What is going on at Twitter? Earlier this month it lost its head of communications Sean Garrett and it is now being reported that its new Twitter communications director, Lynn Fox, has also left the company.

Fox leaves the company after only four months having joined from video-streaming site Ustream. Both Garrett and Fox have left around the same time as Twitter’s head of marketing Pam Kramer.

Kramer’s depature was reported earlier this week.  Kramer only joined the micro-blogging platform as its first vice-president of consumer marketing in July.

Like Fox, Kramer has had a very brief stay at Twitter at a time when it is growing very fast in terms of staff numbers. It seems to be experiencing a combination of growing pains and a tussle for control of key departments.

According to a post on TechCrunch Kramer’s exit has led to Twitter founder Jack Dorsey replacing her, at least for the time being, as part of a move to increase his influence within Twitter.

It says that his efforts to be more involved and CEO Dick Costolo’s “heavy operations hand” has led to conflict and confusion in many staff members eyes and senior departures.

“According to one source, this “Do I do what Dick says or do I do what Jack says?” dilemma has put extra special strain on the Twitter Communications team, which seemingly doesn’t know whose message they should be communicating. Others say that its Jack’s Jobsian management approach that has led to the frustration among staff in all departments.

“Whether they’re on Team Dick or on Team Jack (or Team Biz and Ev), the fact remains that everyone is still rooting for Twitter to get past the growing pains of its adolescence and flourish in adulthood. Just think about it, how much has the thing improved your life.?” TechCrunch reports.

In addition Twitter has also recently parted company with other senior executives. Mike Abbott, VP of engineering, announced last month that he would be leaving for a role as Entrepreneur in Residence at Benchmark Capital.

Also gone is chief scientist Abdur Chowbury. He was responsible for implementing Twitter’s search recommendations.

Another exit was that of Loren Britcher, who created the Tweetie app, which Twitter bought last year.