NDT Advance Access originally published online on November 9, 2005
Nephrology Dialysis Transplantation 2006 21(1):223-225; doi:10.1093/ndt/gfh990
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© The Author [2005]. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org
Nephroquiz
(Section Editor: M. G. Zeier)
The suddenly speechless florist on chronic dialysis: the unexpected threats of a flower shop?
1 Department of Internal Medicine University of Turin, Italy 2 Neuroradiology ASO Molinette, Torino, Italy 3 Neurology, Ospedale Valdese Torino, Italy
Email: gbpiccoli{at}hotmail.com or gbpiccoli{at}yahoo.it
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Maria is a 50-year-old florist, on dialysis since March 2000 because of biopsy-proven IgA nephropathy, previously treated with pulse and oral steroids, and with a short period (about 6 months) of low protein diet. She has a history of breast cancer (in situ lobular carcinoma) for which she underwent mastectomy in 1993.
Dialysis follow-up was uneventful; since September 2001 the patient had been on an active transplant waiting list. She was completely rehabilitated, working full time in her flower shop. Karnofski score was 100 (no sign of disease), the patient participated in regular non-competitive sport. Nutritional status was good (SGA 1; height 163, weight 61 kg, BMI 23), despite a moderate weight reduction since the start of dialysis (8 kg in 2 years), due to changes in eating habits following the advice of the transplant surgeons, who suggested weight reduction in preparation for the surgical intervention.
On January 6 2002, after intense working stress during the Christmas period, the patient consulted her nephrologist, her usual caregiver, complaining of nausea, severe anorexia, marked fatigue and abulia. The patient and the dialysis nurses also reported slurred speech, slight gait disturbances and impairment of fine movements of the hands.
The previous clinical control had been performed 18 days before (December 18) by the same nephrologist; on that occasion none of the symptoms were reported and clinical examination was unremarkable; dialysis efficiency was in the target range; normotension was achieved without therapy. No problem was reported at the recent clinical history, except for a flu-like episode in the previous week (Table 1).
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Therapy had not been modified over the last 6 months (Table 1); the patient denied taking any other therapy; drug and alcohol abuse were ruled out by patient and by family questioning, smoking was moderate (8–10 cigarettes/day).
On January 6 the patient was afebrile, blood pressure was below the usual range (70/50 mmHg). Neurological examination showed intention tremor and gait disturbances but the prevailing aspects were mental clouding and speech impairment: the patient's language was unusually slow and poor, with difficulty in ‘finding the right word’; physical examination was otherwise unremarkable.
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- What is your diagnosis?
- Which tests would you suggest?
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Answer to the quiz on the preceding page |
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The diagnosis was dialysis-related Wernicke encephalopathy.
Diffusion-weighted brain magnetic resonance (NMR) with gadolinium was performed 2 days later and showed bilateral, symmetric basal ganglia alterations (T2 hyperintensity and T1 hypointensity) extending caudally to the hypothalamus, partially involving the internal and external capsules, with important oedematous reaction (Figure 1). The neuroradiological picture was suggestive of Wernicke encefalopathy.
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Electroencephalogram showed diffusely slowed activity, consistent with a metabolic encephalopathy. Visual and hearing evoked potentials were normal. Thiamine therapy was started (100 mg/day, i.m.), together with oral multi-vitamin supplementation.
A couple of days after the start of thiamine supplementation, nausea, speech and gait disturbances started to diminish, followed by fine hands movements; after a week the patient was able to perform most of her daily activities. Complete resolution of the symptoms was reported within 1 month. The subjective and objective improvement was confirmed at the subsequent imaging controls (NMR and CT scans, see Figure 2) and at electroencephalography.
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Three months later, in a period of full clinical remission, thiamine was tapered and switched from i.m. to oral administration, also taking into account high thiamine serum levels (ranging from 200 to 230 nmol/l). About 2 weeks later, however, despite serum thiamine levels in the normal range (82.3 nmol/l, with a 24% post dialysis decrease: 62.8 nmol/l) a clinical relapse occurred, although to a lesser extent if compared to the first manifestation. Thiamine supplementation was immediately started again and reversal of symptoms occurred within few days. The clinical relapse was also documented at the CT scan (Figure 3).
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Two mild thiamine-dependent relapses occurred over the following year: the first one coincided again with intense working activity over Christmas time, the second occurred after a period of thiamine withdrawal during the summer holidays. In both cases, timely diagnosis and treatment presumably prevented the development of the full-blown radiological and clinical picture.
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Diagnosis of neurological impairment in uraemic patients may prove difficult, due to the overlapping features of common problems, such as cerebro-vascular disease, severe depression, uraemic encephalopathy, dialysis disequilibrium, dialysis dementia, and infections. Therefore, uncommon disorders may be overlooked, with serious consequences in progressive, potentially fatal diseases [1,2].
Wernicke encephalopathy is a rare but probably underdiagnosed occurrence outside the usual context of alcoholism. Recently, a growing number of reports have referred to this diagnosis in the setting of eating disorders, hyperemesis gravidarum and of chronic diseases, including uraemia [1–4]. In non-alcoholic patients, presentation is often atypical and diagnosis may be difficult [3].
Wernicke encephalopathy has been described as a rare occurrence and as a diagnostic challenge in dialysis patients. In the cases so far reported a prominent feature was the presence of relevant co-morbidities or of acute precipitating events (sepsis, acute cardiovascular events) [5–8]. The clinical presentation is often atypical: in only a minority of the cases reported on dialysis was the classic triad (confusion, ophtalmoplaegia, ataxia) present; confusion was usually present while oculomotion disorders and ataxia were reported in less than one-fourth of the cases [5–8]. Relapses are common in the patients who survive the first episode of the disease [8].
Our patient presents some further peculiarities. The first one is the lack of evident predisposing factors other than dialysis: she was relatively young, well nourished, with normal functional status, short dialysis follow-up, very good dialysis efficiency and metabolic control. The lack of predisposing factors was shared by very few dialysis-related cases [8], but has been occasionally reported in ‘normal’ individuals, suggesting a genetic predisposition [3]. These individuals may need higher thiamine levels to achieve a therapeutic response.
Genetic polymorphism of pyruvate dehydrogenase (PDH), the most important thiamine-dependent mitocondrial enzyme, was hypothesized to influence thiamine sensitivity. In our patient, PDH activity was tested and was markedly reduced (semiquantitative biological test). Since PDH is very sensitive to external challenges, an environmental cause, in addition to dialysis, was also searched for. Organophosphoric compounds, commonly employed in pesticides (the patient worked in a flower shop) may depress PDH activity and are associated with several neurological syndromes, including the ‘chronic organophosphate-induced neuropsychiatric disorders’ and a delayed polyneuropathy [9,10]. Of note, the patient experienced the first severe episode after a period of overwork in her flower shop. While a cause–effect relationship is difficult to assess, the reappearance of the symptoms coincided with periods of intense working activity. She recently reorganized her working activity, with shorter times in her shop.
In conclusion, this case draws attention to Wernicke syndrome in the differential diagnosis of acute and subacute mental impairment in dialysis patients, eventually also in combination with other environmental noxae or genetic background and, in keeping with other reports, raises suspicion that the few cases published so far are only the tip of the iceberg of a rather common but very elusive condition [2,5–8].
Conflict of interest statement. None declared.
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References |
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- Burn DJ, Bates D. Neurology and the kidney. J Neurol Neurosur Ps 1998; 65: 810–821
[Abstract/Free Full Text] - Wang HC, Brown P, Lees JA. Acute movement disorders with bilateral basal ganglia lesions in uremia. Movement Disord 1998; 13: 952–957[Medline]
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- Hung S-C, Hung S-H, Tarng D-C, Yang W-C, Huang T-P. Chorea induced by thiamine deficiency in hemodialysis patients. Am J Kidney Dis 2001; 37: 427–430[Medline]
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- Hung SC, Hung SH, Tarng DC, Yang WC, Chen TW, Huang TP. Thiamine deficiency and unexplained encephalopathy in hemodialysis and peritoneal dialysis patients. Am J Kidney Dis 2001; 38: 941–947[Web of Science][Medline]
- Singh S, Sharma N. Neurological syndromes following organophosphate poisoning. Neurol India 2000; 48: 308–313[Web of Science][Medline]
- Behan PD. Chronic fatigue syndrome as a delayed reaction to low dose organophosphate exposure. J Nutr Environ Med 1996; 6: 341–350
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