Akinesia

Akinesia refers to the loss of spontaneous, voluntary muscle movement. The term akinesia is derived from the Greek word “akinesis,” with the prefix “a” meaning without, and “kinesis” meaning motion. It is most commonly associated with Parkinson disease (PD) but can be experienced as a symptom of other medical conditions, such as hypothyroidism and fetal akinesia deformation sequence. 

Akinesia can be caused by various medical conditions: most commonly Parkinson disease, which is a neurodegenerative disease characterized by a loss of striatal dopamine neurons. Dopamine is a neurotransmitter that plays a role in the initiation of movement. Its depletion, particularly in the later stages of Parkinson disease, can cause a subsequent loss of purposeful movement. Medications that inhibit the amount of dopamine released, including antipsychotics (e.g., ziprasidone, chlorpromazine, haloperidol) can similarly lead to medication-induced, Parkinson-like symptoms and akinesia. Severe hypothyroidism, which is caused by severely low levels of the thyroid hormone thyroxine (T4), can result in akinesia. Lastly, akinesia is a prominent symptom in fetal akinesia deformation sequence (FADS). FADS is a rare condition characterized by fetal akinesia, intrauterine growth restriction, multiple joint deformities, facial anomalies, underdevelopment of the lungs, and other developmental abnormalities. 

Akinesia may be diagnosed by physical examination, specifically using a motor exam during which a neurologist or clinician monitors movement while an individual is asked to perform certain tasks, such as walking or tapping their fingers. Magnetic resonance imaging (MRI) can be used to assess for brain abnormalities seen in Parkinson disease (e.g., atrophy of the midbrain with enlargement of the third ventricle as well as frontal and temporal lobe atrophy). Akinesia caused by hypothyroidism can be diagnosed by assessing the levels of thyroid-stimulating hormone (TSH) through serology. Abnormally high levels of TSH with the presence of low T4 indicate hypothyroidism. Additionally, if the clinician is suspicious of FADS, genetic testing is available to test for the DOK7 and RAPSN gene mutations, and karyotyping can be conducted to rule out other developmental conditions. Diagnosis of FADS may also be made while the fetus is in the womb if the clinician observes reduced fetal movement, fixed limb posturing, or fetal edema (i.e., accumulation of fluid in the fetus) on ultrasonography. 

Treatment of akinesia depends on the underlying cause. If an individual has akinesia due to Parkinson disease, a healthcare professional may prescribe medications that increase the amount of the dopamine in the body (e.g., levodopa, pramipexole, selegiline). If the individual’s symptoms are refractory to medication, patients with Parkinson disease may try deep brain stimulation, which is a surgical approach that involves implanting a device to stimulate targeted regions of the brain with electrical impulses. Those who have medication-induced akinesia may stop taking the causative medication, which can eventually reverse the symptoms. Similarly, akinesia caused by severe hypothyroidism can be cured by administering thyroid replacement medications, such as levothyroxine. The treatment for fetal akinesia is primarily supportive due to a poor prognosis at live birth. Typically, resuscitation is required to combat pulmonary hypoplasia, and medications, like sildenafil and iloprost, may be administered to control raised pulmonary pressures.

Despite the cause of akinesia, there may be pain and discomfort experienced as a result of constant muscle rigidity. Over-the-counter pain relievers, such as nonsteroidal anti-inflammatory drugs (e.g., ibuprofen) or acetaminophen, can help. 

Akinesia refers to the inability to voluntarily move one’s muscles and limbs. It is most commonly associated with advanced Parkinson disease due to the degeneration of dopaminergic neurons. Other conditions where akinesia is present include hypothyroidism, medication-induced Parkinson-like symptoms, and fetal akinesia deformation sequence. The symptoms of akinesia usually involve feeling frozen and unable to move. Diagnosis is made on physical examination, and the clinician may perform a motor examination where they observe the individual’s gait. MRI may be used to confirm the atrophic changes of the midbrain, temporal, and frontal lobes seen in Parkinson disease. Laboratory testing, including blood tests and genetic testing, may also be performed to diagnose akinesia caused by hypothyroidism or FADS, respectively. The treatment for akinesia depends on the underlying cause. For akinesia related to Parkinson disease, the clinician may prescribe medications that increase dopamine levels in the brain. Additionally, pain relievers can help alleviate the discomfort associated with muscle rigidity.