Postinfectious polyneuritis cranialis: A case report

Polyneuritis cranialis is characterized by the simultaneous or sequential inflammation of multiple cranial nerves, which may occur unilaterally or bilaterally. Although it is often related to infection, its exact etiology remains unclear. Due to its nonspecific clinical manifestations, diagnosis typically relies on the exclusion of other conditions. Herein, we report a case of postinfectious polyneuritis cranialis. The patient presented to our hospital with restricted mouth opening, dysphagia, coughing while drinking, dysarthria, and posterior neck pain following a finger injury. Laboratory tests showed markedly elevated inflammatory markers. Neurological examination revealed involvement of cranial nerves V, IX, X, and XII. Motor nerve conduction studies of the facial nerve suggested partial facial nerve damage. Brain magnetic resonance imaging demonstrated mild nonspecific white matter changes. After exclusion of alternative diagnoses, the patient was diagnosed with polyneuritis cranialis. The patient's condition improved following corticosteroid pulse therapy and was subsequently discharged. This case highlights that the diagnosis of polyneuritis cranialis remains one of exclusion and is often clinically challenging. When encountering patients with rapidly progressive cranial nerve palsies, polyneuritis cranialis should be included in the differential diagnosis after more common structural or systemic etiologies have been excluded.