Loss of knee tendon reflexes

Introduction Knee reflex is a reaction that gently slams the knee when the knee is half-flexed and the lower leg is free to sag, causing the quadriceps to contract and causing the calf to kick quickly. This reflection belongs to the reflection. The sensor is a muscle shuttle that can feel mechanical traction. The muscle spindle is arranged in parallel with the general muscle fibers, and is shaped like a shuttle. The two ends are attached to the tendon (or the extrafusal muscle fiber) and the connective tissue capsule is external. The capsule contains 2 to 12 specialized muscle fibers, and the middle part is filled with nuclei, without horizontal stripes, and can feel the pulling stimulation. There are horizontal stripes at both ends and there is contraction force. When slamming the lower tendon of the knee joint, due to the rapid pulling of the muscle, the muscle fibers in the shuttle contract, the muscle spindle is stimulated to stimulate the nerve impulse, and the afferent nerve fibers located in the femoral nerve are transmitted to the spinal cord (the waist 2~ 4)). The sputum reflex is a single synaptic reflex, and the afferent nerve fibers are directly associated with the cell body of the efferent neuron. The impulse is transmitted by the efferent fibers located in the femoral nerve to the motor endplate of the effector quadriceps muscle, causing the muscles to be contracted to contract and the calves to extend forward. This reflex is usually affected by the high-level part of the central nervous system. The strength and slowness of the reaction can reflect the functional status of the central nervous system, and it is clinically used to examine the central nervous system. Patients with lost knee reflexes had a higher rate of impaired glucose tolerance than those with normal knee reflexes (P<0.01). The disappearance of knee reflex can be used as a means to prompt clinicians to find patients with impaired glucose tolerance.

Cause

The weakening or disappearance of knee reflex is most common in spinal cord or peripheral neuropathy. It is one of the signs of lower motor neuron spasm. It is more common in myopathy, cerebellum and extrapyramidal diseases. Reflexes weaken and disappear multi-systemic lesions, such as peripheral neuritis, radiculitis, anterior horn keratitis and other central damage, knee hyperreflexia. Spinal cord localized injury: knee reflex emission center L2-4, Achilles tendon reflex S1-2; peripheral nerve injury, muscle lesions.

an examination

Related inspection

Nervous system examination

The patient is in the supine position. The examiner holds the patient's part with the left hand or the forearm. The hip joint and the knee joint are bent at an obtuse angle. The heel does not leave the bed surface, so as not to affect the reflective movement and it is not easy to get the correct result. The examiner used the right hand-held percussion hammer to hit the quadriceps tendon and the calf was straight. When sitting, the calf completely sag and fall at right angles to the thigh, slamming the lower quadriceps tendon of the knee, and the reaction is for the calf to stretch. Leg reflex enhancement is more common in pyramidal tract damage, and knee reflex height is often accompanied by sputum.

Knee reflex reflects the entire reflex process by simply controlling the spinal cord. Kneeling reflexes occur when normal people relax. But these muscles can also be controlled by the brain's high center. This time is what you said is prepared. The muscles that antagonize the knee reflex are nervous with the consciousness, and the knee reflex cannot occur.

Differential diagnosis

Differential diagnosis of the disappearance of knee flexion:

(a) peripheral neuritis (peripheral neuritis)

Symmetrical symmetry and dyskinesia of the distal part of the limb develop from the distal end to the proximal end, accompanied by burning pain, and tenderness in the lesion area. Distal symmetry of motor neuron spasm, decreased muscle tone, muscle atrophy, autonomic dysfunction, hyperhidrosis or no sweat, quadriplegia reflexes decreased or disappeared, and sputum reflex decreased earlier than knee reflex.

(2) Guillain-Barre's syndrome

There is a history of upper respiratory tract infection, symmetrical ascending flaccid paralysis, distal end is more severe than the proximal end, and severe cases may cause respiratory paralysis due to involvement of the intercostal muscles and diaphragm. Often accompanied by cranial nerve involvement, transient paresthesia or hyperalgesia, obvious muscle tenderness at the distal extremities, weakened or disappeared tendon reflexes, negative pathological reflexes. Cerebrospinal fluid showed white-cell separation after 2 weeks.

(3) progressive myodystrophy (progressive myodystrophy)

It belongs to concomitant recessive inheritance, almost all male, and women are rare. More often between the ages of 3 to 6 years, and gradually increased, unable to self-driving and the proximal extremities began, the lower limbs were heavier than the upper limbs. It is difficult to walk and climb the stairs. When walking, the pelvis is unstable. When standing up from the back, there is a Gowers sign. About 90% of the cases begin to show pseudohypertrophy of the gastrocnemius muscle, that is, the volume is increased and the muscle strength is not increased. After 6 years old, gradually Associated with muscle atrophy and contracture. The tendon reflex is first reduced, and when the muscle atrophy reaches the severity, the knee reflex disappears, and in the early stage of pseudohypertrophy, the tendon reflex can be active.

(4) Periodic paralysis

The disease is mostly caused by children to young people. It is often caused by eating and intense activities, cold and emotional agitation. More than nighttime onset, when the morning wake up, the limb symmetry is found. A typical episode begins at the proximal back of the lower back and both lower extremities and spreads distally to the lower extremities. Upward expansion can also affect the upper limbs and neck muscles. At the beginning of the attack, there is often sweating, dry mouth, oliguria, constipation and muscle bloating. Examination of visible sputum sputum, knee tendon reflexes reduced or disappeared. The diseased muscle is full and firm, the feeling is normal, the consciousness is clear, the serum potassium is generally only slightly reduced, and the potassium content in the urine is significantly reduced.

(5) epidemic myalgia symptom

Occurred in children and adolescents, rapid onset, fever, sore throat, headache, and soon the pain and tenderness of the lower chest and upper abdominal muscles. Breathing, coughing, and exertion are often exacerbated, sometimes involving the neck, back, and shoulders, or knee reflexes, and skin irritation. Some patients may be associated with mild meningitis symptoms such as apathy, dizziness, photophobia, and neck strength. Enteritis, myocarditis, orchitis can also occur.

(6) oposemauritis (ophthalmoneuromyelitis, neuro-optic myelitis)

There is a history of sensation before the disease, acute or subacute onset, the first side of the vision blurred, and gradually developed to both sides. Poor eyesight, eyelids or sputum pain, and some appear first. After 2 to 3 months, numbness, paralysis or quadriplegia of the extremities appeared. The field of vision is concentric, narrow or quadrant blind. At first, the muscle strength is reduced, the tendon reflex is weakened or disappeared, and the tendon reflex is still bilateral extensibility. After that, the muscle tension is increased, the knee tendon is hyperreflexive, and the pathological reflex is positive. Loss of sensation usually rises to the middle thoracic segment. Sensory loss and autonomic dysfunction below the lesion plane, accompanied by autonomic dysfunction, abnormal sweating, and dysfunction.

(7) Congenital-muscular maldev-elopment

It is an infancy myopathy, which is autosomal recessive, or dominant. Both sexes are seen. When the sick child is born, there is a decrease in muscle tone and muscle weakness. The limbs and trunk muscles are obvious. Some of the diseases and the head cannot be erected, and the knees are not able to sit upright or stand up, and the knee tendon reflex and quadriplegia reflexes are reduced or disappeared. No fake hypertrophy. Most of the course of disease does not develop, and some can cause muscle atrophy. Severe cases affect breathing. Can be associated with joint contracture, or congenital majority of joint bending.

(8) Familial autonomic dysfunction (familial autonomic dysfunction)

The disease is mostly in the onset of infants and young children, and the symptoms are variable. If the lacrimal gland is less or less secreted, the excitement will obviously cause the blood pressure to rise, and it will easily cause the blood pressure to drop when standing up. Cold hands and feet, red skin, fast breathing, elevated body temperature, swallowing and speech disorder, accompanied by diarrhea or constipation, paroxysmal vomiting, excessive or no saliva, low muscle tone, incoordination, biceps, spasm The triceps and knee tendon reflexes disappear, are not sensitive to pain, emotionally irritating, mentally retarded, and often accompanied by left and right asymmetry and deformity.

(9) Pellagra (pellargra, pellagrosis, chichism)

Slow onset, insidious, long course. In the early stages, it is often tired, weak, anorexia, and tongue pain. There are diarrhea, glossitis and lack of gastric juice. There are erythema and dermatitis in the exposed parts of the body. Initial neurasthenia-like symptoms are often overlooked, followed by memory impairment, impotence or mania, depression, usually manifested as dementia at the end. The most common posterior lateral cord combined damage, showing lower extremity rigidity, ataxia, knee hyperreflexia, Babinski sign positive. Deep feeling the obstacle. Symmetrical peripheral neuropathy, mainly limb pain. Vision loss and diplopia can occur, as well as tinnitus, dizziness and facial nerve spasms.

(10) Hematoporosis (hematoporpnyria, porpnyria)

Mainly pain in the lower extremities, muscle spasm at the distal end of the limb, showing a wrist-foot disease. There is no sensory disturbance, and the knee reflex disappears. Sometimes it is quadriplegia, and the upper limbs are characterized by heavy weight. The upper limbs are often heavier from the extensor tendons. Eyelid drooping, double vision, difficulty swallowing, hoarseness, and difficulty breathing. There may also be seizures, confusion, and coma. With headache, fatigue, insomnia and irritability. Emotional instability, mental disorders, arrogance, depression, hallucinations, etc. Acute abdominal pain caused by gastrointestinal smooth muscle spasm.

(11) Nodular arteritis (arteritis nodosa)

It is symmetrical, with obvious distal limbs, showing limb paralysis, sensory disturbance, and disappearance of knee reflex. Some manifest as single neuritis, asymmetry of limb movement dysfunction. Deuterium is more common than sensory loss, often causing symptoms of brain inflammation, such as headache, vomiting, disturbance of consciousness, fundus varices, papilledema, Retinal artery thrombosis or nodules. Hemiplegia, aphasia, hemianopia, localized epilepsy, and extrapyramidal symptoms may occur. There are also two lower limb weakness, muscle atrophy, muscle weakness and muscle tenderness.

(12) Alcoholic polyneuritis (alcoholic polyneuritis)

The onset is generally slow, but there are also acute onsets within a few days. Feeling dyskinesia, the lower limbs are prominent, the anterior lateral muscles of the calves are obvious, and the muscles of the back of the calf or quadriceps can also be affected. It is flaccid paralysis, knee reflex disappears, muscle atrophy may occur, and there may be autonomic nerve changes such as edema of the skin, thin skin, dry dullness, cold or cyanosis, pigmentation, nail changes, and hair loss. In the advanced stage of muscular atrophy, muscle contracture may occur, and the gastrocnemius muscle may have tenderness.

(13) Syringomyelia (syringaomyeli)

More men than women, mostly in the 20 to 30 years old. The onset is slow, often starting from the side of the neck to enlarge the base of the posterior horn. Therefore, the early symptoms are often the pain in the corresponding dominating area of the ipsilateral upper limb, the loss of temperature and the relative sense of tactile and deep sense. The skin of the patient is often burned and unconscious. . The cavity expands to the anterior gray commissure and has bilateral segmental separation pain and temperature sensation (short blouse shape). The sensory missing area has spontaneous and indescribable burning pain, which is persistent and is called central pain. After the expansion of the anterior angle, the corresponding segments have muscle atrophy and fasciculation. For example, the cavity is mostly in the neck, and the muscles of the hands are atrophied. The upper limbs of the second and third triceps tendon reflexes are reduced or even disappeared. Invasion of the spinal thalamus bundle damages the contralateral skin pain and loss of temperature. When the pyramidal tract is damaged, the ipsilateral limb below the diseased side plane is paralyzed and the knee tendon is reflected. Due to malnutrition, joint swelling is called the cnarcot joint.

(14) Poliomyelitis (poliomyelitis)

The sputum is the lower motor neuron, which is flaccid, with low muscle tone and weakened knee flexion. The distribution of the diaphragm muscles is asymmetrical, varying in weight and weight. Common in the lower limbs, the upper limbs are rare, the proximal large muscle group appears earlier and heavier than the distal small muscle group, which can affect the cervical back muscles and can not stand up, sit up and turn over. If the cervical and thoracic spinal cord is involved, the diaphragm and intercostal muscles (respiratory muscles) are paralyzed, which affects respiratory movement. There are slow breathing, nasal vibrations, low voice, intermittent speech, cough, weakness, abdominal muscle spasm sneezing, cough, rectus abdominis does not shrink, and may have intractable constipation, urinary retention or incontinence.

(15) Cerebellar ataxia (cerebellar ataxia)

When the patient is standing, swinging or skewing forward or backward or left and right, the two feet are often separated, and the eyes are aggravated when the eyes are closed, and the closed eyes are difficult to sign negative. In patients with unilateral cerebellar lesions, the head and trunk are biased toward the disease side, and it is easy to dump to the disease side. It is like a drunkard, so it is called a drunken gait. When you close your eyes, you will turn on the side of the disease. The muscle tension of the limbs decreased, and the counterattack phenomenon occurred due to insufficient antagonism. The tendon reflex is reduced, and the knee reflex can be a pendulum-like action. The head and neck are biased to the side of the disease, sometimes the eyes are slightly inclined to the healthy side, occasionally the eye is separated from the strabismus, and the large horizontal nystagmus. The ataxia of the lips, tongue, and laryngeal muscles of the organs is slow, ambiguous, intermittent, and explosive.

(16) Cerebral ataxia (cerebrumataxia)

Mainly due to postural balance disorder, gait is unstable, dumping backwards or to one side. Frontal lobe ataxia, in addition to contralateral limb ataxia, often accompanied by knee reflexes and other tendon reflexes, increased muscle tone, Babinski sign, positive cardinal sign, and mental symptoms and strong grip Reflexes are equal to the symptoms of frontal lobe damage. In the parietal lobe lesions, there are different degrees of ataxia in the contralateral limbs. The symptoms are obvious when the eyes are closed, and the deep sensory disturbances are not heavy or transient. A transient balance disorder occurs in temporal lobe lesions. Cerebral ataxia is less associated with nystagmus.

The patient is in the supine position. The examiner holds the patient's part with the left hand or the forearm. The hip joint and the knee joint are bent at an obtuse angle. The heel does not leave the bed surface, so as not to affect the reflective movement and it is not easy to get the correct result. The examiner used the right hand-held percussion hammer to hit the quadriceps tendon and the calf was straight. When sitting, the calf completely sag and fall at right angles to the thigh, slamming the lower quadriceps tendon of the knee, and the reaction is for the calf to stretch. Leg reflex enhancement is more common in pyramidal tract damage, and knee reflex height is often accompanied by sputum.

Knee reflex reflects the entire reflex process by simply controlling the spinal cord. Kneeling reflexes occur when normal people relax. But these muscles can also be controlled by the brain's high center. This time is what you said is prepared. The muscles that antagonize the knee reflex are nervous with the consciousness, and the knee reflex cannot occur.

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