Headache After Anaesthetic: Causes and Warning Signs

A headache after anaesthetic is relatively common and is usually short-lived. It may be related to fasting, dehydration, stress, caffeine withdrawal, pain medicines, or—less commonly—a spinal or epidural procedure, which requires specific assessment and treatment.

Overview: why a headache can happen after anaesthetic

A headache after anaesthetic is usually temporary and does not necessarily mean that something has gone wrong. In the first day or two after surgery, common contributors include not drinking enough, fasting before the procedure, poor sleep, anxiety, missed caffeine, pain, and the body’s normal response to surgery. Headaches are often manageable with hydration, a light meal if permitted, rest, and the pain medicine recommended by the treating team.

The word “anaesthetic” covers several types of care. General anaesthesia causes temporary unconsciousness, while spinal and epidural anaesthesia numb the lower body and may be used for childbirth or operations below the waist. Sedation and nerve blocks are other options. A headache can occur after any procedure, but a distinctive positional headache following a spinal or epidural injection deserves medical advice because it can occasionally be caused by a small leak of spinal fluid.

The timing, severity and pattern of symptoms help clinicians understand the likely cause. A mild, familiar headache that steadily improves is often less concerning than a new severe headache, one that worsens rapidly, or one occurring with neurological symptoms. Patients should contact their healthcare team if they are uncertain, particularly after leaving hospital.

Common triggers during recovery

Dehydration is one of the most frequent and reversible explanations. Patients may have limited fluids before surgery, lose fluid through sweating or vomiting, or be slow to drink afterwards because of nausea or a sore throat. Low blood sugar after fasting, particularly when a person has not yet resumed normal eating, can also contribute to feeling headachy, shaky or tired.

Caffeine withdrawal is another possible trigger. Someone who usually drinks coffee, tea, energy drinks or caffeinated soft drinks daily may develop a headache if they suddenly stop before surgery and do not resume their usual intake afterwards. The clinical team may advise when it is safe to drink caffeine, as this depends on the procedure, other health conditions and recovery instructions.

Other contributors include tension in the neck and shoulders from positioning during surgery, disrupted sleep, emotional stress, and changes in regular medicines. Some medicines given around an operation, including certain pain medicines or anti-nausea medicines, may cause headache in some people. Conversely, taking too much headache medication over several days can sometimes perpetuate headaches, so patients should use medicines only as directed.

General anaesthesia itself is not usually the sole cause of a prolonged headache. However, its after-effects, combined with the physical stress of an operation and changes to normal routine, can make a person who is prone to migraine or tension-type headache more likely to have an episode.

Spinal headache after spinal or epidural anaesthesia

A post-dural puncture headache, often called a spinal headache, can develop when the thin membrane around the spinal fluid is punctured during a spinal anaesthetic, epidural procedure, or occasionally another procedure involving the lower back. A tiny amount of cerebrospinal fluid may leak through the opening. This changes pressure around the brain and spinal cord and can produce a characteristic headache.

The typical pattern is a headache that is clearly worse when the person sits or stands and improves significantly when they lie flat. It often starts within a few days of the procedure and may be felt at the front or back of the head. Neck stiffness, nausea, sensitivity to light, ringing in the ears, muffled hearing, or dizziness can accompany it. Not every headache after a spinal or epidural is a spinal headache, but this positional pattern is important to report.

Initial care may include fluids, rest and appropriate pain relief, based on the clinician’s advice. If symptoms are severe, persistent, or interfere with caring for a newborn or returning to normal activity, an anaesthetist may discuss an epidural blood patch. This procedure uses a small amount of the patient’s own blood in the epidural space to help seal the leak. The decision is individualized after assessment of symptoms, timing and medical history.

Factors that can increase the likelihood of headache

People who regularly experience migraine, tension-type headache or other recurrent headaches may be more likely to have a headache during the stress and routine disruption of surgery. A history of headaches does not automatically indicate a complication, but it is useful information for the anaesthetist. Sharing what a usual headache feels like can also help distinguish a familiar pattern from a new one.

Long fasting periods, low fluid intake, nausea and vomiting, sleep deprivation, and abruptly stopping caffeine may all increase the chance of headache. Surgery itself can involve blood loss or changes in blood pressure, which clinicians monitor closely. In some cases, conditions unrelated to anaesthesia—such as infection, sinus symptoms, high blood pressure, or a viral illness—may be responsible.

The risk of post-dural puncture headache depends on factors such as the type of needle and procedure, whether an unintended dural puncture occurred during epidural placement, and individual characteristics. It can occur even when a procedure is performed carefully and correctly. Patients should not delay contacting the anaesthesia department because they worry they have done something wrong; prompt communication supports appropriate care.

How clinicians assess a headache after anaesthetic

Assessment begins with a detailed description of the headache. Clinicians ask when it started, where it is felt, how severe it is, whether it changes with position, and whether it resembles previous headaches. They also review the type of anaesthesia, medicines used, the operation performed, fluid intake, nausea, blood loss and relevant medical history.

A physical examination may include blood pressure, temperature, hydration status, and a neurological assessment of vision, speech, balance, strength, sensation and alertness. For a suspected spinal headache, the relationship between symptoms and standing or lying down is especially helpful. The healthcare team may also consider other causes, including migraine or medication effects.

Most mild headaches do not require scans or extensive testing. However, blood tests, brain imaging, or other investigations may be needed if there are red-flag symptoms, an atypical presentation, a severe or worsening headache, or concern about another medical condition. This careful approach helps make sure that serious but uncommon causes are not missed.

Relief and recovery at home

Patients should follow their surgeon’s and anaesthetist’s recovery instructions first, as these are tailored to the operation. If fluids are allowed, sipping water or other suitable drinks regularly may help. Resuming small, nourishing meals when tolerated can support recovery after fasting. Resting in a quiet, dimly lit room may be useful for those with light sensitivity or a migraine-like headache.

Only pain medicines approved by the clinical team should be used after surgery. This is particularly important after some operations because certain anti-inflammatory medicines may not be suitable, may interact with prescribed medicines, or may increase bleeding risk for particular patients. Alcohol should be avoided while recovering from anaesthesia or while taking opioid pain medicines or sedating medication.

Patients who suspect a spinal headache should contact the hospital, anaesthesia department, maternity unit, or their doctor rather than relying only on home measures. Lying flat may provide temporary relief, but a persistent positional headache should be assessed. It is also sensible to arrange support at home if symptoms make standing, walking, eating or caring for a child difficult.

At Acıbadem Health Point, multidisciplinary specialists in JCI-accredited hospitals can assess post-procedure symptoms and coordinate care for international patients when further evaluation is needed.

When to seek medical care

Patients should contact their surgeon, anaesthetist, primary care clinician or the hospital team promptly if a headache is severe, lasts longer than expected, is getting worse, or does not improve with the recovery measures they have been advised to use. A headache that is much worse upright and better lying down after a spinal or epidural procedure should be reported on the same day where possible.

Urgent medical care is needed for a sudden “worst-ever” headache, fainting, confusion, seizure, new weakness or numbness, difficulty speaking, facial drooping, persistent vision changes, severe neck stiffness, fever, chest pain, shortness of breath, or repeated vomiting. These symptoms may be unrelated to anaesthesia, but they require prompt assessment.

People who have recently given birth should seek urgent advice for a severe new headache, especially if it occurs with high blood pressure, visual disturbances, upper abdominal pain, swelling, breathlessness or neurological symptoms. Postpartum headaches have several possible causes, including spinal headache, migraine and conditions that need urgent treatment. It is safest not to self-diagnose.

Frequently asked questions