Thank you Chuka and Lauren for presenting 2 twin cases today:
1) Case 1 was of a young man who presented with an acute onset of emesis with progression to bloody emesis, melena, and significant anemia, following a trip to the Carribean. We discussed the differential for acute diarrhea in a returned traveler (including possibility EHEC and risk for hemolytic-uremic syndrome). He was ultimately diagnosed with a Mallory-weiss tear, likely in the setting of acute retching secondary to presumed viral gastroenteritis.
2) Case 2 was a case of an elderly woman presenting with constitutional symptoms & a mechanical fall, who was found to have a large pulmonary mass, that was thought to be a met from new gastric cancer. ____________________________________________________________________________________
- Pulmonary metastatic lesions tend to have proclivity for the lung bases, are subpleural in location, and have sharply demarcated borders (there are exceptions, however!)
- HUS is a rare but potentially fatal complication of E. Coli O157:H7 infection!
- Not all Mallory-weiss tears bleed, but when they do, upto 70% of them will require blood transfusions.
- Mallory-Weiss tears are longitudinal, mucosal lacerations in the distal esophagus & proximal stomach, usually associated with forceful retching.
- Not all tears bleed, but bleeding involves underlying esophageal venous or arterial plexus; 40-70% patients with bleeding Mallory-weiss tears require blood transfusions (think, brisk, arterial bleeding!)
- Predisposing conditions:
- Hiatal hernia: a higher pressure gradient develops in the hernia during retching, increasing the potential for mucosal laceration
- Alcoholism-induced vomiting
- Age: although age has been proposed as a predisposing condition, most MW tears occur in patients < 40 yoa
- Treatment: epinephrine injection, electrocoagulation (thermal therapy), endoscopic band ligation
Radiographic findings of Pulmonary Metastases
- Note, in a patient with a history of extrathoracic malignancy, the probability of metastasis is ~25% when a solitary pulmonary nodule is detected on CXR.
- Common cancers that metastasize to the lungs: Bladder, Breast, colon, RCC, Melanoma, Ovarian, Sarcoma, Thyroid
- In general, they have a proclivity for the lung bases and tend to be subpleural in location.
- Usually, metastastic lesions are round with sharply demarcated borders, but mets that tend to hemorrhage (choriocarcinoma, RCC, melanoma, thyroid, Kaposi’s) may have indistinct borders and have a ground-glass opacity look.
- Cavitation rarely happens (<5 %) and is preferentially seen in squamous cell carcinoma
Hemolytic Uremic Syndrome associated with E. Coli O157:H7 infection
- Characterized by MAHA, thrombocytopenia, and acute renal injury. Rare neurologic complications can also occur.
- 6-9% of STEC (Shiga-Toxin secreting E. Coli) infections
- Pathophysiology 1) Shiga toxin released by E. coli binds to globotriaosylceramide (Gb3) on surface of vascular endothelial cells, particularly in the kidney and brain à inhibits protein synthesis à induces broad inflammatory response à releases cytokines and chemokines à thrombosis and organ damage! 2) Shiga toxin also activates alternative pathway of complement system by binding to factor H proteins!
- Best approach: Basic supportive care
- Under investigation but not standard-of-care:
- PLEX: remove Shiga-like toxin and prothrombotic factors and replace them with coagulation, tissue, and complement factors
- Oral Shiga toxin-binding agent
- Eculizumab: Monoclonal antibody to C5 complement factor blocking complement activation. There are case series demonstrating the benefit of using eculizumab in children with STEC-HUS