Temporal (or Giant Cell) Arteritis

What is it? A large vessel vasculitis of unknown etiology that affects the temporal artery and it's branches.

Why is it dangerous? It can lead to permanent blindness if not diagnosed and treated expeditiously.

Who gets it? People over the age of 50 (median age = 72), commonly of Northern European descent, and commonly with the HLA-DR4 haplotype. It is much more common in those with Polymyalgia Rheumatica.

What are the symptoms? Classically, this presents subacutely with a localised headache in the temporal region, jaw claudication ("I get a cramping pain when I chew my food"), decreasing visual acuity, or blindness in one or both eyes. Patients may also describe exquisite scalp tenderness ("It really hurts to comb my hair"). It is very closely associated with Polymyalgia Rheumatica - roughly 15% go on to develop temporal arteritis. These patients will typically describe an aching pain in the shoulders, hips, and neck.

What Do you see on Physical Exam? Patients will appear unwell. Feel the temporal artery for tenderness, enlargement, and to see if a pulse is indeed present. An ophthalmologic exam is warranted - looking for ischemic neuropathy (swollen disc +/- blurred margins).

Any pertinent diagnostic tests? By definition, the erythrocyte sedimentation rate (ESR) should be greater than 50 mm/hr, however it is usually over 100. A definitive diagnosis can be made via temporal artery biopsy. This is often a contentious issue for a few reasons (see review article below), and may be difficult to arrange expeditiously. Regardless, you should not delay treatment waiting for biopsy. Interestingly, ultrasonography of the temporal arteries may be helpful . See this NEJM article from 1997 for details.

What about treatment? Prednisone in high doses (like 1mg/kg) initially. Patients will need months and months of therapy with a slow taper guided by their symptoms. Remember bone protection while on steroids - Calcium, Vitamin D, and a Bisphosphonate.

A great review article here on Polymyalgia Rheumatica and Temporal Arteritis from the Annals of Internal Medicine.

Managment of Diabetic Ketoacidosis...a few tips

These patients can be very ill and need close observation - preferably in a step-up unit.

There are a few major principles:

1. Stability: patients will need close monitoring of vitals signs, electrolytes, and volume status

2. Volume: initial fluid resuscitation with normal saline. No need to be stingy here with the fluids...patients are litres (usually 6+) low.

3. Glucose: some give an initial small bolus of IV humulin R, others do not. Then IV insulin should be given at about 0.1 U/kg/hr. Follow the anion gap closely - do not stop IV insulin until the anion gap has normalized. If your patients glucose normalizes, you can add dextrose to the IV, but keep them on insulin to prevent ketone production

4. Lytes: Potassium should be watched very closely and replaced. The values may look normal (or even high), but this is from the shift of K into the extracellular compartment secondary to acidosis - there are actually very low total body stores of potassium. Also remember that potassium levels will drop precipitously when insulin is administered as it will shift back into cells. Hmmmm. A good idea is to add 20 meq/L of K to fluids if the serum potassium is between 3.3 - 5 mmol/L, and 40 meq/L if serum potassium is under 3.3 mmol/L. Don't forget about good 'ol sodium too. You may see artificially low levels secondary to the hyperglycemia.

5. Acidosis: Sometimes sodium bicarbonate is given in situations where the pH is low....like less than 7.

6. Precipitants: Ask yourself why this patient went into this state in the first place....See the blog entry from Sept 23, 2008

Here is a great article on the management of DKA and the Hyperosmolar Non-Ketotic State from the CMAJ.

Approach to Pancytopenia...and a bit about PNH

Pancytopenia: Think about general etiologies...

1. Medications/Toxins: methotrexate (folic acid antagonist), Septra, chemotherapeutic agents, NSAIDs benzene

2. Infections: Sepsis (any cause), HIV, Parvovirus B19, EBV

3. Malignancy: more common with Leukemia or Lymphoma

4. Bone Marrow replacement: think about fibrosis, solid tumors, or granulomatous diseases like TB

5. Nutrition: severe folate or B12 deficiency

6. Myelodysplastic syndromes

7.Autoimmune phenomena: eg. Lupus, Paroxysmal nocturnal hemoglobinuria

8.Radiation

Paroxysmal Nocturnal Hemoglobinurea is a rare, acquired condition manifested by intermittent hemolytic anemia, venous thrombosis, cytopenias, and recurrent bouts of hemoglobinurea (from hemolysis). There is a mutation in the PIG-A gene, resulting in complement being able to damage RBC surface proteins, causing the hemolysis. It can be diagnosed with Ham's test (yes...PIG, HAM...it's not a Kosher disease). More recently, PNH can be diagnosed via flow cytometry on peripheral blood. A great article Here.

Morning Report Tapas

HoPingKong-isms

1. "....Did you go camping this summer in a tent..." referring to tenting, or peaked T waves seen on ECG in hyperkalemia. Take a look at this article for more info on ST and T wave changes in various medical conditions.


2. "....Your ankle bone is connected to your knee bone..." referring to Ancylostoma duodenalis, one of two common species of hookworms that infect humans (the other being Necator americanus). This is very common cause of anemia worldwide with an estimated 800 million people infected. Yes, the adjacent picture is of a hungry hookworm. How can you be angry at a punim like that? (if you don't know what 'punim' is come find me).

3. "...Be quick, give me the answer in a flash..." referring to flash pulmonary edema as seen in mitral stenosis. this may also be associated with acute myocardial infarctions, aortic or mitral regurgitation, and renal artery stenosis.

4. "...Anybody here wearing pants, or are you wearing trousers..." referring to Trousseau's Syndrome, a migratory thrombophlebitis typically seen with underlying malignancies and an associated hypercoaguable state.

5. "...You're lagging behind me..." referring to the lid lag, often seen in Graves Disease. Other features of Graves disease include lid retraction, acropachy, and pretibial myxedema. A great review article on Graves Disease Here

6. "...Think about how you make muffins, bread, and bagels..." referring to baking - a Bakers cyst. This was in reference to creating a differential diagnosis for unilateral leg swelling: deep vein thrombosis, cellulitis, chronic venous insufficiency, Achillies tendon rupture or gastrocnemius muscle injury, ruptured bakers cysts, and lymphatic obstrction (with the example of Filariasis - Wuchereria bancrofti)

A word on Sodium Correction....

In patients who are truly hypo-osmolar and hypovolemic and have symptoms of hyponatremia and/or hypovolemia, a careful correction must be made. These patients must be in a closely supervised setting like an intensive care unit or step-up unit where frequent blood work and monitoring can occur. The rapid correction of sodium can be dangerous - leading to permanent neurologic deficits including central pontine myelinolysis - a spastic quadriplegia and pseudobulbar palsy resulting from pontine demyelination of corticospinal and corticobulbar tracts.

Normal saline can be used to correct hypovolemia in most cases: it will raise the plasma sodium a bit as well as it has 154 mEq of Na in it. Remember, we want to raise the sodium up to a level where patients are not seizing or at risk of seizing. We not targeting normal sodium levels here - essentially, we do not want to raise the serum sodium more than 8 mmol/L per day. Hypovolemic patients will have a lot of ADH released - sucking up every drop of water through the cortical collecting ducts. When volume is restored, the stimulus for ADH will be turned off and patients may start to diurese. This can cause an unintentional and overly rapid correction of serum sodium and can lead to neurologic injury. We can be prevent this overly rapid correction by giving DDAVP (desmopressin, a synthetic version of ADH) back to the patient.

Finally, if patients are profoundly hyponatremic and symtomatic, hypertonic (3%) saline can be administered in emergency situations. This is usually done in an acute setting to stop or prevent seizure activity. Again, these patients will need very close monitoring of their neurologic status and electrolytes - and this is best done in an intensive care unit.

This equation can be used to predict the rise in sodium based on the fluids being administered:

Increase in PNa = (Infusate [Na] - PNa) ÷ (Total Body Water + 1)

(TBW is the estimated by: lean body weight times 0.5 for women, or 0.6 for men)

A great review article HERE

Pericarditis

Clinical presentation: usually a sudden onset of retrosternal chest pain with a pleuritic component to it, often relieved by sitting up. You may hear a pericardial rub - this is classically described as a triphasic, high-pitched sound. The 'tri' refers to 1. atrial systole, 2. ventricular systole, and 3. ventricular diastole. It may be a transient phenomenon so listen again if you don't hear it.

ECG: may show diffuse, concave ST elevations that do not fit any particular vascular territory. PR depression is also seen. Check out the ECG above.

Treatment: In most cases of idiopathic pericarditis, high dose NSAIDS are effective. Steroids and colchicine also may have a role. Interestingly, newer evidence suggests that colchicine may be a good first line agent (http://www.circ.ahajournals.org/cgi/content/full/112/13/2012).

A great review article: http://content.nejm.org/cgi/content/full/351/21/2195

Acute Pancreatitis

The mainstays of treating pancreatitis includes identifying an underlying cause and correcting it (eg. gallstone, hypertriglyceridemia, hypercalcemia, etc.), pain control and fluid resuscitation. Other issues that should be considered are feeding status and preventing infection.

1. Infection: patients are prone to infection by translocation of gut organisms if pancreatic necrosis is present. There is debate in the literature whether prophylactic antibiotics are indicated, and this uncertainty is reflected in guidelines from gastroenterology societies - one recommends it, one does not. Take a look at this Cochrane review and decide for yourself: http://www.cochrane.org/reviews/en/ab002941.html

2. Feeding: The classic teaching was that we do not feed our patients with acute pancreatitis. Newer evidence suggests that early oral feeding is alright if the patient can tolerate it. (http://www.ncbi.nlm.nih.gov/sites/entrez)

Here is a good review article touching on most of these topics: http://content.nejm.org/cgi/content/full/354/20/2142

Stigmata of Liver Disease

HoPingKong-isms:

1. "...does the patient live near the liberty bell?..." referring to the Philadelphia chromosome and the bcr-abl gene in CML.

2. "...this thing is hidden...it's like crypton..." referring to cryptogenic cirrhosis.

3. "...I'm getting colder and colder...and I'm constipated..." referring to hypothyroidism as a rare cause of rhabdomyolysis.

Stigmata of Liver disease:

1) Liver failure
a. Encephalopathy
b. Asterixis
c. Jaundice / icterus of sclera or frenulum
d. Fetor hepaticus
e. Bruising
f. Muscle wasting (Temporalis muscle, interosseous muscles)
g. Clubbing

2) Causes of cirrhosis
a. Duputryen’s contracture (alcohol)
b. Track marks (IV drug use)
c. Keiser Fleischer rings (Wilson’s disease)
d. "Bronzed" complexion of skin (hemachromatosis)

3) High estrogen state
a. Palmar erythema
b. Spider Nevi
c. Gynacomastia
d. Pectoral allopecia and feminization of body hair
e. Testicular atrophy

4) Portal Hypertension
a. Pedal Edema and ascites
b. Distended abdominal veins
c. Caput medusae
d. Splenomegaly

spider angiomas, Dupuytren's contracture, and palmar erythema seen below...

Approach to the Confused Patient

An approach to the confused patient...think about 4 major categories.

1. Drugs/Toxins: make sure you ask about both prescribed and non-prescribed drugs - like herbal supplements, traditional medications, and street drugs

2. Infection: think about common sites - like urinary tract, pneumonia, intra-abdominal, and endovascular sources of infection. Also consider less common areas like meningitis and cerebritis.

3. Metabolic: "pick an organ and make it fail". Common things include hyper/hyponatremia, hyper/hypoglycemia, hypercalcemia, hepatic or uremic encephalopathy, hyper/hypothyroidism, hypercarbia or hypoxia, etc.

4. Structural: think big, like heart (eg. myocardial infarction), gut (eg. ischemia, obstruction), brain (eg. mass, infarct), muscle (eg. rhabdo), lung (eg. pulmonary embolus), etc.

Necrotising Fasciitis

Necrotising Fasciitis is a rapidly progressing soft tissue infection of the underlying fascia and fat. Organisms involved are either Group A beta-hemolytic streptococcus (Streptococcus pyogenes), or polymicrobial infections. The polymicrobial variety is more commonly found in patients with diabetes or in the post operative period. It is crucial to recognise these infections early as there is rapid tissue destruction. Severe pain, rapidly progressing erythema, and hemorrhagic bullae may be seen. About 10% of cases have crepitus. Patients commonly have fever, hypotension, and tachycardia and appear septic - sometimes out of proportion to their skin findings. CT and MRI are both very helpful visualizing gas along the fascial planes...however it is likely way easier to get a CT scan expeditiously.

Treatment revolves around a few principles. Most importantly, our surgical colleagues should get involved as early as possible as infected tissue must be debrided. Antibiotics should include a Beta-lactam with a beta-lactamase-inhibitor and Clindamycin. If a polymicrobial infection is suspected, it would be prudent to add metronidazole and better gram negative coverage.Clindamycin is kind of neat as it may be helpful not only by killing bacteria, but also by turning off the toxin-producing machinery of these bacteria. Interestingly, Intravenous Immunoglubulin therapy may be useful in necrotising fasciitis secondary to S. pyogenes infection.

Here is a great article guiding the reader how to approach a case:

http://content.nejm.org/cgi/content/full/347/11/831

Here is an article from Toronto looking at the evidence for IVIG: http://www.journals.uchicago.edu/doi/pdf/10.1086/515199