrition and alcoholism).
  • Vitamin B12: Subacute combined degeneration of the spinal cord and cerebellar dysfunction.
  • Vitamin E: Ataxia caused by oxidative stress and neuronal damage (e.g., Ataxia with Vitamin E Deficiency, AVED).

• Hormonal Deficiencies:

  • Hypothyroidism: Can lead to cerebellar dysfunction.
  • Hypoparathyroidism: Associated with hypocalcemia, causing neurological symptoms.

Toxins

• Chronic Exposure to Toxins:
  • Alcohol (chronic alcohol-related cerebellar degeneration).
  • Heavy Metals (e.g., mercury, lead).
  • Phencyclidine, toluene, solvents, and pesticides (occupational or recreational exposure).

Medications

• Chronic Effects of Drugs:
  • Antiepileptic drugs (e.g., phenytoin, carbamazepine, valproate).
  • Chemotherapy agents (e.g., cisplatin, cytarabine).

Infections

• Chronic or recurrent infections causing cerebellar dysfunction:
  • HIV: Chronic HIV-associated neurocognitive disorders (HAND).
  • Tuberculosis: Central nervous system tuberculosis.
  • Syphilis: Tertiary syphilis (tabes dorsalis, neurosyphilis).
  • Lyme Disease: Chronic neurological complications.
  • Creutzfeldt-Jakob Disease: A prion disease causing progressive ataxia.

Autoimmune Disorders

• Progressive Autoimmune Disorders:
  • Progressive Multiple Sclerosis (MS): Chronic demyelination affecting the cerebellum and spinal cord.

Neurodegenerative Disorders

• Chronic Neurodegenerative Ataxias:
  • Multiple System Atrophy (MSA): Atypical parkinsonism with cerebellar involvement.
  • Progressive Supranuclear Palsy (PSP): Neurodegeneration affecting motor and cerebellar pathways.

Structural Disorders

• Congenital or Acquired Causes:
  • Arnold-Chiari Malformation: Herniation of cerebellar tonsils causing chronic ataxia.
  • Normal Pressure Hydrocephalus (NPH): Gait ataxia with cognitive decline and urinary incontinence.
  • Superficial Siderosis: Chronic bleeding into the subarachnoid space leading to hemosiderin deposition in the cerebellum.

Psychogenic Ataxia

• Functional (non-organic) ataxia resulting from psychological or emotional factors rather than structural or physiological causes.