Head injuries prompt immediate concern. A common question is whether the involuntary spasm known as a hiccup can be a sign of a concussion. A concussion, or mild traumatic brain injury, can manifest in numerous ways that affect physical and cognitive functions. This article clarifies the connection between hiccups and head trauma.
The Direct Answer: Hiccups and Concussion Link
Hiccups are generally not considered a standard or expected symptom of a mild concussion. A mild concussion, the most common form of head injury, results from a temporary disturbance in brain function rather than a structural injury. A simple bout of hiccups after head trauma is likely coincidental, triggered by common, benign factors.
However, the medical literature describes a link between persistent hiccups and more severe forms of traumatic brain injury (TBI). Intractable hiccups (lasting longer than one month) or persistent hiccups (lasting over 48 hours) can rarely signal a deep central nervous system injury. This occurs when trauma is severe enough to damage the brainstem, specifically the medulla, which controls the hiccup reflex arc. The presence of hiccups suggests concern for a severe TBI rather than a typical mild concussion.
Common Symptoms of Concussion
It is important to recognize the physical and cognitive symptoms that commonly signal a concussion. Physical symptoms often appear immediately, including a headache that may worsen over time, nausea, or vomiting. Dizziness and balance problems are also frequently reported, stemming from the injury’s disruption to the brain’s equilibrium centers.
Other physical signs include blurred or double vision and increased sensitivity to light and loud noises. On the cognitive and emotional side, a person may experience confusion, feeling foggy or slowed down, or memory issues concerning the events immediately before or after the injury. Emotional changes, such as irritability, anxiety, or sadness, can also be present. Sleep disturbances, like insomnia or sleeping more than usual, are characteristic signs of a concussion.
The Physiology of Hiccups and Neurological Control
Hiccups, medically termed singultus, are the result of an involuntary, spasmodic contraction of the diaphragm muscle. This contraction is immediately followed by the sudden closure of the glottis, which is the space between the vocal cords, producing the characteristic “hic” sound. This whole process is mediated by a complex neurological reflex arc involving several nerves and a central control center in the brain.
The afferent, or incoming, pathway of this reflex arc is carried by three main nerve groups: the vagus nerve, the phrenic nerve, and sympathetic nerves. These nerves transmit signals from the chest and abdomen to the brainstem. The central processing component of the reflex is located in the medulla oblongata, the lowest part of the brainstem, and is not typically affected by a mild concussion.
The efferent, or outgoing, signal is then transmitted primarily by the phrenic nerve to the diaphragm. Irritation along any point of this reflex arc can trigger a hiccup episode. Common causes, such as stomach distension from eating too quickly or drinking carbonated beverages, irritate the peripheral portions of the vagus or phrenic nerves, which is why most hiccups are benign and short-lived.
When Persistent Hiccups Require Emergency Medical Attention
While a brief episode of hiccups after a bump to the head is likely harmless, a sustained period of hiccupping can signal a serious medical concern. Hiccups are classified as persistent if they continue for more than 48 hours and intractable if they last for over a month. When hiccups reach this level of duration, they can lead to exhaustion, sleep deprivation, and difficulties with eating.
In rare neurological cases, persistent hiccups may indicate a structural issue, such as a stroke affecting the brainstem or a tumor compressing the medulla. A specific type of stroke, lateral medullary syndrome, is known to sometimes present with intractable hiccups because it directly impacts the reflex’s central control center.
If a person experiences hiccups that are persistent and are combined with other severe symptoms, immediate emergency medical attention is necessary. These severe signs include loss of consciousness, severe vomiting, sudden weakness on one side of the body, or difficulty speaking.