A lethargic puppy can be very worrisome for a (new) puppy owner, since we all know how wound up puppies usually are. If your puppy is lethargic then you might want to know about what causes this to happen because sometimes it can be life-threatening.

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You also should know when to see a vet immediately. Lethargy in a puppy is often times a side effect or symptom of an underlying condition or problem.

Lethargy is defined as a lack of energy or exhaustion.

Symptoms of a lethargic puppy

There are many symptoms that you might notice if you have a lethargic puppy on your hands. Symptoms include your puppy appearing confused or disoriented. Lethargy often times manifests in your puppy sleeping a lot more and not having energy.

Vomiting and or diarrhea are also common symptoms. You also might notice panting, tremors, a high fever or signs of pain in your puppy as well. Your puppy might not be interested in treats or interested in greeting you when you arrive home for the day.

Your pup also might end up not eating normally. This could be not eating usual amounts or simply not eating at all. If your puppy is housetrained then you might notice that accidents are happening in the house more often as well.

If you notice the symptoms in your pup going on for more than 24 hours, this might be a good time to call the vet. If you notice blood in vomit or diarrhea then you should immediately call the vet.

This could be a sign of a more serious and life-threatening illness. This advice however is not a substitute for a proper consultation with a vet. The information should only be intended as a guide to help you find out if and why your puppy is lethargic.

Diseases and other issues that could cause lethargy

There are a lot of diseases and conditions that can cause lethargy, as well as other issues you might not think about. Here are some of the most common reasons why your puppy might be lethargic:

  • Heartworms – Heartworms can cause a lethargic puppy and can be the result of a mosquito bite. Preventing heartworms is the best way to prevent this from happening. Heartworms causes symptoms like lethargy and depression or fever.
  • Puppy Distemper – Distemper is a very serious virus that has no cure. It can be spread through direct or indirect contact with an infected pet or through air. It often attacks lymph nodes and tonsils. Within a week the gastrointestinal system, nervous sytem and respiratory system are all affected. Lethgargy is a  main symptom along with high fever and discharge from the nose and eyes. The only treatment is focused on mitigating the symptoms of the disease. However, this virus is preventable by vaccination, you should consult with your vet about timely protection.
  • Trauma or Injury – Your puppy could have become injured or have some trauma you did not know about. This includes falling from a bed or off a ledge outside. It could be simple trauma or something more severe internally that could be causing the lethargy. In some cases abuse you are unaware of could cause this too. An example of this would be a dogwalker mistreating your puppy when you are away.
  • Kennel Cough – A puppy with kennel cough will be lethargic and have a fever. Dry coughing is the biggest symptom of kennel cough. Cough suppressants and antibiotics are common ways to treat this condition. If it is severe enough intravenous antibiotics might have to be given.
  • Parvovirus – Your puppy could get parvovirus as a result of feces and it can include symptoms such as lethargy, abdominal pain and diarrhea.
  • Heart Disease – Heart disease and congestive heart failure could also cause your puppy to become lethargic. Loss of appetite and fast breathing also are symptoms after the disease progresses. Treatments can include heart medication, water pills and other lifestyle changes. The treatments often depends on how far the disease has progressed.
  • Liver Disease – A lethargic puppy could be the result of liver disease as lethargy and loss of appetite are big symptoms. Your puppy might also have bloating in the abdomen if liver disease is present. Often times treatment includes medication and possibly surgery if the disease has progressed.
  • Hypoglycemia – Your puppy might also have hypoglycemia which could be causing the lethargy. In plain terms this is low blood sugar, which is opposite of diabetes. It can lead to weakness and also could cause tremors or seizures. The treatment really depends on the cause, but  intravenous glucose might be given short-term.
  • Poisoning – Various poisonings could cause your puppy to be lethargic. This could be things like your puppy eating human food it should not be eating, such as onions or garlic. Adult or human medication could cause lethargy as well. Did you know most medications like ibuprofen are toxic to puppies? Poisoning could be any number of things as puppies love to pick up anything off the ground and eat it, and the biggest symptom of poisoning is lethargy.
  • Diabetes – Diabetes could be a reason why you have a lethargic puppy. Often times lethargy and increased thirst are the biggest symptoms. Your puppy might also be going through appetite changes and weight loss. Insulin and lifestyle changes such as dietary changes are typical treatments if diabetes is present.
  • Depression – Simple depression could be the cause and it would also show up with symptoms such as sleeping a lot and eating less. Depression can be caused by changes in the environment such as a new house, a new baby or pet, and other changes. Hormonal imbalances also could be to blame.
  • Various Pet Products or Medications – If your puppy is lethargic it could be due to pet products and various pet medications. Over-the-counter pet products are often more likely to cause reactions such as lethargy. Be aware if any changes you have made lately such as even a new puppy food or brand. It could simply be a reaction to a chemical within the product causing the lethargy.
  • Tumors – A puppy that is lethargic could also have a tumor you don’t know about, which is definitely scary. This is a reason why it is important to see a vet if the symptoms persist for more than 24 hours.
  • Snake Bites – We all know puppies do get into everything, so a snake bite could be why your puppy is lethargic as well. If you have a very curious puppy and live where snakes often roam, this could be a common but often overlooked cause.
  • Hormone Imbalances – Puppies could also end up having hormonal problems and imbalances, just like people. Hormonal imbalances in puppies often express with symptoms like lethargy, and simple diagnostic tests such as blood tests can determine whether a hormonal imbalance is the cause.

Treatments of puppy lethargy

Most of the treatment involves finding what caused the puppy lethargy in the first place, whether it is a disease or simply your puppy getting into something it should not. The treatments can vary also depending on the severity of the disease or condition responsible for causing the lethargy.

Although we talked about most common causes of lethargy, make sure you take your puppy to a vet within 24 hours so your puppy can be diagnosed correctly. This should only be a guide to help you narrow down what might be the cause of this condition. Our guide should not be considered medical advice and cannot replace the advice of a professional.