# Morel-Lavallée Lesion in a Patient With Metformin-Induced B12 Deficiency: A Rare Complication Following a Fall

## TL;DR

A 68-year-old man developed a rare Morel-Lavallée lesion after a fall caused by metformin-induced vitamin B12 deficiency, highlighting the need for routine B12 screening in metformin users.

## Contribution

This case highlights the rare but important complication of metformin-induced B12 deficiency leading to a Morel-Lavallée lesion.

## Key findings

- Metformin-induced vitamin B12 deficiency can lead to balance issues and falls.
- Vitamin B12 deficiency may result in a Morel-Lavallée lesion following a moderate-impact fall.
- Routine screening for B12 deficiency in metformin users is emphasized to prevent complications.

## Abstract

A Morel-Lavallée lesion (MLL) is a type of closed injury resulting in the internal shearing of superficial skin and subcutaneous tissue from the underlying fascial layer, usually occurring after traumatic accidents such as sports injuries or motor vehicle accidents. In this case, a 68-year-old man developed an MLL as a complication following a moderate-impact fall due to metformin-induced vitamin B12 deficiency. A known complication of metformin use is vitamin B12 deficiency, but this is often underdiagnosed due to a lack of routine screening. This case illustrates the importance of being aware of this complication and the many roles of vitamin B12 in terms of its effects on balance, proprioception, blood vessel integrity, and wound healing, emphasizing the importance of routine vitamin B12 screening in metformin users.