# September 2021

- Link: https://isnr.in/september-2021/
- Published: 2021-08-31T20:24:56+05:30
- Author: ISNR

## September 2021

## **CASE HISTORY**

53 year old female presented with complains of gait imbalance and ataxia.

She has chronic kidney disease and was recently started on anti tubercular therapy(
ATT) for pulmonary tuberculosis

**Case contributed by –**

Dr. Sam K George, Dr. Savith Kumar.

Department of Radiology and Imaging Sciences

Apollo hospitals, Bannerghatta -Bangalore

| [⌊Sep 2021_img1⌉](https://isnr.in/wp-content/uploads/2021/08/Sep-2021-Pic-1-min.jpg) | [⌊Sep 2021_img2⌉](https://isnr.in/wp-content/uploads/2021/08/Sep-2021-Pic-2-min.jpg) | 
| [⌊Sep 2021_img3⌉](https://isnr.in/wp-content/uploads/2021/08/Sep-2021-Pic-3-min.jpg) | [⌊Sep 2021_img4⌉](https://isnr.in/wp-content/uploads/2021/08/Sep-2021-Pic-4-min.jpg) |

| [⌊Sept 2021 Case of the month⌉](https://isnr.in/wp-content/uploads/2021/09/Sept-case_result-img-1.jpg) | [⌊Sept Case of the month⌉](https://isnr.in/wp-content/uploads/2021/08/Sept-case_result-img-2.jpg) | 
| [⌊Sept case of the month 2021⌉](https://isnr.in/wp-content/uploads/2021/09/Sept-case_result-img-3.jpg) | [⌊Sept Case of the month⌉](https://isnr.in/wp-content/uploads/2021/08/Sept-case_result-img-4.jpg) |

Axial DWI (A), ADC (B), T2WI -axial (C) & FLAIR axial(D )  images shows symmetrical
hyperintensities involving bilateral dentate nuclei(white arrows).

**Final diagnosis **– Isoniazid Induced Neurotoxicity(INH) (Drug induced Cerebellitis).

Neurotoxicity  seen in chronic  kidney  patient  taking  isoniazid  due  to  reduced
clearance  of  INH.

The  mechanism  for INH  toxicity  is  due  to  energy  deprivation  and  deficiency
of  Vitamin B complex. There  is  interruption  of  pathways  responsible  for  
pyridoxine  phosphorylation  resulting  in  decreased  production  of  pyridoxal
5-phosphate  required  for neurotransmission  via gamma aminobutyric acid (GABA).
GABA  is  an  inhibitory  neurotransmitter in  the  central nervous  system. Deficiency
of  GABA  results  in  cerebellar  signs.

Pyridoxine  supplementation  is  always advised with INH therapy.  However,  even
with  pyridoxine  supplementation  (15–50  mg/day),  up  to  5%  of   patients  
would  still  have  some  adverse  effects,  with  the  proportion  rising  fourfold
when  pyridoxine  dosage  is   inadequate.

**Clinical presentation: **INH neurotoxicity can present with seizures,  encephalopathy,
and  peripheral  neuropathy. Cerebellar  ataxia  is rare

**Key imaging  features: **T2  and  FLAIR  image  showing  symmetrical  hyperintensities
involving  bilateral  dentate  nuclei  due  to  its  toxicity-induced  edema.

**Differential diagnosis  **-Metronidazole  toxicity, Enteroviral  encephalopathy,
Atypical Wernicke’s  encephalopathy.

**Treatment-** Starting  patient  on  pyridoxine  and  ATT  regime  need  to  be
modified.

**References**:

1.Navni Garg, Rahul Mutreja. Bilateral dentate hyperintensities: Isoniazid –induced
toxicity European society of Radiology 10.1594/EURORAD/CASE.13907

2. Prashant Peter, Mary John (2014) Isoniazid-induced cerebellitis: a disguised 
presentation. Singapore Med J 55(1):e17–e19. (PMID: 4291918)

3.S Senthil Raj Kumar, S Shanmuga Jayanthan,G Rupesh (2020) Isoniazid: A rare drug-
induced cause for bilateral dentate nuclei hyperintensity. Indian Journal of Radiology
and Imaging.