Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to obtain a history from you and examine you, I can not comment on a formal diagnosis or treatment plan for your symptoms. However, I will try to provide you with some information regarding this matter.
There are many reasons for “shakes”. Depends on what the “shakes” look like and the setting they occur. I will not discuss seizures and epilepsy at this time, but this is one reason for “shakes”.
Diabetes can cause a person to have tremors from the associated hypoglycemia that may occur. It would be important to check your husband’s blood sugars during the shakes, if the shakes are intermittent.
However, if the shakes are constant, it may be related to the lithium your husband is taking for his bipolar. Tremor is a common side effect of lithium. It is this is the case, you may need to have a change in medication.
Another common reason for tremors is a condition called essential tremor. This is an oscillatory movement of a body part that occurs during posture and/or with action. The treatment is simple with medication, but it requires a correct diagnosis.
I recommend that you and your husband discuss the tremors with your primary physician. It is difficult to provide you with correct information without knowing more details. However, I briefly highlighted three common causes of tremors in patients such as your husband. Thank you for using the forum, I hope you find this information useful, good luck.