96.The answer is a.(Rosen, pp 1263-1264.)Amebic abscessesare com-
mon in countries with tropical and subtropical climates and areas with
poor sanitation. Entamoeba histolyticacauses an intestinal infection, and
the liver is seeded via the portal system. The clinical presentation includes
abdominal tenderness in the RUQ, leukocytosis, and fever. Diagnosis is
supported by identifying a pathogenic protozoan in the stool. Management
consists of supportive care and administering metronidazole. If medical
therapy is unsuccessful, percutaneous catheter drainage is required.
(b)Cholecystitis will present with fever, leukocytosis, and pain.
A Murphy sign is usually present. (c)Cryptosporidium is the most common
cause of chronic diarrhea in individuals with AIDS. Patients present with
profuse watery diarrhea, abdominal cramping, anorexia, nausea, and flatu-
lence. Symptoms persist in the immunocompetent for approximately 1 to
3 weeks and are self-limited. Dehydration is common. There was a cryp-
tosporidium outbreak in Milwaukee, Wisconsin in 1993 after a water
purification plant was contaminated. More than 100 people died, among
them mostly the elderly and immunocompromised. (d)Patients with
enterobiasis or pinworms complain of itching in the anal region, particu-
larly at night, as the adult worm lays eggs in the anus. (e)Pyogenic abscess
is the most common type of liver abscess; however, the history of travel,
and lack of primary source for the pyogenic abscess make it less likely a
diagnosis. Underlying biliary disease with extrahepatic biliary obstruction
leading to ascending cholangitis and abscess formation is the most com-
mon cause and is usually associated with choledocholithiasis, benign and
malignant tumors, or postsurgical strictures.
97.The answer is d.(Tintinalli, pp 561-565.)The ultrasound shows a
gallbladderwith multiple echogenic gallstones associated with well-
definedacoustic shadows.This image is typical for cholelithiasis.If the
patient was febrile and thought to have cholecystitis, then one may also
observe gallbladder distention, wall thickening, and pericholecystic fluid in
addition to gallstones. The most common clinical manifestation of cholelithi-
asis is biliary colic.
(a)Renal stones will also appear as echogenic structures casting shad-
ows within a central cavity, namely the renal calyx; however, the cavity in
the figure does not have the appearance of a renal calyx on ultrasound. In
addition, the clearly depicted anterior liver in the ultrasound also helps us
lean toward identifying a gallbladder, rather than more posterior renal
structures. (b)An ultrasound of a pancreatic pseudocyst would show a
Abdominal and Pelvic Pain Answers 115