Hi,
Thanks for posting your query.
Fever in a cirrhotic patient as common as in normal person but the only difference is that cirrhotic patient has decreased immunity.
Kindly mention other symptoms along with fever.
Does he have chest pain/ cough/ breathlessness/ sputum production?
Does he have vomiting/ watery shit/ spasmodic abdominal pain?
Does he have burning and increased frequency of urination?
Fever occurring in body is associated with other symptoms also.
Correct antibiotics selection may prevent 
septicemia and proper treatment at time.
You should consult with physician and should go for 
complete blood count, urine routine & microscopy, 
widal test  for 
enteric fever, malaria parasite examination.
Lowering of potassium ion may cause decreased intestinal movement with development of 
paralytic ileus.
Take care,
Dr.  Mayank Bhargava