Hyporeflexia

Every person has a set of muscle reflexes. When they are stimulated, they respond in a specific way. For example, if a healthcare provider lightly taps your knee during a reflex test, your leg should move. If it moves only slightly, you may have what is known as hyporeflexia.

Hyporeflexia presents as a lessened response in skeletal muscle reflexes. It is referred to as a symptom rather than a disorder in and of itself because it is caused by underlying medical conditions. Typically, those medical conditions are neurological.

This article discusses the causes and treatments of hyporeflexia.

Symptoms of Hyporeflexia

The main sign of hyporeflexia is when the reflexes don’t respond as they should when touched or stimulated. People with hyporeflexia may also experience a decrease in muscle tone and mass and muscle weakness, depending on the cause.

Causes of Hyporeflexia

Hyporeflexia occurs when the reflex arc is damaged. The reflex arc is a type of brain circuit that relies on both sensory and motor nerves to signal the reflexes in the body.

Both parts of the nervous system, the communication pathway between the brain and the rest of the body, can be affected. That means that nerve fibers, nerve cells, and the spinal cord can all be damaged and result in hyporeflexia.

Several health disorders that result from damage to nerves and other areas along the reflex arc can lead to hyporeflexia, including:

• Amyotrophic lateral sclerosis (ALS)
• Guillain-Barré Syndrome (GBS)
• Polyneuropathy

ALS develops when the motor neurons in the brain and spinal cord become damaged or destroyed. When that happens, hyporeflexia can occur because the communication between the reflexes and the brain is compromised.

In GBS, the immune system mistakes nerves for dangerous pathogens and attacks them by mistake. This leads to nerve damage, eventually causing hyporeflexia to occur.  

Polyneuropathy is the failure of peripheral nerves throughout the body. When these nerves fail, the action of the reflex arc is hindered, leading to hyporeflexia. Some specific types of polyneuropathies that can lead to hyporeflexia include chronic inflammatory demyelinating polyneuropathy (CIDP) and diabetic polyneuropathy.

How to Treat Hyporeflexia

There is no one treatment option for people who develop hyporeflexia because the causes range significantly. For example, healthcare providers would not treat ALS and diabetic polyneuropathy using the same methods. The therapies chosen will be determined based on the condition as a whole and not on the symptom of hyporeflexia.

Are There Tests to Diagnose the Cause of Hyporeflexia?

Healthcare providers will conduct what is known as a deep tendon reflex (DTR) exam to determine if someone has hyporeflexia. The exam uses a small rubber hammer-like object to lightly hit the reflexes to see how well they work. Reflexes can be found in:

• The knees
• The outside of the elbows
• In the ankles and wrists
• On the chin

The DTR test is often used in neurological examinations because the reflexes can be a helpful diagnostic aspect in determining neurological disease. Since there are many causes of hyporeflexia, other neurological tests will be conducted following the DTR to determine the underlying health condition causing the symptom.

When to See a Healthcare Provider

There is a difference between hyporeflexia and having regularly weak reflexes. If you’ve never noticed that your reflexes were poor and the symptom is new, it is worth visiting your healthcare provider.

They will conduct a reflex test to determine just how weak the reflexes are, alongside other possible neurological examinations. By doing so, they can decide if you need to see a brain specialist known as a neurologist.

Book an appointment immediately if you notice the reflexes change alongside other symptoms, such as muscle weakness or wasting. While it’s not always a severe health disorder, it can be a serious neurological disease. The quicker you see your healthcare provider, the better.

Summary

Hyporeflexia is not a disease in and of itself but rather a symptom that occurs in several neurological disorders such as ALS, GBS, and polyneuropathy. Depending on the cause, other signs may be present alongside the weakened reflexes, such as muscle weakness or wasting.  

Since treating hyporeflexia relies heavily on uncovering a cause, you must see your healthcare provider if you notice your reflexes change. They can do the appropriate tests and refer you to a neurologist if necessary.

A Word From Verywell

Having weak reflexes can be completely normal. However, hyporeflexia can also signal a neurological disease. If your reflexes aren't what they once were, you don't have to panic. However, it may be worth visiting your healthcare provider for a reflex test to be sure.

Neurological disorders typically present with symptoms alongside weak reflexes, so be sure to pay attention to how you're feeling otherwise. That will help your healthcare provider determine if you need further testing or to keep an eye on things.