NORMAL SWALLOWING & DISORDERS OF SWALLOWING; For the #Neurologist & #NeuroCriticalCare #Physician

  •   Cranial nerves V,VII,IX,X,XI,XII contributes 
  •   2 brain stem nuclei control swallowing: (1) Nucleus Tractus Solitarius(NTS) which is a pure sensory nucleus in the medulla (2) Nucleus Ambiguous (NA) which is a motor nucleus situated deep in the reticular formation in medulla 
  •   Sensory info sent via cranial nerves to NTS. Interneurons relay info to NA & surrounding reticular formation which sends efferent messages to cranial nerve pathways. 
  •   Muscles innervated by Trigeminal nerve helps in Mastication, jaw closure, upward movement of larynx, backward movement of tongue to soft palate, tensing and elevation of soft palate and posterior pharyngeal wall constriction 
  •   Muscles innervated by Facial nerve helps in mandibular depression and contributes to hyoid elevation 
  •   Glossopharyngeal nerve supplies Stylopharyngeus , contributes to palatoglossus – portion of middle pharyngeal constrictor Ⓜ️NEMO> “Glossy nerve helps Stylish Middle Class”  
  •   Vagus supplies muscles of soft palate (except Tensor Veli Palatini) – Superior, middle and inferior pharyngeal constrictors – Intrinsic muscles of larynx and muscles of esophagus Ⓜ️NEMO> “Vague nerve helps all classes” 
  •   Recurrent Laryngeal Nerve innervates Cricopharyngeus muscle.  
  •   Hypoglossal nerve innervates all intrinsic and some extrinsic muscles of tongue and geniohyoid ; hence responsible for all movements of the tongue  
  •   Aetiology of swallowing disorders: Stroke, Traumatic Brain Injury, Brain Tumor , Cerebral Palsy, Neuroleptic drug- induced Tardive dyskinesia , Surgery ( Generally damage to the pharyngeal plexus may occur with anterior cervical fusion. Injury of the seventh, tenth, and twelfth cranial nerves may occur with carotid endarterectomy, as these nerves are close to the carotid bifurcation), various forms of dementia, Movement disorders including Parkinsons disease, Multiple Sclerosis , Amyotrophic Lateral Sclerosis (ALS) 
  •   It has been suggested that recovery of swallowing in acute stroke patients may be rapid, warranting reassessment within 3 weeks of the initial swallowing evaluation  
  •   Abnormal volitional cough, abnormal gag,dysarthria,dysphonia, cough after swallow, voice change after swallow are indicators of risk of aspiration after acute stroke 
  •   But many of the neurologic disorders that affect swallowing are progressive; thus swallowing can be expected to decline as the disease worsens. 
  •   Dysarthria may correlate with dysphagia with bulbar Amyotrophic Lateral Sclerosis (ALS). Dysphagia increases as respiratory capacity decreases regardless of the form of ALS. Vital capacity should be consistently measured, as accurate and timely assessment of a clinically relevant decline in respiratory status is crucial for determining the timing of feeding tube placement 
  •   Pneumonia can be a frequent complication in patients with dysphagia owing to CNS disease 
  •   Although an abnormal gag reflex may be apparent in patients with dysphagia resulting from various neurologic disorders, it may be absent in healthy control subjects or it may be normal in patients with neurogenic dysphagia 
  •   The two imaging tools used to evaluate oropharyngeal dysphagia are Video Fluoroscopic Swallow Study (VSS- Gold Standard) and videoendoscopy. The Penetration-Aspiration Scale (PAS) provides an objective way during the VSS to measure the depth, response, and clearance of material entering the larynx and trachea. 
  •   They are also valuable in identifying and teaching maneuvers that may facilitate swallowing and prevent aspiration in a patient. 
  •   When significant aspiration cannot be prevented, alternatives to oral feeding such as percutaneous endoscopic gastrostomy (PEG) tube placement should be considered. 
  •   Patients with oropharyngeal dysphagia owing to CNS lesions are best managed by a team approach including a speech pathologist, neurologist, and gastroenterologist. 
  •   Swallowing therapy may include compensatory or rehabilitative strategies. Compensatory therapy does not change the physiology of the swallow; rather, bolus flow is redirected 
  •   Compensatory strategies consist of manipulation of posture, consistency of the liquid, and sensory input. Facilitatory postures that have been studied in the neurogenic population include chin tuck and head rotation to the weak side 
  •   Rehabilitative therapy includes muscular strengthening and range of motion exercises, thermal-tactile application, and swallowing maneuvers 
  •   Vocal fold medialization is the procedure generally performed to treat aspiration owing to an incompetent larynx 
  •   A tracheotomy may be performed for neurologic patients with chronic aspiration. Although it does not improve swallowing, it facilitates pulmonary toileting 
  •   Laryngotracheal separation is a more radical attempt to prevent chronic aspiration while allowing for oral intake. Although patients may return to oral diets, the ability to phonate is eliminated. If physiologic aspects of swallowing improve sufficiently, this procedure can be reversed, as the glottis is not affected. 

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