Loiasis is endemic in Western and Central Africa and Loa loa is one of the nine nematodes using humans as definitive host.1 The typical presentation includes transient edematous lesions of the extremities (Calabar swellings), migration of the adult worm through the conjunctiva, and blood hypereosinophilia. We describe an atypical case of loiasis with a chronic pleuroperitoneal effusion.
We describe a case of atypical loiasis presenting with a chronic pleuroperitoneal effusion in a 50-year-old woman from the Democratic Republic of Congo. Effusions disappeared with conventional treatment and no recurrence was detected after 4 months of follow-up. Such cases of loiasis involving visceral sites have been unusually reported in the literature.
A 50-year-old woman, arriving directly from her village in the Kasai-province of the Democratic Republic of Congo was admitted in July 2010 to our department. She presented with painful abdominal distension that appeared 6 months before. Her past clinical history was unremarkable except for a Graves-Basedow disease discovered in 2008 and left untreated. She suffered from chronic weakness and severe dyspnea due to abdominal distention. She had neither ocular complaint nor cutaneous itching. Physical examination was characterized by extreme cachexia (body weight: 33 kg; body mass index 12 kg/m2), clear lung auscultation, presence of ascites, and the absence of fever.
Laboratory tests showed mild leukocytosis (11,490/µL) without peripheral eosinophilia (30/µL). She had moderate microcytic anemia (hemoglobin 10.8 g/dL; MCV 78 fL). C-reactive protein level was 9.3 mg/dL. The thyroid function tests demonstrated Graves' disease [serum-free triiodothyronine level, 9.4 pg/mL (reference range, 2.0–4.0 pg/mL); free thyroxine level, 3.3 ng/dL (reference range, 0.54–1.40 ng/dL); thyroid-stimulating hormone level, <0.003 microU/mL (reference range, 0.34–5.60 microU/mL); and thyrotropin receptor antibodies, 37.6 UI/L (reference value, <1 UI/L)] which was treated upon admission with thiamazol 10 mg b.i.d and levothyroxin 75 µg q.d.
Biological liver and kidney functions were normal. Albumin level was low (2.1 g/dL). Hepatitis B and C serology was not in favor of chronic infection and human immunodeficiency virus antibodies were absent. Initial cardiac ultrasound showed a mild reduction of the left ventricular ejection fraction (LVEF) at 40% which declined further during the hospital course (LVEF: 20%), despite adequate treatment of thyrotoxicosis. Metabolic and toxic liver disease was excluded (absence of alcoholism, diabetes, dyslipidemia, non-alcoholic steatohepatitis, alpha-1 antitrypsin deficiency, and absence of apparent autoimmune disease). Computed tomography of the abdomen failed to detect any intraperitoneal expansive process. However, large amounts of ascitic and pleural fluids were present. Positron Emission Tomography did not show any pathological intraperitoneal activity. Abdominal and pleural paracentesis fluid was citreous and foamy with exudate parameters (protein levels were 39.9 and 42.2 g/L successively). No neoplastic cells were detected. Mycobacterium tuberculosis culture of peritoneal and pleural fluids remained negative beyond 6 weeks. Biopsy of peritoneal tissue showed chronic inflammation without granulomas. Polymerase chain reaction and culture of peritoneal fluid were both negative for M tuberculosis.
Filarial serology using an enzyme-linked immunosorbent assay homemade assay (rat antibodies) was positive.
Serologies for other helminths were negative. Smears of cytocentrifugated blood and pleural fluids showed the presence of L loa (Figure 1). The Giemsa-stained thick blood smear revealed microfilaremia at 0.7/µL. Despite several peritoneal punctures, L loa could not be detected in ascitic fluid. The treatment consisted of an initial dose of ivermectin (150 µg/kg) and after a treatment-free period of 5 days, a 3-week course of diethylcarbamazine (DEC) was started. Following 5 days and a cumulative dose of 93.75 mg (first day 6.25 mg; second day 12.5 mg; third day 25 mg; fourth day 50 mg, and the dose given the fifth day was insignificant) of DEC, an acute and severe encephalopathy concomitant to a respiratory distress appeared. This was unexpected since microfilaremia load was low. The patient developed a confusional state characterized by blurred vision and disorientation without any specific neurological defect.
Albendazole 200 mg b.i.d was initiated 5 days after the neurological event and pursued for 4 weeks. This treatment has induced an important reduction in ascites and pleurisies. No neurological sequelae were noted at discharge and follow-up period.
Microbiological cure was confirmed by the disappearance of blood microfilaremia. During 4 months of follow-up, there was no reappearance of signs and symptoms suggesting the relapse of the disease.
This case shows an original presentation with visceral involvement but absence of Calabar swellings, migration of the adult worm through the conjunctiva, and blood hypereosinophilia. In addition, the outcome was surprising given the occurrence of DEC-related encephalopathy despite low microfilaremia.
Calabar swellings are angioedemas and the absence of such clinical signs in our patient could be linked to an immune dysfunction, related to the patient's cachexia. Patients may also experience the passage of the adult worm through the conjunctiva but this is an uncommon feature although it is one of the most commonly reported. These symptoms and signs may last for a long time, since adult worms may live for more than 17 years.1
Atypical cases of loiasis involving visceral sites have been seldom reported. Indeed, macrofilaria is not known to enter into the organs, though extra-cutaneous manifestations of loiasis have been rarely described and most often limited to pleuropulmonary manifestations.2 Cases of isolated pleural and ascetic effusions have also been described3,4 and may be related to a very high parasitic load. However, this report is the first to describe a case of pleuroperitoneal loiasis associated with low parasitic load. Although L loa could not be isolated from peritoneal fluid, the clinical response to anti-helminthic treatment can reasonably be considered as a proof of diagnosis. Another explanation for the worms' intrusion into pleuroperitoneal spaces may be due to extreme cachexia of our patient causing weak osmotic pressure due to very low albuminemia.
The pathogenesis of the cardiac failure remains unclear. Cardiothyrotoxicosis is generally characterized by a hyperdynamic circulatory state. Despite some cases of systolic cardiac failure, as present in our patient, restoring normal levels of thyroid hormone always reverses the dysfunction, which makes thyrotoxic heart failure a curable entity.5 On the other hand, tropical endomyocardial fibrosis (EMF) which is due to hypereosinophilia is mostly observed during the first 6 months of microfilaraemia.6,7 However, EMF cannot be worked out in this context because eosinophilia has low incidence in chronical form of parasitic infections.
Treatment of loiasis is based on the use of the microfilaricidal and macrofilaricidal drug DEC, of which sometimes repeated courses are required. Ivermectin can be administered prior to DEC, especially when microfilaremia is high (>2/µL). Both drugs may cause fatal encephalopathy but in conditions with high microfilaremia. Conversely, microfilaremia was low in our patient even before Ivermectin treatment. We could not find an explanation to the encephalopathy that occurred in our patient.
In conclusion, we described a case of atypical loiasis presenting with a chronic pleuroperitoneal effusion in a 50-year-old woman from Central Africa. Loiasis has to be kept in mind when facing patients with chronic pleuroperitoneal effusion.
Declaration of Interests
The authors state they have no conflicts of interest to declare.