Enlist the clinical features of dengue fever.

Clinical Features of Dengue Fever

The clinical course of dengue fever is typically divided into three phases: febrile, critical, and recovery. Each phase is characterized by distinct clinical features.

1. Febrile Phase (2-7 days)

This phase is marked by the onset of fever and other systemic symptoms.

• Fever: High-grade fever (40°C or 104°F) with sudden onset.
• Headache: Severe frontal headache, often retro-orbital pain (pain behind the eyes).
• Myalgia and Arthralgia: Prominent muscle and joint pain, giving rise to the nickname "breakbone fever."
• Nausea and Vomiting: Common gastrointestinal symptoms.
• Skin Rash: Maculopapular rash appearing 3-4 days after the onset of fever.
• Minor Bleeding Manifestations: Petechiae (small red spots on the skin), epistaxis (nosebleeds), gingival bleeding (bleeding gums).
• Leukopenia: Decreased white blood cell count.

2. Critical Phase (24-48 hours)

This is the most dangerous phase, typically occurring around days 3-7 of illness. Plasma leakage leads to potentially life-threatening complications.

• Plasma Leakage: Increased capillary permeability leading to fluid accumulation in body cavities (pleural effusion, ascites).
• Severe Abdominal Pain: Intense and persistent abdominal pain.
• Persistent Vomiting: Frequent and unrelenting vomiting.
• Clinical Signs of Shock: Restlessness, irritability, cold and clammy skin, weak pulse, hypotension (low blood pressure).
• Severe Bleeding: Gastrointestinal bleeding (hematemesis, melena), vaginal bleeding, bleeding from injection sites.
• Hepatomegaly: Enlargement of the liver, often tender to palpation.
• Thrombocytopenia: Significantly decreased platelet count (<100,000/µL).
• Increased Hematocrit: Due to hemoconcentration from plasma leakage.

3. Recovery Phase (2-3 days)

This phase marks the gradual resolution of symptoms and restoration of fluid balance.

• Gradual Improvement of Symptoms: Fever subsides, and general well-being improves.
• Reabsorption of Fluid: Fluid accumulated in body cavities is gradually reabsorbed.
• Bradycardia: Slow heart rate.
• Rash: A confluent, itchy rash may appear, often described as "islands of white in a sea of red."
• Platelet Count Recovery: Platelet count begins to rise.
• Diuresis: Increased urine output as fluid balance is restored.

Severe Dengue: A subset of dengue cases develops into severe dengue, characterized by any of the following:

• Dengue shock syndrome (DSS)
• Severe bleeding
• Severe organ impairment (liver, kidneys, brain)

Phase	Key Features	Warning Signs
Febrile	High fever, headache, myalgia, rash	Severe abdominal pain, persistent vomiting
Critical	Plasma leakage, shock, severe bleeding	Worsening abdominal pain, lethargy, bleeding from gums or nose
Recovery	Improvement in symptoms, fluid reabsorption	Bradycardia, rash