Bladder Management (UMN vs LMN)
Posted: Tuesday, February 8th, 2022 | Updated: Sunday, January 15th, 2023
Posted: Tuesday, February 8th, 2022 | Updated: Sunday, January 15th, 2023
Upper Motor Neuron (UMN) Bladder
The motor activity of the body is controlled by the neurons of the brain. Upper motor neuron disease localizes to the central nervous system. Cell bodies are located in the cerebrum, brainstem, and spinal cord. Properly functioning upper motor neurons are able to stimulate or inhibit the lower motor neurons. Patients with upper motor neuron disease may be paretic or paralyzed. Their reflexes are usually present, but are increased to exaggerated and their muscle tone is generally normal to increased. An UMN bladder is seen with lesions cranial to L4. This bladder type has excess urethral sphincter tone and is often large and difficult to express. The patient may have periods of incontinence, but ultimately needs the bladder drained via a urinary catheter or expressed. Medications like prazosin (an alpha-adrenergic antagonist) and diazepam (a skeletal muscle relaxant) may help facilitate expression. Opisthotonus may indicate an UMN diagnosis
1. If the lesion is localized to the brain, the thoracic and pelvic limbs may be affected (UMN). The bladder may be an UMN bladder
2. If the lesion is localized to C1-C5, the thoracic and pelvic limbs may be affected (UMN). The bladder may be an UMN bladder
3. If the lesion is localized to C6-T2, the thoracic limbs may be affected (LMN). The bladder may be an UMN bladder
4. If the lesion is localized to T3-L3, the pelvic limbs may be affected (UMN). The bladder may be an UMN bladder
The motor activity of the body is controlled by the neurons of the brain. Upper motor neuron disease localizes to the central nervous system. Cell bodies are located in the cerebrum, brainstem, and spinal cord. Properly functioning upper motor neurons are able to stimulate or inhibit the lower motor neurons. Patients with upper motor neuron disease may be paretic or paralyzed. Their reflexes are usually present, but are increased to exaggerated and their muscle tone is generally normal to increased. An UMN bladder is seen with lesions cranial to L4. This bladder type has excess urethral sphincter tone and is often large and difficult to express. The patient may have periods of incontinence, but ultimately needs the bladder drained via a urinary catheter or expressed. Medications like prazosin (an alpha-adrenergic antagonist) and diazepam (a skeletal muscle relaxant) may help facilitate expression. Opisthotonus may indicate an UMN diagnosis
1. If the lesion is localized to the brain, the thoracic and pelvic limbs may be affected (UMN). The bladder may be an UMN bladder
2. If the lesion is localized to C1-C5, the thoracic and pelvic limbs may be affected (UMN). The bladder may be an UMN bladder
3. If the lesion is localized to C6-T2, the thoracic limbs may be affected (LMN). The bladder may be an UMN bladder
4. If the lesion is localized to T3-L3, the pelvic limbs may be affected (UMN). The bladder may be an UMN bladder
Lower Motor Neuron (LMN) Bladder
Lower motor neuron disease localizes to the neurons that innervate the muscles. Cell bodies are located within the ventral portion of the spinal cord. The lower motor neurons connect the central nervous system with the muscles and receive input from the upper motor neurons. Patients with lower motor neuron disease may also be paretic or paralyzed. Their reflexes may be present, but are very slow and their muscle tone is generally decreased. Typically, you'll notice a loss of tail tone, decreased anal tone, and fecal incontinence. A LMN bladder is seen with lesions caudal to L4. This bladder type has little to no urethral sphincter tone and is often large, flaccid, and easy to express. This patient will likely dribble urine constantly. Medications may be given to help promote bladder contraction by stimulating the muscarinic receptors
1. If the lesion is localized to L4-S3, the pelvic limbs may be affected (LMN). The bladder may be a LMN bladder
2. With diffuse LMN disease, the thoracic and pelvic limbs may be affected (LMN). The bladder may be a LMN bladder
Lower motor neuron disease localizes to the neurons that innervate the muscles. Cell bodies are located within the ventral portion of the spinal cord. The lower motor neurons connect the central nervous system with the muscles and receive input from the upper motor neurons. Patients with lower motor neuron disease may also be paretic or paralyzed. Their reflexes may be present, but are very slow and their muscle tone is generally decreased. Typically, you'll notice a loss of tail tone, decreased anal tone, and fecal incontinence. A LMN bladder is seen with lesions caudal to L4. This bladder type has little to no urethral sphincter tone and is often large, flaccid, and easy to express. This patient will likely dribble urine constantly. Medications may be given to help promote bladder contraction by stimulating the muscarinic receptors
1. If the lesion is localized to L4-S3, the pelvic limbs may be affected (LMN). The bladder may be a LMN bladder
2. With diffuse LMN disease, the thoracic and pelvic limbs may be affected (LMN). The bladder may be a LMN bladder
Sources:
Brewer, David. Upper Motor Neuron Lower Motor Neuron. Bush Veterinary Neurology Service. 2015.
Ford, Richard B., and Elisa M. Mazzaferro. Kirk and Bistner's Handbook of Veterinary Procedures and Emergency Treatment. 8th ed., Saunders Elsevier, 2006.
Brewer, David. Upper Motor Neuron Lower Motor Neuron. Bush Veterinary Neurology Service. 2015.
Ford, Richard B., and Elisa M. Mazzaferro. Kirk and Bistner's Handbook of Veterinary Procedures and Emergency Treatment. 8th ed., Saunders Elsevier, 2006.