A few points:
- 4 months isn't yet an especially worrisome gap in employment, in my opinion.
- Think of your resume as an ad for you as an employee. Its job is to make you look good. You don't have to include things on it that make you look bad.
- On the other hand, many employers ask for you to disclose your full work history. This is where leaving jobs off might get you into trouble. It is somewhat unlikely that your 1 week stint will show up on a credit report, but it is not at all impossible. It is more likely to show up if you applied for credit or financing while employed at this job. Also, be aware of which hospitals and facilities in your area are owned by the same larger group. They do share information.
- It is possible that just discussing your medical situation with a prospective employer will clear up any concerns over an employment gap or a 1 week stint at a previous job. But this depends a whole lot on the nature of your medical condition (I'm not inviting you to share it here, by the way). If a future employer thinks your medical condition is likely to affect your employment with them, I would advise against disclosing more than you have to. But if we're talking about a medical issue from which you are fully recovered, then a frank talk with HR might work in your favor.
- Do take care of yourself. As tight as the market seems at times, there are nursing jobs
out there. You only have one body.