A 25 year old woman developed progressive weakness of the left arm during the second trimester of her first pregnancy. She had a past medical history of asthma, treated with inhaled steroids, and there was no family history of neurological disease. During the last month of pregnancy she developed pre-eclampsia and underwent a Caesarian section. Over the next few months she developed progressive weakness of the arms and later the legs and respiratory muscles. On examination she had reduced limb reflexes, with grade 1 power in the arms and grade 1 - 2 in the legs. Wasting and fasciculation were not seen. Sensation was normal. Nerve conduction studies showed evidence of axonal degeneration in motor nerves only. Normal investigations included MRI of the brain, cervical spine and brachial plexus, sural nerve biopsy, antiganglioside antibodies, CSF examination, lyme, syphilis and HIV serology, heavy metal levels, hexosaminidase levels, SOD-1 gene and mitochondrial DNA analyses. 10 months after the onset of her symptoms she required ventilation. Despite treatment with intravenous gammaglobulin, methyl prednisolone and plasma exchange her condition deteriorated and she became globally weak and areflexic, with involvement of bulbar muscles. Ocular movements were preserved until shortly before death. At times she appeared inappropriately cheerful, but cognition was normal. Sensation and autonomic function remained normal throughout the disease duration. She was ventilated for 27 months prior to death.
The brain weighed 1273g and had a normal appearance. The spinal cord showed atrophy and brown discolouration of the anterior nerve roots, most marked in the cervical and lumbar regions (Figure 1).