Makindo Medical Notes.com

As of October 2020 there are insufficient data to recommend either for or against any antiviral or immune-based therapy in patients with COVID-19 who have mild illness.

About

• Caused by SARS-CoV-2, the virus that causes COVID-19

Origin

• Originated in Wuhan China in late 2019
• Possibly from wet markets
• Live animals especially Bats close contact with humans

Aetiology

• Coronavirus: has four major structural proteins
  • Spike surface glycoprotein binds to host receptors via the receptor-binding domains (RBDs) of angiotensin-converting enzyme 2. The ACE2 protein has been identified in various human organs, including the respiratory system, GI tract, lymph nodes, thymus, bone marrow, spleen, liver, kidney, and brain
  • Small envelope protein
  • Matrix protein
  • Nucleocapsid protein
• Causes a Pneumonia
• Mortality approximately 1%

Pathology

• Thick hyaline membrane mixed with desquamative pneumocytes and mononuclear inflammatory cells. Focal hyaline membrane, type II pneumocyte hyperplasia, and mild interstitial thickening.
• Alveolar spaces were filled with red blood cell exudation, and small fibrin plugs seen in adjacent alveoli.
• Organization with intra-alveolar fibroblasts mixed with fibrin and inflammatory cellular infiltration.
• Diffuse type II pneumocyte hyperplasia in the background (inset: fibrinoid vascular necrosis, arrowheads). Changes of bronchopneumonia with prominent neutrophilic infiltration filling up alveolar spaces.
• ACE2, the entry receptor for the causative coronavirus SARS-CoV-2, is expressed in multiple extrapulmonary tissues

Groups at higher risk

• Older patients, Nursing homes
• South east Asian and Afro-Caribbean
• Diabetes, Obesity, Hypertension, Heart failure
• Malignancy, Immunosuppression, Chronic respiratory disease
• Low vitamin D may play a role in immunity

Clinical

• Incubation period up to 14 days mean 5 days
• Fever, dry cough, dyspnoea, muscle pain, confusion
• Headache, sore throat, rhinorrhea, chest pain, diarrhea, nausea, and vomiting
• Viral Pneumonia often with Type 1 RF
• Superimposed bacterial pneumonia
• Myocarditis, Acute kidney injury

Severity

• Asymptomatic or Presymptomatic Infection: Individuals who test positive for SARS-CoV-2 by virologic testing using a molecular diagnostic (e.g., polymerase chain reaction) or antigen test, but have no symptoms.
• Mild Illness: Individuals who have any of the various signs and symptoms of COVID 19 (e.g., fever, cough, sore throat, malaise, headache, muscle pain) without shortness of breath, dyspnoea, or abnormal chest imaging.
• Moderate Illness: Individuals who have evidence of lower respiratory disease by clinical assessment or imaging and saturation of oxygen (SpO₂) = 94% on room air at sea level.
• Severe Illness: Individuals who have respiratory frequency >30 breaths per minute, SpO₂ <94% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO₂/FiO₂) <300 mmHg, or lung infiltrates >50%
• Critical Illness: Individuals who have respiratory failure, septic shock, and/or multiple organ dysfunction.

Complications

• Septic Shock and Cytokine Storm: high levels of an array of inflammatory cytokines, often in the setting of deteriorating haemodynamic or respiratory status. However exclude other treatable causes of shock (e.g., bacterial sepsis due to pneumonia or an extra-pulmonary source, hypovolaemic shock due to a gastrointestinal haemorrhage that is unrelated to COVID-19, cardiac dysfunction related to COVID-19 or comorbid atherosclerotic disease, stress-related adrenal insufficiency)
• Myocarditis and pericardial dysfunction and acute cardiac injury and arrhythmias have also been described in patients with COVID-19. Can mimic ACS
• Renal/Liver: dysfunction is consistently described in patients with severe disease. Continuous renal replacement therapy was needed in more than 15% of cases of critical disease in one series.

Investigations

• FBC: Low or Raised WCC but lymphocytopenia
• CRP may be significantly elevated
• Dimer elevated even in absence of PE
• Raised AST/ALT may be seen
• CXR : patchy consolidation bilaterally
• CT chest: ground glass changes
• CTPA may sometimes be indicated to exclude PE
• Polymerase chain reaction assay for SARS-COV-2 by nasal swabs
• Antibody testing
• Troponin and BNP may also be elevated

Prevention

• Minimise contact using social distancing and masks and hand hygiene
• Contact tracing and isolation
• Environmental Actions
  • hand hygiene;
  • appropriate use of personal protective equipment;
  • patient placement;
  • appropriate use of antiseptics, disinfectants and detergents;
  • decontamination of medical devices;
  • safe handling of linen and laundry;
  • health care waste management;
  • respiratory hygiene and cough etiquette;
  • environmental cleaning;
  • principles of asepsis;
  • injection safety, prevention of injuries from sharp instruments
  • post-exposure prophylaxis and medical surveillance;

Management

• There are insufficient data to recommend either for or against any antiviral or immune-based therapy in patients with COVID-19 who have mild illness.
• Moderate COVID-19 illness is defined as evidence of lower respiratory disease by clinical assessment or imaging with SpO₂ = 94% on room air at sea level
• Patients with COVID-19 are considered to have severe illness if they have SpO₂ <94% on room air at sea level, respiratory rate >30, PaO₂/FiO₂ <300 mmHg, or lung infiltrates >50%.
• IV fluids may be needed for hypotension but there is a trend to keeping patients dry. Consider minimum repeated 250 ml Bolus of crystalloid titrated to SBP/MAP
• Supportive treatment involving Oxygen +/- NIV Target > 92%
  • High-flow nasal cannula (HFNC) oxygen over NIPPV
  • Trial of CPAP may be started at 10cm H₂O with 60% Oxygen or BIPAP if T2RF
  • Awake half or full prone positioning to improve oxygenation
• Intubation and ventilation as needed
  • Mechanical ventilation in Type 1 RF and ARDS using low tidal volume (VT) ventilation (VT 4-8 mL/kg of predicted body weight) over higher tidal volumes (VT >8 mL/kg) (AI).
  • Prone ventilation for 12-16 hrs/day
  • Consider a trial of inhaled pulmonary vasodilator as a rescue therapy
  • Insufficient data to recommend either for or against the routine use of extracorporeal membrane oxygenation for patients with COVID-19 and refractory hypoxemia.
• Dexamethasone 6 mg OD IV or PO for 10 days or until discharge in those with severe disease requiring oxygen with confirmed infection has been shown to reduce mortality. Consider additional PPI. Discontinue if discharge prior to 10 days.
• Antibiotics are not usually indicated but may be used for superimposed bacterial pneumonia including HAP may occur
• Other treatments : Remdesivir is an experimental antiviral
• AKI: continuous renal replacement therapy (CRRT) where needed in critically ill patients with COVID-19
• Thromboprophylaxis should be instituted,

References

• NIH information on COVID 19
• Coronavirus (COVID-19)
• Extrapulmonary manifestations of COVID-19 Aakriti Gupta, Mahesh V. Madhavan, Donald W. LandryNature Medicine volume 26, pages1017-1032(2020)