acute radiation proctitis

Q; 38 year old female is admitted to oncology ICU for observation after her pelvic radiation session due to pelvic pain. Which of the following is unlikely for acute radiation proctitis? (select one)

A) diarrhea

B) mucus discharge

C) urgency

D) tenesmus

E) rectal bleeding

Answer: E

Rectal bleeding is rare in acute radiation proctitis. The most likely symptoms are abdominal or pelvic pain, diarrhea, mucus discharge, urgency, and tenesmus. 

Formaldehyde 4%–10% is the treatment of choice to apply over the mucosa of affected areas under direct vision via proctoscopy. Hyperbaric oxygen has also been described. In severe cases surgical intervention may be needed.

References:

1. Isenberg GA, Goldstein SD, Resnik AM. Formalin therapy for radiation proctitis. JAMA. 1994 Dec 21;272(23):1822

2. Oscarsson N, Arnell P, Lodding P, Ricksten SE, Seeman-Lodding H. Hyperbaric oxygen treatment in radiation-induced cystitis and proctitis: a prospective cohort study on patient-perceived quality of recovery. Int J Radiat Oncol Biol Phys. 2013 Nov 15;87(4):670-5

3. Jao SW, Beart RW, Gunderson LL. Surgical treatment of radiation injuries of the colon and rectum. Am J Surg. 1986 Feb;151(2):272-7

4. Dahiya DS, Kichloo A, Tuma F, Albosta M, Wani F. Radiation Proctitis and Management Strategies. Clin Endosc. 2022 Jan;55(1):22-32. doi: 10.5946/ce.2020.288. Epub 2021 Nov 18. PMID: 34788934; PMCID: PMC8831406.

CAPS

Q: Which of the following has the highest risk factor for Catastrophic antiphospholipid syndrome (CAPS)? (select one)

A) Sepsis

B) Cancer

C) Estrogen 

D) Pregnancy/postpartum 

E) Active systemic lupus erythematosus (SLE)

Answer: A

Many patients with antiphospholipid antibodies present CAPS as an initial symptom. The most inciting trigger event is known to be an infection. Interestingly the lowest risk factor is with SLE. In descending order, the risk factors are:

• Infection
• Surgery
• Cancer 
• Estrogen
• Pregnancy 
• Active systemic lupus erythematosus (SLE) 

#rheumatology

References:

1. Cervera R, Rodríguez-Pintó I, Legault K, Erkan D. 16th International Congress on Antiphospholipid Antibodies Task Force Report on Catastrophic Antiphospholipid Syndrome. Lupus 2020; 29:1594.

2. Bayraktar UD, Erkan D, Bucciarelli S, et al. The clinical spectrum of catastrophic antiphospholipid syndrome in the absence and presence of lupus. J Rheumatol 2007; 34:346.

aminoglycosides in burn patients

Q: Burn patients when receiving aminoglycosides, may require ___________ maintenance dose? (select one)

A) higher

B) lower

Answer: A

Gentamicin and Tobramycin are frequently used in ICUs. Burn patients have larger volumes of distribution, and may require up to 7 to 8 mg/kg per day to attain therapeutic serum concentrations. These are usually given in divided doses. 

Clinically this is of importance as serum concentration monitoring and individualized dosing highly correlates with survival in burn patients.

#pharmacology

References:

1. Zaske DE. Aminoglycosides. In: Applied Pharmacokinetics, 3rd Ed, William EE, Schentag EJ, Jusko WJ (Eds), Applied Therapeutics Inc, Vancouver, WA 1994.

2. Hollingsed TC, Harper DJ, Jennings JP, Morris SE, Saffle JR. Aminoglycoside dosing in burn patients using first-dose pharmacokinetics. J Trauma. 1993 Sep;35(3):394-8. PMID: 8371297.

Primary Hemochromatosis and Diabetes Mellitus

Q: What are the components of the triad of "bronze diabetes"?

Answer: Skin hyperpigmentation occurs in patients with iron overload due to the combination of iron deposition and melanin. The classic triad of bronze diabetes is

• skin pigmentation
• cirrhosis
• diabetes

Skin hyperpigmentation usually occurs when total-body iron content reaches around 20 grams.

#endocrinology

#elements-overdose

References:

1. L N A, Shenoy MT, Yadav C, M S R, Kamath N. Bronze diabetes. J Clin Diagn Res. 2015 Apr;9(4):BD01-2. doi: 10.7860/JCDR/2015/11515.5799. Epub 2015 Apr 1. PMID: 26023548; PMCID: PMC4437060.

2. Raju K, Venkataramappa SM. Primary Hemochromatosis Presenting as Type 2 Diabetes Mellitus: A Case Report with Review of Literature. Int J Appl Basic Med Res. 2018 Jan-Mar;8(1):57-60. doi: 10.4103/ijabmr.IJABMR_402_16. PMID: 29552540; PMCID: PMC5846224.

rT3

Q: Reverse T3 is an __________ metabolite of thyroxine? (select one)

A) active

B) inactive

Answer: B

Reverse T3 (rT3) is an inactive metabolite of thyroxine. Although it has limited utility in conventional outpatient practice but in ICU it helps in distinguishing central hypothyroidism from nonthyroidal illness.

It is also used in the diagnosis of consumptive hypothyroidism, and MCT8 or SBP2 mutations.

#endocrinology

References:

Schmidt RL, LoPresti JS, McDermott MT, et al. Does Reverse Triiodothyronine Testing Have Clinical Utility? An Analysis of Practice Variation Based on Order Data from a National Reference Laboratory. Thyroid 2018; 28:842.

inhaled glucocorticoids

Q: 80% of inhaled glucocorticoids are swallowed?

A) True

B) False

Answer: A

The bioavailability of inhaled glucocorticoids largely depends on the technique and on its lipophilic characteristic. Only 20% of inhaled glucocorticoids get deposited in the lungs. If the compound is lipophilic, though it gets retained longer in the lungs but is poorly absorbed from the enteral route.

The overall absorption of inhaled glucocorticoids is 20 to 40 percent.

#pharmacology

Reference:

Johnson M. Pharmacodynamics and pharmacokinetics of inhaled glucocorticoids. J Allergy Clin Immunol 1996; 97:169.

Potassium in Alcoholic ketoacidosis

Q: Alcoholic ketoacidosis results in? (select one)

A) hyperkalemia

B) hypokalemia

Answer: B

Unlike other conditions which produce hyperkalemia in metabolic acidosis, alcoholic ketoacidosis mostly results in hypokalemia. There are four major reasons for it.

1. Gastrointestinal loss due to vomiting or diarrhea.

2. Urinary losses due to excretion of potassium salts of ketone anions (beta-hydroxybutyrate and acetoacetate) 

3. Poor nutrition and reduced oral potassium intake.

4. In contrast to other conditions with metabolic acidosis, alcoholic ketoacidosis does not results in much potassium redistribution between intra and extracellular space.

#electrolyte

#acid-base balance

References:

1. Noor NM, Basavaraju K, Sharpstone D. Alcoholic ketoacidosis: a case report and review of the literature. Oxf Med Case Reports. 2016 Mar 3;2016(3):31-3. doi: 10.1093/omcr/omw006. PMID: 26949539; PMCID: PMC4776050.

2. McGuire LC, Cruickshank AM, Munro PT. Alcoholic ketoacidosis. Emerg Med J. 2006 Jun;23(6):417-20. doi: 10.1136/emj.2004.017590. PMID: 16714496; PMCID: PMC2564331.

Vertical transmission of HCV

Case: 24 years old female with known history of Hepatitis C (HCV) and HIV is in ICU. She is 37 weeks pregnant. Ob-Gyn service asked your opinion about vertical transmission of HCV if patient requires to go to OR?

Answer: Some of the well-known factors in the vertical transmission of HCV in a pregnant patients are:

• HCV viremia
• HIV coinfection
• Maternal intravenous drug use
• Peripheral blood mononuclear cell infection 
• Invasive prenatal testing
• Prolonged rupture of membranes, and
• Invasive obstetric procedures

Any increase in the risk of exposure of the fetus to maternal blood may increase the risk of transmission.

#ob-gyn

#ID

References:

1. Ades AE, Gordon F, Scott K, Collins IJ, Claire T, Pembrey L, Chappell E, Mariné-Barjoan E, Butler K, Indolfi G, Gibb DM, Judd A. Overall Vertical Transmission of Hepatitis C Virus, Transmission Net of Clearance, and Timing of Transmission. Clin Infect Dis. 2023 Mar 4;76(5):905-912. doi: 10.1093/cid/ciac270. PMID: 35403676; PMCID: PMC9989130.

2. Fauteux-Daniel S, Larouche A, Calderon V, Boulais J, Béland C, Ransy DG, Boucher M, Lamarre V, Lapointe N, Boucoiran I, Le Campion A, Soudeyns H. Vertical Transmission of Hepatitis C Virus: Variable Transmission Bottleneck and Evidence of Midgestation In Utero Infection. J Virol. 2017 Nov 14;91(23):e01372-17. doi: 10.1128/JVI.01372-17. PMID: 28931691; PMCID: PMC5686730.

lab in thyroid storm

Q: Which is more common in thyroid storm?

A) hypercalcemia

B) hypocalcemia

Answer: A

The usual lab findings in thyroid storm are:

• low TSH 
• high free T4 and/or T3 
• mild hyperglycemia 
• mild hypercalcemia 
• deranged liver function test
• either leukocytosis or leukopenia

#endocrinology

Reference:

Nayak B, Burman K. Thyrotoxicosis and thyroid storm. Endocrinol Metab Clin North Am 2006; 35:663.

COVID and bacterial pneumonia

Q: Hospitalized patients with COVID-19 are highly prone to develop secondary bacterial pneumonia?

A) True

B) False

Answer: B

Contrary to popular belief, patients with known COVID-19 are not very prone to develop secondary bacterial pneumonia. There is no need to start empiric antibiotics. Only 1 in 5 patients develop superimposed bacterial pneumonia in selected patients.

In patients with uncertain COVID-19 infection, it may be prudent to start empiric antibiotics but should be quickly curtailed at the confirmation of the diagnosis unless doubts persist. Although positive procalcitonin is well-known in COVID patients, it carries a good value if it turns out to be low or negative.

#ID

#COVID

References:

1. Wang D, Hu B, Hu C, et al. Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China. JAMA 2020; 323:1061.

2. Zhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet 2020; 395:1054.

IV insulin-D5 in hyperkalemia

Q: How intravenous (IV) insulin and IV 5%-dextrose works in hyperkalemia?

Answer: Although it is true that insulin is administrated with dextrose in the treatment of hyperkalemia to avoid hypoglycemia, there is another vital reason to do it.

Dextrose and insulin works synergistically in hyperkalemia. IV 5% dextrose in water stimulates endogenous insulin, which along with IV insulin drives extracellular potassium into cells.

Dextrose infusion should precede the insulin bolus.

#electrolytes

#endocrinology

References:

Moussavi K, Fitter S, Gabrielson SW, Koyfman A, Long B. Management of Hyperkalemia With Insulin and Glucose: Pearls for the Emergency Clinician. J Emerg Med. 2019 Jul;57(1):36-42. doi: 10.1016/j.jemermed.2019.03.043. Epub 2019 May 11. PMID: 31084947.

Crnobrnja L, Metlapalli M, Jiang C, Govinna M, Lim AKH. The Association of Insulin-dextrose Treatment with Hypoglycemia in Patients with Hyperkalemia. Sci Rep. 2020 Dec 16;10(1):22044. doi: 10.1038/s41598-020-79180-7. PMID: 33328554; PMCID: PMC7745028.

Ljutić D, Rumboldt Z. Should glucose be administered before, with, or after insulin, in the management of hyperkalemia? Ren Fail. 1993;15(1):73-6. doi: 10.3109/08860229309065576. PMID: 8441841.

Disulfiram use in substance abuse

Q;  44 years old male with history of alcohol (ETOH) and cocaine abuse disorder is admitted to ICU with hypertensive crisis. Patient is now recovering in ICU. In the morning multi-disciplinary round, Disulfiram has been suggested to be added in his med profile before transfer to floor. Disulfiram can be used in the treatment of which disorder? (select one)

A) ETOH

B) Cocaine 

C) Both

Answer: C

Disulfiram is well known to have efficacy in ETOH abuse. It also has some promising potential in the treatment of cocaine use disorder. Disulfiram affects the cocaine use by decreasing the reinforcing properties of cocaine. It makes the use of cocaine aversive. 

Disulfiram works via two mechanisms:

1. It blocks the degradation of cocaine by plasma esterases. This leads to extremely high cocaine levels.

 

2. It blocks the conversion of dopamine to norepinephrine by the enzyme dopamine beta-hydroxylase. This alters the dopamine/norepinephrine balance in neurons.

These effects enhance the likelihood of cocaine abstinence.

Moreover, when disulfiram is combined with naltrexone, it provides better-sustained abstinence from both cocaine and alcohol. The recommended dose for disulfiram is 250 mg daily and for naltrexone is 100 mg daily.

#toxicology

References:

1. McCance-Katz EF, Kosten TR, Jatlow P. Disulfiram effects on acute cocaine administration. Drug Alcohol Depend 1998; 52:27.

2. Hameedi FA, Rosen MI, McCance-Katz EF, et al. Behavioral, physiological, and pharmacological interaction of cocaine and disulfiram in humans. Biol Psychiatry 1995; 37:560.

3. Carroll KM, Nich C, Ball SA, et al. Treatment of cocaine and alcohol dependence with psychotherapy and disulfiram. Addiction 1998; 93:713.

4. Pettinati HM, Kampman KM, Lynch KG, et al. A double blind, placebo-controlled trial that combines disulfiram and naltrexone for treating co-occurring cocaine and alcohol dependence. Addict Behav 2008; 33:651.

capgras synfrome

Q: 84 years old male recovering from pneumonia in ICU consistently complains of imposters in the room while family members are there. What's the diagnosis?

Answer: Capgras syndrome

Paranoid delusions are common in patients with baseline dementia or Alzheimer's disease (AD). Common paranoid delusions include intruders in the house, stolen personal objects, spouse's unfaithfulness, or Capgras syndrome.

Capgras syndrome, named after the French psychiatrist, is the belief that impostors have replaced family members.

#psychiatry

References:

1. Shah K, Jain SB, Wadhwa R. Capgras Syndrome. [Updated 2022 Jun 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK570557/

2. Barrelle A, Luauté JP. Capgras Syndrome and Other Delusional Misidentification Syndromes. Front Neurol Neurosci. 2018;42:35-43. doi: 10.1159/000475680. Epub 2017 Nov 17. PMID: 29151089.

hypothermia in severe hypothyroidism

Q: The severity of hypothermia is directly related to mortality in severe hypothyroidism?

A) True

B) False

Answer: A

The severity of hypothermia is related to mortality in severe hypothyroidism; the lower the body temperature, more likely the mortality. It is important to note that hypothermia may not be recognized initially. One of the reasons is that many automatic thermometers do not register frankly hypothermic body temperatures. Extreme care should be taken to accurately gauge the temperature in Myxedema coma.

#endocrinology

References:

1. Wiersinga WM. Myxedema and Coma (Severe Hypothyroidism) [Updated 2018 Apr 25]. In: Feingold KR, Anawalt B, Blackman MR, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279007/

2. Acharya R, Cheng C, Bourgeois M, Masoud J, McCray E. Myxedema Coma: A Forgotten Medical Emergency With a Precipitous Onset. Cureus. 2020 Sep 16;12(9):e10478. doi: 10.7759/cureus.10478. PMID: 33083180; PMCID: PMC7567317.

3. Kogan A, Kassif Y, Shadel M, Shwarz Y, Lavee J, Or J, Raanani E. Severe hypothermia in myxoedema coma: a rewarming by extracorporeal circulation. Emerg Med Australas. 2011 Dec;23(6):773-5. doi: 10.1111/j.1742-6723.2011.01460.x. PMID: 22151678.

Irukandji syndrome

Q: What is Irukandji syndrome?

Answer: Systemic envenomation from the sting of some Jellywish species

Systemic envenomation from some jellyfish species can be fatal. It starts as mild to moderate painful local stinging sensation but within minutes can set into waves of severe generalized back, chest, and abdominal pain, vomiting, sweating, agitation, severe hypertension, tachycardia, myocardial injury (MI), pulmonary edema (PE), and intracranial hemorrhage (ICH).

Patients need management on various fronts. Pain control with opioids, wound irrigation with vinegar, removing any jellyfish tentacles if found, hot packs at the site (or immersion in hot water).

The underlying pathology is catecholamine release leading to severe hypertension resulting in MI, PE and ICH. Benzodiazepines may help. For BP control, nitroglycerin, sodium nitroprusside, or phentolamine can be utilized.

Magnesium has been proposed, but counting risk vs. benefit is not recommended.

#toxicity

References:

1. Cegolon L, Heymann WC, Lange JH, Mastrangelo G. Jellyfish stings and their management: a review. Mar Drugs 2013; 11:523.

2. Macrokanis CJ, Hall NL, Mein JK. Irukandji syndrome in northern Western Australia: an emerging health problem. Med J Aust 2004; 181:699.

3. Lippmann JM, Fenner PJ, Winkel K, Gershwin LA. Fatal and severe box jellyfish stings, including Irukandji stings, in Malaysia, 2000-2010. J Travel Med 2011; 18:275.

4. Fenner PJ, Hadok JC. Fatal envenomation by jellyfish causing Irukandji syndrome. Med J Aust 2002; 177:362.

Behçet syndrome

Q: Behçet syndrome involves the vessels of? (select one)

A) large size

B) medium size

C) small size

D) all sizes 

Answer: D

Behçet syndrome is a form of vasculitis and can involve blood vessels of all sizes as well as both the arterial and venous sides of the circulation. In contrast to many vasculitides, it is more common in men

Its major clinical manifestations are

• Deep venous thrombosis DVT)
• Subcutaneous thrombophlebitis
• Venal Caval occlusions
• Cerebral sinus thrombosis
• Budd-Chiari syndrome
• Pulmonary artery occlusion or aneurysm
• Aortic aneurysm
• Extremity arterial occlusion or aneurysm

#rheumatology

References:

1. Koc, Y, Gullu, I, Akpek, G, et al. J Rheumatol 1992; 19:402.

2. Hamuryudan V, Er T, Seyahi E, et al. Pulmonary artery aneurysms in Behçet syndrome. Am J Med 2004; 117:867.

3. Zouboulis CC, Vaiopoulos G, Marcomichelakis N, et al. Onset signs, clinical course, prognosis, treatment and outcome of adult patients with Adamantiades-Behçet's disease in Greece. Clin Exp Rheumatol 2003; 21:S19.

4. Zou J, Luo JF, Shen Y, et al. Cluster analysis of phenotypes of patients with Behçet's syndrome: a large cohort study from a referral center in China. Arthritis Res Ther 2021; 23:45.

5. Yazici H, Ugurlu S, Seyahi E. Behçet syndrome: is it one condition? Clin Rev Allergy Immunol 2012; 43:275.

6. Yazici Y, Hatemi G, Bodaghi B, et al. Behçet syndrome. Nat Rev Dis Primers 2021; 7:67.

arrhythmias in HD patients

Q:  The most common cardiac arrhythmia in patients with end-stage kidney disease (ESRD) who are on hemodialysis(HD) is? (select one)

A) Ventricular tachycardia/fibrillation (VT/VF)

B) asystole

Answer: A

A literature search showed only a small study of 75 patients in this regard. These patients were analyzed while wearing a cardioverter-defibrillator (WCD). Almost 80% of patients experienced VT/VF and about 20% has asystole. 

ESRD patients who are on HD may not be a candidate for an implantable cardiac defibrillator (ICD) due to their inherent issues of infection, bleeding, and vasculopathy. These patients (if not a candidate for ICD), may need to apply a WCD jacket to their chest. 

It saves 7 out of 10 patients in the early 24 hours of arrhythmia.

#cardiology

#nephrology

Reference:

Wan C, Herzog CA, Zareba W, Szymkiewicz SJ. Sudden cardiac arrest in hemodialysis patients with wearable cardioverter defibrillator. Ann Noninvasive Electrocardiol 2014; 19:247.

Colors of urine

Q: Pink urine is due to? (select one)

A) phosphate crystals

B) uric acid crystals

Answer: B

For a long time, different colors of urine have excited clinicians (see references). 

The five common colors of urine found in ICU patients are following with potential clues for the underlying pathologies:

1. White: phosphate crystals, chyluria, or propofol.

2. Pink: uric acid crystals or propofol.

3. Green: methylene blue, propofol, amitriptyline, or Pseudomonas aeruginosa infection.

4. Black: hemoglobinuria, myoglobulinuria, melanuria (metastatic melanoma), or alkaptonuria. 

5. Purple: bacteriuria in patients with urinary catheters (purple bag syndrome) co-administration of methylene blue and hydroxycobalamin.

#nephrology

References:

1. Aycock RD, Kass DA. Abnormal urine color. South Med J. 2012 Jan;105(1):43-7. doi: 10.1097/SMJ.0b013e31823c413e. PMID: 22189666.

2. Raymond JR, Yarger WE. Abnormal urine color: differential diagnosis. South Med J. 1988 Jul;81(7):837-41. doi: 10.1097/00007611-198807000-00008. PMID: 3393939.

Lead poisoning

Q: Hemodialysis is a mainstay of treatment for Lead toxicity?

A) True

B) False

Answer: B

Usually, lead toxicity occurs with chronic exposure and the development of chronic symptoms. Removal from exposure is still the mainstay of treatment. In acute symptoms such as colicky pain, chelation therapy can be used to decrease the Blood Lead Level (BLL). The two chelating agents recommended are

• DMSA (2,3-dimercaptosuccinic acid, succimer) 
• calcium disodium ethylenediaminetetraacetic acid (EDTA)

A Toxicologist should be consulted before the administration of the chelating agent.

#toxicology

References:

1. Frith D, Yeung K, Thrush S, et al. Lead poisoning--a differential diagnosis for abdominal pain. Lancet 2005; 366:2146.

2. Kosnett MJ. Lead. In: Critical Care Toxicology, Brent J, Burkhart J, Dargan P, et al (Eds), Springer International Publishing, 2016. p.1.

INR in AF and risk of bleed

Q: 76 years old male with chronic atrial fibrillation (AF) is admitted to ICU with intracranial hemorrhage. Patient is on chronic warfarin treatment for AF. INR is 3.8. INR above 3 predispose patients to the increased risk of bleeding?

A) True

B) False

Answer: A

AF patients on chronic warfarin are recommended to have an INR between 2.0 and 3.0 with an average annual Time in the Therapeutic Range (TTR) >70%. The risk of ischemic stroke increases proportionally as INR values go below 2. Simultaneously, the risk of bleeding increases as INR goes above 3.

Age above 74 years (as our patient in this question) is an independent risk factor for bleeding. Despite this independent risk an INR between 2.0 and 3.0 is recommended in this age group.

#cardiology

References:

1. Fuster V, Rydén LE, Asinger RW, et al. ACC/AHA/ESC Guidelines for the Management of Patients With Atrial Fibrillation: Executive Summary A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients With Atrial Fibrillation) Developed in Collaboration With the North American Society of Pacing and Electrophysiology. Circulation 2001; 104:2118.

2. Hylek EM, Go AS, Chang Y, et al. Effect of intensity of oral anticoagulation on stroke severity and mortality in atrial fibrillation. N Engl J Med 2003; 349:1019.

3. Singer DE, Chang Y, Fang MC, et al. Should patient characteristics influence target anticoagulation intensity for stroke prevention in nonvalvular atrial fibrillation?: the ATRIA study. Circ Cardiovasc Qual Outcomes 2009; 2:297.

TMP-SMX and creatinine

Q: Trimethoprim-sulfamethoxazole (TMP-SMX) (bactrim) increases the serum creatinine by which method? (select one)

A) increasing the muscle breakdown (high CPK)

B) decreasing the tubular secretion of creatinine

Answer: B

(TMP-SMX) decreases the tubular secretion of creatinine, which reflexly can make clinicians believe that the patient is in renal failure. This rise in serum creatinine is not a true renal failure. 

In contrast, hyperkalemia associated with TMP-SMX is real and can be fatal. This has been found particularly true in patients with HIV (high dosage use), on angiotensin-converting enzyme (ACE) inhibitors, or on angiotensin receptor blockers (ARB). 

Other side effects can be renal tubular acidosis, hepatitis, hypoglycemia, hyponatremia, and hemolysis in patients with glucose-6-phosphate dehydrogenase deficiency. It should be given with caution in patients with folate deficiency.

#pharmacology

#nephrology

References;

1. Masters PA, O'Bryan TA, Zurlo J, et al. Trimethoprim-sulfamethoxazole revisited. Arch Intern Med 2003; 163:402.

2. Ho JM, Juurlink DN. Considerations when prescribing trimethoprim-sulfamethoxazole. CMAJ. 2011 Nov 8;183(16):1851-8. doi: 10.1503/cmaj.111152. Epub 2011 Oct 11. PMID: 21989472; PMCID: PMC3216436.

JVP and RAP

Q: What is the 'rule of thumb formula to assess Right Atrial Pressure (RAP) from Jugular Venous Pressure (JVP)?

Answer: RAP (in cm of water*) = JVP + 5cm

* 1 cm water = 0.74 mmHg

Although this formula is a rough estimate but provides a general idea of RAP to determine further workup and establish a differential diagnosis.

5 cm is added due to the understanding that the right atrium is located about 5 cm below the sternal angle. It has been suggested that 5 cm should be used only when the patient is supine. The number should be increased to 8 cm or 10 cm depending on head elevation. Overall body habitus also influences this number. Said that again, 5 cm provides a clinician a pretty general idea of cardiac pathology.

#physical exam

#cardiology

References:

1. Stein JH, Neumann A, Marcus RH. Comparison of estimates of right atrial pressure by physical examination and echocardiography in patients with congestive heart failure and reasons for discrepancies. Am J Cardiol 1997; 80:1615.

2. Devine PJ, Sullenberger LE, Bellin DA, Atwood JE. Jugular venous pulse: window into the right heart. South Med J 2007; 100:1022.

3. Seth R, Magner P, Matzinger F, van Walraven C. How far is the sternal angle from the mid-right atrium? J Gen Intern Med 2002; 17:852.

4. McGee SR. Physical examination of venous pressure: a critical review. Am Heart J 1998; 136:10.

Stored platelets

Q: Platelet should be stored at? (select one)

A) room temperature

B) cold temperature

Answer: A

Platelets should be stored at room temperature. If stored in cold, von Willebrand factor (WVF) receptors will cluster on platelet surfaces. Also, it changes the morphology of platelets, which leads to the increased destruction by the hepatic macrophages. Saving bags should allow oxygen and carbon dioxide gas exchange. Addition of citrate prevents clotting and maintain proper PH. Dextrose provides the energy source.

The shelf-life of stored platelets is about five days but there are FDA approved containers available for storage up to a week.

#hematology

#blood-bank

References:

1. McCullough J. Overview of platelet transfusion. Semin Hematol 2010; 47:235.

2. Hoffmeister KM, Felbinger TW, Falet H, et al. The clearance mechanism of chilled blood platelets. Cell 2003; 112:87.

Blast crisis in CML

Q; Which blast crisis is more common in chronic myeloid leukemia (CML)? - select one

A) Lymphoid 

B) Myeloid 

Answer: B

Myeloid blast crisis i.e., AML accounts for 70 percent of CML blast crisis. In such instance, the preferred initial treatment is tyrosine kinase inhibitor (TKI), with or without chemotherapy followed by an allogeneic  hematopoietic cell transplantation (HCT).

Lymphoid blast crisis i.e., acute lymphoblastic leukemia ALL accounts for about 30 percent of CML blast crisis. Lymphoid blast crisis often responds to treatments used for Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL). For TKI and chemotherapy oncology should be consulted.

#oncology 

Reference:

WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, revised 4th edition, Swerdlow SH, Campo E, Harris NL, et al. (Eds), International Agency for Research on Cancer (IARC), Lyon 2017.