Overview of Canine Lethargy

Lethargy is a state of drowsiness, inactivity, or indifference in which there are delayed responses to external stimuli such as auditory (sound), visual (sight), or tactile (touch) stimuli. Lethargy may also refer to the general malaise and decreased activity exhibited by dogs that do not feel well.

Lethargy is a nonspecific sign associated with many possible underlying systemic disorders. It may have little to no impact on the affected individual; however its presence may represent severe or life-threatening illness. Lethargy of more than a day’s duration should not be ignored, and should be addressed, especially if it persists.

General Causes of Canine Lethargy

Anemia (low red blood cell count)

Other blood disorders

Cardiovascular (heart and vessels) and pulmonary (respiratory) disorders

Chronic inflammation or infection

Drug or medication related

Electrolyte abnormalities

Endocrine (hormonal) or metabolic disorders

Gastrointestinal diseases

Urinary tract disorders

Cancer

Immune diseases

Certain severe skin diseases

Certain eye diseases, particularly those associated with blindness

Neurologic and neuromuscular disorders

Nutritional disorders

Behavioral disorders

Skeletal diseases

Infectious diseases

Exposure to certain toxins

Physical trauma

What to Watch For

A general change in demeanor

Listlessness

Reluctance to play, exercise or perform normal behaviors

Hiding, avoiding contact with people or other pets

Decrease in appetite or thirst

Gastrointestinal signs (vomiting, diarrhea, weight loss)

Difficulty breathing

Tremors

Weakness

Changes in the level of consciousness

Fever

Diagnosis of Lethargy in Dogs

As lethargy is a very nonspecific sign and is associated with dozens of physical ailments, baseline laboratory tests are useful in identifying any systemic abnormalities that should be pursued with further testing. Examples of these baseline screening tests include: 

Complete blood count (CBC)

Biochemical profile

Urinalysis

Fecal examination

Chest and abdominal radiographs (X-rays)

If baseline tests are inconclusive or if abnormalities are detected, your veterinarian may consider doing additional diagnostic tests, such as:

Abdominal or thoracic/cardiac ultrasound

Serologic testing for infectious diseases

Bacterial culture of the urine, feces or blood

Endocrine (hormone) assays

X-rays of various parts of the skeleton

Cytology and biopsy of abnormal fluid or tissues

Complete eye examination

Complete neurologic examination

Complete behavioral assessment

Certain immunologic tests

Computed Tomography (CT scan)

Magnetic resonance imaging (MRI)

Treatment of Lethargy in Dogs

When the underlying problem is unknown, it may be difficult or even impossible to treat lethargy symptomatically. Identifying an underlying cause is essential in determining the appropriate treatment plan and care of the patient.

Home Care 

Once therapy has been instituted administer any prescribed medications as directed by your veterinarian. Observe your pet’s general activity and appetite, and notify your veterinarian if any of the symptoms worsen or change.