Certified Neuroscience Registered Nurse (CNRN) Practice Exam

A patient presenting with pure mental neuropathy, also known as numb chin syndrome, is most likely suffering from?

1. Multiple sclerosis

2. Metastatic cancer

3. Chronic migraines

4. Hematological disorders

The correct answer is: Metastatic cancer

The association of numb chin syndrome, or pure mental neuropathy, with metastatic cancer is well-documented. This phenomenon typically arises when malignant cells infiltrate the mental nerve, which is responsible for sensation in the chin and lower lip. This can occur as a result of cancer spreading from other sites, particularly from the breast, lung, or prostate. The mechanism often involves direct invasion or pressure from a tumor or lymphadenopathy. While other conditions like multiple sclerosis, chronic migraines, and hematological disorders can have neurological manifestations, they are less specifically linked to the isolated symptom of numb chin syndrome. For example, multiple sclerosis often presents with a variety of neurological symptoms including motor deficits and visual disturbances, while chronic migraines are characterized by recurrent headaches rather than isolated sensory loss in the chin area. Hematological disorders might involve peripheral nerve issues but do not specifically manifest as numb chin syndrome.