Hello and welcome to the Zero to Finals podcast.

My name is Tom, and in this episode I'm going to be talking to you about myocitis.

And you can find written notes on this topic at zero tofinals.com slash myocitis,

or in the rheumatology section of the second edition of the zero to finals medicine book.

So let's get straight into it.

Polymyocytis and dermatomyocytis are autoimmune conditions that cause muscle inflammation,

which is called myocytis.

Both conditions present with proximal muscle weakness at the tops of the arms and the tops of the

legs.

Dermato myocytis also involves characteristic skin changes, specifically Gotron Papules

affecting the backs of the hands and the heliotrope rash affecting the

eyelids. Polymyocitis and dematomyocitis can be caused by an underlying cancer which makes

them paroneoplastic syndromes. A viral infection may be the trigger, for example, Coxsacky virus or HIV.

Certain HLA genes are risk factors for the conditions.

Let's talk about the presentation.

The typical presenting symptom is a gradual onset, symmetrical, proximal muscle weakness, which causes

difficulties in standing from a chair, climbing stairs or lifting items overhead.

There may be muscle pain or myalgia, but this is not always the case.

Polymyocytus occurs without any skin changes.

Potential skin changes in dematomyocytus include Gotron lesions,

which are scaly erythematous patches over the knuckles, elbows and knees.

The heliotrope rash, which is a purple rash on the face and eyelids,

...