Description 🎙️
Andrew presents a case of a common cross-cover call: AFib w/ RVR. Once rate-controlled, she looks well & euvolemic. The CXR is normal, but SpO2 92%. Are you done?
Case Images 🩻
Chest X-Ray
CT Chest w/ IV Contrast
Teaching ✍️
- Diagnosis of Adrenal Insufficiency 2/2 Chronic Steroid Withdrawal: in the world of adrenal insufficiency (AI), primary AI refers to dysfunction of the adrenal gland itself, secondary AI refers to pituitary dysfunction (i.e. ACTH deficiency), & tertiary AI refers to hypothalamic dysfunction (i.e. CRH deficiency). Since patients on chronic steroids have no need for their bodies to synthesize CRH / ACTH / cortisol, AI related to steroid withdrawal ends up falling into the tertiary bucket. While the risk of AI due to steroid withdrawal is thought related to steroid duration, dose, & potency, the data on who exactly develops AI is murky, & there are no clear rules-of-thumb. If you do have concern for adrenal insufficiency during a steroid taper, you can do the standard “ACTH stim” test for diagnosis. (That said, in early central AI, meaning either secondary or tertiary, the usual post-stimulation cortisol cutoff of > 18 ug/dL is not necessarily a rule-out, because incomplete adrenal gland atrophy can leave enough residual tissue to produce an output of > 18. However, when the patient is NOT being given ACTH in the hospital, adrenal atrophy is enough so that they still suffer the symptoms of adrenal insufficiency outside of the hospital.) The net result of all of this is that the Dx of AI in patients with steroid withdrawal is fairly contingent on the clinical picture (i.e. do they have fatigue, o-hTN, nausea, hypoglycemia).
- Sensitivity of CXR for Pneumonia: in one study, the sensitivity for pneumonia is estimated around ~45%. The implication of this is that if your pre-test probability for pneumonia or other parenchymal lung disease is high, a negative CXR is NOT sufficient for rule-out, & you need a chest CT for a detailed parenchyma assessment.
