CCM Interhospital Meeting on 20 Jan 2009
ABSTRACT OF PRESENTATION AVAILABLE
Presenter: Dr CHAN Yan Fat Alfred (Caritas Medical Centre)
Chairman: Dr Tai Kian Bun (Alice Ho Miu Ling Nethersole Hospital)
Upper photo: Dr CHAN Yan Fat Alfred giving lecture; Lower photo: Dr TAI Kian Bun introducing Dr CHAN Yan Fat Alfred
We presented an 82-year-old woman who had known history of ocular myasthenia gravis (MG) since year 2002. She presented to the casualty for subjective double vision and bilateral upper limb weakness after a week of upper respiratory tract infection. She developed choking and aspiration on the next day of hospitalization, and required endotracheal intubation. In ICU, she was treated as myasthenia crisis using intravenous immunoglobulin (IVIG) at dose of 0.4g/ kg body weight.
However, her serum acetylcholine receptor binding antibody titer was 10.57 (reference <0.45), Tensilon test result was negative, and there was no improvement in limb power with Pyridostigmine (Mestinon). EMG showed no typical decremental change in amplitude on repetitive stimulation. Over the next few days, physical examination showed gradual development of global areflexia. Urgent MRI was arranged to exclude spinal cord pathology, and it showed presence of serpentine intradural extramedullary flow-related signals and flow voids from C5 to T9 levels, compatible with spinal vascular malformation. However, the cord itself had no sign of ischemia or hemorrhages.
Nerve conduction test on day 9 showed absent F wave, prolonged distal latency but normal velocity, compatible with axonal degeneration. A diagnosis of Miller Fisher syndrome, a variant of Guillain Barre syndrome, was hence made. On retrospective review of patient's vital sign record, a tremendous fluctuation in blood pressure, pulse and temperature was observed in first few days, compatible with dysautonomia which had been frequently seen in Guillain Barre syndrome. Cerebrospinal fluid protein was raised at 1.85 despite a normal white cell count. The diagnosis was further confirmed by grossly raised anti-Ganglioside Q1b antibody level of 105 (reference <20).
A contrast CT of spine was performed because of severe neck pain after lumbar puncture, but turned out to be normal. The neck pain was presumably related to disease process itself. She received total 5 days of IVIG, and was extubated on day 10. She was discharged home at day 48 with no neurological deficit.
This case illustrated the diagnostic challenge encountered in daily practice. Though it is always preferred to obtain one single working diagnosis to account for clinical problems, this patient had three different diseases together, namely ocular MG, long upper spinal cord AVM and Miller Fisher syndrome.
In managing a patient with possible MG, one has to pay attention to the fact that more than one half of patients will firstly present with ocular symptoms, although most of the generalized type will have progressed in full-blown picture within 2 years. Bedside diagnostic tests include Tensilon test and ice-pad test, which the latter avoiding the need for intravenous Tensilon injection though its use is more sensitive only at ocular type. Repetitive stimulation of muscle fiber causes classical change in EMG, namely decrement in compound muscle action potential >10%, post-activation exhaustion and post-tetanus potentiation. Auto-antibody assay may help establishing the diagnosis, with acetylcholine receptor binding antibody being most commonly used, though a raised striational antibody titer may suggest presence of thymoma.
Guillain Barre Syndrome is typically caused by demyelinating polyneuropathy. Its clinical feature is characterized by progressive symmetrical muscle weakness associated with depressed tendon reflexes, with severity varying from mild walking difficulty to respiratory failure. Dysautonomia may happen in 70%, and facial muscle weakness can be seen in 50% of cases. Since the National Institute of Neurological Diseases and Stroke (NINDS) had issued diagnostic criteria of the syndrome in 1978, atypical features were being reported frequently. One example is meningism, which is sometimes so severe that clinician is alarmed for alternate pathology. Clinicians have to pay attention to the variants of syndrome, such as axonal polyneuropathy, Miller Fisher Syndrome and Bickerstaff encephalitis. Treatment options include IVIG and plasma exchange, and there is no adequate evidence to suggest either one option is superior to the other, but it is essential to initiate treatment at early stage of disease. Prognosis after treatment is generally favorable, with median time taken to walk independently at 53-85 days after disease onset.
Miller Fisher Syndrome, the culprit for this lady, classically presents with the triad of ophthalmoplegia, ataxia and areflexia. Bulbar palsy and limb weakness is commonly seen in 26% and 20% of cases respectively. Anti-Ganglioside Q1b antibody, which is elevated in 85-90% of cases, may help confirm the diagnosis.
1. Benatar M. A systemic review of diagnostic studies in myasthenia gravis. Neuromuscular Disorders 2006; 16: 459-167.
2. Golnik KC, Pena R, Lee AG, et al. An Ice Test for the diagnosis of myasthenia gravis. Ophthalmology 1999; 106: 1282-1286.
3. Meriggioli MN, Sanders DB. Myasthenia gravis: diagnosis. Semin Neurol 2004; 24 : 31-29.
4. Lennon VA. Serologic profile of myasthenia gravis and distinction from the Lambert-Eaton myasthenic syndrome. Neurology 1997; 48 (suppl 5): S23-27.
5. Ropper AH. The Guillain Barre Syndrome. N Engl J Med 1992; 326: 1130.
6. Cochen V, Arnulf I, Demeret S, et al. Vivid dreams, hallucinations, psychosis and REM sleep in Guillain Barre syndrome. Brain 2005; 128: 2535.
7. Criteria for diagnosis of Guillain Barre syndrome. Ann Neurol 1978; 3: 565.
8. Mori M, Kuwabara S, Fukutake T, et al. Clinical features and prognosis of Miller Fisher syndrome. Neurology 2001; 56: 1104-1106.
9. Hughes RAC, Swan AV, Raphael JC, et al. Immunotherapy for Guillain Barre syndrome: a systemic review. Brain 2007; 130: 2245-2257.
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