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Differential Diagnosis of Nervous System Disorders

Bilateral Basal Ganglia Lesions in Childhood!!navigator!!

◊Basal ganglia are susceptible to damage during childhood because of high energy requirements (ATP) mandating a rich blood supply + high concentration of trace metals (iron, copper, manganese)

  • increased irritability, lethargy, dystonia
  • seizure, behavioral changes
  • bilateral necrosis of basal ganglia

Acute Basal Ganglia Lesions

  1. Compromise of vascular supply
    1. Hemolytic-uremic syndrome → microthrombosis of basal ganglia, thalami, hippocampi, cortex
    2. Arterial occlusion
    3. Deep cerebral venous thrombosis
  2. Infection
    1. Encephalitis: Japanese encephalitis (Asia), West Nile fever (Middle East, North America), Murray Valley fever (Australia) by flavivirus infection
    2. Neurologic Behçet disease
    3. Toxoplasmosis
  3. Compromise of nutrient supply
    1. Hypoxic ischemic encephalopathy
    2. Osmotic myelinolysis
    3. Hypoglycemia
      • hemorrhage rarely seen

      In unexplained coma obtain blood sugar levels to differentiate this perhaps reversible condition from other causes!
  4. Acute toxic poisoning
    = impairment of mitochondrial cellular respiratory enzymes
    • acute cognitive impairment, coma
    1. Carbon monoxide poisoning
      Action: inhibition of electron transport
      Site: preferentially affects globus pallidus
      1. acute phase
        • foci of T2-hyperintensity
        • restricted diffusion
      2. delayed
        • delayed leukoencephalopathy in deep white matter
        • T1 shortening in globus pallidus

      rare in children:
    2. Hydrogen sulfide
    3. Cyanide poisoning
      Action: blockage of trivalent iron in respiratory chain
      • hemorrhagic necrosis in putamen
    4. Methanol poisoning
      • optic neuritis (initial symptom)
      • hemorrhagic necrosis in putamen
      • ± white matter edema
      • hypoattenuating areas in lentiform nuclei + corpus callosum + subcortical deep white matter in frontal and parietooccipital regions

Chronic Basal Ganglia Lesions

  1. INBORN ERRORS OF METABOLISM
    1. Leigh disease
    2. Wilson disease

      Basal Ganglia Lesion

      Thalamus involvedThalamus NOT involved
      HypoxiaToxic poisoning
      Osmotic myelinolysisHypoglycemia
      Wilson diseaseHyperglycemia
      Leigh diseaseLiver disease
      Fahr diseaseHuntington disease
      Creutzfeldt-Jacob diseaseNeurofibromatosis 1
      Deep cerebral vein thrombosisNeurodegeneration with Brain Iron Accumulation
      Infection
      Primary CNS lymphoma
    3. Mitochondrial encephalomyelopathies
      = subset of lactic acidemias with structurally abnormal mitochondria
      • “ragged red” fibers in muscle biopsy
    4. Maple syrup urine disease
      = inability to catabolize branched-chain amino acids (leucine, isoleucine, valine)
      • urine smells of maple syrup
    5. Methylmalonic acidemia
      = group of genetically distinct autosomal recessive disorders of organic acid metabolism affecting conversion of methylmalonyl-CoA to succinyl-CoA
      • accumulation of methylmalonic acid in blood + urine

    Symmetric diffuse abnormalities of the entire lentiform and caudate nuclei suggest systemic / metabolic causes!
  2. DEGENERATIVE DISEASE
    1. Huntington disease
    2. Creutzfeldt-Jakob disease
    3. Fahr disease
    4. Neurodegeneration with brain iron accumulation (NBIA)
  3. DYSMYELINATING DISEASE
    N.B.: basal ganglia are a mixture of gray + white matter
    1. Canavan disease
    2. Metachromatic leukodystrophy
  4. MALIGNANCY
    1. Primary CNS lymphoma
    2. Primary bilateral thalamic glioma

    Asymmetric focal discrete lesions affecting only part of basal ganglia suggest involvement by infection / neoplasm
  5. OTHERS
    1. Neurofibromatosis type 1
      • bilateral bright objects in globus pallidus, brainstem, cerebellum on T2WI (? hamartomas)
    2. Hepatic cirrhosis
      • bilateral T1-hyperintense areas in globus pallidus + substantia nigra ← deposition of manganese
    3. Acute hyperammonemia
      • bilateral symmetric swelling + T2 prolongation + restricted diffusion in basal ganglia + insular cortex + cingulate gyrus
    4. Wernicke encephalopathy

Low-attenuation Lesion in Basal Ganglia!!navigator!!

  1. Poisoning: carbon monoxide, cyanide poisoning, methanol intoxication, barbiturate intoxication, hydrogen sulfide poisoning
  2. Hypoxic ischemic encephalopathy
  3. Hypoglycemia
  4. Hypotension (lacunar infarcts)
  5. Wilson disease

Hemorrhagic Basal Ganglia Lesions!!navigator!!

  1. Poisoning
  2. CNS toxoplasmosis
  3. Venous infarction
  4. Flavivirus infection

Basal Ganglia Calcification!!navigator!!

Prevalence in children: 1.1–1.6%

  1. PHYSIOLOGIC WITH AGING
  2. ENDOCRINE
    1. Hypoparathyroidism, pseudo-, pseudopseudo- (60%)
    2. Hyperparathyroidism
    3. Hypothyroidism
  3. METABOLIC
    1. Leigh disease
    2. Mitochondrial cytopathy
      1. Kearns-Sayre syndrome = ophthalmoplegia, retinal pigmentary degeneration, complete heart block, short stature, mental deterioration
      2. MELAS = Mitochondrial myopathy, Encephalopathy, Lactic acidosis, And Strokelike episodes
      3. MERRF = Myoclonic Epilepsy with Ragged Red Fibers
    3. Fahr disease
  4. CONGENITAL / DEVELOPMENTAL
    1. Familial idiopathic symmetric basal ganglia calcification
    2. Hastings-James syndrome
    3. Cockayne syndrome
    4. Lipoid proteinosis = hyalinosis cutis
    5. Neurofibromatosis
    6. Tuberous sclerosis
    7. Oculocraniosomatic disease
    8. Methemoglobinopathy
    9. Down syndrome
  5. INFLAMMATION / INFECTION
    1. Toxoplasmosis, congenital rubella, CMV
    2. Measles, chicken pox
    3. Pertussis, Coxsackie B virus
    4. Cysticercosis
    5. Systemic lupus erythematosus
    6. AIDS
  6. TRAUMA
    1. Childhood leukemia following methotrexate therapy
    2. S/P radiation therapy
    3. Birth anoxia, hypoxia
    4. Cardiovascular event
  7. TOXIC
    1. Carbon monoxide poisoning
    2. Lead intoxication
    3. Nephrotic syndrome

mnemonic: “BIRTH”

  • Birth anoxia
  • Idiopathic (most common), Infarct
  • Radiation therapy
  • Toxoplasmosis / CMV
  • Hypoparathyroidism / pseudoHPT

Multiple Small Enhancing Lesions in Deep Nuclei!!navigator!!

  1. Metastases
  2. Primary CNS lymphoma
  3. Disseminated infection
  4. Noninfectious inflammatory process
  5. Subacute multifocal infarction
  6. Vasculitis

Linear Echogenic Foci in Thalamus + Basal Ganglia!!navigator!!

  1. IN UTERO INFECTION
    = mineralizing vasculopathy = lenticulostriate vasculopathy = destruction of wall of lenticulostriate arteries + replacement by deposits of amorphous granular basophilic material
    1. STORCH agents: Syphilis, Toxoplasma, Others (hepatitis, zoster), Rubella virus, Cytomegalovirus, Herpes virus
    2. Human immunodeficiency virus
  2. CHROMOSOMAL ABNORMALITY
    1. Down syndrome
    2. Trisomy 13
  3. OTHERS (anoxic injury?)
    1. Perinatal asphyxia, respiratory distress syndrome, cyanotic congenital heart disease, necrotizing enterocolitis
    2. Fetal alcohol syndrome
    3. Nonimmune hydrops

Bithalamic T2-hyperintense Lesions!!navigator!!

Only a few naturally occurring substances (methemoglobin, melanin, lipid, protein, minerals) are known to reduce T1 relaxation times, and the extent of that reduction depends on their occurrence in substantial concentrations.

  1. Artery of Percheron infarction
  2. Encephalitis
  3. Acute disseminated encephalomyelitis (ADEM)
  4. Creutzfeldt-Jakob disease
  5. Wernicke encephalitis

Hypothalamic Lesions!!navigator!!

  • hormonal disorders; diencephalic syndrome (failure to thrive, vomiting, emaciation), precocious puberty, stunted growth, diabetes insipidus
  • neurologic disorders: epilepsy (laughing fits)
  1. DEVELOPMENTAL CYSTS
    1. Epidermoid cyst /dermoid
    2. Rathke cleft cyst
    3. Colloid cyst
  2. DEVELOPMENTAL TUMORS
    1. Craniopharyngioma
    2. Germinoma
    3. Hamartoma
    4. Lipoma
  3. INFLAMMATORY
    1. Langerhans cell histiocytosis
    2. Lymphocytic infundibuloneurohypophysitis
    3. Sarcoidosis
  4. VASCULAR TUMORS
    1. Hemangioblastoma
    2. Cavernoma
  5. PRIMARY CNS TUMORS
    1. Hypothalamic-chismatic glioma
    2. Ganglioglioma
    3. Choristoma

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