Milk aspiration pneumonia occurs when milk is inhaled into the respiratory tract during swallowing or when residual milk is inhaled into the lungs due to prolonged emptying time in the pharynx. During vomiting or milk regurgitation, milk is inhaled into the respiratory tract, often with predisposing factors.

bubble_chart Etiology

1. Swallowing disorders Premature infants have immature swallowing reflexes and uncoordinated swallowing movements, making them prone to milk aspiration. Brain injury or cranial nerve disorders can also cause迟钝 or incomplete swallowing reflexes. The emptying time of milk in the pharynx is prolonged. Sometimes, due to neuromuscular incoordination in the pharynx, during swallowing, part of the milk enters the esophagus, part flows out through the nasal cavity, and part is aspirated into the respiratory tract, leading to pneumonia.

2. Esophageal malformations In cases of esophageal atresia, milk cannot pass from the esophagus into the stomach and remains in the pharynx, where it is aspirated into the lungs along with saliva. In cases of tracheoesophageal fistula alone, milk can directly enter the lungs through the fistula. However, sometimes the fistula is very small and difficult to detect.

3. Esophageal insufficiency After entering the esophagus, milk refluxes back to the pharynx and is then aspirated. For example, infants with松弛 of the esophageal cardia are prone to aspiration after vomiting. Sometimes, esophageal neuromuscular incoordination can also cause reflux.

4. Severe cleft palate or hare lip Generally, cleft palate does not affect swallowing, but severe defects can make sucking difficult and lead to aspiration.

When milk is aspirated into the alveoli, the lung tissue exhibits an inflammatory response. Within hours, neutrophils, phagocytes, and red blood cells exude, the alveolar walls thicken, and interstitial inflammation becomes evident. Fibrosis develops after several weeks. If aspiration occurs repeatedly, it can lead to chronic interstitial pneumonia.

bubble_chart Clinical Manifestations

1. Symptoms of the primary disease causing aspiration: For infants with swallowing dysfunction, milk flows out from the nasal cavity, accompanied by cough, and sometimes cyanosis occurs. For infants with a blind-ended esophagus, milk remains in the pharynx, producing gurgling sounds during breathing. Those with esophageal-tracheal fistula experience choking, shortness of breath, and cyanosis during feeding. Individuals with esophageal insufficiency are prone to milk regurgitation.

2. Respiratory symptoms and signs: The severity (Grade III) is related to the amount and frequency of aspiration. Those with minor or occasional aspiration primarily present with bronchitis, exhibiting symptoms such as cough, wheezing, and shortness of breath. Larger amounts of aspiration may lead to pneumonia, while a single massive aspiration can cause asphyxia and respiratory arrest. After breathing resumes, severe shortness of breath and abundant lung rales become evident. Chronic and repeated aspiration results in aspiration pneumonia, eventually leading to pulmonary fibrosis or complicating bronchiectasis.

3. X-ray findings: In the early stage, due to bronchial irritation by foreign substances, incomplete obstruction occurs, manifesting as extensive lung emphysema and bronchial inflammatory changes on X-ray, including widened hilar shadows, thickened lung markings, or patchy inflammatory shadows. Repeated aspiration involving the interstitium leads to interstitial pneumonia.

Immediate endotracheal intubation to suction milk from the trachea. Strengthen nursing care, ensure warmth, and maintain airway patency. Begin intravenous nutrition initially, then switch to nasogastric or oral feeding as the condition improves. Use antibiotics to prevent secondary infections and treat the underlying disease cause.