Transcript Paragonimus - Division of Infectious Diseases

Pulmonary Paragonimiasis Mimicking Tuberculosis in a Middle-Aged Burmese Female.
Amjad Ali, MD¹ , Allen T. Griffin, MD,¹ Hanan Farghaly, MD,² and Forest W. Arnold, DO, Msc¹
1Division
of Infectious Diseases, University of Louisville. 2Department of Pathology, University of Louisville , Louisville, KY
BACKGROUND
CASE REPORT (Cont’d)
Paragonimiasis is a food-borne parasitic infection resulting from
ingestion of undercooked crustaceans. While uncommon in the United
States, Paragonimus species are endemic in North America, South
America, Asia, and Africa.
Pulmonary symptoms are most common, but cerebral, dermatologic,
and abdominal variations are recognized. Diagnosis is supported by
positive serology and a typical exposure history.
Pathologic
confirmation by visualization of eggs, however, is preferred. In the
subsequent case presentation, we elucidate an instance of pulmonary
paragonimiasis mimicking tuberculosis in a middle-aged Burmese
female
The patient had a negative enzyme-linked immunoabsorbent assay
(ELISA) for human immunodeficiency virus and a negative
QuantiFERON® TB Gold (Cellestis, Ltd., Carnegie, Australia). Chest
roentgenogram revealed a right lower lobe infiltrate that corresponded
to an ovoid area of mass-like consolidation on computed tomography
(CT) in the right lower lobe measuring 5.3 cm x 3.2 cm in greatest
transverse diameter and approximately 5.8 cm craniocaudal with
suspicion of early cavitation (Fig. 1).
Mediastinal and hilar
lymphadenopathy were noted as was a partially calcified linear lesion
emanating from the diaphragm (Fig. 2). The patient was suspected to
have a subacute community-acquired pneumonia (CAP). She was felt
unlikely to be infected with organisms causing acute CAP; therefore,
antibiotics were not initiated. The predominant differential diagnostic
considerations were tuberculosis, non-tuberculous mycobacteria,
Nocardia or Actinomyces infection, or less likely an endemic fungal
infection contracted in the United States or Burma. Sputum was
induced to ascertain the etiology of her illness. Stains for acid fast
bacilli and fungi were negative, as were cultures for these organisms.
Standard bacterial cultures yielded normal flora.
A CT-guided lung biopsy was pursued for definitive diagnosis, and the
biopsied tissue was submitted for microscopic evaluation as well as
cultures. Pathologic examination of the biopsied tissue revealed
scattered eggs embedded in the lung parenchyma, producing an
eosinophil-rich,
dense
inflammatory
reaction
with
nodular
granulomatous lesions. The visualized eggs [90-100 µm x 50-60 µm
(length x width)] were ovoid and contained exudate and debris (Fig.
3A). A Paragonimus parasitic infection was suspected morphologically
and was further supported using a polarized lens. The visualized eggs
were birefringent under polarized light, a distinctive characteristic of
Paragonimus species (Fig. 3B).
Polymerase chain reaction testing for unequivocal species identification
was not undertaken, and details of ova morphology were partially
distorted on processing. However, based on the size of the ova and
suspected region of acquisition, Paragonimus westermani was thought
to be the etiology in this instance. Special stains were performed on
the lung biopsy for acid fast bacilli and fungi; these stains, as well as
cultures performed for these organisms, were all negative. As the
diagnosis was secured pathologically, serology for Paragonimus was
not procured. Given the diagnosis of paragonimiasis, the patient was
treated with praziquantel at 25 mg/kg three times per day for two days
and discharged from the hospital. She was followed in clinic within one
month, and she reported a demonstrable improvement in symptoms
CASE REPORT
A 51-year-old Burmese female was admitted to the hospital for cough
and hemoptysis. She relayed a history of hyperlipidemia and mild
chronic-obstructive pulmonary disease (COPD), but was otherwise
healthy. Upon her current hospital presentation, she described having a
non-productive cough intermittently for two years, which had been
attributed to COPD.
However, during the past month, the cough had become more forceful
with production of sputum and blood. She could not recall specific
circumstances that exacerbated the cough and noted no post-tussive
emesis. Associated signs and symptoms of the current illness included
night sweats, shortness of breath on exertion, malaise, periodic fevers
to 101°F, and weight loss of 10 pounds in the previous month.
On one occasion since becoming ill, the patient had been diagnosed
with bronchitis by her primary care physician and treated with
doxycycline, but her symptoms did not abate. On the day of hospital
admission, she was brought to the emergency room after an episode of
syncope associated with coughing.
The patient was being treated with low-dose inhaled corticosteroids for
COPD associated with smoking and baclofen for intermittent muscle
spasms. She reported no medication allergies. Past surgeries included
a tubal ligation 13 years earlier. She was a 30 pack year smoker, but
consumed no alcohol or illicit drugs.
She resided in the city of Louisville, Kentucky, with her two teen-age
children as well as three other adults from Burma. The patient worked
in a laundromat and immigrated from Burma three years prior; however,
she would occasionally return to her home country to visit family where
she would consume uncooked, freshwater crustaceans, including
crayfish and crab. Although she was not certain, she could not recall
direct exposure to individuals with tuberculosis and had never been
incarcerated.
On physical examination, the patient was alert, but appeared
uncomfortable. Her temperature was 98.0° F, pulse 61 beats per
minute, blood pressure 117/72 mm of Hg, and respiratory rate 16
breaths per minute. Oxygen saturation was 98 % on ambient air.
The oral mucosa was dry, but revealed no lesions or thrush. There was
no cervical, supraclavicular, axillary, or inguinal lymphadenopathy. The
cardiac exam was without murmurs. Diffuse wheezing was detected on
the pulmonary exam with focal rales in the right lower lung zones noted.
The remainder of the physical exam was unremarkable. Laboratory
findings, including a complete blood count and complete metabolic
panel, were unrevealing, with the exception of a slight eosinophilia of 9
% and an erythrocyte sedimentation rate of 66 mm/hour (Table 1).
Figure 1: Computed tomography of the chest illustrating a large
cavitary infiltrate in the right lower lobe.
CASE REPORT (Cont’d)
.
Figure 3: Paragonimus egg embedded within a granulomatous
inflammation, 40X (Fig. 3A). The polarized lens highlights the
Paragonimus egg’s refractile wall, 40 X (Fig. 3B). Eggs are 95 µm x
55 µm (length x width).
DISCUSSIONS
The Paragonimus genus is of the Trematode class within the phylum
Platyhelminthes and, thus, is closely related to the schistosomes. While
the Paragonimus genus may contain nearly 40 distinct species, only a
few are routinely found in man, the most common of which worldwide is
Paragonimus westermani (P. westermani). Regional differences exist
with respect to the species routinely encountered, with the most
frequently diagnosed in indigenous cases in the United States being
Paragonimus kellicotti (P. kellicotti).1
Paragonimus species are found in Asia, Africa, and North and South
America.1 The propensity to acquire the disease is less a function of
endemicity than regional dietary customs.
Eggs released from
mammalian hosts typically hatch and mature into miracidia that are
ingested by mollusks such as snails. Within the snail, the miracidia
eventually mature into cercariae. Subsequently, when the snail is
consumed by a crustacean, cercariae are released and encyst in the
crustacean as metacercariae. Upon consumption of the crustacean by a
mammal, metacercariae excyst, penetrate the duodenum of the
mammalian host, travel through the peritoneal cavity, and cross the
diaphragm to encyst in the lungs where they mature into adults.2 Thus,
consumption of uncooked crustaceans, crayfish3 or freshwater crabs,4 a
more common practice in Asia and Africa, results in paragonimiasis.
The signs and symptoms of paragonimiasis are usually pulmonary, as
metacercariae typically encyst and mature into adults in the lungs. The
typical presentation involves cough and hemoptysis with the variable
presence of fever and other systemic complaints;5 however, if infection is
limited to the pleura, hemoptysis and cough can be absent, and pleuritic
chest pain may dominate the clinical picture.6 Elevated levels of blood
eosinophils and immunoglobulin E, though common, are not invariably
present.1 While pleural effusions,6 pneumothoraces,7 and chylothoraces8
have all been noted, the most common radiologic features are cystic
pulmonary lesions, nodules, or cavitary lung lesions.8,9 Linear opacities
representative of trematode migration may also be seen,10 as illustrated
in the present case (Fig. 2). Given the protean manifestations and
frequent overlap of pulmonary tuberculosis in areas of the world where
paragonimiasis is common, tuberculosis is initially suspected
DISCUSSIONS (Cont’d)
Although an ELISA is available through the Centers for Disease Control and
Prevention,14 confirmation of disease by visualization of ova or adult worms
is preferential. Adult worms are infrequently identified in patient specimens;
however, if present, the adults are distinctively large and contain a
conspicuous cuticular spine.1 For lung parenchymal involvement, acid-fast
stains15 and standard ova and parasite examinations of sputum may reveal
diagnostic ova, but these techniques are insensitive. Specimens procured
by bronchoscopy with biopsy or other means are more sensitive and may
reveal large parasite ova (60-120µm)1 in addition to eosinophilic infiltration
and possibly granulomas in biopsy specimens.16 Ova may be particularly
difficult to locate in the event of a pleural effusion with no parenchymal
involvement. In such cases, a careful epidemiologic history and serology
are most useful, as pleural fluid eosinophilia is an inconstant and nonspecific finding.6 Serology may also be of use in other instances in which
pathologic samples are nondiagnostic or when sensitive areas, such as the
eye or brainstem, would have to be biopsied to attain a pathologic
diagnosis.Ova from Paragonimus species can be discerned from related
genera such as Schistosoma by birefringence under polarized light, as in
the current case (Fig. 3B), and the presence of an operculum. Cytologic, in
contrast to histologic, analysis may be most beneficial in equivocal cases,
as ova morphology is less likely to be compromised.1
The best studied antihelminthics for this disease are praziquantel18 and
triclabendazole.19 Triclabendazole is not available in the United States;
therefore, the recommended regimen in the Unites States is praziquantel
given as 25 mg/kg orally three times per day for two days.
CONCLUSIONS
In summary:
• our patient presented with progressive cough and hemoptysis and
was discovered to have a cavitary infiltrate on chest CT with a worm
migration track.
• Pathologic examination of lung tissue revealed ova diagnostic of
pulmonary paragonimiasis likely contracted from eating undercooked,
freshwater crustaceans in the patient’s native country of Burma.
• Similar to many cases of paragonimiasis, the current case closely
resembled pulmonary tuberculosis and emphasizes the need for a
careful review of dietary habits and meticulous pathologic examination
of tissue to ascertain the correct diagnosis.
REFERENCES
1. Procop G. North American paragonimiasis (caused by Paragonimus
kellicotti) in the context of global Paragonimiasis. Clin Microbiol Rev.
2009;22:415-446.
2. Hu W. Studies on the life cycle of Paragonimus heterotremus. Zhongguo
Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi. 1998;16:347-352.
3. Diaz J. Boil before eating: paragonimiasis after eating raw crayfish in the
Mississippi River Basin. J La State Med Soc. 2011;163:261-266.