Nausea and vomiting are common and are usually linked to stomach-related issues, whether it is vomiting due to acidity, food poisoning or nausea triggered by motion sickness on hilly roads with hairpin bends. But when they happen repeatedly without any obvious or explainable cause, the problem may not be related to the gut. In some cases, the cause can actually be in the brain!
Why do vomiting and nausea happen when someone is silently suffering from a neurological condition? We asked a neurologist to unpack the physiological connection and explain when these seemingly simple symptoms, which are dismissed because they can be managed at home, may actually signal something serious or even become a medical emergency. Dr Manoj Khanal, Director – neurology at Max Hospital, Shalimar Bagh, provided his insights and helped connect the dots between nausea, vomiting and brain health.
“Unexplained vomiting and nausea occurs due to overstimulation of the chemoreceptors trigger zone (CTZ) or the brain stem vomiting centre in the lower brain stem or medulla,” Dr Khanal said, sharing how when certain areas in brains are overstimulated because of any existing neurological condition, then body may show signs of nausea and vomiting, despite absence of digestive ailments.
What are the neurological causes?
Here are the 6 causes, as outlined by the doctor:
1. Migraines
- Migraines may cause nausea and vomiting because of increased sensitivity of brainstem receptors, along with gastric stasis.
2. Vestibulopathy
- Inner ear disorders as BPPV or Ménière’s disease causes sensory mismatch in the balance system.
- This may trigger vertigo, nausea, and vomiting.
3. Brain swelling or space-occupying lesions
- Conditions such as brain tumours or hydrocephalus can increase intracranial pressure that triggers vomiting reflex without nausea.
- Sudden projectile vomiting, especially in the morning, can occur due to pressure on the lower brainstem.
- Important sign of brain tumour.
4. CNS disorders
- Conditions such as multiple sclerosis and neuromyelitis optica can cause specific lesions on the brainstem, particularly in the area postrema.
- This can stimulate brainstem receptors and lead to recurrent nausea and vomiting.
5. Meningitis, encephalitis or brain infections:
- Infections involving the brain or its coverings can cause vomiting either by irritating the basal meninges around the lower brainstem or by directly affecting the lower brain.
6. Head injury
- A direct head injury or brain irritation can trigger nausea and vomiting.
- In some cases, these symptoms may occur even when bleeding or structural damage is not immediately detected.
Signs when recurrent nausea/vomiting could be a medical emergency
Medical emergencies requiring immediate medical attention if projectile vomiting or nausea is accompanied by red flag symptoms. Here are some of the signs you should watch out for, as outlined by the neurologist:
1. Sudden severe headache, which might feel like the ‘worst headache of your life.’
2. Confusion or lethargy
3. Sudden balance problem
4. Facial drooping
5. Arm or leg weakness
6. Speech problems
4. Vision blurry or double vision
5. Fever with stiff neck
6. Dysphagia or inability to keep fluids down for more than 24 hours
In the end, the doctor advised that to determine the exact cause, evaluate by brain imaging; EEG; lumbar puncture and other neurological tests.
Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.
