Background and Importance Peripheral neuropathy is one of the most common adverse reactions to bortezomib. However, bortezomib can much less frequently produce other nervous system alterations. We present the case of a patient undergoing bortezomib treatment for multiple myeloma (MM), who developed toxicity in the form of autonomic neuropathy.

Aim and Objectives A 68-year-old patient with a history of hypertension, dyslipidaemia and depressive syndrome. In May 2023, MM was diagnosed, and induction treatment with daratumumab/bortezomib/lenalidomide/dexamethasone (D-VRd) was initiated.

During the first cycle of treatment, tolerance was excellent. The patient was included in the home chemotherapy administration programme for the second cycle. On the 8th day of the second cycle, the patient reported significant diarrhoea in the previous days. Hygienic-dietary recommendations were provided. After seven doses of bortezomib (cumulative dose: 16.8 mg), on the 11th day of the second cycle, when the nurse visited the patient at home, she found the patient hypo-reactive, having difficulty speaking and standing, non-reactive pupils, and skin pallor.

Material and Methods During hospitalisation, the patient experienced significant hypotension (76/52mm Hg), and dizziness, along with intolerance to standing and diarrhoea (grade 2). After ruling out cardiac causes (echocardiography), structural brain abnormalities (CT scan), amyloidosis and infectious origin, it was suspected to be vasovagal episodes secondary to autonomic neurological toxicity due to bortezomib. Intensive fluid therapy was administered. Progressive improvement was observed and the patient was discharged on the sixth day of admission with the ability to walk without recurrence of symptoms.

Results The treatment for MM was resumed after 15 days without bortezomib. Bortezomib was not administered again, and the symptoms did not recur. The reaction was classified as ‘probable’ according to the Naranjo algorithm.

Conclusion and Relevance There are few reported cases of autonomic neurological toxicity due to bortezomib.^1–4 Similar to our case, Suyani et al. and Stratogianni et al. reported two cases of patients who required hospitalisation due to dizziness and orthostatic hypotension, ultimately associated with bortezomib. In conclusion, autonomic neuropathic toxicity caused by bortezomib should be considered in the differential diagnosis of orthostatic hypotension in haematological patients. Home chemotherapy administration allows for early detection of toxicities and streamlines healthcare processes.

References and/or Acknowledgements 1. 10.1007/s10286–012-0164–8

2. 10.5505/tjh.2012.90377

3. 10.1182/blood.V108.11.5101.5101

4. 10.1182/blood-2022–166437

Conflict of Interest No conflict of interest.