3 | Discussion
O. tsutsugamushi being a mite-borne bacterium poses the risk of a
serious disease called Scrub Typhus. Rodents function as animal
reservoirs for O. tsutsugamushi, however, the microorganism also can be
maintained among mite colonies through transovarial transmission.(4)
Studies show scrub typhus is an evolving public health problem with
numerous outbreaks since 2015 in Nepal. Scrub typhus is a neglected
tropical disease, is one of the important causes of undifferentiated
treatable fever in Asia.(5)
Scrub typhus is associated with the eschar, which is a pathognomonic
lesion. It’s the first lesion that appears after being bitten by a
chigger (Leptotrombidium mite). Because eschar is where O. tsutsugamushi
is multiplying and a huge number of organisms are found there, it has
been demonstrated to be a superior sample for PCR test than blood.(6)
Scrub typhus is defined by small vessel vasculitis, which affects the
lungs, heart, brain, and kidneys in particular. Scrub typhus has
non-specific clinical signs, and patients frequently report to the
physician with a generalized fever of uncertain etiology. Severe
symptoms of MOF, ARDS, shock, and DIC, on the other hand, may
develop.(7)
Primary HLH occurs due to hereditary immune conditions, while on the
contrary secondary HLH occurs in settings such as infection, malignancy,
autoimmune disease, post-allogeneic hematopoietic stem cell
transplantation, and drug hypersensitivity.(5) Interconnection between
HLH and infection is vital as both familial and sporadic cases are
commonly provoked by infectious diseases. HLH imitates infectious
diseases concealing the identification of a causative agent leading to
serious health problems.(8)
Patients with HLH die because of bleeding in visceral organs,
opportunistic infection secondary to neutropenia, or Multiple organ
failure within 2 months which accounts for more than 10% of cases.(4)
With an increasing number of cases documented in the last ten years, HLH
is a potentially serious consequence of scrub typhus. However, the
majority of instances recorded thus far have been single cases or case
series with limited sample size. As a result, the clinical symptoms and
prognosis of individuals with HLH linked with scrub typhus are mostly
unknown.(2)
In the present case, the patient had a high-grade intermittent fever
with eschar which was not responding to broad-spectrum antibiotics.
During the initial work, the patient was diagnosed with a case of Scrub
typhus not responding to Doxycycline and Ciprofloxacin. For this reason,
an extensive workup was carried out to rule out other etiologies of
fever which failed to establish the cause. Bi-cytopenia and Hyperactive
macrophages with erythrophagocytosis in bone marrow biopsy suggested the
possibility of HLH. Similarly, in line with HLH, biochemical parameters
met the criteria for diagnosis of HLH. The patient initially responded
well to the treatment but eventually, his condition deteriorated due to
multi-organ failure leading to death.