Take-home point #1: when a patient presents with a new rash after a hospitalization, think about drug reactions (esp from antibiotics, antiepileptics, or allopurinol). The characteristic of the rash can be helpful: painful rashes suggest infection or SJS/TEN, pruritic rashes suggest urticarial and other allergic reactions, and neither painful nor pruritic suggest autoimmune processes.
Take-home point #2: RCC as another great mimicker: 1/3 of patients with RCC show s/sx of a paraneoplastic syndrome!! The presence of this is not always a marker of metastatic disease or prognosis, and nephrectomy often leads to resolution. More below and attached.
Eosinophilic lung disease (*note, this can be suggested by peripheral eosinophilia + e/o pulmonary parenchymal dz, but you need evidence of LUNG TISSUE eosinophilia by BAL or biopsy to confirm true lung eosinophilia)
- Infections: Helminthic infections (eg Strongyloides) and nonhelminthic infections (eg cocci, TB)
- Drugs: NSAIDs, amoxicillin, amiodarone, AEDs, ACEi, others
- Idiopathic acute eosinophilic pneumonia: usually p/w rapid development of acute respiratory failure in a previously healthy patient
- Other things: EGPA (Churg Strauss), allergic bronchopulmonary aspergillosis (seen in pts with asthma, CF), hypereosinophilic syndrome
Paraneoplastic syndromes in RCC: the great mimicker!!
- Hypercalcemia is the most common paraneoplastic syndrome – can be from PTHrP or from bony mets
- Leukemoid reaction (from increased GCSF)
- Polycythemia: from increased EPO
- Endocrinopathies: including elevated HCG or ACTH, Cushing’s syndrome, hyper/hypoglycemia
- More here: http://www.ncbi.nlm.nih.gov/pubmed/16985675