Middle East Respiratory Syndrome Coronavirus (MERS-CoV)

MERS is a zoonotic coronavirus that causes severe respiratory illness, and it kills 3 or 4 out of every 10 reported patients. There is no vaccine and no approved drug, so the nursing priorities are airborne isolation, supportive respiratory care, and protecting yourself and other patients from spread. Treat travel and exposure history as part of the assessment, not an afterthought.

What is Middle East Respiratory Syndrome (MERS)?

MERS is caused by a novel coronavirus (MERS-CoV). It was first identified in Saudi Arabia in 2012 and has infected more than 2,000 people worldwide.

• Although first reported in Saudi Arabia, the first known cases occurred in Jordan in April 2012.
• Most patients develop severe respiratory illness with fever, cough, and shortness of breath.
• A large outbreak occurred in the Republic of Korea in 2015, linked to a traveler from the Arabian Peninsula.
• Travel-associated cases have been identified across the Arabian Peninsula, Europe, Asia, North Africa, and the United States.
• The CDC has published guidance for health departments and infection-control programs on investigating potential cases and preventing spread.

Pathophysiology

MERS is considered an international threat to public health.

• Unlike SARS-CoV, MERS-CoV can establish infection in monocyte-derived macrophages (MDMs) and macrophages.
• It triggers release of proinflammatory cytokines, driving severe inflammation and tissue damage that can present as severe pneumonia and respiratory failure.
• Vascular endothelial cells in the pulmonary interstitium can also be infected, and because the MERS-CoV receptor DPP4 is expressed across many human tissues, the infection can disseminate.
• Lymphopenia is noted in most infected patients, as in SARS, from cytokine-induced immune cell sequestration and induction of monocyte chemotactic protein-1 (MCP-1) and interferon-gamma-inducible protein-10 (IP-10), which suppress proliferation of human myeloid progenitor cells.

Causes

Coronaviruses are the largest RNA viruses, with positive-sense single-stranded RNA genomes of 26-32 kb.

• Betacoronavirus. MERS-CoV is a betacoronavirus of lineage C, first reported in Saudi Arabia in 2012. Its exact origin is unknown. It is closely related to two bat coronaviruses of the same lineage, which may be its wild reservoir.
• Dromedary camels. Animal transmission is not fully understood but appears to involve contact with dromedary camels or their urine, or consuming their undercooked meat or unpasteurized dairy.

Statistics and Incidences

About 3 or 4 out of every 10 reported MERS patients have died.

• In May 2014, the CDC confirmed two unlinked imported US cases, one in Indiana and one in Florida. Both were healthcare providers who lived and worked in Saudi Arabia and traveled to the US from there.
• Since 2012, 2,374 laboratory-confirmed cases have been reported to the WHO, including at least 823 related deaths.
• 27 countries have reported MERS cases. The vast majority occurred in Saudi Arabia.
• The largest outbreak outside Saudi Arabia, in the Republic of Korea in 2015, involved 186 confirmed cases and 36 deaths. It prompted quarantine of more than 5,000 people and closure of 2,000 schools before ending.

Clinical Manifestations

Findings resemble any flu-like illness:

• Fever
• Rhinorrhea, mostly clear
• Pulmonary findings: hypoxemia, rhonchi, and rales (some patients have normal auscultation)
• Tachycardia
• Hypotension with severe illness, reflecting systemic inflammatory response syndrome

Assessment and Diagnostic Findings

Most state labs can test for MERS-CoV using the CDC's rRT-PCR assay.

• rRT-PCR assay. The FDA issued an Emergency Use Authorization on June 5, 2013, for the CDC's 2012 real-time RT-PCR assay to test respiratory, serum, and stool specimens.
• Serology. Available as a research/surveillance test from the CDC. Not diagnostic, but it offers epidemiologic data; it must be ordered in consultation with and approval of the CDC.
• Laboratory studies. Findings may include leukopenia, lymphopenia, thrombocytopenia, and elevated lactate dehydrogenase, more likely with increasing severity.
• Imaging studies. Chest imaging is abnormal in more than 80% of cases. Ground-glass opacity (GGO) appears in over 60% of chest radiographs, with about 20% showing consolidation; some infiltrates are nodular.

Medical Management

Care is supportive: hydration, antipyretics, analgesics, respiratory support, and antibiotics if a bacterial superinfection develops.

• Isolation. On suspicion of MERS, place the patient in an airborne infection isolation room (AIIR) with at least 12 air exchanges per hour. Use PPE for contact and airborne precautions: gown, gloves, goggles, and an N-95 respirator or powered air-purifying respirator (PAPR).
• Medical care. Supportive, scaled to severity.
• Prevention. No vaccine is commercially available. In areas of active transmission, avoid potentially infectious secretions and maintain strict hand and respiratory hygiene.

Pharmacologic Management

No medications are approved for coronavirus infections. Clinical trials are needed to establish any benefit from ribavirin and/or interferon alfa.

Nursing Management

Nursing Assessment

• History. A high index of suspicion is essential, and travel and exposure history is key to the diagnosis. The case definition centers on residence or travel in the Arabian Peninsula, in countries where MERS-CoV circulates in dromedary camels, or where human infections have recently occurred, with exposure within the 14-day incubation period.
• Physical exam. Clinically indistinguishable from other respiratory viruses, ranging from no symptoms to rapidly progressive multiorgan failure and death.

Nursing Diagnosis

• Infection related to exposure to MERS-CoV.
• Deficient knowledge related to unfamiliarity with disease transmission.
• Hyperthermia related to increased metabolic rate.
• Ineffective airway clearance related to excessive pulmonary secretions.
• Anxiety related to the unknown course of the disease.

Nursing Care Planning and Goals

• Prevent the spread of infection.
• Build understanding of the disease and its management.
• Reduce temperature.
• Maintain a patent airway.
• Reduce anxiety.

Nursing Interventions

• Monitor vital signs. Track temperature; infection usually starts with a high fever. Monitor respiratory rate, since shortness of breath is common.
• Educate the patient and family. Set learning objectives at the start of the session; give clear explanations and demonstrations; use visual aids such as diagrams, pictures, and videos.
• Reduce temperature. Adjust room temperature and bed linens; encourage oral fluids; remove excess clothing and covers; give antipyretics as prescribed.
• Ensure a patent airway. Teach proper coughing and breathing (deep breath, hold for 2 seconds, cough two or three times in succession); position upright if tolerated; encourage oral fluids up to 3 liters per day within cardiac and renal limits.
• Reduce anxiety. Use presence, touch (with permission), and calm demeanor to reassure the patient; accept their defenses without arguing; use simple language and brief statements; let the patient talk through anxious feelings and triggers.

Evaluation

Goals are met when spread is prevented, the patient and family understand the disease, temperature drops, the airway stays patent, and anxiety eases.

Documentation

• Individual findings: factors affecting the patient, interactions, social exchanges, specifics of behavior.
• Cultural and religious beliefs and expectations.
• Plan of care.
• Teaching plan.
• Responses to interventions, teaching, and actions performed.
• Attainment or progress toward desired outcomes.