Differential Diagnosis for Slurred Speech and One-Side Arm Stiffness

Single Most Likely Diagnosis

• Stroke: The combination of slurred speech and one-sided arm stiffness is highly suggestive of a stroke, particularly if the symptoms are acute. Strokes can cause sudden weakness or numbness in parts of the body, difficulty speaking or understanding speech, and other neurological deficits.

Other Likely Diagnoses

• Parkinson’s Disease: As mentioned in the question, Parkinson’s disease can cause stiffness and slowness of movement, which might be perceived as arm stiffness. However, slurred speech (dysarthria) is also common in Parkinson’s, making it a plausible diagnosis.
• Multiple Sclerosis (MS): MS can cause a wide range of neurological symptoms, including speech difficulties and muscle stiffness or weakness, often on one side of the body. The symptoms can be relapsing and remitting.
• Cerebral Vasculitis: Inflammation of the blood vessels in the brain can lead to neurological symptoms similar to those of a stroke, including speech difficulties and localized weakness or stiffness.

Do Not Miss Diagnoses

• Brain Tumor: A tumor in the brain can cause localized neurological deficits, including speech difficulties and weakness or stiffness on one side of the body, depending on its location. Early diagnosis is crucial for treatment.
• Meningitis or Encephalitis: Infections of the brain and its membranes can cause a range of symptoms, including sudden onset of speech difficulties, weakness, and stiffness, along with fever, headache, and confusion.
• Subdural Hematoma: Bleeding into the space between the brain and the skull can cause neurological symptoms, including speech difficulties and one-sided weakness or stiffness, especially in the elderly after a fall.

Rare Diagnoses

• Progressive Supranuclear Palsy (PSP): A rare brain disorder that causes serious problems with walking, balance, and eye movements, and can also lead to speech and swallowing difficulties.
• Corticobasal Degeneration: A rare, progressive neurological disorder characterized by nerve cell loss and atrophy (shrinkage) of multiple areas of the brain, leading to symptoms such as stiffness and weakness on one side of the body, and speech difficulties.
• Wilson’s Disease: A genetic disorder that leads to copper accumulation in the brain and liver, causing neurological symptoms, including tremors, stiffness, and difficulty with speech and coordination.