H1N1 or flu: Fever has settled but weakness remains? When to see a doctor

When the fever goes, but the weakness stays

Fever is one of the most visible signs of an infection, so people often use it as a measure of recovery. Once the temperature becomes normal, they expect their energy to return as well. But the body may take longer to recover.

During an infection, a person may eat less, lose fluids, sleep poorly and remain physically inactive for several days. The immune response to the infection also takes time to settle. As a result, weakness, poor appetite, body ache and reduced stamina may continue even after the fever has gone. This does not necessarily mean that the infection is still active. A negative test is reassuring, but it is not a measure of how quickly the body has regained its strength.

Why do some patients feel better and then worse again?

One reason is that people often return to their routine too quickly. After several days of illness, a person may feel better for a day or two and resume full working hours, exercise or travel. The following day, the fatigue may become much more pronounced.

This can feel like a relapse but sometimes it is simply the result of doing more than the body is ready for. A gradual return to activity is therefore important. Strenuous exercise should not be resumed simply because the fever has disappeared.

But a new infection is also possible

This is where overlapping infections become important. A person recovering from one viral infection can still be exposed to another infection. Seasonal infections may produce similar early symptoms such as fever, body ache, headache and fatigue. It can, therefore, be difficult to determine from symptoms alone whether someone is still recovering or has developed another illness. Government guidance also notes that one infection does not necessarily exclude another, and co-infections can occur.

For example, a patient may recover from influenza, return to work and then develop fever again after a fresh exposure. Another person may initially be diagnosed with a viral fever and later test positive for dengue. These situations need clinical assessment rather than assuming that every recurrence of weakness is simply “post-viral fatigue.”

Dengue needs particular attention when fever settles

There is another reason why a returning patient should not simply be reassured because the fever has come down. In dengue, the period when the fever starts settling can be important. The critical phase generally occurs around this time in patients who develop complications. Warning signs include persistent vomiting, severe abdominal pain, bleeding, increasing drowsiness, difficulty breathing, restlessness or reduced urine output. These symptoms require prompt medical evaluation.

Platelet count is also not the only measure of recovery in dengue. Hydration, blood pressure, haematocrit (percentage of your blood that is made up of red blood cells and is evidence of plasma leakage) and the patient’s overall clinical condition are important in deciding how the illness is progressing.

How should prolonged malaise be managed?

If there is no evidence of a continuing or new infection, the focus is usually on recovery. Adequate sleep, regular, balanced meals, sufficient fluids and gradual physical activity are important.

It is also important not to start antibiotics simply because fatigue continues. Antibiotics do not treat viral infections. Steroids and other medicines should similarly not be taken without a clear medical reason.

When is it more than normal recovery?

Most people gradually improve. But persistent or worsening symptoms deserve reassessment. A returning fever, breathlessness, chest discomfort, repeated vomiting, fainting, confusion, reduced urine output or a significant deterioration in general health should not be dismissed as weakness after a viral infection.

The same applies when symptoms continue for longer than expected without any clear improvement. The important point is that recovery from an infection is not always linear.

(Dr Chatterjee is Senior Consultant, Internal Medicine, Indraprastha Apollo Hospital, Delhi)