Chronic Kidney Failure and bicarbonate supplementation

The goal in caring for a patient with chronic kidney failure is to retard the progression of renal function deterioration. In a study published in the Journal of American Society of Nephrology, it was shown that daily supplementation with sodium bicarbonate was effective in slowing the progression of kidney failure. The study focused on people who are in stage 4 and 5 chronic kidney disease which is defined by their creatinine clearance. Creatinine clearance is a way to measure kidney function or glomerular filtration rate (GFR). Stage 4 is a GFR of 15 to 29 ml/min and stage 5 is <15 ml/min. Usually when people reach stage 4, they are already preparing to get dialysis. People that reach stage 5 have end stage kidney disease and dialysis is needed for life.

The study followed these patient for 2 years and noticed that patients who received the sodium bicarbonate supplementation had slower deterioration of the GFR in comparison to patients who did not receive the sodium bicarbonate supplementation (5.93 vs 1.88 ml/min.) Although the amount seems small (roughly deter 2ml/min/yr), to patient who are nearing end stage renal disease, those 2ml/min/yr could mean being put on dialysis a year or two later. This effect was also shown in the comparison of people reaching end stage renal disease (6.5 versus 33%).

Social commentary: sodium bicarbonate is the chemical name for the every day baking soda. The patients in these studies basically received baking soda compressed into a pill form. Baking soda is not patented and costs next to nothing. A jar of 1000 sodium bicarbonate pill costs 10 dollars. In comparison, a year of dialysis will costs upward of $30,000 according to American Association of Kidney patients. In 2007, Medicare spent about $8.6 billion on patients who need dialysis. If we can just push back their need for dialysis by 2 years, we essentially save 60,000 dollars off of every patient who will need dialysis assuming their lifespan stays the same. With 350,000 Americans on dialysis, we would have saved $10.5 billion on their treatment if they start dialysis one year later or $21billion if two years later. There is another study that looked at if sodium bicarbonate treatment has an effect in patients who are at earlier stages of renal disease and it does. It was also effective in retarding renal function deterioration in patients that are in stage 2 and 3 renal failure. If we start patients earlier on this treatment, we can potentially push off the need for dialysis till much much later. The quality of life for the patient is much better without dialysis. Also, the financial incentive for the failure American health system is also huge.

Of course more research is needed in order to make sodium bicarbonate a standardized therapy for patients with end stage renal disease. Currently there are multiple clinical trials underway to further substantiate the results of the study quoted earlier. If successful, it will be another tool in our arsenal in treating chronic kidney disease and our overburdened health system.

CPK level in psychiatric patient

Recently we had a psychiatric patient that was transferred to us due to high creatinin phosphokinase (CPK) level in the blood stream. Generally CPK level is higher in psychiotic patient due to the medications that they are taking. There are various studies published in the 70's about the effect of typical anti-psychotic (neuroleptic) drugs on CPK level. Namely it causes a benign rise in CPK level that can often be confused with underlying pathology. However, in certain instances, the rise in CPK level can be due to pathological process.

In patient that's taking neuroleptic, we're worried about neuroleptic malignant syndrome (NMS) which is characterized by muscle rigidity, fever (>106F), and cognitive changes such as delirium. Mainstay of treatment for this syndrome is to discontinue the medication (classic anti-psychotic) and supportive care. The msucle rigidity causes rhabdomyolysis and thus high CPK level. In instances when the patient has severely elevated CPK level (>15000) or underlying renal problems or risk factors for renal damage, the patient will receive intra-venous fluid (IVF) to help clear out CPK and preserve renal function. This is done because CPK is mainly cleared from the body by the kidneys and high levels of it will kill the kidney. This brings us to why the patient previously mentioned wind up in our care.

The patient was transferred to us because of elevated CPK level and the psych ward decided the patient needed IVF to protect the patient's renal function. However, the patient has no predisposing factors nor prior renal pathology. In addition, the patient's CPK level was high, but not THAT high (~6000.)

In a study published on exertional rhabdomyolysis, healthy patient can reach level as high as 10,000 without any symptoms. Other more recent case report on elevated CPK and psych patient showed two cases where level of around 10,000 was treated with oral fluid and did fine clinically without any sequelae (future pathological process associated with this instance.)

In managing the patient, the CPK serum level should be drawn to monitor progress. Generally, the patient's CPK serum level should decrease by 40% each day provided that all insults were removed and patient is resting. The most dramatic decrease should be within the first 6 to 8 hours.

In summary:

-admit patient if

-CPK >15,000 (if otherwise healthy)

-has predisposing renal risk (sickle cell, PCKD, transplanted kidney)

-has renal failure

-the patient is a lawyer

Augmentin - How does it work?

Augmentin is a combination of amoxicillin and clavulanate.

Amoxicillin is a beta lactam antibiotics which binds to and inhibits penicillin binding protein (PBP). PBP is what makes the cell wall of the bacteria and, by inhibiting it, amoxicillin prevents new synthesis and replicating capacity of the bacteria.

The above image is a picture of the beta-lactam ring that binds to PBP.

However, bacteria are smart and they evolve at a rapid pace to overcome the antibiotics. One of the way that bacteria do this is to produce what's called the beta-lactamase which breaks the beta-lactam ring. The arrow on the picture shows where the beta-lactamse acts on to break the 4 carbon ring structure.

In order to deal with beta-lactamase, we added clavulanate to the mixture. Clavulanate is a beta-lactamase inhibitor. Thus it stops the activity of the enzyme to break down the antibiotics and let amoxicillin does what it is supposed to do.

Some of the side effect of this drug is nausea and vomiting that generally is better if taken with milk or food. Other side effects that are particularly higher with augmentin is diarrhea which is said to be up to 30% higher incidence than other antibiotics. Recently the FDA approved a higher dosage of amoxicillin combine with the same dose of clavulanate which seems to have less incidence of diarrhea than the older formulation.

Other more uncommon but dreaded complications are C. Diff colitis and steven-johnson syndrome. C. Diff pseudomembranous colitis can be treated with oral vancomycin or metronidazole (flagyl). If the disease evolved into toxic megacolon then surgical solution is required. In the case of steven-johnson syndrome, it's an autoimmune mediated response triggered by the penicillin-like medications. This syndrome is where the patient's skin sloughs off in patches leading to severe-burn like symptoms. Most of these patients are sent to the burn unit to be treated with mortality ranging from 3 to 90% depending on the severity of the disease. Treatment for steven-johnson is mostly supportive and discontinuing the offending agent (in this case the antibiotics.)

Teaching post

I've decided to start posting at least once a week on a medical topic that I have either learned or have presented. I think this will be mostly beneficial for me as a learning tool and also as a reference for me later on.

Back from almost 2 year hiatus

so to update on everything that has happened since my interview...

I got accepted! although it was a pretty late acceptance, all that matters is I am going to medical school. when i received the acceptance letter, i felt that at least i have a future now.

I'm currently in my 2nd year at medical school and i'm currently writing on this blog in order to procrastinate on my step 1 study. all my excitement since getting into medical school has mostly faded and i'm just left with frustration and stress. my study schedule involves me waking up at 8am and start studying by first reading first aid (USMLE bible essentially). this would take almost the entire morning. Like the good book, first aid is very dense and requires immense amount of time and concentration just to finish a couple pages. Just last friday, it took me 3 hours to read/memorize 6 pages. that's 1 page every 30 mins....

The morning session is followed by a quick lunch then continue reading first aid to finish what i couldn't in the morning. afterwards, it's on to doing USMLE World (Question bank). Uworld is basically a bunch of questions that are meant to simulate the actual test. it's very discouraging when i do them. currently, i'm consistently scoring 50% on every practice test. that's not even enough to pass... i keep telling myself that at least i'm learning more with every question that i get wrong by reading the explanation. however, i expected to at least see some improvements by now.

k enough procrastination, time to study.