What are the symptoms of forest encephalitis

Symptoms of forest encephalitis include fever, headache, muscle pain all over the body, lack of appetite, nausea and vomiting. Some patients may also show symptoms such as impaired consciousness and mental damage.

(1) Fever usually reaches its peak (39.5℃～41℃) 2 to 3 days after onset, and in most patients it lasts for 5 to 10 days, then decreases in a step-like manner, returning to normal within 2 to 3 days. The fever type is mostly retained fever, and some patients may experience remittent fever, bimodal fever or irregular fever.

(2) Symptoms of systemic poisoning: High fever is accompanied by headache, muscle pain, weakness, lack of appetite, nausea, vomiting, etc. Due to damage to the vasomotor center, the patient may also experience flushing of the face and neck, conjunctival congestion, and slow pulse. Some critically ill patients have symptoms of myocarditis, often with dull heart sounds, increased heart rate, and T wave changes on electrocardiogram. Severe patients may suddenly develop heart failure, acute pulmonary edema, etc.

(3) Consciousness disorders and mental damage: More than half of the patients have varying degrees of mental and consciousness changes, such as drowsiness, apathy, confusion, coma, and may also experience delirium and mental confusion.

(4) The most common symptom of meningeal involvement is severe headache, which is often a continuous dull pain in the temporal and occipital regions, sometimes explosive and throbbing, presenting as a tearing headache, accompanied by nausea, vomiting, neck stiffness, and meningeal irritation signs. It usually lasts for 5 to 10 days and may exist at the same time as coma. Once consciousness is restored, it can last for about a week.

(5) Muscle paralysis is most common in the form of combined paralysis of the cervical and scapular muscles and upper limbs, with lower limb and facial muscles less common. Paralysis is mostly flaccid, which is different from Japanese encephalitis. It usually appears on the 2nd to 5th day of the disease. Most patients gradually recover after 2 to 3 weeks, but a few have sequelae and experience muscle atrophy, becoming disabled. The disease's unique head drooping symptom occurs due to paralysis of the cervical and scapular muscles. When the scapular muscles are paralyzed, the arms are in a swinging and helpless state.

(6) Other manifestations of nervous system damage: Some patients show signs of extrapyramidal system damage, such as tremor and involuntary movements. Occasionally, symptoms of bulbar paralysis such as speech disorders and dysphagia, or mild paresis of the central facial and hypoglossal nerves may be seen.