Differential Diagnosis for Restless Leg Syndrome and Associated Symptoms

The patient presents with a chief complaint of restless leg syndrome, difficulty sleeping, anxiety, and difficulty maintaining weight. The following differential diagnosis is organized into categories to guide further evaluation and management.

• Single Most Likely Diagnosis
  • Restless Leg Syndrome (RLS): The patient's symptoms of involuntary leg movements, quadriceps soreness, and leg pain primarily at night are consistent with RLS. The temporary relief with stretching and walking also supports this diagnosis.
• Other Likely Diagnoses
  • Iron Deficiency Anemia: This condition can cause RLS symptoms and is also associated with difficulty maintaining weight. The patient's rapid weight loss if they miss a day of eating goals could be related to an underlying nutritional deficiency.
  • Anxiety Disorder: The patient's symptoms of feeling nervous, anxious, and easily annoyed or irritable, although mild, could be contributing to their RLS symptoms and difficulty sleeping.
  • Sleep Disorder: The patient's difficulty sleeping due to leg soreness and pain could be related to an underlying sleep disorder, such as insomnia or sleep apnea.
• Do Not Miss Diagnoses
  • Peripheral Neuropathy: This condition can cause similar symptoms to RLS, including leg pain and numbness. It is essential to rule out peripheral neuropathy, as it can be a sign of an underlying condition, such as diabetes or vitamin deficiency.
  • Dopamine Deficiency: Dopamine deficiency can cause RLS symptoms, and it is essential to consider this diagnosis, especially if the patient has a history of dopamine-depleting medications or conditions.
  • Kidney Disease: Kidney disease can cause RLS symptoms, and it is crucial to rule out this condition, as it can have severe consequences if left untreated.
• Rare Diagnoses
  • Akathisia: This is a rare condition characterized by involuntary movements, often caused by medication side effects. Although the patient discontinued mirtazapine due to worsening anxiety symptoms, it is essential to consider akathisia as a possible diagnosis.
  • Neurodegenerative Disorders: Certain neurodegenerative disorders, such as Parkinson's disease, can cause RLS symptoms. Although these conditions are rare, it is essential to consider them in the differential diagnosis, especially if the patient has a family history or other symptoms suggestive of a neurodegenerative disorder.