ABIM Exam Prep: How to Work Up a Thyroid Nodule

Interacting with residents studying for the ABIM Internal Medicine board exam, I have found that one of the topics folks often find frustrating to master is working up a thyroid nodule. Dealing with a thyroid nodule can be intimidating initially but following a systematic algorithm makes it very simple. Thyroid nodules can be detected either on palpation during the physical examination or incidentally when imaging is performed. Some of the most common imaging studies that can detect a thyroid nodule are: carotid ultrasonography, CT scan of the neck, or PET scan.

The cancer risk for a thyroid nodule is 5-10%. Some risk factors for cancer associated with thyroid nodules include:

• Age less than 20 or greater than 60 years
• Family history of thyroid cancer
• Head or neck irradiation therapy

The initial workup of a thyroid nodule, whether discovered via physical exam or incidentally, is to check a TSH level. If a TSH level is normal or elevated, the next step is to check a thyroid ultrasound.

A thyroid ultrasound yields important information such as accurate detection and sizing of all nodules of the thyroid gland. It will also help determine if a thyroid nodule is expected to be benign or malignant. If the thyroid nodule has a risk of being malignant, then ultrasound guided fine needle aspiration needs to be performed.

Ultrasonography characteristics of thyroid nodules that suggest the possibility of malignancy include:

• Micro-calcification or speckled calcification within the nodule
• Increased central nodule vascularity
• Hypo-echogenicity
• Irregular border
• Nodule greater than 3cm in size

These ultrasound characteristics warrant a fine needle aspiration to determine if a patient does indeed have underlying thyroid cancer.

If the fine needle aspiration (FNA) is benign, then serial follow up is necessary.

If the FNA yields indeterminate results, then a repeat ultrasound guided FNA is warranted.

If FNA shows follicular neoplasm or suspicion for malignancy, surgical intervention is required.

In the context of a suppressed TSH, a thyroid scan and radioactive iodine uptake (RAIU) scan are the next appropriate diagnostic tests to perform.

These tests determine what portion of the thyroid gland is taking up radioactive tracer. Many times, a toxic nodule or multi-nodular goiter may be present. Uptake of radioactive tracer identifies the nodule as “hot” or hyper-functioning or “cold” and hypo-functioning.

Hot nodules rarely harbor a malignancy potential as these nodules have less than one percent of being malignant.

Cold nodules, on the other hand, are non-functioning as they do not take up the radioactive tracer and harbor a greater chance of malignancy. Therefore, these nodules require fine needle aspiration to determine if they are malignant or not.

This is a general approach to working up thyroid nodules, as relevant for your preparation for the ABIM Internal Medicine board exam.

10 High Yield Nephrology Pearls for Clinical Practice and the ABIM Board Exam (Part 2 of 2)

As discussed in part one, I have decided to take an article I recently tweeted out and summarize it here high yield nephrology pearls for clinical practice and ABIM Internal Medicine board exam preparation. The article was titled “The Top 10 Things Nephrologists Wish Every Primary Care Physician Knew” by Paige NM et al. The first 5 pearls were already discussed inpart one; in part two, I’ll discuss the final 5 pearls:

6. Anemia in Patients With CKD Should be Treated, but not Overtreated

• Anemia of Chronic Disease can lead to fatigue, left ventricular hypertrophy, and increased risk of cardiovascular events
• Hemoglobin target for CKD should be between 11 – 12 g/dL NOT to exceed 13g/dL
• Overcorrection of hemoglobin can result in higher risk of stroke, thrombosis, and hypertension
• Correct all other reversible causes of anemia

7. Phosphate-Containing Bowel Preps Should be Used With Caution

• Sodium phosphate bowel preparations are more convenient than some other preps (Easier to use)
• However, some studies have suggested that they can cause phosphate nephropathy leading to AKI or worsening CKD
• Instead use polyethylene glycol for the bowel prep (only downside is the volume that has to be consumed; Does not cause volume or electrolyte shifts)

8. Patients With Severe CKD Should Avoid Magnesium- or Aluminum-Containing Preparations

• These include over-the-counter agents such as Maalox and Mylanta
• Use of these agents can lead to hypermagnesemia, acute aluminum toxicity, worsening renal function, bone disease, and neurotoxicity
• The preferred quantitative test is spot urine protein to creatinine ratio (accurate & more convenient than 24-hr urine collection)
• A urine protein to creatinine ratio ≥ 1 has a higher risk of progression of CKD

9.Most Patients With Hypertension Should NOT Be Screened for Secondary Hypertension, But be Aware of Certain Clinical Clues

• In general 95% of patients have primary or essential hypertension, and only 5% have a secondary cause
• Clues include: Severe or difficult to control HTN, HTN that suddenly develops, or HTN that is associated with other clinical findings are some clues
• Hypokalemia: Consider primary hyperaldosteronism
• Headaches, palpitations, and sweats: Consider Pheochromocytoma
• Moon facies and/or striae: Consider Cushing Syndrome
• History of snoring in obese patient: Consider Obstructive Sleep Apnea
• Bruit on one side of the abdomen: Consider Renal Artery Stenosis
• Over-the-counter medications (NSAIDs, Birth Control Pills, or Decongestants)
• Non-compliance with Diet (High Sodium Intake)

10. Recurrent Nephrolithiasis, Needs a Metabolic Evaluation to Identify and Treat Modifiable Risk Factors

• Nephrolithiasis recurrence over a 10 year period for calcium oxalate stones is about 50% without treatment
• Family History of nephrolithiasis, inflammatory bowel disease, frequent urinary tract infections, or history of nephrocalcinosis should be referred to a nephrologist
• Initial workup should start with: diet history, medications, serum calcium, phosphorous, electrolytes and uric acid

Bonus: Cyclosporine and Tacrolimus (Calcineurin Inhibitors) Have Many Drug-Drug Interactions

• Any new medication or supplement that a post-kidney transplant patient requests should be reviewed first before prescribing
• St. John’s Wort, rifampin, phenytoin, and carbamazepine can all lower cyclosporine levels
• Diltiazem, verapamil, and erythromycin can increase cyclosporine levels
• Cyclosporine can interfere with certain statins such as simvastatin, increasing the risk of statin-induced rhabdomyolysis

Hopefully, between the two posts, you gained some high yield pearls for the management of your patients with chronic kidney disease. I’d also enjoy hearing from any nephrologists who read these posts, to get your comments and add any additional pearls of wisdom that general practitioners could use in their day-to-day practice as well as ABIM Internal Medicine exam certification/re-certification preparation.

References:

1. Markowitz GS et al. Acute Phosphate Nephropathy Following Oral Sodium Phosphate Bowel Purgative: An Underrecognized Cause of Chronic Renal Failure. J Am Soc Nephrol. 2005 Nov. 16 (11): 3389 – 3396. PMID: 16192415

2. Paige NM et al. The Top 10 Things Nephrologists Wish Every Primary Care Physician Knew. May Clin Proc. 2009 Feb; 84 (2): 180 – 186. PMID: 19181652

3. Phrommintidul A et al. Mortality and Target Haemoglobin Concentrations in Anaemic Patients With Chronic Kidney Disease Treated With Erythropoietin: A Meta-Analysis. Lancet 2007; 369 (9559): 381 – 388. PMID: 17276778

10 High Yield Nephrology Pearls for Clinical Practice and the ABIM Board Exam (Part 1 of 2)

Recently, I read an article on some very useful chronic kidney disease (CKD) pearls to help those healthcare providers who are not nephrologists care for their patients and also prepare for the ABIM Internal Medicine Board exam at the same time. The article was titled “The Top 10 Things Nephrologists Wish Every Primary Care Physician Knew” by Paige NM et al and basically stated: early recognition of kidney disease is essential in order to begin measures to prevent progression and complications such as kidney failure, cardiovascular disease, and premature death. I have decided to break the content into two parts; the first half will be discussed in this post:

1. A “Normal” Creatinine Level May Not Be Normal

• Make sure to take muscle mass, age, sex, height, and limb amputation into account
• Consider using MDRD or Cockcroft-Gault equations to calculate glomerular filtration rate (GFR)
• MDRD and Cockcroft-Gault equations are imprecise at high values for GFR (low values for serum creatinine)

2. Know the Medications That Falsely Elevate Serum Creatinine Levels

• Trimethoprim-sulfamethoxazole and cimetidine decrease secretion of creatinine
• Both medications can increase creatinine level by as much as 0.4 – 0.5mg/dL
• An increase in creatinine level is a true decrease in GFR only if there is also a corresponding increase in BUN

3. Patients with Decreased GFR or Proteinuria Need to be Evaluated for the Cause

• Urine dipstick detects concentration of albumin in urine
• Urine concentration can affect dipstick results therefore a quantitative estimation of proteinuria is required to evaluate dipstick proteinuria
• The preferred quantitative test is spot urine protein to creatinine ratio (accurate & more convenient than 24-hr urine collection)
• A urine protein to creatinine ratio ≥ 1 has a higher risk of progression of CKD

4. Early-Stage CKD Should Have Periodic Evaluation and Intervention to Slow Progression

• Try and avoid nephrotoxic agents (NSAIDs, aminoglycoside antibiotics, and radiocontrast)
• Monitor and control blood pressure with a goal of <130/80 mmHg
• Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) may slow progression of CKD, especially in patients with proteinuria
• Monitor phosphorous, calcium, and parathyroid hormone levels in all patients with stage 3 to 4 CKD
• Patients with CKD are at higher risk of cardiovascular events and should be on a baby aspirin, and a lipid lowering agent with goal LDL <100mg/dL (Maybe <70mg/dL for LDL in patients with CAD and CKD)
• Consider referral and co-management with a nephrologist if a patient has CKD progression, active urine sediment and/or stage 3 CKD
• ALL patients with Stage 4 – 5 CKD should be referred to a nephrologist

5. DO NOT Discontinue an ACEI or ARB Because of a Small Increase in Serum Creatinine or Potassium

• Both ACEIs and ARBs are the drugs of choice to prevent progression of proteinuric CKD
• An increase of 20 to 30% of the creatinine level is acceptable
• Just make sure to confirm the creatinine stabilizes and does not continue to increase
• Also a serum potassium of 5.5 mEq/L is acceptable as long as it is stable and as long as the patient is aware of dietary restrictions
• Serum creatinine and potassium levels should be ordered within one week of increase in dose of ACEI or ARB
• If a patient has an increase in creatinine from 1.5 to 1.9 (<30% increase) CONTINUE THE ACEI
• If the same patient has an increase in creatinine from 1.5 to 2.2 (>30% increase) STOP THE ACEI

As chronic kidney disease is increasing world wide, we as primary care practitioners need to make sure we are doing our part to help catch this disease process early, slow down progression, and make referrals when necessary to nephrology. Stay tuned for Part 2 of this series, hopefully this provides some useful clinical pearls for your practice as well as ABIM Internal Medicine exam certification or re-certification preparation.

References:

1. Bakris GL et al. Angiotensin-Converting Enzyme Inhibitor-Associated Elevations in Serum Creatinine: Is this a Cause for Concern? Arch Intern Med. 2000; 160 (5): 685 – 693. PMID: 10724055

2. Douglas K et al. Meta-analysis: The Effect of Statins on Albuminuria. Ann Intern Med. 2006; 145 (2): 117 – 124. PMID: 16847294

3. Levey AS et al. Definition and Classification of Chronic Kidney Disease: A Position Statement from Kidney Disease: Improvemeng Global Outcomes (KDIGO). Kidney Int. 2005; 67 (6): 2089 – 2100. PMID: 15882252

4. Paige NM et al. The Top 10 Things Nephrologists Wish Every Primary Care Physician Knew. May Clin Proc. 2009 Feb; 84 (2): 180 – 186. PMID: 19181652

Internal Medicine ABIM Board Exam Style Question

e’s a practice question directly from Knowmedge’s Internal Medicine Board (ABIM) Exam QVault.

In which of the following scenarios is it appropriate to allow outpatient treatment of community-acquired pneumonia (CAP)?

A. 67-year-old male with CAP, blood pressure of 120/85mmHg, and confusion

B. 68-year old male with CAP, blood pressure of 130/80mmHg, and respiratory rate of 18/min

C. 69-year old female with CAP, blood pressure of 125/82mmHg, and creatinine of 2.1mg/dL (Baseline is 0.8mg/dL)

D. 58-year old female with CAP, blood pressure of 100/50mmHg, and confusion

E. 32-year-old female with CAP, blood pressure of 90/50mmHg, altered mental status, and respiratory rate 34/min

Explanation

After diagnosing a patient with community-acquired pneumonia, we must determine whether the patient needs to be hospitalized or not. In order to facilitate this decision, the CURB-65 guidelines can be used. CURB stands for:

● C – Confusion (altered mental status) 
● U – Uremia
● R – Respiratory rate greater than 30/minute 
● B – Blood pressure that is low (Systolic <90mmHg or Diastolic <60mmHg) 
● 65 – Age 65 years or greater

Each category is assigned 1 point

● 0-1 points total means the patient can be treated as an outpatient 
● 2 points total requirements treatment in the medical ward 
● 3 or more points requires ICU admission

Let’s go over the answer choices:

● Choice A (67-year-old male with CAP, blood pressure of 120/85mmHg, and confusion) has 2 points (age greater than 65 and confusion) and should require admission to the medical ward.

● Choice B (68-year-old male with CAP, blood pressure of 130/80mmHg, and respiratory rate of 18/min) will be the scenario that will require outpatient therapy. This patient only has one point (age greater than 65) so he can be treated for CAP as an outpatient.

● Choice C (69-year old female with CAP, blood pressure of 125/82mmHg, and creatinine of 2.1mg/dL) has 2 points (age greater than 65 and compromised renal function) which means admission to medical ward is most appropriate. 

● Choice D (58-year old female with CAP, blood pressure of 100/50mmHg and some confusion) has 2 points (low blood pressure and confusion). Even though this patient has 2 points, this patient may require ICU admission because the patient may be septic. For such scenarios, the CURB score simply serves a guideline but the clinical picture plays a bigger role in deciding where the patient will receive the most appropriate care. 

● Choice E (32-year-old female with CAP, blood pressure of 90/50mmHg, altered mental status, and respiratory rate 34/min) has 3 points (altered mental status, respiratory rate greater than 30/min and low blood pressure) that will require the patient to go to the ICU.

You can see all the previous ABIM Exam Review Questions of the Week at the Knowmedge Blog. You can also find additional topics and questions directly from the Knowmedge Internal Medicine ABIM Board Exam Review Questions QVault.

The Knowmedge free study guide contains 50 high-yield questions selected from the Knowmedge QVault to help you prepare for the Internal Medicine Board (ABIM) exam.

Enrich your ABIM exam prep and build your Knowmedge! Download your copy of the Internal Medicine Practice Questions eBook below!

Knowmedge Internal Medicine Practice Questions by Knowmedge

ABIM Exam Review: Bacterial vs. Viral Meningitis

Overview of Bacterial vs. Viral Meningitis. This is an important topic in general and good to understand for the Internal Medicine ABIM Board Exam. Source: http://www.knowmedge.com