In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: This case illustrates a number of problems that may be encountered in women with eating disorders in pregnancy , including prolonged and recurrent metabolic disturbances and diuretic abuse .
### Output Text:
This case illustrates a number of problems that may be encountered in women with eating disorders in pregnancy , including prolonged and recurrent metabolic disturbances and diuretic abuse . 