Sir,
We read with great interest the article titled “Sequential MR imaging (with diffusion-weighted
imaging) changes in metronidazole-induced encephalopathy” by Singh et al. in the April–June 2017 issue of the Indian Journal of Radiology and Imaging.[1] The article is highly informative and describes signal changes in splenium and dentate
nuclei following metronidazole ingestion. In this article, we describe a few drugs
that cause similar signal changes in the cerebellar dentate nuclei [Table 1]:
Table 1
Drugs that cause signal change in dentate nuclei
Drug
|
Use
|
Area of brain affected
|
T2/FLAIR hyperintense
|
Resolution upon discontinuation of drug
|
A[1],[2] Metronidazole
|
Antibiotic, amebicide, antiprotozoal agent
|
Dentate nuclei, midbrain, inferior colliculus, dorsal pons and medulla, inferior olivary
nucleus, splenium
|
Yes, shows diffusion restriction
|
Yes
|
B[2] Monohalothane
|
Fumigative pesticide
|
Dentate nuclei, periaqueductal region of midbrain, inferior colliculus, splenium,
globus pallidus, thalamus, lower cranial nerve nuclei
|
Yes, no diffusion restriction
|
Yes
|
C[3] Isoniazid
|
First line antitubercular therapy
|
Dentate nuclei
|
Yes, may show diffusion restriction
|
Yes
|
D[2],[4] Cycloserine
|
Second line antitubercular therapy
|
Dentate nuclei
|
Yes, shows diffusion restriction
|
Yes
|
Thus, we see that the dentate nuclei can be affected by many drugs with nonspecific
magnetic resonance imaging findings. Hence, integration of clinical data is crucial
for definitive diagnosis.[4]