Question 14

Created on Sun, 05/24/2015 - 21:14
Last updated on Fri, 04/28/2017 - 18:06
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List the possible causes of an altered swallowing reflex in a critically ill patient, and outline how you could assess this.

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College Answer

Causes:

•    Iatrogenic - Medications – chemotherapy, antihistaminics, neuroleptics. Trauma - TOE, intubation , tracheostomy
•    Infectious - candidial mucositis. Metabolic – thyrotoxicosis, Cushing’s
•    Myopathic – myasthenia gravis, connective tissue disorders, myotonic dystrophy
•    Neurological – severe head injury, stroke, Guillain-Barre syndrome. Structural - Zenker's diverticulum, Oropharyngeal and oesophageal tumours.

Assessment:

•    History – hoarseness, weak cough – vocal cord palsy, slurred speech, nasal regurgitation – neuromuscular. Odynophagia – infections , malignancy
•    Clinical assessment – oral cavity –poor dentition, dry mouth. Neurological –
cranial nerves – V. VII, IX, X, XI, XII.
•    Bedside assessment by speech therapist – coordination of swallowing, aspiration of dye (methylene blue).
•    Nasopharyngeal laryngoscopy – visual inspection oropharynx, vocal cords for anatomical abnormality.
•    Video fluoroscopy – accurately analyses aspiration, pooling of secretions and movements of muscles during swallowing.
•    Barium swallow – identifies anatomical abnormalities – diverticuli, tumours, Upper GI endoscopy.

Discussion

Altered swallowing in an ICU patient could be the result of a number of aetiological processes. Not all of the belowmentioned processes are causing an "altered reflex" per se.

A List of Causes for Altered Swallowing Function in Critical Illness

Vascular causes:

  • Ischaemic stroke

Infectious causes:

  • Oral and pharyngeal candidiasis
  • Retropharyngeal abscess, pharyngitis, toncillitis
  • Meningitis or brain abscess compressing the cranial nerves
  • Botulism
  • Tetanus

Neoplastic causes:

  • Oropharyngeal or laryngeal neoplasm

Drug-induced swallowing dyfunction:

  • Neuroleptic drugs causing "swallowing ataxia" as an extrapyramidal side-effect
  • Sedatives

Idiopathic miscellaneous causes:

  • Head and neck radiotherapy
  • Critical illness neuromyopathy

Autoimmune causes

  • Dermatomyositis
  • Multiple sclerosis
  • Myasthenia gravis
  • Guillain-Barre syndrome

Traumatic causes:

  • Base of skull fracture severing the cranial nerves
  • Traumatic neck injury
  • Facial trauma
  • Surgical complications following head and neck surgery
  • Prolonged intubation or tracheostomy, desensitising the swallowing reflex
  • Nasogastric tube

Endocrine and metabolic causes:

  • Hypocalcemia
  • Goitre, or invasive thyroid carcinoma
  • Metabolic encephalopathy, eg. uraemia

Investigation of abnormal swallowing in ICU follows a familiar pattern:

  • History (suggestive of stroke or malignancy)
  • Examination (of whole body neurology, but focusing on the cranial nerves)
  • Speech therapist assessment
  • Nasendoscopy to observe the vocal cords directly
  • Barium swallow
  • CT of the neck
  • A VFSS (videofluoroscopic swallowing study) is the gold standard.

References

de Larminat, Valentine, et al. "Alteration in swallowing reflex after extubation in intensive care unit patients." Critical care medicine 23.3 (1995): 486-490.

Macht, Madison, et al. "ICU-Acquired Swallowing Disorders." Critical care medicine 41.10 (2013): 2396-2405.