Reversible Metronidazole-Induced Lesions of the Cerebellar Dentate Nuclei

Abstract

Manson and Martin review the clinical controversies surrounding hormone-replacement therapy. 1 The findings of the Heart and Estrogen/Progestin Replacement Study (HERS) suggest reasons to be cautious about the use of hormonereplacement therapy in women who are 65 years of age or older. Of 2763 women (mean age, 67 years) with established coronary heart disease, women who were randomly assigned to receive hormone-replacement therapy had an excess risk of one additional blood clot per 64 women and of one additional gallbladder operation per 69 women during a fouryear period.2,3 Hormone-replacement therapy was significantly associated with worsening urinary incontinence. 4 Side effects of hormone-replacement therapy included breast tenderness and uterine bleeding, and only 70 percent of the women remained adherent to therapy by the end of year 3. 2Manson and Martin did not include stroke in their evaluation of benefits and risks. Among 652 women (mean age, 71 years) who had had a transient ischemic attack or nondisabling stroke, women who were randomly assigned to receive oral estradiol did not have lower rates of death or stroke. 5 The risk of fatal stroke was significantly increased (relative risk, 3.86; 95 percent confidence interval, 1.09 to 13.63) with the use of estrogen therapy. 5Before older women begin receiving hormone-replacement therapy, clinicians should inform them of the increased risk of blood clots, gallbladder disease, urinary incontinence, and fatal stroke. Clinicians should correct the misperception that hormone-replacement therapy is cardioprotective, since both the Women's Health Initiative 6 and HERS reported an increased risk of cardiovascular events in the first one to two years of use. Clinicians should alert women that, in 1999, the Food and Drug Administration removed the treatment of osteoporosis as an indication for estrogen therapy because of the lack of evidence from randomized trials of the effect of estrogen on the risk of fracture.

MR Imaging of Metronidazole-Induced Encephalopathy: Lesion Distribution and Diffusion-Weighted Imaging Findings

“…According to the previously reported 13 cases of MIE, [7][8][9][10][11][12][13][14][15][16] cerebellar dentate nuclei are most commonly involved on MR images, and this was found in 100% of our 7 cases and in 10 of the 13 previously reported cases. Less common locations included the corpus callosum (n ϭ 6), midbrain (n ϭ 4), basal ganglia (n ϭ 4), and cerebral subcortical white matter (n ϭ 4).…”

“…2,3 The incidence of MIE is unknown, though several previous studies have addressed brain change caused by metronidazole neurotoxicity. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] To our knowledge, several reports on 13 patients with MIE have documented MR brain imaging of abnormalities, [7][8][9][10][11][12][13][14][15][16] and diffusion-weighted imaging (DWI) data have been presented for 3 patients with MIE. 11,12,14 Previous case reports have focused on cerebellar lesions, and little radiologic investigation of MR imaging findings with respect to brain stem pathology and topographic lesion distribution has been performed in patients with MIE.…”

Reversible cerebellar syndrome caused by metronidazole

“…[4][5][6][7] Patients usually present with cerebellar dysarthria and ataxia that may occasionally fluctuate, as in our first patient. The duration of treatment with metronidazole before cerebellar symptoms manifest is variable, ranging from 28 days 6 to 3 months, 7 and cumulative doses range from 25 g (as in our second patient) to 90 g. 7 Patients usually experience complete resolution of the symptoms after discontinuation of metronidazole, sometimes within a few days.…”

Serially Changing Metronidazole-Induced Encephalopathy

“…This temporal relationship also supports the diagnosis of MIE, although our patient did not exhibit the cerebellar lesion characteristic of MIE. 5 It is not clear why only a few patients develop metronidazole toxicity and that they do so with therapeutic serum levels. 5 Clinical characteristics of the reports published to date * of metronidazole neurotoxicity are summarized in the cerebellum is the most commonly involved lesion of MIE, except for one case,* which was similar to our patient.…”

“…5 It is not clear why only a few patients develop metronidazole toxicity and that they do so with therapeutic serum levels. 5 Clinical characteristics of the reports published to date * of metronidazole neurotoxicity are summarized in the cerebellum is the most commonly involved lesion of MIE, except for one case,* which was similar to our patient. It is noticeable that all reported patients, including our patient, were mostly Asian males: 22 Asians (88%) and 16 males (64%) among the total 25 patients.…”