Cerebral Disorders
The urge-to-cough (UTC) is a cognitive sensation required to initiate and inhibit the reflexive cough elicited by stimuli lower than those normally required to elicit a motor cough. The cough is mediated by the cerebral cortical or subcortical regions (8). Cough that has no identifiable medical cause and does not respond to traditional medical measures used to be called psychogenic, habitual, or tic cough. Nowadays, the term ”psychogenic” is replaced by ”somatic” cough, and the term ”habitual” has been replaced by ”tic” cough, according to the Diagnostic and Statistical Manual of Mental Disorders, 5th (DSM-5) Edition (9).
The distinction between somatic and non-somatic chronic cough is occasionally challenging, as patients with chronic cough are more prone to psychomorbidities such as anxiety and depression, which in turn can trigger chronic cough. The diagnosis of somatic cough syndrome should only be made if the patient meets DSM-5 criteria, and not based on the presence or absence of a nocturnal cough or a cough with a barking/honking quality. Some categories of patients with somatic cough disorders (such as children) may benefit from nonpharmacologic trials of hypnosis or suggestion therapy (10). Tic-cough is a form of vocal or phonic tics characterized by coughing suddenly, briefly, intermittently, involuntarily, or semi-voluntarily. It may be associated with other motor or vocal tics such as throat clearing, sniffing, grunting, squealing, screaming, barking, blowing, and sucking (11). The diagnosis of a tic cough is based on the presence of the core clinical elements of tics such as suppressibility, distractibility, suggestibility, variability, and the presence of a premonitory sensation, whether the cough is a single tic or one of many (12). Tourette syndrome is a neuropsychiatric disorder characterized by the occurrence of involuntary motor and phonic tics such as coughing, grunting, and wheezing. These phonic tics can be misdiagnosed as respiratory disorders such as asthma, upper and lower respiratory tract infections. A careful history and thorough neurological examination are necessary to make a correct diagnosis. (13). When chronic cough is associated with cerebral manifestations such as truncal ataxia, nystagmus, or incoordination, a central cause should be suspected in the cough center or superior control area. Primary central causes of chronic cough are extremely rare. In patients with type-I Chiari malformations, cough may be the first symptom due to a lesion in the dorsal medullary region of the brainstem. A space-occupying lesion in the brainstem involving the cough center or pressing on the efferent fibers may be a rare cause of chronic cough (14).