aspiration pneumonitis (Mendelson's syndrome)
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Etiology
- regurgitation of stomach contents & aspiration of chemical material, generally gastric juices
- often follows anesthesia when the gag reflex is depressed
Pathology
- low pH (< 2.5) of aspirated gastric contents
- large volume of aspirate
- pulmonary inflammation
- destruction of the alveolar lining
- transudation of fluid into the alveolar space
- ARDS may develop
- bacterial superinfection
Clinical manifestations
- develops within hours
- cough
- wheezing
- rales
- tachypnea
- dyspnea
- hypoxia
- low-grade fever
- tachycardia
- hypotension
- sputum production is minimal; significant sputum production suggests bacterial superinfection
- evidence of sepsis (bacterial superinfection)
Laboratory
- complete blood count (CBC)
- WBC may be increased without bacterial infection
- bacterial superinfection generally accompanied by leukocytosis
- arterial blood gas (ABG) may show increased P(A-a)O2
- pulse oximetry may show diminished SaO2
- blood cultures & sputum cultures to rule out aspiration pneumonia
Radiology
- chest X-ray
- may be normal (in contrast to aspiration pneumonia)[3]
- may change from normal to complete white-out within 8-24 hours
- a case described with new lower lung opacity[7]
Complications
- significant risk for aspiration pneumonia
Differential diagnosis
- aspiration pneumonia with abnormal chest X-ray[3]
- develops days not hours after pulmonary aspiration
Management
- supportive care (without antibiotics) is the most appropriate therapy[4]
- respiratory support
- supplemental oxygen
- positive pressure ventilation with more severe disease
- mechanical ventilation of a last resort[3]
- respiratory support
- standard antibiotic therapy for community-acquired pneumonia[6]
- discontinue antibiotics if cultures negative
- withold antibiotics until evidence of bacterial superinfection, except in association with:
- prognosis
- may resolve quickly with symptomatic therapy
- bacterial superinfection may result may develop over a period of days
- symptoms that persist or increase after 48 hours suggest aspiration pneumonia[3]
More general terms
Additional terms
References
- ↑ Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 252-53
- ↑ Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 993-4
- ↑ 3.0 3.1 3.2 3.3 3.4 Geriatric Review Syllabus, 9th edition (GRS9) Medinal-Walpole A, Pacala JT, Porter JF (eds) American Geriatrics Society, 2016
- ↑ 4.0 4.1 Marik PE. Aspiration pneumonitis and aspiration pneumonia. N Engl J Med. 2001 Mar 1;344(9):665-71. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/11228282
- ↑ Raghavendran K, Nemzek J, Napolitano LM, Knight PR. Aspiration-induced lung injury. Crit Care Med. 2011 Apr;39(4):818-26. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/21263315 Free PMC Article
- ↑ 6.0 6.1 Medical Knowledge Self Assessment Program (MKSAP) 19 American College of Physicians, Philadelphia 2022
- ↑ 7.0 7.1 NEJM Knowledge+