1) A – ds-DNA in lupus is associated with disease activity (increased in active ongoing lupus nephritis)
2) C – HSP is associated with IgA deposition in mesangium. Note the fleeting type of symptoms, which is classic for HSP a) Intermittent abdominal pain
b) Migratory polyarthritis
c) Waxing and Waning palpable purpuric rash
IgA nephropathy is a primary renal disease secondary to under galactosylated IgA and subsequent IgG orIgA1 antibody against the abnormal IgA with deposition of antigen + antibody complex in the mesangium. HSP is a systemic vasculitis !
3) B – MPO ANCA vasculitis with GPA presentation! Given the RPGN picture, cytoxan and glucocoticoids is the right answer. However, if this question is framed as a very mild case of MPO ANCA associated GPA, rituximab with glucocorticoids is the answer.(RITUXVAS)
4) C – APSGN. Low C3 and normal C4 indicated alternate complement pathway activation(strep infection classically leads to alternate complement activation). You dont expect C1q, C4 in the biopsy !
5) A – Anti-GBM disease
6) D -C3 glomerulopathy. Uninhibited alternate complement pathway activation by the deficiency of complement regulatory factors! In this case factor H related proteins!
What about these X linked diseases in kidney !
From board stand point, Alport syndrome and Fabry disease are important AND both these disorders are X linked.
Alport syndrome : Mutation in COL4A5 gene (Thin membrane disease is a structural anomaly secondary to mutation in COL4A3 and COL4A4)
Fabry disease : Mutation in alpha galactosidase A gene.
There are autosomal variants of these diseases and can rarely affect females but not tested in the boards usually!
Dent’s disease – familial nephrolithiasis is also X linked.
ADPKD is autosomal dominant (as the name implies) – 40% associated with liver cysts, 5% associated with AVM . It is not cost effective to do screening for AVM in all patients with ADPKD. However, if there is a family history of Hemorrhagic stroke (where the risk of AVM goes up to 20%), Screening is recommended !
Medullary sponge kidney is usually a developmental anomaly but can have a hereditary predisposition!
1) Should be able to identify stone – hypoechoic shadow is a clue
2) Should be able to identify ADPKD, Aquired cystic disease of dialysis (history will be helpful), Benign cyst and RCC – Understanding Bosniak classification of cyst is helpful for diagnosis
3) Irregular margin and contrast enhancing cyst is RCC
4) US screening for Renal artery stenosis – RA/A >3.5/1
It is also useful to understand the downstream waveform in the lobar and lobular arteries- Tardus parvus waveform and loss of ESP(early systolic peak) notch suggests significant RAS
5) Should be able to identify hydronephrosis
6) RI in normal kidney is<75 and Transplant kidney is<80 . RI is systolic/systolic +diastolic flow. RI of1 indicates no diastolic flow.
7) Granulomatous pyelonephritis – easily identified. Needs nephrectomy!
8) Non contrast CT stone protocol has 98%PPV and 98%NPV
9) Calcification – Medullary calcification and cortical calcification is easily recognized by location. Irregular bilateral asymmetric medullary calcification is usually Medullary sponge kidney
10) In post transplant kidney – elevated RI and Elevated Peak systolic velocity in Renal artery >300 cm/sec doen not indicate stenosis and it should normalize within 72 hours of transplant.
These are some of the high yield points in imaging. Please tag other points you may consider worthwhile revising or for understanding.(tag to this post)
1) C – ANCA vasculitis treatment – prednisone and Cyclophosphamide. There is plasmapheresis in the choice . If they specifically ask for initial therapy, then prednisone and plasmapheresis could be considered. This patient did not have pulmonary hemorrhage and was not sick !
2) B – Fabry disease. This is an X linked recessive disease which predominantly affects male ! Deficiency of Alpha galactosidase A causes accumulation of sphingolipids(glycolipids and in this disease specifically galactoacylcerebrosidase) in blood vessels , nerves kidney and heart. The manifestations are neurological(pain and tingling in extremities, progressive CKD-especially in 3 decade, Cardiac hypertrophy, abdominal pain(accumulation of sphingolipids in blood vessels supplying intestines) and skin rash(especially around the umbilicus)
3) D – Sickle cell/Tylenol/NSAID combination should raise suspicion about papillary necrosis
4)A – Arterial line is negative pressure and is causes dialysis catheter to flatten out!
5) B – most common cause of intradialytic hypotension is diastolic dysfunction. I was tempted to choose pericardial effusion given the stem of the case .
6) E – Hyperglycemia- very common cause of PD ultrafiltration failure since it decreases the solute gradient dramatically!
7) C – Isolated scrotal swelling should raise concerns about patent processes vaginalis in a new PD patient
8) E -Gentamycin toxicity- hypomagnesemia
9) C – Cyclosporine toxicity causes hirsutism
10) B – Increased urine oxalate -pathogenesis for calcium oxalate stone in Chron’s disease
Hope the explanation helps!
Good morning everybody!
We are rejuvenating the blog site with vigor ! I thought we should start a blog discussion on board exam to help us prepare for the BOARDS.
The point of discussion should be precise and board oriented. We could also discuss answers to some of the board type questions.
We discussed about a case of salicylate poisoning in noon conference today.
We had some interesting discussion about the role of Acetazolamide in salicylate poisoning.
Acetazolamide is a non bacteriostatic sulfonamide which acts as a carbonic anhydrase inhibitor and thereby causes bicarbonate , sodium and potassium loss in urine. It causes urine alkalization and this is favourable for salicylate excretion in its ionic form. However , acetazolamide has a tendency to decrease systemic Ph because of bicarbonate loss in urine and can potentially increase the neurotoxicity of salicylate. In the clinical setting where we are constantly infusing sodium bicarbonate to achieve alkalemia, the systemic acidosis caused by acetazolamide may not have clinical implication, especially since it is a long acting drug which needs several hours to cause systemic acidosis. If we are aggressively infusing sodium bicarbonate(after a bolus of 2-3 mEq/kg) to prevent systemic acidosis, starting acetazolamide appears reasonable.
There are several case reports of using acetazolamide successfully in older literature(1950-1980)
I do not see any evidence for its use or contra-indication in recent literature.
Many of the salicylate poisoning patients have concomitant hypokalemia and volume contraction.
Hypokalemia leads to increased ammoniageneis and subsequent increased net acid excretion. Volume contraction leads to secondary hyperaldosteronism and subsequent hypokalemia and alkalemia(by increasing net acid excretion). Both hypokalemia and volume contraction do not favor the excretion of salicylate !
The focus should be on aggressively managing hypokalemia(even if not manifested at the time of presentation, we notice hypokalemia while treating with sodium bicarbonate) , alkalinizing the blood and urine. It is not now considered a standard of care to give acetazolamide for salicylate poisoning since it aggravates hypokalemia, volume contraction and systemic acidosis (although theoretically it can help alkalinize urine -which may not occur in the setting of volume contraction and hypokalemia-both factors resist urine alkalinization)and potentially worsens neurotoxicity of salicylate!
Can we consider acetazolamide to sustain high urine pH after aggressively correcting the volume, hypokalemia and achieving systemic alkalosis? The answer is anybody’s guess!
Hypokalemia is associated with alkalosis and Hyperkalemia is associated with acidosis! We have heard about this but did ‘t know if this had mechanistic/pathogenetic significance until we heard Dr.Weiner’s lecture today.
Hypokalemia increases ammonia production in proximal tubule which is absorbed into the interstitium in the ascending loop of Henle through NKCl cotransporter (since the concentration of ammonia is several hundred folds higher than potassium in hypokalemic state). The ammonia decreases the activity of ENaC in the principal cell , which decreases potassium excretion(this is favourable in hypokaleic state since K is conserved by this) and ammonia combines with proton secreted in the alpha intercalating cell thereby increasing net acid excretion.
In short, hypokalemia signals the cortical collecting duct to decrease potassium excretion by increasing the production of ammonia.
Hyperkalemia decreases ammonia production in proximal tubule and the net acid excretion is decreased.
It was interesting to know the cause of hyperkalemia in acidosis!
This explanation based on ammonia generation hypothesis holds good only in chronic acidosis and not in acute acidosis such as DKA and lactic acidosis.