Neuro-ophthalmologic findings in konzo, an upper motor neuron disorder in Africa

J. C K Mwanza, Daniel Tshala-Katumbay, D. L. Kayembe, K. E. Eeg-Olofsson, T. Tylleskär

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

PURPOSE. To investigate the neuro-ophthalmological manifestations in konzo, a non-progressive symmetric spastic para/tetraparesis of acute onset associated with consumption of insufficiently processed bitter cassava roots combined with a low protein intake. METHODS. Twenty-one Congolese konzo patients underwent neuro-ophthalmological investigations including visual acuity testing, assessment of light pupillary reflexes, evaluation of ocular motility and deviation, direct ophthalmoscopy, and visual field perimetry. Objective refraction including retinoscopy and keratometry, and slit-lamp biomicroscopy were also done. RESULTS. Five patients had visual impairment, and 14 had temporal pallor of the optic disc. Fourteen presented visual field defects, the most frequent being concentric constriction and peripheral defects. Overall, 11 subjects had symptoms qualifying for the diagnosis of optic neuropathy. Two had spontaneous pendular nystagmus in primary position of gaze. Visual field defects and pallor of the optic discs were found in mild, moderate and severe forms of konzo. No correlation was found between the severity of the motor disability of konzo and the extent of visual field loss. CONCLUSIONS. Konzo was associated with optic neuropathy and a few patients had nystagmus. Although the etiopathogenesis of this optic neuropathy remains to be elucidated, the symmetry of the involvement suggests a toxic origin. We suggest that cyanide causes the neuro-ophthalmological damage in konzo. However, the optic neuropathy in konzo patients does not resemble the features of the epidemic optic neuropathy in Tanzania, Cuba or Nigeria, Leber's hereditary optic neuropathy, tobacco amblyopia or vitamin B deficiency.

Original languageEnglish (US)
Pages (from-to)383-389
Number of pages7
JournalEuropean Journal of Ophthalmology
Volume13
Issue number4
StatePublished - May 2003

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Optic Nerve Diseases
Motor Neurons
Visual Fields
Pallor
Optic Disk
Vitamin B Deficiency
Retinoscopy
Pupillary Reflex
Leber's Hereditary Optic Atrophy
Pathologic Nystagmus
Ophthalmoscopy
Manihot
Cuba
Visual Field Tests
Amblyopia
Muscle Spasticity
Tanzania
Poisons
Vision Disorders
Cyanides

Keywords

  • Cassava
  • Cyanide
  • Konzo
  • Motor neuron disorder
  • Optic neuropathy

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Mwanza, J. C. K., Tshala-Katumbay, D., Kayembe, D. L., Eeg-Olofsson, K. E., & Tylleskär, T. (2003). Neuro-ophthalmologic findings in konzo, an upper motor neuron disorder in Africa. European Journal of Ophthalmology, 13(4), 383-389.

Neuro-ophthalmologic findings in konzo, an upper motor neuron disorder in Africa. / Mwanza, J. C K; Tshala-Katumbay, Daniel; Kayembe, D. L.; Eeg-Olofsson, K. E.; Tylleskär, T.

In: European Journal of Ophthalmology, Vol. 13, No. 4, 05.2003, p. 383-389.

Research output: Contribution to journalArticle

Mwanza, JCK, Tshala-Katumbay, D, Kayembe, DL, Eeg-Olofsson, KE & Tylleskär, T 2003, 'Neuro-ophthalmologic findings in konzo, an upper motor neuron disorder in Africa', European Journal of Ophthalmology, vol. 13, no. 4, pp. 383-389.
Mwanza, J. C K ; Tshala-Katumbay, Daniel ; Kayembe, D. L. ; Eeg-Olofsson, K. E. ; Tylleskär, T. / Neuro-ophthalmologic findings in konzo, an upper motor neuron disorder in Africa. In: European Journal of Ophthalmology. 2003 ; Vol. 13, No. 4. pp. 383-389.
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