Let's individually categorise and tackle her problems 1 by 1
36/F with a background of Chronic T cell mediated Immunosuppression with HIV
Presenting with 6 month Hx of Dyspnea, Cough and Expectoration
Her past Hx is significant for two cardiac surgeries. Now whether they have any bearing on the current problem, remains to be seen.
Cough and expectoration with Dyspnea strongly favouring a lung cause. Sputum + for AFB. So this explains her lung problem, her dyspnea and her systemic symptoms.
Her current problem is Jaundice and it appears that from the history of urinary excretion of bile salts and pigments (need to see the CUE), and the labs showing a Conjugated Hyperbilirubinemia, this is a cholestatic jaundice.
So let's review the hepatic plumbing system here - 80% via Portal Vein and 20% via Hepatic Artery. Spleen being the major destroyer of RBCs releases unconjugated bilirubin, which is immediately bound to Albumin and then transported to the liver via splenic vein and portal vein. This process appears to be intact, however a caveat here is that the patient has profound hypoalbuminemia and a very mild rise in AST (which can be released from red cells, apart from hepatocytes. The LDH may help here, to rule out hemolysis).
The portal vein brings this unconjugated bilirubin to the hepatocytes and enters the cells via BSEP (bile salt extrusor protein) and NaTCP (Sodium taurocholate contransporter) and a few other pumps. Pump failure here would mean uncojugated bilirubinemia, which doesn't appear to be happening here.
Next step is the process of conjugation, where UGT1A1 conjugates, aka adds cholate or taurocholate to bilirubin. This process also appears to be okay as direct bilirubin is increased, meaning its production is normal. So Gilbert and Criggler Najjar very unlikely.
Next, and rightly so the most common reason are the failure to extrude this direct bilirubin into the blood via certain pumps, whose names I forgot (probably BSEP and NaTCP ?)
These pumps are highly susceptible to drugs and are commonly inhibited by Rifampicin, Augmentin, Phenytoin, Sulfonylureas, OCPs etc. This patient is on Rifampicin and so this could be a likely cause.
Once the pumps extrude conjugated bilirubin out, any impairment in flow can cause cholestatic jaundice - causes include CBD Stones, Failure of gall bladder contractions, pancreatic adenocarcinoma, IgG4 related disease, PSC and PBC. However, hallmark feature of all these obstructive jaundice causes is that enterohepatic circulation is impaired and they may develop features of malabsorption and Vitamin D (hypocalcemia and hypophosphatemia) with Vitamin B12 deficiency too. B12 deficiency can explain her limb weakness but the process should have begun nearly 6 months ago.
If this is so, the jaundice should have appeared months ago. However temporally, the jaudice appeared after she was started on ATT and therefore obstructive jaundice is fairly unlikely here.
Therefore, I think her current problem of Jaundice is due to Rifampicin.
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