What is the diagnosis, treatment, and prognosis for a patient suspected of having COVID-19 (Coronavirus Disease 2019)?

COVID-19 Diagnosis and Treatment

Diagnosis

For symptomatic individuals suspected of COVID-19, perform RT-PCR testing on a nasopharyngeal swab as the first-line diagnostic method—this remains the reference standard for definitive diagnosis. 1, 2

Primary Diagnostic Approach

• RT-PCR (nucleic acid amplification test) is the gold standard with pooled sensitivity of 97% (95% CI, 93-99%) and specificity of 100% (95% CI, 96-100%) in symptomatic patients 1
• Nasopharyngeal specimens are superior to oropharyngeal samples, particularly in early disease stages 1, 2
• Alternative specimen types can be used if nasopharyngeal swabs are unavailable: anterior nasal swabs, midturbinate swabs, oropharyngeal swabs, saliva, or mouth gargle—all have acceptable sensitivity (78-92%) though slightly lower than nasopharyngeal samples 1
• Testing should target at least two distinct viral gene sequences for optimal accuracy 2

Rapid Antigen Testing

• A single antigen test is recommended over no test for symptomatic individuals, with strong specificity allowing positive results to guide treatment and isolation decisions without confirmation 1
• Antigen tests should be performed within 5 days of symptom onset for optimal performance 1
• If clinical suspicion remains high and antigen test is negative, confirm with RT-PCR as antigen tests are less sensitive than molecular methods 1, 2
• Positive antigen tests have high specificity and do not require RT-PCR confirmation 1, 2

Imaging Studies

• Chest CT scan is the most accurate radiological tool for uncertain cases and should be used when RT-PCR is negative but clinical suspicion remains high 1, 2
• Chest X-ray can substitute when CT is unavailable 1, 2
• Lung ultrasound serves as a first-line screening tool when performed by skilled operators with limited CT access 2
• Negative chest CT does not exclude COVID-19, especially in early infection stages 1

Repeat Testing Strategy

• For high clinical suspicion with negative RT-PCR, repeat nasopharyngeal RT-PCR testing and add chest imaging to confirm diagnosis and assess pneumonia severity 1, 2
• False-negatives occur due to timing of sample collection, improper sampling technique, or missing the viral replication window 1, 2
• RT-PCR should be performed at least twice in uncertain patients, with tests taken at least 24 hours apart 1

Laboratory Findings (Supportive but Non-Diagnostic)

• Lymphopenia (absolute lymphocyte count <0.87 × 10⁹/L) is common 1
• Elevated inflammatory markers: CRP, ESR, IL-6, D-dimer 1
• Elevated liver enzymes (ALT, AST) and creatine kinase may be present 1
• These findings support diagnosis but cannot confirm COVID-19 alone 1

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Treatment

Antiviral Therapy

Remdesivir is the FDA-approved antiviral for COVID-19 treatment in hospitalized patients and high-risk non-hospitalized patients. 3

Remdesivir Dosing (FDA-Approved)

Adults and pediatric patients ≥40 kg:

• Loading dose: 200 mg IV on Day 1
• Maintenance: 100 mg IV once daily from Day 2 3

Pediatric patients <40 kg (weight-based dosing):

• Neonates ≥1.5 kg (<28 days old): 2.5 mg/kg loading dose, then 1.25 mg/kg daily 3
• Infants/children ≥28 days old (1.5-40 kg): 5 mg/kg loading dose, then 2.5 mg/kg daily 3

Treatment Duration

• Hospitalized patients on mechanical ventilation/ECMO: 10 days total 3
• Hospitalized patients not requiring mechanical ventilation: 5 days (may extend up to 10 days if no clinical improvement) 3
• Non-hospitalized high-risk patients: 3 days total, initiated within 7 days of symptom onset 3

Administration

• Administer via IV infusion over 30-120 minutes 3
• Must be diluted in 0.9% sodium chloride prior to infusion 3
• No dosage adjustment needed for renal impairment, including dialysis patients 3

Monitoring Requirements

• Perform hepatic laboratory testing before starting and during treatment as clinically appropriate 3
• Assess prothrombin time before starting and monitor during treatment 3

Antibiotic Therapy

Routine antibiotics are NOT recommended for COVID-19 patients unless there is clinical justification for bacterial coinfection. 2

• Use antibiotics only when disease severity, radiographic findings, and laboratory evidence suggest bacterial coinfection 2
• Critically ill patients (ICU admission, mechanical ventilation) have higher risk of bacterial coinfection and may require empirical antibiotics 2
• Higher WBC counts, elevated CRP, or procalcitonin >0.5 ng/mL suggest possible bacterial coinfection, but do not use biomarkers alone to initiate antibiotics in non-critically ill patients 2
• Perform comprehensive microbiologic workup before starting empirical antibiotics to facilitate de-escalation 2

Supportive Care

Oxygen therapy is the cornerstone for patients with respiratory distress, hypoxemia, or shock. 1

• Initial flow rate: 5 L/min, titrate to maintain SpO₂ ≥90-96% 1, 2
• Escalate oxygen delivery as needed: nasal cannula → mask → high-flow nasal oxygen (HFNO) → non-invasive ventilation (NIV) → invasive mechanical ventilation 1
• Consider ECMO for refractory hypoxemia unresponsive to protective lung ventilation 1

Monitoring Requirements

• Monitor vital signs: heart rate, pulse oximetry, respiratory rate, blood pressure 1, 2
• Laboratory monitoring: complete blood count, CRP, procalcitonin, liver enzymes, bilirubin, cardiac enzymes, creatinine, urea nitrogen, urine output, coagulation function, arterial blood gas 1
• Serial chest imaging to assess progression 1

Additional Supportive Measures

• Ensure adequate energy intake (25-30 kcal/kg/day) and maintain water-electrolyte balance 1, 2
• Use H2 receptor antagonists or proton pump inhibitors in patients with GI bleeding risk factors (mechanical ventilation ≥48 hours, coagulation dysfunction, renal replacement therapy) 2
• Assess venous thromboembolism risk and use low-molecular-weight heparin in high-risk patients without contraindications 2

Isolation and Infection Control

Isolate patients for at least 5 days from symptom onset when fever has been absent for 24 hours without antipyretics, symptoms are resolving, and ideally after a negative rapid antigen test. 2

• Extend isolation up to 10 days if symptoms persist, fever continues, or antigen testing remains positive 2
• Place patients in well-ventilated single rooms with restricted activity 2
• Patients must wear medical masks (N95 preferred) when in presence of others 2
• Implement hand hygiene immediately after coughing, sneezing, or touching contaminated surfaces 2

Surgical Patients with COVID-19

• Surgery indications are not different in confirmed COVID-19 patients, but morbidity and mortality rates are higher compared to negative patients 1
• If RT-PCR unavailable and surgery cannot be delayed, manage patient as COVID-19 positive with full protective measures 1
• Use dedicated COVID-19 operating rooms and pathways when available 1

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Prognosis

COVID-19 has mild symptoms in approximately 85% of cases, with 3-10% progressing to critical illness and overall mortality around 5-7%. 4

Risk Stratification

• Symptomatic patients with positive testing require monitoring for progression, particularly those with risk factors for severe disease 4, 5
• Approximately 10% of patients require intensive care unit admission 4
• More severe cases present with pneumonia, dyspnea, or uncontrollable fever requiring inpatient management 4

Indicators of Severe Disease

• Respiratory rate ≥30/min 2
• Persistent hypoxemia despite oxygen supplementation 1
• Progression to acute respiratory distress syndrome (ARDS) 4, 5
• Multi-organ failure in critical cases 4, 6

Post-Discharge Management

• After hospital discharge, confirmed COVID-19 patients should remain in isolation for at least 2 weeks from first positive test until negative RT-PCR is obtained 1
• Some patients may show intermittent positive RT-PCR tests after 14-day quarantine, though contagiosity of these patients remains unclear 1

Common Pitfalls

• Do not use negative RT-PCR to guide discontinuation of isolation or prior to procedures—clinical criteria should guide these decisions 1
• Avoid relying solely on chest imaging to exclude COVID-19, especially in early infection 1
• Do not delay urgent surgery for RT-PCR confirmation in hemodynamically unstable patients—proceed with full COVID-19 precautions 1