Mixed cestode infection: an incidental association in an immunocompetent person
- 1Department of Internal Medicine, PGIMER & Dr Ram Manohar Lohia Hospital, New Delhi, India
- 2Department of Radiodiagnosis, Vardhman Mahavir Medical College & Safdarjung Hospital, New Delhi, India
- Correspondence to Dr Puneet Aggarwal,
Echinococcus and Taenia infection are the two most relevant forms of cestode infection in humans. These infections occur worldwide, but with higher prevalence in developing countries like India, where poor hygiene facilitates their transmission. We report a case of a middle-aged man who presented with seizures and was found to have dual worm infection including Taenia and Echinococcus. The patient was treated with steroids and albendazole followed by PAIR (puncture, aspiration, injection of scolicidal agent and reaspiration). After 6 months of follow-up, the patient is asymptomatic and seizure-free without any relapse.
Human beings serve as both definite and intermediate hosts for cestodes. Clinical presentation of cestode infections varies from asymptomatic to severe life-threatening fatal disease. The therapeutic approach is often complex especially in mixed cestodal infection.
A 42-year-old man presented with complaints of headache and two episodes of generalised tonic clonic seizure. The patient also gave history of vomiting, abdominal discomfort and heaviness on right side of the abdomen for last 6 months. There was no history of fever, cough, blurred or double vision. The patient was a strict vegetarian. There was no history of any addictions or any drug intake.
On examination, the patient was conscious and oriented with Mini Mental State Examination Score of 30/30. No signs of raised intracranial tension or meningeal irritation were present. The patient had hepatomegaly of 6 cm below the right mid-costal margin. Rest of the system examinations were normal.
Haematological investigations revealed microcytic normochromic anaemia with haemoglobin of 7.6 gm/dl, total leucocyte count of 6200/mm3, differential count with 40% eosinophils, 50% neutrophils and 10% lymphocytes.
Liver function tests, renal function tests and serum electrolytes were within normal limits. Electrocardiography was also within normal limits. Mantoux test was negative.
Skiagram of the patient revealed multiple elongated calcifications (Rice-Grain calcifications) involving soft tissue of neck, chest, back and bilateral lower limbs, suggestive of cysticercosis (figure 1).
Ultrasonography of the abdomen revealed well-defined large cystic lesion with posterior acoustic enhancement in anterior segment of right lobe of liver (figure 2). Multiple internal septations and echogenic debris suggestive of hydatid sand were present. According to the WHO classification1 it was categorised under Cystic Echinococcosis 3A (CE 3A) category, and according to Gharbis Classification,2 it was type 3 cyst.
CT of head revealed multiple calcified lesions distributed diffusely in bilateral cerebral hemispheres without any perilesional oedema, suggestive of neurocysticercosis (figure 3).
ELISA for IgM of cysticercosis was positive.
ELISA for hydatid cyst was also positive.
Slit lamp examination of eye was normal.
Stool for ova and cyst was negative.
Serology for HIV was non-reactive.
The patient was treated with steroid, albendazole (15 mg/kg/day in twice-divided doses) for 7 days along with anticonvulsant therapy. This was followed by PAIR (puncture, aspiration, injection of scolicidal agent and reaspiration) and again treatment with albendazole for 1 month.
Outcome and follow-up
After 6 months of treatment, the patient is asymptomatic and seizure free without any relapse.
Cestodes (commonly known as tapeworms) have different stages of their life cycle in humans. The most common infections by tapeworms include cysticercosis and echinococcosis. Cysticercosis is caused owing to infection by the larval stage of Taenia solium whereas echinococcosis is caused by Echinococcus granulosus. Exact incidence of both the infections is not known. Clinical features of cestode infection range from asymptomatic infection to severe life-threatening fatal disease.
Echinococcosis presents as hydatid cyst. Liver is the primary site, constituting nearly 70% of cases.3 It usually presents with upper abdominal discomfort and pain, poor appetite and abdominal lump. However, complicated cysts may manifest as jaundice, colicky pain, portal hypertension, ascites or compression of inferior vena cava.
In cysticercosis, the clinical manifestations are variable. Cysticercosis can be found anywhere in the body but is most commonly detected in the brain, cerebrospinal fluid, skeletal muscles, subcutaneous tissue or orbit. The clinical presentation of cysticercosis depends on the number, location and extent of associated inflammatory response. Neurological manifestations are most common which may include headache, seizures or features of increased intracranial tension. In studies from endemic areas, approximately 30% of cases of seizure disorder have evidence of neurocysticercosis on imaging studies.3
Imaging studies are the main diagnostic tests for Echinococcosis. Ultrasonography is the most common procedure for diagnosing asymptomatic Echinococcosis. Ultrasonologically, echinococcal cyst can be classified using WHO Informal Group on Echinococcosis classification1 or Hassen Gharbi classification2 as shown in tables 1 and 2, respectively. Class CE 3b and above, according to WHO classification, represent inactive cysts.
Our patient had a well-defined cystic lesion with internal septations and echogenic debris in dependent portion (Hydatid sand) suggestive of CE 3A category according to WHO classification and type 3 cyst according to Gharbis Classification.
Plain radiographs, CT and MRI are other imaging tests helpful in diagnosing Hydatid cyst.
Serological tests, ELISA, indirect haemagglutination (IHA) and immunoblotting also aid in diagnosis of Hydatid cyst. Eosinophilia is low grade or absent whereas routine laboratory investigations are non-specific. In cases with diagnostic dilemma, Fine needle aspiration cytology (FNAC) may be used to distinguish hydatid cyst from other cystic lesions.
Imaging studies (eg, CT and MRI scans) are the mainstay of diagnosis for neurocysticercosis. CT scans are more sensitive in identifying calcified lesions, which appear as 2–5 mm well-defined hyperdense nodules. Scolex inside a cystic lesion is diagnostic of cysticercosis. Antigen detection assays and enzyme-linked immunotransfer blot are serological tests helpful in diagnosis. Ultrasonography and plain radiographs help in detection of cysticercosis in muscles.
The appropriate treatment depends on hydatid cyst characteristics (for hepatic cysts, size and stage are the most important criteria), the therapeutic resources available and the physician's preference. Surgery has been the traditional approach for the treatment of cystic echinococossis (CE). However, chemotherapy, percutaneous procedures and a wait-and-watch approach has been successfully introduced now. These alternatives have replaced surgery as the treatment of choice in many cases.4
Albendazole should always be administered for at least 30 days after puncture. Antiparasitic drugs are playing an increasing role in the management of CE. Albendazole, 10–15 mg/kg/day, should be administered continuously without interruption. Albendazole usually causes solidification of small-sized and medium-sized CE1 and CE 3A cysts. In contrast, it is usually ineffective for larger (diameter more than 10 cm) CE1 and CE 3A cysts. Chemotherapy alone has no permanent effect on CE2 and CE 3b cysts.5
Optimal treatment of neurocysticercosis often includes symptomatic therapy for seizures and specific therapy for parasites (including antiparasitic drugs or surgical removal).6–8 Antiepileptic drugs are used to control the seizures.
Patients with calcified lesions do not have viable cysticerci and do not benefit from antiparasitic drugs.
In various randomised-controlled trials, it has been demonstrated that patients with parenchymal neurocysticercosis show more rapid resolution of parenchymal cystic lesions and have fewer generalised seizures when treated with corticosteroids and Albendazole (15 mg/kg/day in twice daily doses usually for 7–8 days) as compared with a placebo.9–11 Praziquantel (50–100 mg/kg/day in thrice daily doses) may also be used, but its benefits are not well defined. Patients with single enhancing lesion do well with or without antiparasitic therapy, but studies have demonstrated a slightly more rapid radiological resolution and fewer seizures when treated with steroids and/or antiparasitic drugs.
In our patient, the treatment was mainly targeted for echinococcus since the lesions of cysticercosis were disseminated and calcified. Our patient was treated with steroids, albendazole and PAIR of hydatid cyst.
Echinococcus and Taenia infection are the two most relevant forms of cestode infection in humans.
Mixed cestode infection is a therapeutic challenge.
Ultrasonography of cyst can determine the activity of echinococcal cyst.
The appropriate treatment of cystode infection depends on patient characteristics, the therapeutic resources available and the physician's preference.