Cranial n. Learning Resource

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Causes of Secondary Hypertension

I am currently on my Ambulatory Medicine rotation at a hospital that sees a patient population primarily comprised of the homeless, imprisoned, and uninsured. The staff is incredibly nice and I'm loving my time there. Every week I am assigned a couple of topics to look up and present orally to the attending. I thought I would share my findings on each topic.

Ambulatory Topic #1: Causes of Secondary Hypertension

1.     Primary renal disease — Both acute and chronic kidney disease, particularly with glomerular or vascular disorders.
*You see elevated serum Cr concentration and/or an abnormal urinalysis.

2.     Oral contraceptives — Oral contraceptives typically raise the BP within the normal range but can also induce overt hypertension.

3.     Drug-induced — Long term use of NSAIDs + many antidepressants can induce HTN. Chronic ETOH intake and ETOH abuse can also raise blood pressure.

4.     Pheochromocytoma — About 1/2 of patients with a "pheo" have paroxysmal HTN, most of the rest have what appears to be primary HTN.
* You see:
-paroxysmal elevations in blood pressure (which may be superimposed upon stable chronic hypertension)
-triad of headache (usually pounding), palpitations, and sweating
-drug-resistant hypertension and those with an adrenal incidentaloma should be evaluated for pheochromocytoma. Patients identified with pheochromocytoma are rarely asymptomatic.

5.     Primary aldosteronism — The presence of primary mineralocorticoid excess, primarily aldosterone, should be suspected in any patient with the
*You see:
-triad of hypertension, unexplained hypokalemia, and metabolic alkalosis. However, some patients have a normal plasma K+ concentration.
-otherwise unexplained or easily provoked hypokalemia due to urinary potassium wasting.
->1/2 pts =normal serum K+ concentration.
-suspected in the presence of slight hypernatremia, drug-resistant hypertension, and/or hypertension with an adrenal incidentaloma

6.     Renovascular disease — Renovascular disease = common disorder, occurring primarily in patients with generalized atherosclerosis.

7.     Cushing's syndrome — HTN is a major cause of morbidity + death in pts with Cushing's syndrome.
-Cushing's syndrome (including that due to glucocorticoid administration) is usually suggested by the classic physical findings of cushingoid facies, central obesity, proximal muscle weakness, and ecchymoses.
-Cushing’s or subclinical Cushing’s syndrome should also be suspected in patients with drug-resistant hypertension and in those with an adrenal incidentaloma.

8.     Other endocrine disorders — Hypothyroidism, hyperthyroidism, and hyperparathyroidism
-HTN may be associated with both hypothyroidism, which may be suspected because of suggestive symptoms or an elevated serum TSH level, and primary hyperparathyroidism. The latter is most often suspected because of otherwise unexplained hypercalcemia, which may affect vascular reactivity, day-night blood pressure regulation, and renal function

9.     Obstructive sleep apnea — Disordered breathing during sleep appears to be an independent risk factor for systemic hypertension.
-sleep apnea syndrome is most commonly identified in obese men who snore loudly while asleep. These patients have repeated apneic episodes at night due to passive collapse of the pharyngeal muscles during inspiration, such that the airway becomes occluded from the apposition of the tongue and soft palate against the posterior oropharynx.
-A variety of other symptoms may be seen including headache, daytime somnolence and fatigue, morning confusion with difficulty in concentration, personality changes, depression, persistent systemic hypertension, and potentially life-threatening cardiac arrhythmias.
-Patients with obstructive sleep apnea often retain sodium and fail to respond optimally to antihypertensive drug therapy

  10.  Coarctation of the aorta — Coarctation of the aorta is one of the major causes of secondary hypertension in young children
               -Coarctation of the aorta is one of the major causes of secondary hypertension in young children but may first be detected in adulthood (picture 1A-B). The classic findings are HTN in the upper extremities, diminished or delayed femoral pulses ("brachial-femoral delay"), and low or unobtainable arterial blood pressure in the lower extremities. In addition, a prominent “to-and-fro machinery murmur” from the aorta may be heard over the posterior chest.

Source: uptodate.com
Pic: http://www.angiologist.com/secondary-hypertension/


Nephrolithiasis - When Should I Admit?

I recently had a patient who came in complaining of severe flank pain radiating to his groin with nausea and vomiting… it was determined that he had nephrolithiasis (kidney stones). My attending asked me whether or not we should admit the patient… Good question, I thought. I was able to rattle off the text book treatments, but I wasn’t clear on the guidelines for admission vs. out-patient treatment. Below is an overview of treatment including some clear indications for admission.

General Treatment (for all types of stones):
a-PO analgesic or IV morphine, situation dependent
b-Parenteral NSAID (Ketorolac)
2-Hydration (vigorous)
3-Antibx, if UTI present

Additional treatment measures based on pain severity:
MILD-MOD pain = high fluid intake, oral analgesics, wait for stones to pass (Give pt a urine strainer because you want to know what “kind” of stone the patient has.)
SEVERE pain = IV fluids and pain control, KUB, IVP to find site of obstruction, consult urology (surgery) if stones do not pass in 3 days
ONGOING pain w/o relief from narcotics = Surgery

Types of Surgery (10,000 foot view):
Shock wave lithotripsy: most common, it breaks apart the larger stones so they can be passed spontaneously, typically used for stone >5mm and < 2cm
Percutaneous nephrolithotomy: used if the above fails, if stones are > 2cm, for struvite stones

Admission is indicated if:
1-Oral analgesics are insufficient to manage the pain.
2-Ureteral obstruction from a stone occurs in a solitary or transplanted kidney.
3-Ureteral obstruction from a stone occurs in the presence of a urinary tract infection (UTI), fever, sepsis, or pyonephrosis.
4-Large stones (>1cm)

*The above indications were found in a couple of sources, but more say that the ultimate decision is made on a clinical basis, not solely on guidelines.

Parting suggestion: brush up on the different kinds of kidney stones

Medscape: Nephrolithiasis and Treatment, http://emedicine.medscape.com/article/437096-treatment
Step Up to Medicine 2nd Ed. by Agabegi and Agabegi
Picture: http://knol.google.com/k/kidney-stones#


Treating Hyponatremia in the ED

After reading this blog entry from EM CRIT BLOG I felt better regarding the treatment of hyponatremia so I thought I would share. This blog has some great information and most blogs have a podcast option.

"In this podcast, I discuss the management of hyponatremia in the ED. After reading countless articles from the nephrology literature…I can still attest that I have not a friggin’ clue about renal physiology. But I think I have found a simpler path to the work-up and treatment of low sodium in the ED."


Levothyroxine vs Brand-Name

I vaguely remembered a comment from our endocrine teacher about not putting our patients on generic levothyroxine for hypothyroidism and that we should always opt for a brand name if the patient could afford it -- but the exact reason why had escaped me. I was recently presented with a situation in which I needed to make the call - generic vs brand - so I did some research and spoke to an endocrinologist. These are the main points that I came up with...

1. For tight control of TSH, use a brand name (which brand isn't important)
2. Tight control is particularly important in pregnant women, those looking to get pregnant, and those with h/o goiter or thyroid cancer
3. Once you pick a brand, try to stick to the same brand-name each month
4. The problem with generic levothyroxine is that the manufacturers producing the drug are variable and there are many companies moving in and out of the market so it is difficult to get the SAME generic pill each month from the pharmacy
5. If your pt can only afford generic, encourage them to take a photo of the pills that they get from the pharmacy - if they ever pick up their Rx and the pills look different then they should contact you to schedule thyroid blood work check in 5-6 weeks since the new generic could vary as much as 12.5%. If they are receiving the same generic pill each month, you should schedule normal follow ups. The bottom line is that each time they get a new generic pill from a new manufacturer, they should be re-tested.

This becomes important because many primary care providers Rx the generic because they believe that it isn't any different from brand names - and in most cases they are completely right. Ibuprofen vs Advil - no real noticeable clinical difference. The thyroid, however, is extremely sensitive and even the slightest variation from generic #1 to generic #2 can make someone's TSH impossible to tightly control and may even make them thyroid toxic.

When I presented this to several PCPs, it was received with a lot of skepticism. The first question they all asked was "Who did the study, the drug companies?" A great question to ask. The answer is... in addition to drug company studies... there have been independent studies and results have been examined by the FDA, Endocrinologist Societies (world-wide), and the Thyroid Association - all are in agreement about the results. There is a ppt available describing the results of these studies. They show the bioequivalence of generic vs brand, but also demonstrate the vast variability between generic manufacturers.

If you are looking for a quick 1 page break down of this subject - check out the following: Hennessey JV. Levothyroxine dosage and the limitations of current bioequivalence standards


Thyroid Resource

Quick post to share a great website resource I just found on the thyroid. It has up to date information and reviews of studies as well as ppts to explain relevant treatments for thyroid disease.

Click on pic to enlarge


OB/GYN Study Sources

I have had a few people ask me which books I used to prepare for my OB/GYN rotation so I thought it would be a good idea to share with everyone. The 4 main sources that I used to study before/during my rotation are:

1. Blueprints: OB/GYN ($35-40)
2. Case Files: OB/GYN ($25-30)
3. Obstetrics, Gynecology, and Infertility (Great pocket guide) ($15)
4. UpToDate.com (which I can only use at the hospital because I do not have a personal subscription)

I wanted to share a little about the Case File series because although I had heard of them before, I hadn't used them -- but now that I have - I love the set up. Each chapter starts with a brief case vignette and a couple questions such as: What is the likely diagnosis? or What would you do next? Then you are given the answers along with a brief teaching section on the topic. Lastly, they give you 5 or so multiple choice questions covering the chapter material (answers included). By the end of each chapter I really felt like I knew the material. This set up may not be for everyone so I took some page-shots so you can check it out before you make the purchase. I borrowed mine from the school library for the duration of my rotation.