MICE: 03 - GASTROINTESTINAL CONDITIONS

Question 1

rectal prolapse description

Answer 1

• condition in which there is a visible protrusion of the rectum that presents as reddened, swollen mucosa

Question 2

rectal prolapse etiology

Answer 2

• mouse is predisposed to rectal prolapse, as it has a short rectum of about 1-2 mm in length
• condition is common due to straining
• can also be a nonspecific sign of colitis – inflammation of the colon
  ^^^^^ colitis may be due to infectious agents, genetic modification, or experimental manipulation

Question 3

what are the infectious agents that have been associated with colitis in mice

Answer 3

• citrobacter rodentium
• clostridium poiloforme
• heliobacter spp
• mouse hepatitis virus
• pinworms

—– age or idiopathic

Question 4

management plan

Answer 4

• recommended management plan is based on severity
• of mild –> monitor with no treatment, condition may remain unchanged for many months, mouse will often maintain normal body condition and mentation
• if resolution is desired or prolapse worsens, application of hypertonic solution and/or lubricating ointment may be used
• in more severe cases where there is a decline in body condition (bleeding, ulceration, enlarged size (greater than 5mm), humane euthanasia is appropriate

Question 5

malocclusion definition

Answer 5

• an overgrowth of incisors
• typical presentation of an affected mouse is runting or malnourishment resulting in poor weight gain and small body size when comparted to littermates following weaning

Question 6

malocclusion etiology

Answer 6

• condition may result of a misalignment of maxillary or mandibular incisors
• most common, it has a hereditary basis, with the strain specific phenotype most often seen in C57BL mice
• when observed in older mice, it typically results from oral trauma or neoplasia

Question 7

malocclusion management plan

Answer 7

• some flexibility in the management
• when practical, affected mice, particularly younger mice which are presumed to have a hereditary basics, should be humanely euthanized to prevent perpetuation of the phenotype
• if not possible, management should include regular trimming of teeth and lifelong monitoring
• gel supplement and moistened pellets may be provided

Question 8

Diarrhea: Description

Answer 8

• visible emission of soft, sticky feces
• adherent to surface, may found attached to the wall of cage or perimeun
• may observe bedding stuck to anus or staining of perimeum

Question 9

Diarrhea Etiology

Answer 9

• may result from infection
• commonly involves Helicobacter bilisand H. rodentium in SCID mice, or H. hepaticus in other immunodeficient mice
• less commonly, Citrobacter rodentium and enterotropic MHV (native in suckling mice) have been noted as causative agents
• majority of cases have been from induced models of colitis, such as that induced with dextran sulfate sodium (DSS), 2,4,6-trinitro benzene sulfonic acid (TNBS), and oxazolone
• less commonly, diarrhea may result from neoplasia

Question 10

Diarrhea Management Plan

Answer 10

• treatment plan based on severity
• mild cases where body condition and mentation are maintained within normal range, may be treated with supportive care (gel supplement and moistened pellets)