Neuroimaging in Tick Paralysis: Looking Outside the Box

Round 1

Reviewer 1 Report

Sarwar and colleagues present an interesting case of tick paralysis in a child that was ultimately diagnosed when her mother found an engorged tick on the scalp under some matted hair. This is a very instructive case in terms the importance of physical examinations and careful attention to all available data. While I am not pretending to have thought of looking carefully under the girl's hair had I been taking care of her, it is humbling to see that a condition in the differential diagnosis for this child's presentation of muscle weakness did not lead to a more careful search for a tick (again, I would have missed it) and instead resulted in further neurologic deterioration and interventions such as mechanical ventilation and plasmapheresis.

I have a few suggestions for the authors to enhance this paper:

1) It would be useful to add a line or two on the mechanism of paralysis by the tick neurotoxin (presynaptic inhibition of acetylcholine release by eliminating dependence of transmitter release on extracellular calcium).

2) Line 41, please switch "Mom" (informal) to "Mother".

3) Line 60, "Doxycycline" should start with lower case "d".

4) For the paragraph with lines 95-104, the authors should change the sequence of things. The examination of the hair should precede MRI studies. It is our shortcoming that we do not do so more carefully for a condition in the differential diagnosis, but re-think things when the MRI doesn't provide an answer. In this case, even that did not lead to a diagnosis. It was the mother's finding that solved the case.

5) The MRI findings are interesting for neuroradiologists. Sometimes the answer lies in the most minor of observations.

6) I feel the title of the paper can be improved upon. Imaging is not needed for this diagnosis and the MRI finding was only seen in retrospect. Consider "Neuroimaging in Tick Paralysis: Look Outside the Box" or something like it that is more catchy for the reader.

Author Response

Thanks for the feedback. We addressed each of the 6 recommendations by modifying the text with tracking feature on. 

1) It would be useful to add a line or two on the mechanism of paralysis by the tick neurotoxin (presynaptic inhibition of acetylcholine release by eliminating dependence of transmitter release on extracellular calcium).

reply: This neurotoxin acts by causing presynaptic inhibition of acetylcholine release and eliminates dependence of acetylcholine release on levels of extracellular calcium. 

2) Line 41, please switch "Mom" (informal) to "Mother".

reply: changed to mother.

3) Line 60, "Doxycycline" should start with lower case "d".

reply changed to lower case

4) For the paragraph with lines 95-104, the authors should change the sequence of things. The examination of the hair should precede MRI studies. It is our shortcoming that we do not do so more carefully for a condition in the differential diagnosis, but re-think things when the MRI doesn't provide an answer. In this case, even that did not lead to a diagnosis. It was the mother's finding that solved the case.

reply: added two parts. "Search for a tick in the scalp should be performed in a patient with paralysis." "Search for tick in the scalp can be a daunting task. Locating it on MR or CT may act as a guide to narrow the search area. Sometimes, the answer lies in the most minor of observations. "

5) The MRI findings are interesting for neuroradiologists. Sometimes the answer lies in the most minor of observations.

reply: thank you for your suggestions

6) I feel the title of the paper can be improved upon. Imaging is not needed for this diagnosis and the MRI finding was only seen in retrospect. Consider "Neuroimaging in Tick Paralysis: Look Outside the Box" or something like it that is more catchy for the reader.

reply: title changed to "Neuroimaging in Tick Paralysis: Look Outside the Box"

Reviewer 2 Report

the reviewed article's strengths are its rarity and the underlined issue of special attention that always must be paid to the entirety of the radiological images. Furthermore, it has excellent MRI images and it is a well structured paper. The weakness of the paper is also its rarity and in addition the limited geographical distribution of it.  Finally, I think that the last (Fig 2C) it is not MRI image but a 3D reconstruction CT image. Thats there is need of explanation or/and clarification.

Author Response

Thanks for reviewing the article. We corrected the legend for figure 2. Image B is sagittal MRI image. Image C is 3D rendering from MRI data. Both CT and MR data can be post processed to get 3D rendering of the surface of the head. As we had MRI data, we used MRI data to create the 3D.

Regards