Tropical Medicine Case Presentations: Schistosomiasis

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Introduction

This document summarizes the key findings, discussions, and outcomes of two tropical medicine case presentations. The first case describes a pediatric patient from Peru with symptoms mimicking hematologic malignancy, ultimately diagnosed with paracoccidioidomycosis. The second case involves an adult patient with liver cirrhosis and pulmonary hypertension, presenting with a history of schistosomiasis.

Case Presentation 1: Pediatric Paracoccidioidomycosis

Patient Presentation and Initial Assessment: The first case concerns a previously healthy three-year-old boy from Varika, Peru, a region located 400 kilometers east of Lima at an altitude over 1,400 meters above sea level, characterized by abundant rainfall, warm temperatures, and tropical/subtropical forests. The patient's parents are coffee growers, and he frequently played on the ground in the fields, with exposure to domestic animals including dogs, cats, and chickens.

The child presented with an eight-week history of intermittent fever, weight loss, and progressive lymph node enlargement. Initial symptoms included a low-grade fever (38-38.5°C) that persisted despite antibiotic treatment. By the third week, fever continued, prompting multiple medical visits and additional empirical antibiotic treatments, but his condition did not improve. At week four, a warm, erythematous, and tender cervical lymphadenopathy (1x2 cm) appeared on the left side.

Two weeks later, new symptoms developed, including abdominal pain, distension, approximately 1 kg of weight loss, and intermittent diarrhea. Laboratory tests at this time showed anemia, leukocytosis (>24,000 cells), and thrombocytosis. The symptoms worsened, with increasing anemia and platelet count. Given the persistent fever, hepatosplenomegaly, and lymphadenopathy, the patient was transferred to the National Institute of Neoplastic Diseases in Lima with a preliminary diagnosis of suspected hematologic malignancy.

Upon transfer, vital signs were stable, but physical examination revealed multiple enlarged lymph nodes and hepatosplenomegaly. The most prominent findings were a 4x5 cm left cervical node and a 2x2 cm left retroauricular node, described as firm, non-mobile, and tender. Smaller nodes were present in the axillary and inguinal regions. The abdomen was distended, with a liver span of 11 cm and a palpable spleen 2 cm below the costal margin. The neurological exam was unremarkable.

Diagnostic Workup and Findings: An extensive workup was performed. A complete blood count showed anemia, continued high leukocytes, and a remarkably high count of eosinophils (>2,000). The platelet count remained elevated. Bone marrow aspiration and biopsy showed no blasts and a normal cellular marrow, ruling out malignancy. Blood cultures were negative after five days. Imaging studies, including an abdominal CT, revealed multiple mesenteric lymphadenopathies and confirmed hepatosplenomegaly on abdominal ultrasound. A chest X-ray showed no relevant findings. The prominent left cervical and retroauricular enlarged lymph nodes were also visualized.

Differential Diagnoses: The clinical picture of persistent fever, progressive lymphadenopathy, hepatosplenomegaly, worsening anemia, and marked eosinophilia, with a negative bone study for neoplasms, prompted a broad differential diagnosis. During the discussion, several possibilities were raised, including:

• Bartonella, particularly Bartonella henselae (disseminated cat scratch disease), although Bartonella bacilliformis was considered less likely given the region.
• Tuberculosis (TB), noted as always being in the differential in endemic areas, especially with cervical lymphadenopathy. Non-tuberculosis mycobacteria were also mentioned as a more common cause of pediatric lymphadenopathy and prolonged fever in the region.
• Fungal infections, including coccidioidomycosis (though altitude might not be right), histoplasmosis (still present in South America), blastomycosis, and cryptococcosis. Paracoccidioidomycosis was also mentioned as a possibility.
• Parasitic infections, strongly suggested by the eosinophilia. Specific mentions included soil-transmitted helminths, visceral larva migrans, and potential protozoa like Entamoeba (though noted that protozoa don't typically cause eosinophilia). Schistosomiasis was mentioned in the context of hepatosplenomegaly, although visceral leishmaniasis, which could present similarly, was explicitly ruled out as not being endemic to Peru yet.
• Viral etiologies, such as EBV. Hemorrhagic fever from Dengue virus was suggested but deemed unlikely due to the prolonged duration of fever (>7 days).
• Bacterial infections like brucellosis.
• Non-infectious etiologies like hemophagocytic lymphohistiocytosis (HLH).
• Lymph node syndromes like Kikuchi Fujimoto disease.
• Malignancies, including lymphomas or leukemia (especially eosinophilic types, given the high eosinophilia). The initial suspicion of hematologic malignancy was ruled out by bone marrow studies.
• Immunodeficiency, such as HIV, potentially with opportunistic infections.
• The possibility of multiple conditions occurring concurrently was also considered.

The marked eosinophilia, persistent fever, and hepatosplenomegaly were highlighted as key features helping to narrow the differential towards parasitic or fungal etiologies.

Diagnosis: The definitive diagnosis was reached through a fine needle aspiration and biopsy of the cervical lymph node. A wet direct examination with potassium hydroxide revealed characteristic fungal elements: round, multiple budding cells, sometimes referred to as having a "pilot's wheel" or "Mickey Mouse" appearance. These findings were compatible with a diagnosis of paracoccidioidomycosis. The visual differential diagnosis for these structures can include Histoplasma and Blastomyces, which can resemble Paracoccidioides. The diagnosis was confirmed as paracoccidioidomycosis (or South American blastomycosis), presenting as an acute or subacute (juvenile) form. Subsequent fungal cultures were negative, but serological tests, specifically a qualitative immunodiffusion (ID) test, were positive at diagnosis, supporting the diagnosis and later regressed to negative after three months of treatment.

Disease Severity Assessment: The severity of the disease was assessed using criteria from literature and Brazilian guidelines, although specific criteria for the acute form were hard to find. Criteria considered include weight loss, multiorgan involvement, suppurative lymph nodes, antibody titers correlating with severity, and a negative reaction to the paracoccidioidin skin test (suggesting anergy in severe disease). The patient met several criteria for severe disease:

• Weight loss of more than 10% of his normal weight.
• Involvement of multiple organs, including gastrointestinal compromise with malabsorptive features due to intestinal involvement, generalized lymphadenopathy in multiple chains (cervical, retroauricular, axillary, inguinal, mesenteric), and hepatosplenomegaly.
• Suppurative form of a lymph node, with the biopsied cervical node having persistent suppuration.
• Elevated antibody titers, indirectly inferred from the positive ID test which supported the diagnosis. A negative paracoccidioidin skin test was also a criterion for severe disease, likely related to anergy from marrow infiltration by the fungus. He met four of five criteria, qualifying as severe disease (three or more criteria indicating severe disease).

Management and Outcome: For severe paracoccidioidomycosis, guidelines suggest starting with Amphotericin B for 2-4 weeks until symptoms improve, followed by a transition to oral antifungal therapy. Itraconazole is preferred in children and adults, but cotrimoxazole (trimethoprim-sulfamethoxazole) is a useful option, especially in children. The patient was started on Amphotericin B deoxycolate for 14 days, transitioning to a lipid formulation for a total of four weeks of IV therapy. During treatment, he developed adverse events common with Amphotericin B, including hypokalemia and hypomagnesemia. A peripherally inserted central catheter (PICC) placed for treatment became infected, requiring antibiotic treatment. After the month of IV therapy, fever resolved, and lymph nodes decreased in size. However, concerns remained about gastrointestinal absorption due to persistent intermittent abdominal pain, distension, enlarged mesenteric lymph nodes, and loose stools. This was problematic for the transition to oral treatment.

Given the concern for malabsorption and the need for long-term treatment, an empirical decision was made to combine itraconazole and cotrimoxazole for the initial period of oral therapy, acknowledging the lack of literature supporting this combination. The rationale was based on itraconazole being the preferred drug (though the liquid formulation, which is better absorbed, was unavailable in Peru), and cotrimoxazole being a reliable option for long-term use.

The plan was to start with the combined regimen, wait for clinical improvement, and then continue only with cotrimoxazole. The patient had adequate oral tolerance with the combined regimen in hospital. Abdominal CT showed decreased lymph nodes. He was discharged after one month on the combined treatment and continued for another month at home, then transitioned to only cotrimoxazole. After 10 months of home treatment, he was asymptomatic, gaining weight, and had no relapse or adverse events. He remained on treatment at the time of presentation.

Key Takeaways from Case 1: Paracoccidioidomycosis is an endemic fungal infection that should be considered in children from tropical regions with persistent lymphadenopathy and systemic illness. It can mimic hematological malignancies, leading to diagnostic delays. Marked eosinophilia is a very remarkable finding. Severity criteria exist, and severe cases require early IV Amphotericin B. Intestinal absorption of oral drugs is a key consideration when planning long-term treatment. Diagnosis is typically made by direct visualization of fungal elements in a sample. Serological tests and cultures also aid diagnosis and monitoring.

Case Presentation 2: Schistosomiasis-Associated Liver Disease and Pulmonary Hypertension

Patient Presentation and History: The second case presented a 63-year-old male with a medical history of liver cirrhosis (diagnosed in 2020 in Egypt), esophageal varices, and diabetes. His history also included a splenectomy 20 years prior. He presented with shortness of breath and decreased oral intake in the setting of abdominal distension, suggesting decompensated liver cirrhosis. He had experienced shortness of breath for a month, abdominal distension, low appetite, early satiety, coughing, and poor sleep.

His travel history included being born in Yemen, moving to Saudi Arabia, and later immigrating to the US (California then New Orleans) five years prior. He had also traveled to Egypt for cirrhosis treatment.

Medical History Related to Schistosomiasis: The patient had a significant history of schistosomiasis. He was diagnosed with schistosomiasis during childhood while living in Yemen, where poor sanitation and contaminated water were prevalent. He received treatment for it at that time. Twenty years later, while in Saudi Arabia, he experienced fatigue and abdominal discomfort, and a stool analysis confirmed schistosomiasis reinfection. He received a second treatment and underwent a splenectomy at that time. There was no further history of reinfection or re-exposure mentioned after this period. His liver cirrhosis diagnosis in Egypt was attributed to his previous schistosomiasis infection. He had two hospitalizations in the US in the preceding five years for decompensated liver failure, reportedly due to medication non-compliance and insurance issues.

Initial Assessment and Workup: On physical examination, the abdomen was soft, tender, and distended, with surgical scars and a hernia. Initial labs were notable for normal CBC, liver function tests, coagulation profile, and renal function tests. Blood cultures showed no growth. Imaging included a chest X-ray showing pulmonary edema and an abdominal ultrasound showing liver enlargement and upper abdominal ascites, indicative of advanced cirrhosis. A CT showed ground glass opacity and enlarged pulmonary artery. A VQ scan ruled out pulmonary embolism.

The initial infectious disease consultation was sought for an infectious workup related to his cirrhosis. Spontaneous bacterial peritonitis was an immediate consideration given the ascites. Laboratory results included a high serum-ascites albumin gradient (SAAG) of 1.5, suggesting portal hypertension, and spontaneous bacterial peritonitis was ruled out. Crucially, there was no eosinophilia on CBC with differential. HIV, hepatitis B, and hepatitis C tests were negative. A stool analysis for ova and parasites was negative on one occasion. However, schistosomal serology (IgG) was positive (0.3), which was considered high.

Discussion: Active Schistosomiasis vs. Sequelae: The central question for the infectious disease team was whether the patient's current decompensation was due to active schistosomiasis or the long-term sequelae of prior infection. Arguments against active infection at the time of the initial consult included:

• History of previous diagnosis and treatment.
• No history of recent exposure (last year spent in Saudi Arabia, then US).
• No current clinical symptoms specifically indicative of acute infection.
• Absence of eosinophilia, which is typically associated with acute, but not necessarily chronic, infection.
• Negative stool analysis for ova.
• The positive serology was interpreted in the context of a long-term history of infection and treatment, potentially representing past exposure rather than current active disease.

Based on these points, the initial assessment was that the liver cirrhosis was a consequence of chronic schistosomiasis (sequelae), and there was no active infection. The decision was made not to treat the patient for active schistosomiasis at that time.

Subsequent Clinical Course and Re-evaluation: The patient's condition worsened over time. He was listed for liver transplant but later removed due to cardiac issues. He had recurrent hospitalizations for decompensated liver failure and coagulopathy. Notably, he developed worsening pulmonary hypertension and decompensated right heart failure. A right heart catheterization showed low pulmonary capillary wedge pressure and high pulmonary hypertension.

This progression, particularly the worsening pulmonary hypertension, prompted a reconsideration of whether there might be some active disease. Schistosomiasis is known to cause periportal fibrosis due to eggs deposited in the portal circulation, leading to liver disease, and eggs can also cause inflammation in the pulmonary arterial tree, leading to pulmonary hypertension. The discussion revolved around whether the progressive nature of the disease, despite previous treatment, meant there was ongoing active infection that might benefit from treatment.

Experts debated if this was just the expected progression of cirrhosis with portal hypertension and associated pulmonary hypertension (irreversible sequelae) or if active disease was contributing. The challenge of definitively knowing if the patient had active chronic schistosomiasis was highlighted. Stool checks for eggs can be negative in chronic disease, and serology indicates exposure but not necessarily active infection. Biopsy was considered too risky given the patient's condition.

Management Discussion: The potential benefit of re-treating the patient with anti-helminthic therapy (praziquantel) was debated. Some felt it was unlikely to be helpful, as "the horse is already out of the barn," implying the damage was irreversible. Others argued that with the patient's severe condition and poor prognosis, treating "ain't going to hurt" and "what do you have to lose," even if the benefit was uncertain. The patient's worsening pulmonary hypertension complicated his transplant candidacy. Lowering pulmonary pressures is crucial for liver transplant in these cases.

Outcome and Final Considerations: Despite the debate, the patient initially did not receive treatment for active schistosomiasis. However, a later update mentioned that pulmonary hypertension had improved following repeated right heart catheterization. It was then stated that the patient did receive treatment at the end, contradicting the earlier statement. This discrepancy was not fully resolved in the provided excerpts.

The question of prophylaxis for patients with prior schistosomiasis undergoing liver transplant was raised, but no clear data or experience was presented by the participants.

Key Takeaways from Case 2: Schistosomiasis is a significant cause of chronic liver disease (cirrhosis and periportal fibrosis) and pulmonary hypertension in endemic regions. Determining whether progressive disease in a previously treated patient is due to active infection or irreversible sequelae is challenging. Labs like stool for ova and eosinophilia are often negative in chronic infection, while serology can remain positive from past exposure. The benefit of treating chronic sequelae with anti-helminthic therapy is uncertain. Progressive pulmonary hypertension in this context complicates patient management, particularly regarding liver transplant eligibility.

Overall, these cases highlight the complexity of diagnosing and managing tropical infectious diseases that can present with systemic symptoms, mimic other severe conditions, and lead to long-term sequelae impacting multiple organ systems. They also demonstrate the value of geographic context, detailed history, appropriate diagnostic investigations, and expert discussion in navigating challenging clinical scenarios.

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