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  • A 35-year-old man presents to the emergency department for seizures. Prior to developing seizures, he complained of a headache and was progressively confused. He eventually became nauseous and had multiple episodes of emesis. He recently emigrated from Mexico to the United States and did not have a seizure history. A CT scan of the head demonstrates parenchymal calcifications in the left parieto-occipital region. (Neurocysticercosis)
  • Definition
    • flat and hermaphroditic worms that are parasites of humans
      • may reside in the intestinal lumen or live in extraintestinal tissues
  • Pathogens
    • Taenia solium
    • T. saginata
    • Diphyllobothrium latum
    • Echinococcus granulosus
  • Pathogenesis
    • tapeworm contains a scolex (head) and proglottids (attached segments)
    • scolex of the tapeworm attaches to the intestinal tract and the adjacent proglottids inseminate, leading to the formation and release of eggs that are passed in feces
      • after an intermediate host ingests these eggs in feces, the eggs release an oncosphere
        • penetrates the gut and develops as cysticercus in tissues
          • humans become infected with the tapeworm when they ingest infected animal tissue that contains cysticerci
    • note, ingestion of cysticerci lead to the formation of tapeworms that reside in the proximal small bowel (e.g., Taenia solium and T. saginata) vs ingestion of eggs passed in human or animal feces leads to the formation of oncospheres, causing extraintestinal cystic lesions (e.g., T. solium and Echinococcus)
Tapeworms (Cestodes)
Clinical Manifestation(s)
Transmission Treatment
Taenia solium ("pork tapeworm")
  • Intestinal tapeworm
    • most carriers are asymptomatic
    • passage of proglottids in stool
    • may have nausea, anorexia, or epigastric pain
    • peripheral eosinophilia may be seen
  • Cysticercosis
    • most commonly affecting muscles or subcutaneous tissues
  • Neurocysticercosis 
    • seizures (most common clinical manifestation with involvement of the brain parenchyma)
    • headache
    • altered mental status
  • Consumption of
    • larvae in undercooked pork (intestinal tapeworm)
    • eggs in foods contaminated in human feces (cysticercosis and neurocysticercosis)

  • Albendazole or albendazole and praziquantel (for neurocysticercosis)
Taenia saginata ("beef tapeworm")
  • Intestinal tapeworm
    • most carriers are asymptomatic
    • passage of proglottids in stool
    • may have nausea, anorexia, or epigastric pain
    • peripheral eosinophilia may be seen
  • Consumption of undercooked beef
  • Praziquantel
Diphyllobothrium latum ("fish tapeworm")
  • Vitamin B12 deficiency 
    • leads to development of megaloblastic anemia
  • Consumption of larvae in raw freshwater fish
  • Praziquantel
Echinococcus granulosus
  • Liver hydatid cysts 
    • typically patients are asymptomatic
    • right hepatic lobe is most commonly affected
    • when the cyst is large, patients can present with hepatomegaly and right upper quadrant pain
    • cysts can rupture in the
      • peritoneum, leading to peritonitis
      • pleural space, leading to pulmonary hydatidosis
      • biliary tree, leading to biliary colic, obstructive jaundice, cholangitis, or pancreatitis
  • Consumption of eggs in foods that are contaminated in dog feces
  • Sheep are an intermediate host
  • Albendazole

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Questions (3)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

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(M1.MC.13.115) A 35-year-old shepherd is found to have a large hydatid cyst in his liver. His doctor explains to him that surgery is required to remove the cyst, as aspiration of the contents would risk an anaphylactic reaction in the patient. What is the most likely cause of this patient's cyst? Review Topic | Tested Concept

QID: 101172

Diphyllobothrium latum




Echinococcus granulosus




Taenia solium








Clonorchis sinensis



L 2 E

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