Vomiting is the body’s protective reflex to expel irritants or toxins from the stomach. Projectile vomiting is a distinct and far more forceful expulsion of stomach contents that travels a significant distance away from the body. It is often a sign of high internal pressure or a physical blockage within the digestive system. The extreme force involved requires prompt attention to determine the underlying cause.
The Mechanics of Projectile Vomiting
Unlike standard vomiting, which is typically preceded by nausea and retching, projectile vomiting can occur suddenly with little or no warning. The contents of the stomach are ejected with such velocity that they may travel several feet, distinguishing this event from simple regurgitation or standard emesis. This forceful action is generated not by the stomach itself, but by a powerful, involuntary contraction of the diaphragm and abdominal muscles.
The intense muscular squeezing acts on the stomach, which has relaxed its lower sphincter, building up pressure that expels the contents. This mechanism bypasses the usual coordinated sequence of movements that characterize less severe vomiting episodes. The lack of preparatory muscle movements like retching makes the expulsion abrupt and uncontrolled, resulting in the characteristic distance the material travels.
Underlying Medical Causes
Projectile vomiting is frequently associated with conditions that either physically obstruct the gastrointestinal tract or increase pressure within the central nervous system. In infants, a common cause is pyloric stenosis, a condition where the muscular valve (pylorus) between the stomach and the small intestine thickens. This thickening creates a blockage that prevents food from passing through, forcing the stomach to contract against the obstruction.
The stomach’s efforts to push milk or formula past the narrowed pylorus eventually build up enough pressure to cause a forceful expulsion, often within 30 minutes of a feeding. Since the food does not reach the intestines, the infant often appears hungry immediately after the episode. In adults, gastrointestinal obstructions, such as those caused by tumors or intestinal blockages, can similarly trigger this forceful response as the stomach attempts to overcome the physical barrier.
Increased intracranial pressure (ICP) is another cause, often resulting from conditions like hydrocephalus, head trauma, or brain infections such as meningitis. This elevated pressure irritates the vomiting center located in the brainstem. When this center is directly stimulated by pressure, it instantly triggers the vomiting reflex, resulting in forceful expulsion without preceding nausea. This neurological mechanism requires immediate medical evaluation.
Recognizing Red Flags and Dehydration
Any instance of projectile vomiting should be treated seriously, but certain accompanying signs are red flags that demand immediate medical attention. These include a severe headache, a stiff neck, or a fever, which may suggest an infection like meningitis or another neurological issue. Vomit that contains blood or is green (indicating bile) can signal a complete gastrointestinal obstruction requiring urgent intervention.
The forceful expulsion of fluid and electrolytes makes rapid dehydration a significant danger, particularly for infants and young children. Signs of severe fluid loss must be monitored, such as a lack of tears when crying, a dry mouth, or reduced urination. In infants, a sunken soft spot (fontanelle) or sunken eyes indicate severe dehydration. For adults, extreme thirst, dizziness, and confusion are indications that the body needs immediate professional rehydration, often through intravenous fluids.