April 15th - MHH - Aortic Insufficiency

Today at MHH a patient with endocarditis and severe Aortic Insufficiency was presented.  What follows is a quick board-relevant focus on Aortic Insufficiency.  One must think of the disease in the context of whether the AI is acute or chronic.












Causes:
The more common causes of Chronic Aortic Insufficiency/Regurgitation are:
Bicuspid Aortic Valve
Aortic Dissection
Infective Endocarditis
Calcific Disease of the Aorta/Myxomatous Degeneration
Marfan Syndrome
Hypertension
Rheumatic Heart Disease
Other Rheumatic Conditions (i.e. Rheumatoid Arthritis, Anklyosing Spondylitis, Reactive Arthritis)

Acute AI is usually causes by one of the following:
Infective Endocarditis
Trauma/Dissection of the Ascending Aorta


Symptoms:
Depend somewhat on whether the patient has acute or chronic Aortic Insufficiency.
Acute AI usually presents with sudden onset of pulmonary edema and dyspnea
Chronic AI usually presents with progressive symptoms of congestive heart failure. 
Also - keep in mind the symptoms associated with the cause of AI (i.e. fever with endocarditis)
Physical Exam Findings
Acute:
Patients will present with symptoms of cardiogenic shock - Tachycardia is common.  Look for Pulsus Paradoxus.  May have difference in BP between both arms due to dissection.  The murmur is a very soft  diastolic murmur at the LUSB (or it can he heard at the RUSB with aortic dissection).  The murmur is actually infrequently heard since the equilibrium of pressures occurs quickly. 


Chronic:
Patients with have a widened pulse pressure (Systolic - Diastolic < 100). S1 is soft or sometimes absent.  A Decresendo murmur at the LUSB is common (like acute, this murmur may may be at the RUSB with aortic dissection). A concurrent S3 is commonly heard. 
Multiple other Physical Exam Findings can be present due to the wide pulse pressure - Muller Sign (uvular pulsation), De Musset Sign (Head bobbing in synchrony with systole), Traube sign (Pistol Shot Femoral Murmur), Durosiez Sign (Femoral Mumur heard with compression), Corrigan Pulse (Rapid Upstoke when quick collapse), Becker's Sign (Retinal Pulsations), Quincke Pulse (capillary pulsations)


Workup:
Should include an EKG (may show Left axis and/or LVH), CXR (cardiomegaly, interstitial pulmonary edema, wide mediastinum?) and TTE.  Perform a CT or TEE if suspecting dissection. Most patients should have a serum RPR/VDRL sent.


Treatment:
Acute Aortic Insufficiency will usually need emergent valve replacement. In the meantime, IV nitroprusside or nitroglycerin can be used for preload reduction.  Lasix for volume overload.  Supportive care with dobutamine should be administered for cardiogenic shock.  DO NOT Place an intra-aortic balloon pump!


Medications (i.e. vasodilators such as ACEI, nifedipine or hydralazine) can be given to:
1- Reduce symptoms
2- Patients that have Hypertension
3- Patients with Severe AI that may be asymptomatic, but have LV dilatation


Surgery (AV Replacement) is indicated for:
1- Symptomatic patients that have severe AI regardless of LVEF
2- Asymptomatic patients with severe AI and LVEF <50%
3 -Chronic severe AR when undergoing other cardiac surgery (i.e. CABG)


Prognosis/Followup:
The most important determinant factor is LVEF.
In patients without  symptoms and normal LVEF, an echo is required every 2-3 years
In patients with symptoms or decreased LVEF, an echo is needed every 6-12 months

Image References:
www.pages.drexel.edu/~nag38/index.html

April 15th - LBJ - Sterile Pyuria

Today at LBJ the Renal Service presented patient with HIV that had with multple systemic complaints.  They were consults for AKI (baseline Cr 0.9 - now 5.4) and on the Urinalysis the patient had sterile Pyuria.  Here is a quick review are the causes of sterile pyuria (Significant WBCs - meaning at least 5-8 per hpf on Urinalysis with few/no bacteria and negative Gm Stain).

Make sure the specimen is obtained appropriately (i.e. clean catch) before making the call of sterile pyuria!!!

Infectious Causes
1) Tuberculosis of the GU Tract (work up with Urinary AFB)
2) Gonnorrhea/Chlyamydia infection (Can send G/C Probe to w/up) or UTI with "other" fastidious organisms (i.e. ureaplasma)
3) Fungal Infections of the Urinary Tract
3) Reports of some Viral Infections of GU tract causing sterile pyuria
4) Recently treated UTI (of any cause) in the last 2 weeks

Inflammatory Causes
1) Prostatitis (without active infection)
2) Appendicitis or Diverticulitis (when adjacent to bladder)

Systemic Diseases
1) Lymphoma of the Bladder
2) Amyloidosis, Leukemia and Myeloma (via causing a chronic interstitial nephritis)
2) Sarcoidosis
3) Malignant hypertension (usually with concurrent hematuria)
4) Kawasaki Disease

Renal Causes
1) Renal Vein Thrombosis (Consider in a patient with nephrotic syndrome + flank pain)
2) Intersititial Nephritis (and it's various causes - Analgesic/Antibiotic/other drug induced, lupus nephritis, Sjogren's, vasculitis, treated pyelonephritis, heavy metals)
3) Renal Papillary Necrosis (can be from NSAID use, Sickle Cell Disease or even obstruction)
4) Nephrocalcinosis (suspect with RTA Type I) and chronic/recurrent nephrolithiasis
5) Cholesterol Emboli Syndrome (Consider with concurrent glomerulonephritis and recent vascular intervention)
6) Polycystic Kidney Disease
7) Interstitial cystitis

------------
References:
Dieter, R.  Sterile Pyria: A Differential Diagnosis. COMP THER. 2000;26(3)
Massry et al. Textbook of Nephrology
Fausi et al. Harrison's Principles of Internal Medicine 16th ed

April 9th - MHH - Thyrotoxicosis

Today at Morning Report a Patient with Thyrotoxicosis was presented

So what does this mean?
Hyperthyroidism is the general term for increased thyroid function
Thyrotoxicosis is sometimes used as a synoynm, but generally refers to increased circulating levels of T3/T4. 
Thyroid Storm is a serious complication, usually in untreated patients with infection/surgery/trauma and others







Causes:
Graves Disease
Toxic Multinodular Goiter
Thyroiditis
Thyroid Adenoma
Factitious
Also - Struma Ovarii, which is rare

Some physical signs/symptoms with thyrotoxicosis:
General & Vitals: Tachycardia, Fevers, Heat intolerance, Weight Loss, Anxiety, Insomnia, AMS
HEENT: Graves opthalmopathy ("foreign body sensation," periorbital edema, conjunctival injection, increased lacrimation.  Diploplia and Proptosis can be present as well
Neck: Goiter (Look for bruit in patient with Graves)
Cardiovascular: Tachycardia, Systolic Flow Murmur on Exam.  Patient may have irregular rhythm due to atrial fibrillation.  Remember that thyrotoxicosis can exacerbate/cause CHF or exacerbate CAD
Pulmonary:  Dyspnea
GI: Increased stool frequency
GU: Oligomennorhea
Neuro: Tremors and Hyperreflexia (rapid relaxation phase)
Skin: Moist and warm, palmar erythema may be present, pretibial myxedema
Nails: onycholysis

Caveat for the Elderly - There is a term called apathetic hyperthyroidism.  Instead of presenting "classically," the elderly can have a complaint of just weakness, weight loss and/or atrial fibrillation

Workup/Diagnosis
Send a Serum TSH.  A level <0.1 is consistent, and a Free T4 should then be sent.  If the T4 is normal then T3 should be measured, as there are instances of this alone.  If the TSH is low in the setting of a Normal T4 or T3 then the patient may have either "subclinical hyperthyroisism" (which would technically be a misnomer if the patient presented with the above signs/symptoms) or Sick Euthyroid Syndrome due to underlying disease.  Note in Sick euthyroid syndrome the T4 is common'y either low or normal. You can confirm this state with an elevated reverse T3.

One can order a RAIU to differentiate the causes of hyperthyroidism/toxicosis.
High RAIU States include: Graves Disease, Toxic Multinodular Goiter and Adenoma
Low RAIU States include: Thyroiditis and Factitious Causes

Usually this testing is not always needed as physical findings of Graves disease are obvious in most causes.  The presence of eye findings and/or pretibial myxedema is almost always Graves.  If the patient has either a diffusely nontender goiter OR a non-palpable thyroid usually have Graves as well

Also - workup the causes of what may have exacerbated the thyroid state - i.e. infection

A Note About Thyroid Storm
This can be caused by infection, surgery, trauma, DKA, Pregnancy
Patients will be very tachycardic (or have atrial arrythmias), fevers, N/V, tremors and AMS and can progress to a comatose state.  See below for scoring system:

Treatment for Acutely Ill/Serious Thyrotoxicosis/Storm
PTU 300mg po q6 hours
SSKI 1-2 Drops po q12 hours
Propanolol 40mg po q6hours and titrate if needed



See this link for an article from Endocrinology clinics regarding thyroid storm, with the scoring system:
http://www.scribd.com/doc/6837836/Thyrotoxicosis-and-Thyroid-Storm

April 6th - LBJ - Multiple Myeloma/Amyloid

Today at Morning Report a Case of Multiple Myeloma was Presented. Here is a brief overview of the disease and what you'll need to know for boards regarding plasma cell disorders and amyloidosis






Multiple Myeloma is the most common malignant plasma cell dyscrasia. There are many other malignant and secondary plasma cell disorders, most of which are beyond what you'll need for boards.  Also keep in mind there are various subsets of non-malignant plasma cell disorders (i.e. MGUS) which you should be aware of

Multiple Myeloma - Presenting Symptoms/Physical Exam
General - Fatigue and Weight Loss are Common
Anemia - Pallor is the most common finding on examination
Bone Pain, Osteopenia and Pathologic Fractures - From Osteoclast activity and Lytic Lesions
Renal Failure - Symptoms of azotemia from light chain deposition or calcium impairment of renal perfusion
Nephrotic Syndrome - Can present with edema, increased risk of thrombosis
Hypercalcemia - Can present as various symptoms (i.e. confusion, renal stones, constipation etc)
Recurrent Infections - Due to Immunglobulin Disease
Bleeding Tendancy - Platelet and Coagulation Dysfunction
Neurologic Complications - Radiculopathy, Cord Compression, Polyneuropathy
Leukostasis - Uncommon, but with a very high plasma cell burden - patients can get Blurred Vision/Headache/Heart Failure/Dyspnea.


Always think of Myeloma in a patient (especially elderly) with anemia, renal failure and hypercalcemia

Lab Findings/Workup/Diagnosis:
In General, to diagnose Multiple Myeloma we use the Working Group Criteria or the WHO Criteria. Although there are other lab findings that are not specific parts of the diagnostic criteria. In general, the WHO criteria are a bit more pathology based, and the Working Group is more clinically based.  I'll put both of them here so you are aware:

WHO:
The diagnosis of multiple myeloma requires a minimum of one major Criterion  + one minor criterion OR
three minor criteria with bone marrow plasma cells >10% or a monoclonal protein


Major criteria
I Plasmacytoma on tissue biopsy
II Bone marrow plasmacytosis with > 30% plasma cells
III Monoclonal globulin spike on serum electrophoresis (> 3 g/dL for IgG, > 2 g/dL for IgA) or on concentrated urine electrophoresis (> 1g/24h of k or l light chains)

Minor criteria
Bone marrow plasmacytosis 10 to 30% plasma cells
Monoclonal globulin spike less than the level defined above
Lytic bone lesions
Residual normal IgM <0.05 g/gL, IgA < 0.1g/dL, IgG < 0.6g/dL

Working Group:
1 - Monoclonal Plasma Cells in Bone Marrow >10% OR a plasmocytoma on biopsy
2 - Monoclonal Protein in serum or urine (send SPEP and UPEP with IF and Serum Light Chain Analysis)
3 - Any one of the following organ related diseases:
     Calcium Elevated, Renal Insufficiency, Anemia, Lytic Bone Lesions or Osteopenia
   
Other Lab Findings in patients with myeloma:
BUN decreased
Negative anion Gap acidosis
Proteinuria of various severity on Ua
Globulin Gap
Alk Phos is NORMAL (remember this increases with blastic disease, not lytic disease)
Send LDH and B2 Microglobulin for staging and prognosis

Treatment:
The mainstay of treatment is supportive care: 
Transfusions for severe anemia and most patients should get EPO for anemia
Dialysis for Renal Failure
Bisphosphonates for lytic lesions
Saline and bisphosphonates for hypercalcemia
Prophylactic immunizations
Monthly Immune Globulin Infusion for recurrent infections
Radiation Therapy for Plasmacytomas or refractory bone pain

Remission is rare in patients, and is usually best achieved with autologous bone marrow transplantation. However, this is usually offered to patients that are <70 years old with good performance status - and unfortunately most patients with myeloma do not fit into this category

Positive Response to treatment is seen in about half of patients that recieve various combinations of treatment - including alkylating agents, steroids, anthracyclines and thalidomide.  Chemotherapy regimens including doxorubicin and vincristine are used with treatment failure. Lenalidomide, an analog of thalidomide, has less side effects (i.e. less fatigue) but also carries the risk of thromboembolic disease.  Bortezomib is a proteasome inhibitor that has been used as well. 


Non-Malignant Plasma Cell Disorders. Most are here to be completen, but you should really know MGUS for boards:
1) Monoclonal Gammopathy of Undetermined Signficiance - Less than 10% Plasma Cells with no symptoms or systemic complications.  This is present in about 2% of patients >50 years olf.  Annually, about 2% of patients transform into Myeloma - and about 20% will get myeloma during their lifetime. So, these patients need regular SPEP and UPEPs and physical exams/visits with clinicians to look out for progression to myeloma.  BM Bx will be needed in patients with MGUS that have concerning signs/symptoms that are a change from their regular status.  MGUS is seen in the general population, but is seen with increased incidence in those with autoimmune diseases, cirrhosis, and HIV

2) Smolering Myeloma - Plasma Cells greater than 10% but less than 30% without signs/symptoms

3) Indolent Myeloma - Plasma Cells greater than 10% but less than 30% with only mild anemia or <3 lytic lesions

Waldenstrom's Macroglobulinemia
This disease is causes by increased secretion of IgM paraprotein by plasma cells (as opposed to IgA or IgG in Myeloma.)  Can present very similar to MM, but these patients are at a higher risk of getting a hyperviscosity syndrome (CHF, AMS, MI, CVA, Retinal Complaints) and organomegaly is common. Treat hyperviscosity with plasmapheresis + Chemotherapy (agents used include rituximab, chlorambucil or fludarabine)

Amyloidosis:

Think of AL Amyloidosis in a patient with any plasma cell dyscrasia that has a change in symptoms (especially CHF). There are multiple other forms of amyloid (i.e. AA and inflammatory conditions such as Familial Mediterranean Fever) 

There are multiple findings/clues for amyloid:

General: Constitutional Symptoms
Skin: Purpura around face, neck, eyelids, “Shoulder Pad Sign,” Nodules
CV: Congestive Heart Failure Symptoms, Conduction Blocks, Arrythmias
GI: Dysmotility, Obtruction, Organomegaly
Heme: Anemia, DIC, Bleeding
Nervous System: Paresthesias, syncope, changes in bowel movement, carpal tunnel
Other: Change in Voice/Macroglossia

Remember that CHF is the cause of Death in over half of patients with myeloma.  They will have a restrictive pattern of filling, and classic septal hypertrophy changes/"snowstorm" appearance of the septum:

 
Diagnosis of Amyloid: 
Biopsy of an affected site will give the best yield. So if there is renal failure you may consider renal biopsy.  This will have the highest yield, but of course risks vs benefits must be weighed.  Other less invasive ways to diagnose include: Abdominal Fat Pad or Rectal Biopsy for Congo red stain (looking for apple-green bifringence). These have a reported diagnostic yield of between 70-85%
 
 
 
 
Treatment:
Best survival with high-dose melphalan and stem cell transplant, but this is not offered to most patients

References:
Images Courtesy of:
University of Virginina Dept of Heme/Onc &
http://www.stanfordhospital.org/ - information page on AL Amyloidosis

April 6th - MHH - HIV and Shortness of Breath

Today at Morning Report a Case of Dyspnea in a Patient with HIV was discussed.  The differential for patients with HIV/AIDS presenting with dyspnea is varied, and one must add additional conditions not seen in immunocompetent patients.  Here is a general thought process to causes in these patients






Infectious Causes
Bacterial Pneumonia (i.e. "Community Acquired") is your number one thought in this category, as strept pneumoniae is the most common pathogen in HIV patients.  They are also at an increased risk of getting empyemas. If you see an effusion or consolidation, think this bug first.  Blood Cultures, Sputum Cultures and Urine Antigen can be sent, but you must think of this diagnosis clinically. 


PCP/PJP - We see this very commonly, especially in patients with CD4 Counts Less than 200. The "Classic" presentation is dyspnea on exertion, fever, scant productive cough and hypoxia that is progressive and worsened with exertion.  We all Send LDH Levels - the Sensitivity in studies ranges from about 86-97%, but the specificity hovers around 50%.  CXR can show the "batwing" appearace - but PCP can appear as any bilaterial or unilateral infiltrate.  Early in the disease, the CXR may be negative.  Sputum Cultures can be sent for diagnosis, but the sensitivity is about 40%.  In patients with suspected PCP and negative sputum cultures, bronch should be performed.  Treat with Bactrim and add Steroids is the Pa02<70 or the Aa Gradient >35.


Viral Causes - Especially CMV


Fungal Causes - Histoplasmosis and Crypto are high on the list, especially in Houston. Keep Blastomycosis in mind with Skin Lesions, and Coccidio with contact in the endemic SW region.


Tuberculosis -  Even if you are thinking PCP, sputum cultures for APB can be considered. A PPD can be placed, but doesn't tell you as much...


Atypical Mycobaterium - i.e. MAC. Have a high suspicion especially with CD4 Counts below 50, although not uncommon in counts <100.  Send Sputum Cultures.  If they stain Acid Fast Bacilli, you would usually treat for MTB untill the PCR/culture reveals an atypical organism.  Although, most would add a macrolide to the treatment regimen while awaiting final cutures, when they have a high index of suspicion of atypical mycobacterium.  


Malignancy


Lymphoma - Both NHL and Hodgkin's should be considered. In general, NHL (especially B Cell Types) are highest in these patients. Common forms include Burkitts, DLBC, and Large Immunoblastic Lymphoma.  Keep in mind, that the incidence of Hodgkin's Lymphoma is increasing in the HAART era, and is rising in patients on treatment for HIV.  The tumor burden in the lungs alone/mediastinal involvement can cause dypnea. Always consider that this may be happening with your patient as the CXR with lymphoma can easily mimic infectious causes. 


HHV-8 Associated Malignancies - Kaposi's Sarcoma involving the Lungs, Castleman's Disease (A lymphoproliferative disorder) and Primary Effusion Lymphoma


Consider other Malignancies - Think both Primary Lung Cancer and Metastatic Disease. HIV increases the risk of Primary Lung Cancer regardless of smoking, and there is evidence of increased risk of metastatic spread of other primary cancers.


Lung Disease


Interstitial Lung Disease - Nonspecific interstitial pneumonitis and lymphocytic interstitial pneumonitis are very prevalant in HIV patients. 
There is also reported evidence of increased incidence of pulmonary alveolar proteinosis and desquamative interstitial pneumonitis.


Pneumothorax - A result of PCP/PJP infection, or various other secondary causes


Pulmonary Hypertension - Remember that HIV is a cause of seconary Pulmonary HTN


Pulmomary Embolism


Cardiac Disease
Congestive Heart Failure - Especially Dilated Cardiomyopathy with HIV


Pericardial Effusion/Tamponade - HIV, Fungal, TB, Malignant Causes


Ischemic Heart Disease - There is evidence of increased risk of CAD with HIV and some interesting papers that Protease Inhibitors contribute to this


Other Causes to Consider:
Rheumatic Diseases  - i.e. Vasculitis
Drug Reaction
Anemia (Acute - bleed from carcinoma or other various causes of colitis in HIV Patients. Chronic - consider BM suppression from HIV itself or other malignant/infectious causes - although this is less likely to causes acute dyspnea)

Image courtesy of City University of New York
www.brooklyn.cuny.edu/bc/ahp/SDPS/AtomOxygen.html

February 5th - MHH - Polyuria and Diabetes Insipidus

Today at Morning Report, Endocrine consults presented a patient in her third trimester with polyuria and polydipsia.  Here is a general approach to a patient with polyuria, and info on DI

In general, polyuria is defined as at least 3L of urine a day. The frequency of urination does not matter as much as the total amount.  Patients with polyuria will commonly also have polydipsia (to compensate, as long as their thirst center is intact) and will have nocturia.





The basic causes to know for rotations and the boards are:
Diabetes Mellitus
Diabetes Insipidus (Central and Nephrogenic)  - and their multiple causes
Primary/Psychogenic Polydipsia
Diuretic Use (esp in those using it for weight loss)
Hypercalcemia
Medications (either directly or by causing a nephrogenic DI)
Post-ATN or Post-Obstrutive Uropathy

Your exam in these patients may show signs of dehydration, although this is not as common when the patient has an intact thirst mechanism. A Good neurologic examination is essential with the variety of causes of central DI.  Further examination is directed mostly to other causes of Central/Nephrogenic DI or primary polydipsia (i.e. skin findings with sarcoid, amyloid infiltration, lymph nodes with systemic lymphoma, etc)

For the boards, a key topic is being able to identify and contrast Central Diabetes Insipidus, Nephrogenic Diabetes Insipidus and Primary Polydipsia

Central Diabetes Insipidus occurs from inadequate secretion of vasopressin. 
Causes: There are familial/inherited forms, but this is not as common as other causes - tumors of the CNS (including lymphoma and mets), trauma, granulomatous disease (TB/Sarcoid), infections (meningitis) and Sheenhan Syndrome. 

Nephrogenic Diabetes Insipidus occurs from renal insensitivity to vasopressin. 
Causes: This is commonly an inherited disorder, but can be secondary to medications (esp Lithium, Ampho B), systemic conditions (amyloid, Sjogrens, sickle cell disease, pregnancy), or electrolytes (HyperCA and HypoK)

Primary Polydipsia is simply increased water intake, usually psychogenic in nature (but can also be seen with lesions that affect the thirst center of the brain - sarcoid is a commonly tested one. 

Labs: Basic workup should include ruling out causes listed above, if not already obvious.  The best test to do initially is a BMP and Urine Osmolarity.  Patients will not be hypernatremic if they have an intact thirst mechanism, so don't rule out any of the above three if the patient has access to water, and takes in an amount to offset their urine output.  Undiagnosed DM and secondary osmotic diuresis can be ruled out with the glucose on the chemistry.  The electrolytes are also very important - both Hypercalcemia and Hypokalemia can not only cause polyuria, but in most cases, will make the symptoms worse as they interfere with the kidneys ability to concentrate urine.  Therefore, check these labs and correct as needed. 

Urine Osmolarity will be low in patients with Both forms of DI - generally <200. This is usually also the case with Primary Polydipsia. This is the general first step, although it makes sense because of very dilute urine. 

The other test that is done is the much heard about water deprivation test.  Patients are to be started on this protoco , and are instructed to not drink for about 2 hours before coming to the clinic or hospital for testing. During the time frame, the patient is not given access to fluids -> dehydration -> maximum stimulus for Vasopressin Secretion. Basic labs are drawn, and both Urine Volume/osm are measured every 2 hours. During this time frame, patients with Primary Polydipsia will be able to concentrate their urine. Therefore, in patients with Primary Polydipsia, the Urine osm will rise during the test.  In patients with both Central and Nephrogenic DI, the urine osm does not change much, yet the serum sodium may increase. 

So, now with no change in urine osm, the patient has either Central or Nephrogenic DI. How to tell apart - the patient is given desmopressin and we see what happens to the Urine Osm. Those patients with Central  DI will have at least a 50% increase in the Urine Osm after this medication, whereas patients with nephrogenic DI will have none or a slight increase (<10%) in their urine Osm. In those with primary polydipsis, the urine osm will increase at least 50% as well. 

Of NOTE:  On Boards, some other lab info/approaches may be given to differentiate the conditions.  With a low urine osm, and without the use of the water deprivation test, desmopression may be administered to see what happens to the urine osm.  If it changes >50%, then it is central DI.  Also, on various board review materials, they mention measuring ADH during the deprivation test. This is usually not done much clinically. You should be aware that with the water deprivation test - a rising plasma osm with no change in ADH is Central, and a rising ADH with no change in urine osm is Nephrogenic.  This makes sense, and may be presented on boards - but is not usually the way to diagnose this clinically. 

Treatment:
Central DI: Usually get intranasal Desmopressin lifelong
Nephrogenic DI:  Treat the underlying disorder/change medications.  Treatment is also thiazide Diuretic +/- K-sparing diuretic (The cause voume contraction sensed by the kidneys, and the resulting autoregulatory decrease in GFR will help decrease Urine Output)

Reference:
Image Courtesy of www.operationalmedicine.org

February 2nd - MHH - Mesenteric Ischemia and Ischemic Bowel Disorders

Today at Hermann, a case was presented regarding a patient with post-prandial abdominal pain (and also history of coronary artery disease and PVD).  The diagnosis was Mesenteric Ischemia (aka "Intestinal Angina")

Housestaff frequently interchange the different ischemic diseases of the bowel, and I've hear the term "ischemic colitis" to describe the clinical scenario above. Here is a review of the different ischemic disorders involving the bowel.


There are essentially 4 ischemic disease that affects the mesentery - acute and chronic mesenteric ischemia, mesenteric thrombosis and ischemic colitis. Keep in mind, that each of these has a variety of causes (see below).

Mesenteric Ischemia
In almost all of the causes, the presentation is similar - post prandial abdominal pain, weight loss and "fear of eating." Most of these symptoms occur indolently, yet depending on the cause, this symptoms can present more acutely.  The symptoms simply occur from a supply/demand mismatch, and the SMA is the usual site of involvement.  Overall, these patients DO NOT present with blood in the stool/diarrhea.... that is unless there is another overlapping cause that leads to gut infarction. This overlapping cause is usually caused by severe hypovolemia, cardiogenic shock or sepsis.

On exam, the classic presentation is that the patient's complaint of pain is out of proportion to the exam.  In fact, the way that patients describe pain - one may suspect that they would have peritoneal signs, but they are essentially non-tender during the exam.  (Remember, however, that this would not be the case if there was gut infarction that resulted from an overlapping cause).  In all patients, Auscultation of the abdomen may reveal a bruit. 

   Acute Mesenteric Ischemia - These patients usually present acutely, and are the highest risk of developing infarction of the bowel.  There are a variety of causes, but in all - patients have poor perfusion of the colon - usually at the area of the SMA

Embolic Disease: Common causes of this include atrial fibrillation, or a mural clot post myocardial infarction.This is sometimes seen after vascular surgery as well. Emesis is usually present.

Mesenteric Arterial Thrombosis: Usually causes by rupture of an atherosclerotic plaque. Patients present usually when precipitated by low-flow states.  These cases commonly develop gut infarction/necrosis rapidly. 

Non-occlusive disease: Hypotension from a variety of causes (MI, Sepsis, etc), vasopressors, cocaine and Digoxin

Workup of Acute Mesenteric Ischemia:  CBC (may have elevated white count, and usually hemoconcentration occurs), Amylase usually elevaed.  Can have a lactic acidosis. KUB (to rule out other causes) may have findings later in the disease course (especially c/w SBO). CT may be helpful, but mostly to rule out other causes of abdominal pain.  Diagnosis is usually done via angiography, which is currently preferred over MRA. 

Treatment of Acute Mesenteric Ischemia: This is an emergency, as it can rapidly progress to bowel infarction and gangrene   During angiography, thrombolytics can use used with ischemic disease.  Some may need angioplasty or stents afterwards if there is atherosclerotic disease.  Less emergent cases can be treated with Heparin or LMWH.  If there are any signs of infarction (peritonitis, acidosis, lactic acid up) - then emergent surgery is needed

Chronic Mesenteric Ischemia - Over 90% of patients with this have atherosclerotic disease as the cause.  They usually have more chronic symptoms, and although they rarely get gut infarction, they have a high risk of emboli/thrombosis which can lead to infarction.  Think of this as the cause of abdominal pain in a patient with risk factors for coronary artery disease (esp Smoking, DM, HTN, Dyslipidemia) and/or have a history of CAD/MI/CVA/PVD. 

Workup of Chronic Mesenteric Ischemia: Mostly done to rule out other causes (i.e. liver disease, pancreatitis, biliary disease, nephrolithiasis, etc).  Angiography is the gold standard for diagnosis.

Treament of Chronic Mesenteric Ischemia: Stenting of the SMA.  If this is not possible, endarterectomy or bypass can be performed

Mesenteric Venous Thrombosis -  Usually presents acutely, but can be chronic.  Causes by other things you would think of causing venous thrombosis - hypercoaguable states (esp Factor V Leidin, Protein C/S, PNH), pancreatitis, cirrhosis and sickle cell disease. 

Patients present very similarly to those with mesenteric ischemia - post-prandial abdominal pain, "fear of food" and weight loss. The exam is the same as well - essentially non-tender although the patient complains of a lot of pain.  Bruits are not usually heard. 

Workup: Rule out other causes of abdominal pain.  CT scan is the test of choice. Once imaging shows findings c/w a thrombosis - then workup the cause.

Treatment: Consists of heparin/LMWH then long-term coumading. Thrombolysis for emergent cases. Surgery is signs of infarction/peritonitis develop. 

Ischemic Colitis (aka Colonic Ischemia - confusing huh?)
These Patients have a non-occlusive cause of their disease. Unlike the above causes, which invariably affect the SMA, this disease usually affects the IMA.  Especially involved is the so called "watershed area" of the splenic flexure.  Any area distal from the splenic flexure, however, can be involved. 

There are multiple causes of this - mostly post-operative, low-flow states, hypercoaguable states, vasospastic drugs (cocaine), vasculitis and history of radiation exposure.   Embolism post MI or from Afib is RARELY the cause. 

These patients present very different from mesenteric ischemia.  The presentation is almost always acute, with pain on the left side of the abdomen.  These are the patients that present with a sequence including strong urge to defecate  then diarrhea without blood then diarrhea with blood.  Low grade fever may be present, as well as nausea and emesis.  They are usually very tender on physical exam.

Workup: KUB to r/o other causes, as well as labs to investigate pancreatitis, infectious causes, and other mimics.  Colonoscopy is diagnostic (will show mucosal hemorrhage). 

Treatment: Supportive care - fluids, NPO and antibiotics if severe.  Patients can progress to gangrene of the gut, and will need immediate surgical resection.