Essential Tremor: This is a common movement disorder characterized by tremors during action or with posture. The lower limb shaking for 5 minutes could be a manifestation of essential tremor, especially if it occurs with voluntary movement or when the limb is held in a specific position.

Parkinson's Disease: While more commonly associated with upper limb tremors, Parkinson's disease can also cause lower limb tremors, especially in the early stages or as part of a broader spectrum of motor symptoms.
Orthostatic Tremor: This is a rare condition but should be considered when tremors occur predominantly when standing. The tremor typically stops when the patient sits or lies down.
Anxiety or Stress-induced Tremor: Emotional stress can exacerbate or trigger tremors in susceptible individuals, potentially leading to episodes of lower limb shaking.

Stroke or Transient Ischemic Attack (TIA): Although less common, a sudden onset of limb shaking could be a sign of a stroke or TIA, especially if accompanied by other neurological deficits such as weakness, sensory changes, or difficulties with speech and vision.
Seizure Activity: Certain types of seizures, like focal seizures, can manifest with localized tremors or shaking, which could be mistaken for other movement disorders.
Multiple Sclerosis: This condition can cause a wide range of neurological symptoms, including tremors, due to demyelination in the central nervous system.

Wilson's Disease: A genetic disorder leading to copper accumulation in the body, which can cause neurological symptoms including tremors.
Huntington's Disease: An inherited disorder that causes progressive damage to the brain, leading to motor dysfunction, including chorea (involuntary, abrupt movements) that could be mistaken for tremors.
Neurodegenerative Diseases (e.g., Spinocerebellar Ataxias): These are a group of disorders that affect the cerebellum and/or its connections, leading to ataxia and sometimes tremors.