Differentials
Drug rash
SIGNS / SYMPTOMS
May be clinically indistinguishable from acute GVHD of the skin.
Can occur with use of any drug.
INVESTIGATIONS
If the rash does not improve with removing the offending drug, skin biopsy may reveal infiltration of eosinophilic polymorphonuclear leukocytes suggestive of a drug-induced lesion.
Radiation or chemotherapy-induced rash
SIGNS / SYMPTOMS
May be clinically indistinguishable from acute GVHD of the skin.
Rash may coincide with the timing of recent radiotherapy or chemotherapy.
INVESTIGATIONS
Clinical diagnosis. No differentiating tests.
Bacterial gastroenteritis
SIGNS / SYMPTOMS
May be clinically indistinguishable from gastrointestinal GVHD.
May coincide with contact with contaminated food or water, or contact with infected person.
INVESTIGATIONS
Stool cultures are recommended in order to rule out an infectious cause for the enteritis symptoms that may mimic gastrointestinal GVHD.
Viral gastroenteritis
SIGNS / SYMPTOMS
May be clinically indistinguishable from gastrointestinal GVHD.
May coincide with contact with contaminated food or water, or contact with infected person.
INVESTIGATIONS
Stool rapid antigen testing: may detect rotavirus or calicivirus.
Stool reverse transcriptase polymerase chain reaction: may detect rotavirus, norovirus, astrovirus, or adenovirus.
Stool viral culture and electron microscopy: may detect and identify viral cause.
Neutropenic colitis
SIGNS / SYMPTOMS
May be clinically indistinguishable from gastrointestinal GVHD.
INVESTIGATIONS
Abdominal x-ray or abdominal CT scan: may reveal thickening of the colon with fat stranding (an appearance of stranding in peritoneal fat due to inflammation).
Pseudomembranous colitis
SIGNS / SYMPTOMS
May be clinically indistinguishable from gastrointestinal GVHD.
May coincide with recent antibiotic use.
INVESTIGATIONS
Stool testing for Clostridioides difficile. If negative, colonoscopy or sigmoidoscopy may be warranted.
Drug-induced enterocolitis
SIGNS / SYMPTOMS
May be clinically indistinguishable from gastrointestinal GVHD.
May coincide with introduction of new drug.
INVESTIGATIONS
Trial withdrawal of drug known to affect the gastrointestinal tract may lead to improvement or resolution of abdominal symptoms.
Drug-induced hepatotoxicity
SIGNS / SYMPTOMS
May be clinically indistinguishable from liver GVHD.
Drug history includes drugs with known hepatotoxicity.
Clinical presentation may include pruritus, arthralgia, headache, and anorexia.
INVESTIGATIONS
Trial withdrawal of drug known to be hepatotoxic may lead to improvement or resolution of liver function abnormalities.
Viral hepatitis
SIGNS / SYMPTOMS
Presence of key risk factors (e.g., blood transfusion, intravenous drug use, overseas travel, exposure to infected individuals).
INVESTIGATIONS
Polymerase chain reaction (PCR) may detect hepatitis virus (A, B, C, D, E).
Veno-occlusive disease (VOD)/sinusoidal obstructive syndrome
SIGNS / SYMPTOMS
The classic triad for VOD includes hepatomegaly, right upper quadrant (RUQ) pain, and ascites (or unexplained weight gain).
INVESTIGATIONS
Doppler ultrasound of the liver shows increased phasicity of portal veins with eventual development of portal flow reversal. The liver is usually enlarged but maintains normal echogenicity.
Liver biopsy is required for a definitive diagnosis.
Total parenteral nutrition (TPN) associated cholestasis
SIGNS / SYMPTOMS
Current treatment with TPN is a key differentiating factor.
Pale stools and/or dark urine are non-specific findings with cholestasis. Anorexia and decreased appetite may also be present.
INVESTIGATIONS
Abdominal ultrasound may reveal gall bladder sludge with mild thickening.
Serum triglycerides and cholesterol may also be elevated.
Trial withdrawal of TPN may lead to improvement of liver function abnormalities.
Acalculous cholecystitis
SIGNS / SYMPTOMS
Pain often localised to RUQ or jaundice may be presenting signs for acute or chronic cholecystitis.
INVESTIGATIONS
Abdominal ultrasound may reveal echogenic sludge within a moderately distended gall bladder with no discrete gallstones. The gall bladder wall is not thickened. No biliary ductal dilation seen.
Abdominal CT scan: sludge may be present; no gallstones.
Hepatobiliary scintigraphy is highly sensitive and specific for diagnosing acute cholecystitis. Serial images show normal hepatic uptake of radiotracer with normal visualisation of common duct and bowel at 30 minutes after injection. In acalculous cholecystitis, the gall bladder is not visualised at 1 hour despite an intravenously administered dose of morphine sulfate.
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