History
Many hydatid cysts remain asymptomatic, even into advanced age. The parasite load, the site, and the size of the cysts determine the degree of symptoms. A history of living in or visiting an endemic area must be established. Also, exposure to the parasite through the ingestion of foods or water contaminated by the feces of a definitive host must be determined.
Theoretically, echinococcosis can involve any organ. The liver is the most common organ involved, followed by the lungs. These two organs account for 90% of cases of echinococcosis.
In cystic echinococcosis (CE), symptoms can be produced by a mass effect or cyst complications. Symptoms due to the pressure effect of the cyst usually take a long time to manifest, except when they occur in the brain or the eyes. Most symptomatic cysts are larger than 5 cm in diameter. Organs affected by E granulosus are the liver (63%), lungs (25%), muscles (5%), bones (3%), kidneys (2%), brain (1%), and spleen (1%). Rarely, hydatid cysts have been reported in the heart, [10] spine, [11] and submandibular area. [12, 13] .
Pressure effects are initially vague. They may include nonspecific pain, cough, low-grade fever, and the sensation of abdominal fullness. As the mass grows, the symptoms become more specific because the mass impinges on or obstructs specific organs. Note the following:
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In the liver, the pressure effect of the cyst can produce symptoms of obstructive jaundice and abdominal pain. With biliary rupture, the classic triad of biliary colic, jaundice, and urticaria is observed. Passage of hydatid membranes in the emesis (hydatid emesia) and passage of membranes in the stools (hydatid enterica) may occur rarely.
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Involvement of the lungs produces chronic cough, dyspnea, pleuritic chest pain, and hemoptysis. Expectoration of cyst membranes and cyst fluid is observed with intrabronchial rupture.
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Headache, dizziness, and a decreased level of consciousness may signify cerebral involvement. Specific neurologic deficits may occur depending on the location of the cyst in the brain.
Secondary complications may occur as a result of infection of the cyst or leakage of the cyst. Note the following:
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Minor leaks lead to increased pain and a mild allergic reaction characterized by flushing and urticaria. Major rupture leads to a full-blown anaphylactic reaction, which is fatal if not treated promptly. A rupture into the biliary tree can lead to obstruction by the daughter cysts, producing cholangitis. Rupture into the bronchi can lead to expectoration of cyst fluid.
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Infection of the cyst can occur either as a primary infection or as a secondary infection following an episode of a leak into the biliary tree, a cystobiliary fistula. Symptoms range from mild fever to full-blown sepsis.
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Extremity pain with or without neurologic deficit is a sign of either bone or muscle involvement.
In alveolar echinococcosis (AE), the liver is the primary site of infection, and it closely mimics cirrhosis or carcinoma. Symptomatology is that of progressive liver dysfunction that ultimately leads to liver failure. The progression can occur over weeks, months, or years. Distant metastasis is possible, and involvement of other organs (eg, lung, brain, bone) can occur in as many as 13% of the patients.
Physical Examination
Physical examination findings in patients with echinococcosis are nonspecific. The findings are related to the effect of the cyst on the anatomy or the function of the affected organ(s) and to an acute allergic reaction.
Skin
Jaundice could be a sign of biliary obstruction. Spider angiomas are a sign of cirrhosis of the liver. Urticaria and erythema may be seen.
Vital signs
Fever could be a sign of primary or secondary infection or an allergic reaction. Hypotension is observed with anaphylaxis secondary to a cyst leak.
Lungs
Decreased breath sounds over the affected area are signs of airway obstruction with consolidation of the affected segment, lobule, lobe, or the whole lung.
Abdomen
The most common sign is abdominal tenderness. Hepatomegaly may be present or a mass may be felt. Tender hepatomegaly is a sign of secondary infection of the cyst, especially when coupled with fever and chills. Ascites is rare.
Splenomegaly can be the result of either splenic echinococcosis or portal hypertension.
Extremities
Bone involvement can result in tenderness over the affected area and, rarely, a palpable mass. Muscle involvement is usually characterized by a palpable mass.
Peripheral nerve compression can occur, although extremely rarely. It results in nerve-specific sensory and/or motor deficit.
Brain
Findings from the neurologic examination are nonspecific and depend on the area of the brain involved. They range from very mild to full coma and cerebral herniation.
Eyes
Ocular involvement is rare. Abnormal findings from the ophthalmologic examination include decreased visual acuity, blindness, and exophthalmos.
