Hantavirus pulmonary syndrome (HPS) is an infectious disease that is acquired through exposure to rodents carrying the causative virus, the Hantavirus. A few cases have been documented, where the infection was acquired through human to human contact [1] [2].

HPS usually occurs in specific geographical locations, such as north and south America. The disease appears to affect all individuals equally, although men may have a higher incidence rate due to more recurrent exposure to the vector. For the same reason, HPS typically does not present in young children or the elderly.

HPS is one of many syndromes that can arise from Hantavirus infection [3] [4]. The affected organ systems depend on the specific type of Hantavirus an individual has come in contact with. The severity of illness varies greatly between cases, ranging from mild to severe. Furthermore, it demonstrates significantly high case mortality rates, estimated at up to 50%. This syndrome is characterized by severe respiratory compromise. The illness has several stages entailing a prodromal phase, respiratory phase, and convalescent phase. The disease has an incubation period of one week to one month, after which prodromal symptoms manifest.

Prodromal symptoms are often nonspecific and may involve gastrointestinal discomfort, vomiting, headache, and muscle pain [5]. These individuals also experience pyrexia. The typical signs usually last up to 5 days.

Subsequently, the host immune system attacks endothelial cells lining the lungs, displaying viral antigens. This process leads to increased permeability of the endothelium and thus pulmonary edema. The cardiopulmonary phase lasts up to 48 hours and is characterized by the emergence of respiratory findings such as coughing, tachypnea, crepitations, and dyspnea. Patients frequently require mechanical ventilation during this time. Some individuals may develop hypotension and circulatory collapse due to cardiogenic shock, the latter being the main cause of death in HPS [6] [7] [8]. Oliguria is not an uncommon observation during this phase, and in a few cases, may lead to renal failure.

The third stage is preceded by an episode of diuresis and is made evident by the resolution of cardiopulmonary features.

• Turkish

  Of the 5 hamster species, only Turkish hamsters infected with LNV demonstrated signs consistent with HPS and a fatality rate of 43%. [ncbi.nlm.nih.gov]

  Laguna Negra Virus Infection Causes Hantavirus Pulmonary Syndrome in Turkish Hamsters (Mesocricetus brandti). [science.gov]

  (Germany) 1996-01-01 Two asymptomatic Turkish sibs are presented, a 4-year-old boy and his 7-year-old sister, with pulmonary alveolar microlithiasis (PAM) confirmed by transbronchial lung biopsy and bronchoalveolar lavage. [worldwidescience.org]

• Intravenous Drugs

  HPS treatment with an experimental antiviral intravenous drug, ribavirin, is under investigation. [ncbi.nlm.nih.gov]

• Exertional Dyspnea

  Temporary exertional dyspnea and reduced expiratory flow are common in early convalescence after HPS but resolves in almost all patients. [ncbi.nlm.nih.gov]

  He had noted gradual worsening of exertional dyspnea over the previous 1 month. Chest radiography showed localized oligemia and enlarged hilar vessels. [science.gov]

  Ardalan, Delaram M. 2007-01-01 A 38-year-old Iraqi female, presented with one-year history of exertional dyspnea and exercise intolerance, without systemic or constitutional symptoms. [worldwidescience.org]

• Refractory Shock

  shock despite fluid resuscitation, and vasoactive medications. [ncbi.nlm.nih.gov]

  Both patients developed adult respiratory distress syndrome and refractory shock. A patient died and another one recovered 12 days later. [science.gov]

  Both patients developed adult respiratory distress syndrome and refractory shock. [worldwidescience.org]

• Suggestibility

  Immunoreactivity analysis of white blood cell lysates suggests that some circulating PB are virus-specific but we also observed a significant increase of reactivity against virus-unrelated antigens, which suggests a possible bystander effect by polyclonal [ncbi.nlm.nih.gov]

Upon presentation, baseline blood tests, as well as more specific laboratory testing should be carried out. Often requested laboratory studies include:

• Complete blood count (CBC), urea and electrolytes, peripheral smear, and arterial blood gas analysis (ABGA).
• Immunochemistry.
• Serology.
• PCR (polymerase chain reaction).

CBC may reveal low platelets and elevated white blood cells, with an unusually high proportion of immature cells [9]. Serum lactate dehydrogenase (LDH) is also high. Other parameters may reflect the distributive shock experienced in Hantavirus pulmonary syndrome [6] [7]. One such finding is hemoconcentration. A peripheral blood smear, in addition to the above, may reveal the presence of atypical immune cells, as well as immunoblasts [9]. Once these findings are observed, HPS can be diagnosed.

Imaging studies are usually carried out in the form of a chest radiograph. Signs of pulmonary edema that may be visualized include increased hilar markings, diffuse bilateral infiltrates, Kerley B lines, and peribronchial thickening. The cardiac silhouette is of normal size, and pleural effusions might also be present.

• Kerley A Lines

  Signs of pulmonary edema that may be visualized include increased hilar markings, diffuse bilateral infiltrates, Kerley B lines, and peribronchial thickening. The cardiac silhouette is of normal size, and pleural effusions might also be present. [symptoma.com]

  Almost all patients have chest radiographs with abnormal findings indicative of interstitial edema: specifically, Kerley B lines, hilar indistinctness, or peribronchial cuffing with normal cardiothoracic ratios. [academic.oup.com]

• Kerley B Lines

  Signs of pulmonary edema that may be visualized include increased hilar markings, diffuse bilateral infiltrates, Kerley B lines, and peribronchial thickening. The cardiac silhouette is of normal size, and pleural effusions might also be present. [symptoma.com]

  Almost all patients have chest radiographs with abnormal findings indicative of interstitial edema: specifically, Kerley B lines, hilar indistinctness, or peribronchial cuffing with normal cardiothoracic ratios. [academic.oup.com]

• Bilateral Pulmonary Infiltrate

  Chest X-ray revealed bilateral pulmonary infiltrates. Broad-spectrum antibiotics and intravenous corticosteroids were started. [science.gov]

  The symptom of severe hypoxia requiring mechanical ventilator, and bilateral pulmonary infiltrates on the chest film led to the clinical diagnosis of adult respiratory distress syndrome. [worldwidescience.org]

• Hypocapnia

  Findings of pulmonary evaluation will be distinctly abnormal at this time, with low P O 2 level or low pulse oximetry findings and, often, hypocapnia. In severe cases, there will be metabolic acidosis with an elevated serum lactate level. [academic.oup.com]

1. Martinez VP, Bellomo CM, Cacace ML, Suarez P, Bogni L, Padula PJ. Hantavirus pulmonary syndrome in Argentina, 1995-2008. Emerg Infect Dis. 2010;16(12):1853-1860.
2. Padula PJ, Edelstein A, Miguel SD, López NM, Rossi CM, Rabinovich RD. Hantavirus pulmonary syndrome outbreak in Argentina: molecular evidence for person-to-person transmission of Andes virus. Virology. 1998;241(2):323-330.
3. Khan A, Khan AS. Hantaviruses: a tale of two hemispheres. Panminerva Med. 2003;45(1):43-51.
4. Peters CJ, Khan AS. Hantavirus pulmonary syndrome: the new American hemorrhagic fever. Clin Infect Dis. 2002;34(9):1224-1231.
5. Vinh DC, Embil JM. Hantavirus pulmonary syndrome: a concise clinical review. South Med J. 2009;102(6):620–625.
6. Jonsson CB, Figueiredo LT, Vapalahti O. A global perspective on hantavirus ecology, epidemiology, and disease. Clin Microbiol Rev. 2010;23(2):412–441.
7. Watson DC, Sargianou M, Papa A, Chra P, Starakis I, Panos G. Epidemiology of Hantavirus infections in humans: a comprehensive, global overview. Crit Rev Microbiol. 2014;40(3):261–272.
8. Verity R, Prasad E, Grimsrud K, et al. Hantavirus pulmonary syndrome in Northern Alberta, Canada: clinical and laboratory findings for 19 cases. Clin Infect Dis. 2000;31(4):942–946.
9. Dvorscak L, Czuchlewski DR. Successful triage of suspected hantavirus cardiopulmonary syndrome by peripheral blood smear review—a decade of experience in an endemic region. Am J Clin Pathol. 2014;142(2):196–201.