Monkeypox: Any Coagulation Implications?

by Donna Castellone, MS, MT (ASCP) SH • August 08, 2022

The interpretations below are provided by Donna Castellone, MS, MT (ASCP) SH for Aniara Diagnostica.

It's not enough that we have had and still are in a pandemic now we have monkeypox! Of course, yet again, New York is the epicenter. It is important to have an understanding of how monkeypox presents itself and to investigate if it impacts coagulation.


Monkeypox is caused by the monkeypox virus, an enveloped double stranded DNA virus which is a member of the orthopoxvirus in the genus in the family Poxviridae. It is a viral zoonosis with symptoms similar to those seen in the past in smallpox patients, although it is clinically less severe.(1)

This rare disease was first discovered in monkeys in 1958 and the first human case was identified in 1970. It is usually found in villages in west and central Africa. In November of 2021 multiple cases of monkeypox were reported in the United States and in May of 2022 monkeypox was identified in several non-endemic countries.


Transmission occurs to humans via close contact with either an infected person or animal, or from material contaminated with the virus via lesions, body fluids, or respiratory droplets. It is a self-limiting disease and lasts about 2-4 weeks. The clinical presentation is like smallpox which is a related orthopoxvirus. Smallpox was declared eradicated worldwide in 1980 and is more contagious than monkeypox also resulting in a more severe illness. Patients with monkeypox present with a fever, headache, rash, and swollen lymph nodes.(1) Skin lesions appear 1-3 days post fever and are concentrated on the extremities in up to 75% of cases. Oral mucous membranes, conjunctiva, cornea and genitalia can also be affected. The rash evolves from macules to papules, vesicles, pustules which then will dry up and fall off. It can range from a few to thousands of lesions. While close physical contact is a well-known risk factor for transmission, it is unclear at this time if monkeypox can be transmitted specifically through sexual transmission routes. Studies are needed to better understand this risk.

Laboratory Findings

A study that was conducted on a cohort of patients with monkeypox found that abnormal laboratory findings included elevated transaminase levels, low blood urea nitrogen, hypoalbuminemia, leukocytosis and thrombocytopenia.3

In smallpox both lymphocytosis and thrombocytopenia have been observed early in infection. Patients who presented with hemorrhagic smallpox present with DIC.4 This is the most lethal form of smallpox. In this study only 2 patients with monkeypox had hemorrhage pustular lesions with mild thrombocytopenia.3

Monkeypox patients were also found to have a negative protein or improper nutritional balance and may require volume repletion secondary to these GI issues.3 Patients have presented with respiratory complications, coagulation disorders and rare cases of encephalitis or multiorgan failure. There can be secondary bacterial infections and possible sepsis. In pregnant women, the fetus may be infected. Cases have shown that one fetus was still both with skin lesions and hepatic involve, another was born prematurely while a mildly affected women gave birth to a healthy child.5

Basically, the information on Monkeypox and the impact of coagulation is minimal. It looks like it may impact the liver. As we know coagulation factors are produced in the liver. The patient may present with a decreased platelet count. If the patient requires increased fluids, it also may falsely prolong coagulation parameters. DIC seems to be a small risk but anytime you have the possibility of infection, this may be the outcome. I imagine as time progresses; we will have more information on if monkeypox impacts coagulation.

Smallpox versus Monkeypox:

The clinical presentation resembles smallpox, which has been eradicated with the last case presenting in 1977. In 1980, based on a global campaign of vaccination and containment it was declared to be eradicated worldwide.2 It appears that vaccination against smallpox (that would be the scar on your upper arm) appears to be about 85% effective in preventing monkeypox or a milder illness.

Why Now?

After spending the last 2 years in a pandemic, it is hard to believe that we have the presence of yet another global health emergency. Why is this happening? Theories include a fluke, or a predictable increase which has been predicted by scientists due to the eradication of smallpox. Another possibility is that increased cases are due to traveling more after COVID restriction.6

What about the risk of transmission of monkeypox in healthcare settings? This has important implications for infection prevention and control strategies as well as exposure management. Based on available literature, there had only been one documented case of transmission following exposure outside of endemic areas. The findings support a low risk of nosocomial transmission; however, it will be of the utmost importance to learn from the experiences of facilities that are managing these patients and exposure in healthcare.7


The impact of monkeypox on coagulation results appears to be slight however may be exacerbated based on concurrent conditions. As more information is gathered on laboratory results on these patients, we will learn of how coagulation parameters are affected.


  3. Gregory D. Huhn,1,a Audrey M. Bauer,3 Krista Yorita,2 Mary Beth Graham,4 James Sejvar,2 Anna Likos,2 Inger K. Damon,2 MAbary G. Reynolds,2 and Matthew J. Kuehnert, Clinical Characteristics of Human Monkeypox,and Risk Factors for Severe Disease. Clinical Infectious Diseases 2005; 41:1742–51
  4. Koplan JP, Foster SO. Smallpox: clinical types, causes of death, and treatment J Infect Dis 1979 1404401.
  5. Spickler, Anna Rovid. 2020. Monkeypox.
  6. Bruce Carlson, Laboratories stand ready if needed for monkeypox threat. May 26, 2022
  7. Risk assessment of monkeypox transmission following exposure in healthcare settings.[pull]=omeda|6075F3979423I1Y&oly_enc_id=6075F3979423I1Y, July 11, 2022