Waking up with nausea may set off alarm bells for women within a childbearing age – it is often among the first symptoms of pregnancy. But other possibilities have to be considered when there is nausea in very young or old females where pregnancy is not likely, as well as in men who are experiencing morning nausea. There are a host of possible conditions that could be accounting for this symptom. It should be investigated further if morning nausea is persistent, severe enough to trigger vomiting, prevent eating breakfast or is getting worse over days.
Meaning of Morning Nausea
As with other symptoms such as morning dizziness and morning headaches there are certain reasons why nausea may be more likely to occur in the morning. The first factor to consider is the circadian rhythm. These are the changes in various biological processes that occur within a 24 hour cycle and is often referred to as the body’s internal clock. Some processes become more active at certain times while others are less active. It all works together to ensure that the body is in perfect synchronization with a 24 hour day to ensure a healthy balance.
The next factor to consider is the actual effects of sleeping. While adequate sleep is essential for good health, there are certain consequences of lying flat, not eating and having a lower heart and breathing rate for 8 hours straight. Overall none of these consequences are negative for the healthy body. However, when there is some pre-existing disease then these effects of sleep can exacerbate the underlying disease and trigger symptoms that may not be as severe or obvious during the waking hours.
When it comes to morning nausea, the two factors that need to be taken into consideration includes:
- Stimulation of the chemoreceptor trigger zone (CTZ) and vomit center in the brain.
- Irritation of the upper gastrointestinal tract (esophagus, stomach, first half of the small intestine).
Causes of Morning Nausea
Pregnancy is by far the most common cause of sudden morning nausea in women of childbearing age. This is known as morning sickness and is a normal part of pregnancy, particularly in the first trimester. However, there are times in pregnancy where morning nausea is a sign of problems, like in preeclampsia. There are also many different causes of jaundice in pregnancy which are mainly associated with liver and gallbladder disease. Nausea may be a prominent symptom in these conditions as well.
Even without pregnancy, there are number of other gynecological causes of morning nausea. It is mainly associated with a raised HCG (human chorionic gonadotropin) level which is normal only in pregnancy. Tumors like choriocarcinoma, ovarian cancer and a hydatidiform mole may be responsible for raised HCG levels in women and testicular cancer may increase HCG levels in men.
Acid reflux (GERD), gastritis and peptic ulcer disease are three conditions of the upper digestive tract that may worsen in the early hours of the morning. This is largely due to the increase in gastric acid (stomach acid) production that occurs around this time of the day. Nausea is a common symptom in these conditions and therefore it may seem worse in the mornings.
Changes in blood glucose may present with nausea. This is more prominent with low blood glucose levels (hypoglycemia). Overall hypoglycemia is rare but occurs when the body’s ability to regulate the blood glucose levels within a normal range is impaired. It is usually worse with not eating for long periods, and particularly in the morning.
Nausea may be seen with abnormalities in blood pressure. In every person the blood pressure increases in the morning but usually stays within normal limits. In people with hypertension (high blood pressure) this rise causes it to cross the maximum normal levels. People who suffer with orthostatic hypotension (low blood pressure) may find a dip in blood pressure upon getting out of bed. Nausea may therefore be more prominent at these times.
Hormone Drugs and Other Medication
Many different pharmaceutical drugs can cause nausea. It is among the most common side effect of medication. Some are more likely to result in morning sickness, such as the hormone medication. Women using oral contraceptives or hormone replacement therapy may also experience morning nausea. This is more likely due to the raised estrogen or progesterone levels and not HCG.
It may also be seen with other hormone medication particularly if the doses are incorrect. Excess insulin administration in insulin-dependent diabetics may be another hormonal cause. Morning nausea may also be seen with cancer drugs (chemotherapy). Danazol, drospirenone and tamoxifen are some of the other drugs known to be associated with nausea in the morning. It can also occur with overdosing on many other types of drugs.
Morning nausea is common in excessive alcohol consumption the preceding night. This is well known as being part of a ‘hangover’. However, alcohol consumption may also be responsible for hypoglycemia which in turn can cause nausea. Alcoholics may also report nausea after not drinking for a period of time (withdrawal symptoms).
Apart from the tumors discussed above which may produce or stimulate production of HCG, there may also be other tumors that can contribute to morning nausea. Often these are tumors in the brain and/or meninges (tissue surrounding the brain) that directly or indirectly stimulate the chemoreceptors trigger zone, increase pressure within the cranial cavity or affect the brain in some other way that can lead to nausea.
As discussed above, low blood glucose levels (hypoglycemia) can cause nausea. A tumor that produces insulin, known as an insulinoma, may cause a drop in blood glucose levels. Furthermore tumors that impair kidney function may also be responsible as toxins build up in the body. Similarly tumors that affect the adrenal glands and liver could cause morning nausea.
There are many other less common causes of morning nausea. This may include:
- Systemic infections
- Septicemia (“blood poisoning”)
- Brain infections and abscess
- Cerebral edema (brain swelling)
- Subdural hematoma
- Polymyalgia rheumatica