Homan's sign

Case: 24 years old athletic male presented to the Emergency Room (ER) with severe acute pain in the right calf associated with unilateral leg edema and redness. Homans’ sign is positive. The presence of the Homans’ sign confirms Deep Vein Thrombosis (DVT) unless proven otherwise.

A) True

B) False

Answer: B

This question aims to emphasize that the widely used Homans sign, calf pain upon passive dorsiflexion of the foot, is not a 'very reliable' sign of DVT. It just suggests DVT. History, patient profile, lab, and imaging testing should be used to confirm the diagnosis.

Our patient is a young athlete person who may have DVT due to possible steroid abuse, but most likely, he may have merely muscle strain, tear, or injury to the leg. Other differential diagnoses include cellulitis, lymphangitis or lymph obstruction, venous insufficiency, or popliteal (Baker's) cyst. It may be interesting to know that one-quarter of patients with unilateral calf pain, redness, swelling, and tenderness may not have any established diagnosis, which can be very frustrating for a clinician.

One of the physical exam techniques in such patients is to look for pain or firmness along the course of a vein. More than Homan's sign, a more reliable finding for DVT is a larger calf circumference in the affected leg.

Well's score is another way to calculate the risk factor for DVT. A negative D-Dimer can be an important test to rule out DVT.

#hematology

#physical-exam

References:

1. Hull R, Hirsh J, Sackett DL, et al. Clinical validity of a negative venogram in patients with clinically suspected venous thrombosis. Circulation 1981; 64:622.

2. Gorman WP, Davis KR, Donnelly R. ABC of arterial and venous disease. Swollen lower limb-1: general assessment and deep vein thrombosis. BMJ 2000; 320:1453.

3. Ambesh P, Obiagwu C, Shetty V. Homan's sign for deep vein thrombosis: A grain of salt? Indian Heart J. 2017 May-Jun;69(3):418-419. doi: 10.1016/j.ihj.2017.01.013. Epub 2017 Jan 23. PMID: 28648447; PMCID: PMC5485383.

4. Heick JD, Farris JW. Survey of methods used to determine if a patient has a deep vein thrombosis: An exploratory research report. Physiother Theory Pract. 2017 Sep;33(9):733-742. doi: 10.1080/09593985.2017.1345023. Epub 2017 Jul 17. PMID: 28715289.

Larva Currens

Q: What is Larva currens?

Answer: Larva currens is also called "running" larva of strongyloidiasis. It was first described almost seven decades ago. The most common entry site is via skin due to contaminated soil. Person-to-person transmission occurs due to fecal contamination, larvae-bearing fomites, and sexual contact. Donor-derived strongyloidiasis has been described in transplant recipients. Another major issue with transplant patients is the reactivation of remote infection in the form of hyperinfection/disseminated disease, also called accelerated autoinfection.

Larva currens is a dermatologic manifestation as raised, pink, pruritic, evanescent streaks along the lower trunk, thighs, and buttocks, resulting from migrating larvae through the subcutaneous tissues. It can be dramatic. As the larva moves, the progress can be approximately 1 cm in 5 minutes and 5 to 15 cm per hour. Larvae leave behind a thin red line that gradually fades to brown and disappears within 48 hours. It can be associated with urticaria, pruritus, angioedema, or rash.

Ivermectin is the treatment.

#ID

#dermatology

References:

1. ARTHUR RP, SHELLEY WB. Larva currens; a distinctive variant of cutaneous larva migrans due to Strongyloides stercoralis. AMA Arch Derm 1958; 78:186.

2. Zubrinich CM, Puy RM, O'Hehir RE, Hew M. Strongyloides infection as a reversible cause of chronic urticaria. J Asthma Allergy 2019; 12:67.

3. Tian Y, Monsel G, Paris L, Danis M, Caumes E. Larva Currens: Report of Seven Cases and Literature Review. Am J Trop Med Hyg. 2022 Dec 19;108(2):340-345. doi: 10.4269/ajtmh.21-0135. PMID: 36535252; PMCID: PMC9896332.

4. Puerta-Peña M, Calleja Algarra A. Larva Currens in Strongyloides Hyperinfection Syndrome. N Engl J Med. 2022 Apr 21;386(16):1559. doi: 10.1056/NEJMicm2115708. PMID: 35443110.

BB and K

Q: Beta Blockers (BB) tend to cause? (select one)

A) Hypokalemia 

B) Hyperkalemia

Answer: B

This question emphasizes the concept that catecholamines with beta-2 receptors, like epinephrine, promote the movement of extracellular potassium into the cells. Similarly, beta-adrenergic blockers impair potassium entry into the cells. Although total body potassium stays the same, high serum potassium levels lead to hyperkalemia (so it is not real hyperkalemia).

This effect is most pronounced with nonselective beta-blockers, such as propranolol or labetalol, and less with beta-1 selective, such as atenolol or metoprolol.

On an average, it increases potassium by about 0.5 meq/L . It is usually not significant, but it can become life-threatening in patients with underlying hypoaldosteronism, heart failure exacerbation, renal insufficiency, and a history of renal transplant.

#electrolytes

#pharmacology

References:

1. Reid JL, Whyte KF, Struthers AD. Epinephrine-induced hypokalemia: the role of beta adrenoceptors. Am J Cardiol 1986; 57:23F.

2. Nowicki M, Miszczak-Kuban J. Nonselective Beta-adrenergic blockade augments fasting hyperkalemia in hemodialysis patients. Nephron 2002; 91:222.

3. McCauley J, Murray J, Jordan M, et al. Labetalol-induced hyperkalemia in renal transplant recipients. Am J Nephrol 2002; 22:347.

Clonidine toxicity

Q: What does clonidine overdose tend to cause? (select one)

A) Miosis

B) Mydriasis

Answer: A

Clonidine is an alpha-2 adrenergic agonist. Its overdose causes a cluster of symptoms (toxidrome) as

• Depressed mental status
• Miosis
• Depressed respirations
• Bradycardia 
• Hypotension

Treatment is supportive, as clonidine can't be removed via dialysis.

#toxicity

#pharmacology

References:

1. Isbister GK, Heppell SP, Page CB, Ryan NM. Adult clonidine overdose: prolonged bradycardia and central nervous system depression, but not severe toxicity. Clin Toxicol (Phila). 2017 Mar;55(3):187-192. doi: 10.1080/15563650.2016.1277234. Epub 2017 Jan 20. PMID: 28107093.

2. Manzon L, Nappe TM, DelMaestro C, Maguire NJ. Clonidine Toxicity. 2023 Jun 26. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. PMID: 29083752.

Myocardial Reperfusion Injury

Q: Reperfusion injury of the heart can be effectively controlled by performing 'endovascular cooling' before percutaneous coronary intervention (PCI).

A) True

B) False

Answer: B

This question aims to highlight the importance of reperfusion injury and the fact that no effective management was identified for it. Various treatment modalities have been tested, which include but are not limited to the following:

• Ischemic conditioning 
• Glycoprotein IIb/IIIa inhibitors 
• Adenosine
• Vasodilators such as nitric oxide (NO), and angiotensin converting enzyme (ACE)
• Ion channel modulation 
• Glucose-insulin-potassium solution
• Antineutrophil and anticomplement therapy 
• Antioxidant therapy
• Magnesium 
• Cyclosporine 
• Intravenous MTP-131
• Intravenous sodium nitrite 
• Losmapimod 
• Inhibitors of delta-protein kinase C 

Endovascular cooling on the concept of cardioplegia during cardiac bypass surgery is proposed before performing PCI. It was thought myocardial metabolism would decrease at lower temperatures and provide some cardioprotection. Studies fail to show any such benefits.

In summary, effective therapies remain elusive for reperfusion injury.

#cardiology

References:

1. He J, Liu D, Zhao L, Zhou D, Rong J, Zhang L, Xia Z. Myocardial ischemia/reperfusion injury: Mechanisms of injury and implications for management (Review). Exp Ther Med. 2022 Jun;23(6):430. doi: 10.3892/etm.2022.11357. Epub 2022 May 6. PMID: 35607376; PMCID: PMC9121204.

2. He J, Bellenger NG, Ludman AJ, Shore AC, Strain WD. Treatment of myocardial ischaemia-reperfusion injury in patients with ST-segment elevation myocardial infarction: promise, disappointment, and hope. Rev Cardiovasc Med. 2022 Jan 17;23(1):23. doi: 10.31083/j.rcm2301023. PMID: 35092215.

TLS and choice of fluid in initial phase

Q: Lactate Ringer's (LR) is the fluid of choice in initial resuscitation of Tumor Lysis Syndrome (TLS)? 

A) True

B) False

Answer: B

Ringer's Lactate, named after its inventor, is also known as Lactate Ringer or LR. It contains sodium, chloride, potassium, calcium, and lactate. Due to its more isotonic sodium content than normal saline (NS), it is now considered a primary fluid for resuscitation in the ICU. 

In TLS, LR may worsen hyperkalemia and hyperphosphatemia with calcium phosphate precipitation once the tumor breaks down. 

NS stays the fluid of choice, at least in the initial phase of TLS management.

#oncology

#electrolytes

References:

1. Coiffier B, Altman A, Pui CH, et al. Guidelines for the management of pediatric and adult tumor lysis syndrome: an evidence-based review. J Clin Oncol 2008; 26:2767.

2. Mirrakhimov AE, Voore P, Khan M, Ali AM. Tumor lysis syndrome: A clinical review. World J Crit Care Med. 2015 May 4;4(2):130-8. doi: 10.5492/wjccm.v4.i2.130. PMID: 25938028; PMCID: PMC4411564.

3. McBride A, Trifilio S, Baxter N, Gregory TK, Howard SC. Managing Tumor Lysis Syndrome in the Era of Novel Cancer Therapies. J Adv Pract Oncol. 2017 Nov-Dec;8(7):705-720. Epub 2017 Nov 1. PMID: 30333933; PMCID: PMC6188097.

Decadron in meningitis

Q: Early intravenous (IV) administration of dexamethasone in bacterial meningitis particularly decreases the risk of? (select one)

A) hearing loss

B) vision loss

Answer: A

Administration of IV glucocorticoids has now become the standard of care in the early management of community-acquired bacterial meningitis. Dexamethasone is considered as the drug of choice. The dose is 10 mg administered 15 to 20 minutes prior or with the first dose of antibiotic every 6 hours for 96 hours. It has been found particularly useful in decreasing hearing loss in bacterial meningitis, which can be permanent. It also decreases other neurologic complications and overall mortality by decreasing cerebrospinal fluid (CSF) concentrations of cytokines, CSF inflammation, and cerebral edema.

#neurology

#ID

References:

1. Bhatt SM, Lauretano A, Cabellos C, et al. Progression of hearing loss in experimental pneumococcal meningitis: correlation with cerebrospinal fluid cytochemistry. J Infect Dis 1993; 167:675.

2. de Gans J, van de Beek D; European Dexamethasone in Adulthood Bacterial Meningitis Study Investigators. Dexamethasone in adults with bacterial meningitis. N Engl J Med. 2002 Nov 14;347(20):1549-56. doi: 10.1056/NEJMoa021334. PMID: 12432041.

3. Gijwani D, Kumhar MR, Singh VB, Chadda VS, Soni PK, Nayak KC, Gupta BK. Dexamethasone therapy for bacterial meningitis in adults: a double blind placebo control study. Neurol India. 2002 Mar;50(1):63-7. PMID: 11960154.

Nitrates and platelets

Q: One of the caveats of using nitrates in angina is its prothrombotic characteristic.

A) True

B) False

Answer: B

One less-known positive contributing effect of Nitrates in coronary artery disease or any vasculopathy is its antithrombotic effect. 

The mechanism of action is probably via stimulation of platelet guanylate cyclase, which prevents fibrinogen binding to platelet IIb/IIIa receptors and, thus, platelet aggregation.

This effect is visible via both intravenous and transdermal nitroglycerin.

#pharmacology

#cardiology

#vascular

References:

1. Loscalzo J. Antiplatelet and antithrombotic effects of organic nitrates. Am J Cardiol 1992; 70:18B.

2. Lacoste LL, Théroux P, Lidón RM, et al. Antithrombotic properties of transdermal nitroglycerin in stable angina pectoris. Am J Cardiol 1994; 73:1058.

Listeriosis in pregnancy - treatment

Q: A 20-weeks pregnant patient is admitted to ICU with septic shock. Blood culture grew listeria. The patient is known to have had severe anaphylactic reactions to penicillin (PCN). What is the drug of choice in a pregnant penicillin-allergic patient with listeria bacteremia? (select one)

A) TMP-SMX

B) Clindamycin

C) Vancomycin

D) Ciprofloxacin

Answer: A

The first line of drugs in severe Listeriosis is ampicillin (or penicillin). Although few experts add gentamicin, it is not advisable due to its potential toxicity.

Trimethoprim/sulfamethoxazole (TMP-SMX), popularly known as Bactrim, is the drug of choice if a patient is PCN allergic. Unfortunately, Bactrim should be avoided in the first trimester and the last month of pregnancy. In the first trimester, Bactrim affects folic acid metabolism, and in the last month, it may cause kernicterus in the fetus. In those periods, meropenem can be used. Our patient is way out of those risk periods for Bactrim, so the answer is A.

Vancomycin has been proposed, but the failure rate is very high.

#ID

#ob-gyn

References:

1. Committee Opinion No. 614: Management of pregnant women with presumptive exposure to Listeria monocytogenes. Obstet Gynecol 2014; 124:1241.

2. Charlier C, Perrodeau É, Leclercq A, et al. Clinical features and prognostic factors of listeriosis: the MONALISA national prospective cohort study. Lancet Infect Dis 2017; 17:510.

3. Wang Z, Tao X, Liu S, Zhao Y, Yang X. An Update Review on Listeria Infection in Pregnancy. Infect Drug Resist. 2021 May 26;14:1967-1978. doi: 10.2147/IDR.S313675. PMID: 34079306; PMCID: PMC8165209.

abdominal exam

Q: In an abdominal examination, which is preferred to be performed first? (select one)

A) Palpation

B) Percussion 

Answer: B

In the abdominal examination, gentle percussion is preferred before palpation because patients with peritonitis may feel severe pain with even gentle palpation. Gentle percussion causes less pain, which makes further examination easier. Palpation, particularly rebound tenderness, can be agonizing for patients.

Muscular rigidity, aka "guarding," signifies local or diffuse peritonitis and is not a feature of pain originating from organs such as kidney stones or pancreatitis.

#physical-exam

References:

1. Fritz D, Weilitz PB. Abdominal Assessment. Home Healthc Now. 2016 Mar;34(3):151-5. doi: 10.1097/NHH.0000000000000364. PMID: 26925941.

2. Ferguson CM. Inspection, Auscultation, Palpation, and Percussion of the Abdomen. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 93. Available from: https://www.ncbi.nlm.nih.gov/books/NBK420/

3. Mealie CA, Ali R, Manthey DE. Abdominal Exam. 2022 Oct 10. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. PMID: 29083767.

Supraclavicular Subclavian Vein Catheterization: A Forgotten Central Line

Advantages of the supraclavicular approach over infraclavicular technique include:

• a well-defined insertion landmark (the clavisternomastoid angle);
• a shorter distance from skin to vein;
• a larger target area;
• a straight path to superior vena cava; less proximity to lung; and
• fewer complications of pleural or arterial puncture.
• The supraclavicular approach less often necessitates CPR or tube thoracostomy interruption than the infraclavicular approach.
• A finder or seeker needle (21G and 3.5 cm length) can be used to locate vessel, which minimizes the risk of complications. A finder needle is used mostly when ultrasound is not available during insertion of the internal jugular vein, but it may also help locate the subclavian vein via a supraclavicular approach. The needle should be inserted 1 cm posterior to the sternocleidomastoid and 1 cm cephalad to the clavicle.

 

References:

1. Patrick SP, Tijunelis MA, Johnson S, Herbert ME. Supraclavicular subclavian vein catheterization: the forgotten central line. West J Emerg Med. 2009 May;10(2):110-4. PMID: 19561831; PMCID: PMC2691520.

2. Borisov B, Iliev S. Supraclavicular Approach to the Subclavian Vein - One Well Forgotten Technique with Impressive Results. Pol Przegl Chir. 2019 Jun 6;91(4):19-23. doi: 10.5604/01.3001.0013.2281. PMID: 31481642.

Beta receptors

Q: Activation of beta-3 receptors may reduce heart contractility.

A) True

B) False

Answer: A

Very seldom described, but there are three types of beta receptors:

Beta 1 is primarily in the heart muscle. Activation of these receptors results in tachycardia, increased contractility, increased atrioventricular (AV) conduction, and decreased AV node refractoriness.

Beta 2, although found in heart muscles, is more prominent in bronchial and peripheral vascular smooth muscle. Their activation results in vasodilation and bronchodilation.

Beta 3, which is not frequently described, is found in the heart as well as adipose tissues. Activation of these receptors may mediate catecholamine-induced thermogenesis and tend to reduce cardiac contractility.

#physiology

#cardiology

References:

1. Wachter SB, Gilbert EM. Beta-adrenergic receptors, from their discovery and characterization through their manipulation to beneficial clinical application. Cardiology. 2012;122(2):104-12. doi: 10.1159/000339271. Epub 2012 Jul 3. PMID: 22759389.

2. De Blasi A. Beta-adrenergic receptors: structure, function and regulation. Drugs Exp Clin Res. 1990;16(3):107-12. PMID: 1974837.

EVALI

Q: 24 years old male is admitted to ICU with severe respiratory distress. History corelates with starting E-cigarette one week ago. Presumed diagnosis of E-cigarette or vaping product use-associated lung injury (EVALI) is made. Which of the following is the most dominant feature of EVALI? (select one)

A) fever

B) tachycardia 

C) tachypnea 

D) hemoptysis 

Answer: B

EVALI patients generally present with many constitutional, respiratory, and gastrointestinal (GI) symptoms. EVALI is an umbrella term for various disease pathologies that occur in association with the use of E-Cigarettes or vaping. It includes acute eosinophilic pneumonia, diffuse alveolar hemorrhage, lipoid pneumonia, and respiratory-bronchiolitis interstitial lung disease. Interestingly, it is rarely an infectious process. The usual underlying culprit products are THC, vitamin E acetate, nicotine, CBD or other plant oils, medium-chain triglycerides, petroleum distillates, and terpenes.

Although patients may report subjective feelings of warmth, fever is present only in one-third of the patients. Tachycardia is extremely common. Only less than half have tachypnea, though all of them have some level of shortness of breath (SOB) and cough. Remember: Tachypnea and SOB are two different entities.  Pleuritic chest pain may be present. 

Hemoptysis is rare unless the underlying pathology is diffuse alveolar hemorrhage.

#toxicity

#pulmonary

References:

1. Layden JE, Ghinai I, Pray I, et al. Pulmonary Illness Related to E-Cigarette Use in Illinois and Wisconsin - Final Report. N Engl J Med 2020; 382:903.

2. Kalininskiy A, Bach CT, Nacca NE, Ginsberg G, Marraffa J, Navarette KA, McGraw MD, Croft DP. E-cigarette, or vaping, product use associated lung injury (EVALI): case series and diagnostic approach. Lancet Respir Med. 2019 Dec;7(12):1017-1026. doi: 10.1016/S2213-2600(19)30415-1. Epub 2019 Nov 8. PMID: 31711871.

3. Winnicka L, Shenoy MA. EVALI and the Pulmonary Toxicity of Electronic Cigarettes: A Review. J Gen Intern Med. 2020 Jul;35(7):2130-2135. doi: 10.1007/s11606-020-05813-2. Epub 2020 Apr 3. PMID: 32246394; PMCID: PMC7351931.

A case of skin exam

Q: Which disease comes to mind with the following characteristics of skin rash?

• associated with pharyngitis
• diffuse erythema that blanches with pressure
• sandpaper quality to the skin 
• usually starts in the groin and armpits 
• a strawberry tongue
• palms and soles are usually spared
• Pastia's lines

Answer: Scarlet fever 

The other common name for scarlet fever is scarlatina. It is a diffuse erythematous eruption that requires prior exposure to S. pyogenes. It is a delayed-type skin reactivity to pyrogenic/erythrogenic toxin, usually types A, B, or C).

It appears as numerous small (1 to 2 mm) papular elevations with all the qualities described in the question above. The rash expands quickly to the trunk, followed by the extremities, and ultimately desquamates.

The rash is most marked in the inguinal, axillary, antecubital, and abdominal skin folds and at pressure points. Pastia's lines are linear petechial characters in the antecubital fossae and axillary folds.

With so many tips given, this question aims to emphasize that the diagnosis of scarlet fever is made clinically. However, rapid strep testing and throat culture are required to establish the association.

#ID

#dermatology

#physical-exam

References:

1. Basetti S, Hodgson J, Rawson TM, Majeed A. Scarlet fever: a guide for general practitioners. London J Prim Care (Abingdon). 2017 Aug 11;9(5):77-79. doi: 10.1080/17571472.2017.1365677. PMID: 29081840; PMCID: PMC5649319.

2. Lau SK, Woo PC, Yuen KY. Toxic scarlet fever complicating cellulitis: early clinical diagnosis is crucial to prevent a fatal outcome. New Microbiol. 2004 Apr;27(2):203-6. PMID: 15164635.

3. Hurst JR, Brouwer S, Walker MJ, McCormick JK. Streptococcal superantigens and the return of scarlet fever. PLoS Pathog. 2021 Dec 30;17(12):e1010097. doi: 10.1371/journal.ppat.1010097. PMID: 34969060; PMCID: PMC8717983.

murmurs

Q: Which of the following is NOT considered a heart murmur configuration? (select one)

A) Harsh

B) Plateau 

C) Crescendo 

D) Decrescendo

E) Crescendo-decrescendo

Answer: A

The objective of this question is to make aware of the distinction between configurations, pitch, and intensity of heart murmurs.

Configurations are considered the description of the time course of the murmur. The four major configurations of heart murmurs are:

• Crescendo (increasing)
• Decrescendo (diminishing)
• Crescendo-decrescendo (increasing-decreasing)
• Plateau (unchanged in intensity)

Harsh, rumbling, scratchy, grunting, blowing, squeaky, vibratory, and musical is considered the pitch of the murmurs - can be described as a qualitative description.

The intensity of the murmur runs from Grades 1 to 6, depending on the faintness to the loudness of the murmur.

#cardiology

#physical-exam

References:

1. Ferasin L, Ferasin H, Cala A, Creelman N. Prevalence and Clinical Significance of Heart Murmurs Detected on Cardiac Auscultation in 856 Cats. Vet Sci. 2022 Oct 13;9(10):564. doi: 10.3390/vetsci9100564. PMID: 36288177; PMCID: PMC9611806.

2. Alpert MA. Systolic Murmurs. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 26. Available from: https://www.ncbi.nlm.nih.gov/books/NBK345/

3. Kumar D, Carvalho P, Antunes M, Paiva RP, Henriques J. Heart murmur classification with feature selection. Annu Int Conf IEEE Eng Med Biol Soc. 2010;2010:4566-9. doi: 10.1109/IEMBS.2010.5625940. PMID: 21095796.

Potassium and kidney stones

Q: 42 years old male is admitted to ICU with sepsis due to severe pyelonephritis. The patient has a chronic history of kidney stones. Patient potassium appears to be lower. Aggressive potassium repletion is ordered. Hyperkalemia increases the risk of nephrolithiasis?

A) True

B) False

Answer: B

Hyperkalemia (or a potassium level on the higher side of normal) decreases the risk of kidney stones. High potassium, particularly from an oral route, reduces urinary calcium excretion. It also increases urinary citrate excretion, thereby increasing urine's inhibitory properties. 

#electrolytes

#nephrology

References:

1. Domrongkitchaiporn S, Stitchantrakul W, Kochakarn W. Causes of hypocitraturia in recurrent calcium stone formers: focusing on urinary potassium excretion. Am J Kidney Dis 2006; 48:546.

2. Ferraro PM, Mandel EI, Curhan GC, et al. Dietary Protein and Potassium, Diet-Dependent Net Acid Load, and Risk of Incident Kidney Stones. Clin J Am Soc Nephrol 2016; 11:1834.

3. Lemann J Jr, Pleuss JA, Gray RW, Hoffmann RG. Potassium administration reduces and potassium deprivation increases urinary calcium excretion in healthy adults [corrected]. Kidney Int 1991; 39:973.

Exclusion criteria to be eligible for intravenous thrombolysis in acute ischemic stroke

Q: Which of the following is NOT an exclusion criterion to be eligible for intravenous thrombolysis in acute ischemic stroke? (select one)

A) Intracranial or intraspinal surgery within last 3 months

B) Symptoms suggestive of subarachnoid hemorrhage

C) Active internal bleeding

D) Large (≥10 mm), untreated, unruptured intracranial aneurysm

E) Persistent systolic blood pressure ≥185 mmHg

Answer: D

Exclusion criteria to be eligible for intravenous thrombolysis in acute ischemic stroke is usually divided into four headings:

• Patient history
• Clinical
• Hematologic
• Head CT

Patient history

• Ischemic stroke or severe head trauma in the previous three months
• Previous intracranial hemorrhage
• Intra-axial intracranial neoplasm
• Gastrointestinal malignancy
• Gastrointestinal hemorrhage in the previous 21 days
• Intracranial or intraspinal surgery within the prior three months

Clinical

• Symptoms suggestive of subarachnoid hemorrhage
• Persistent blood pressure elevation (systolic ≥185 mmHg or diastolic ≥110 mmHg)
• Active internal bleeding
• Presentation consistent with infective endocarditis
• Stroke is known or suspected to be associated with aortic arch dissection
• Acute bleeding diathesis, including but not limited to conditions defined under 'Hematologic'

Hematologic

• Platelet count <100,000/mm3
• Current anticoagulant use with an INR >1.7 or PT >15 seconds or aPTT >40 seconds
• Therapeutic doses of low molecular weight heparin received within 24 hours (eg, to treat VTE and ACS); this exclusion does not apply to prophylactic doses (eg, to prevent VTE)
• Current use (i.e., last dose within 48 hours in a patient with normal renal function) of a direct thrombin inhibitor or direct factor Xa inhibitor with evidence of anticoagulant effect by laboratory tests such as aPTT, INR, ECT, TT, or appropriate factor Xa activity assays

  

Head CT

• Evidence of hemorrhage
• Extensive regions of obvious hypodensity consistent with irreversible injury

  

Some conditions may be relative contraindications or warnings or need close monitoring, which includes

• Only minor and isolated neurologic signs or rapidly improving symptoms
• Serum glucose <50 mg/dL (<2.8 mmol/L)
• Serious trauma in the previous 14 days
• Major surgery in the previous 14 days
• History of gastrointestinal bleeding (remote) or genitourinary bleeding
• Seizure at the onset of stroke with postictal neurologic impairments
• Pregnancy
• Arterial puncture at a noncompressible site in the previous seven days
• Large (≥10 mm), untreated, unruptured intracranial aneurysm
• Untreated intracranial vascular malformation

  

There are additional warnings for treatment from 3 to 4.5 hours from symptom onset.

• Age >80 years
• Oral anticoagulant use, regardless of INR
• Severe stroke (NIHSS score >25)
• Combination of both previous ischemic stroke and diabetes mellitus

 

  

#neurology

  

  

References:

  

1. Hacke W, Kaste M, Bluhmki E, et al. Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke. N Engl J Med 2008; 359:1317.

2. Del Zoppo GJ, Saver JL, Jauch EC, et al. Expansion of the time window for treatment of acute ischemic stroke with intravenous tissue plasminogen activator. A science advisory from the American Heart Association/American Stroke Association. Stroke 2009; 40:2945.

3. Re-examining Acute Eligibility for Thrombolysis (TREAT) Task Force:, Levine SR, Khatri P, et al. Review, historical context, and clarifications of the NINDS rt-PA stroke trials exclusion criteria: Part 1: rapidly improving stroke symptoms. Stroke 2013; 44:2500.

4. Demaerschalk BM, Kleindorfer DO, Adeoye OM, et al. Scientific rationale for the inclusion and exclusion criteria for intravenous alteplase in acute ischemic stroke: A statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2016; 47:581.

5. Powers WJ, Rabinstein AA, Ackerson T, et al. Guidelines for the Early Management of Patients With 

Acute Ischemic Stroke: 2019 Update to the 2018 Guidelines for the Early Management of Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke 2019; 50:e344.

Paradoxical undressing

Q: What is "paradoxical undressing"?

Answer: It is a relatively unknown phenomenon, but 20-50% of hypothermia deaths are associated with paradoxical undressing. In moderate to severe hypothermia, as the person becomes disoriented, they may take off their clothing, which, in turn, increases the rate of heat loss.

Rescuers' usual first thought is - victims of hypothermia have been subjected to a sexual assault.  

Several explanations have been proposed, including cold-induced malfunction of the hypothalamus. Another explanation is that the muscles contracting peripheral blood vessels become exhausted, losing vasomotor tone and relaxation. This leads to a sudden surge of blood to the extremities, fooling the person into feeling overheated.

#hypothermia

References:

1. Krispin A, Zaitsev K, Hiss J. [Death due to hypothermia and paradoxical undressing]. Harefuah. 2011 Mar;150(3):227-9, 305. Hebrew. PMID: 21574352.

2. Pisani F, Nittis M. An unusual case of hypothermia and paradoxical undressing. Forensic Sci Med Pathol. 2021 Jun;17(2):338-342. doi: 10.1007/s12024-020-00315-3. Epub 2020 Oct 14. PMID: 33052559.

3. Wedin B, Vanggaard L, Hirvonen J. "Paradoxical undressing" in fatal hypothermia. J Forensic Sci. 1979 Jul;24(3):543-53. PMID: 541627.

AERD

Q: Patients with Aspirin-Exacerbated Respiratory Distress (AERD) are usually sicker than patients with aspirin-tolerant asthma?

A) True

B) False

Answer: A

Popularly known as the Samter triad, it consists of the following:

• asthma
• aspirin sensitivity, and
• nasal polyps  

Patients with a full triad are usually adults, as the three components develop sequentially over the years. Unfortunately, these patients are more likely to have severe and many times resistant asthma, requiring ventilator and systemic steroids. One of the diagnostic points is that lung inflammation is nearly always eosinophilic and more driven by cysteinyl leukotrienes.

#pulmonary

References:

1. Rajan JP, Wineinger NE, Stevenson DD, White AA. Prevalence of aspirin-exacerbated respiratory disease among asthmatic patients: A meta-analysis of the literature. J Allergy Clin Immunol 2015; 135:676.

2. Mascia K, Haselkorn T, Deniz YM, et al. Aspirin sensitivity and severity of asthma: evidence for irreversible airway obstruction in patients with severe or difficult-to-treat asthma. J Allergy Clin Immunol 2005; 116:970.

3. Comhair SAA, Bochenek G, Baicker-McKee S, et al. The utility of biomarkers in diagnosis of aspirin exacerbated respiratory disease. Respir Res 2018; 19:210.

Characteristics of anemia in hypothyroid patients

Q: Hypothyroidism tends to cause? (select one)

A) Macrocytic anemia

B) Microcytic anemia

Answer: A

In hypothyroidism, macrocytic anemia occurs due to various etiologies. Interestingly, these patients may have normal vitamin B12, folate, and iron levels. Not all patients, but some patients may resolve this macrocytosis after thyroxine replacement. MCV in these patients is usually in the range of 90 to 100 fL

A particular subtype of this disease process is autoimmune hypothyroidism, where autoantibodies to gastric parietal cells may have concomitant vitamin B12 deficiency. This situation may co-exist with pernicious anemia.

#hematology

#endocrinology

References:

1. Szczepanek-Parulska E, Hernik A, Ruchała M. Anemia in thyroid diseases. Pol Arch Intern Med. 2017 May 31;127(5):352-360. doi: 10.20452/pamw.3985. Epub 2017 Mar 28. PMID: 28400547.

2. Antonijević N, Nesović M, Trbojević B, Milosević R. Anemije u hipotireozi [Anemia in hypothyroidism]. Med Pregl. 1999 Mar-May;52(3-5):136-40. Croatian. PMID: 10518398.

3. Erdogan M, Kösenli A, Ganidagli S, Kulaksizoglu M. Characteristics of anemia in subclinical and overt hypothyroid patients. Endocr J. 2012;59(3):213-20. doi: 10.1507/endocrj.ej11-0096. Epub 2011 Dec 27. Erratum in: Endocr J. 2013;60(4):541. Mehmet, Erdogan [corrected to Erdogan, Mehmet]; Aybike, Kosenli [corrected to Kösenli, Aybike]; Mustafa, Kulaksizoglu [corrected to Kulaksizoglu, Mustafa]. PMID: 22200582.

Nitrogen Narcosis

Q; What is Nitrogen narcosis?

Answer: Nitrogen Narcosis affects scuba divers and is also called 'rapture of the deep.' As we all know, air comprises 79% of Nitrogen. At the surface pressures, it has no sedating effect. At greater depths, however, nitrogen affects the brain in precisely the same way as nitrous oxide (laughing gas). The effect (the onset and disappearance) are instantaneous. A diver may be quite clear-headed at 20 meters, and yet "silly" at 30 meters. Ascending to 20 meters will almost instantly clear the head. Divers suffering nitrogen narcosis may put themselves at risk by doing life threatening things such as taking off their masks and dance!

#neurology

References:

1. Grover CA, Grover DH. Albert Behnke: nitrogen narcosis. J Emerg Med. 2014 Feb;46(2):225-7. doi: 10.1016/j.jemermed.2013.08.080. Epub 2013 Nov 19. PMID: 24262058.

2. Kirkland PJ, Mathew D, Modi P, Cooper JS. Nitrogen Narcosis In Diving. 2023 Jul 31. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. PMID: 29261931.

Vasopressin in cocaine toxicity

Q: Why vasopressin is preferred over epinephrine in cardio-pulmonary arrest due to cocaine overdose?

Answer: Epinephrine, like cocaine, has alpha-adrenergic effects. Because of this similarity in the cardiovascular effects, administration of epinephrine to a patient who was arrested in a hyperadrenergic state is like "pouring gasoline over the fire." 

 Moreover, cocaine prevents reuptake of exogenously administered epinephrine. Therefore, if epinephrine is used, AHA Guidelines recommend that high-dose epinephrine be avoided and the interval for its administration be increased (q 5-10min). 

 Vasopressin offers considerable advantages over epinephrine in cardiac arrest secondary to cocaine toxicity. The hyperadrenergic state caused by cocaine increases myocardial oxygen demand, and vasopressin increases coronary blood flow, thereby reducing myocardial oxygen availability. Also, cocaine toxicity causes acidosis, and epinephrine loses much of its effectiveness in an acidotic environment, whereas vasopressin demonstrates good efficacy even with severe acidosis.

#hemodynamic

#toxicity

Further reads:

1. Richards JR, Garber D, Laurin EG, Albertson TE, Derlet RW, Amsterdam EA, Olson KR, Ramoska EA, Lange RA. Treatment of cocaine cardiovascular toxicity: a systematic review. Clin Toxicol (Phila). 2016 Jun;54(5):345-64. doi: 10.3109/15563650.2016.1142090. Epub 2016 Feb 26. PMID: 26919414.

2. Richards JR, Le JK. Cocaine Toxicity. 2023 Jun 8. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. PMID: 28613695.

pulmonary nocardial infection via hematogenous dissemination

Q: The most common site from pulmonary nocardial infection via hematogenous dissemination is? (select one)

A) brain

B) heart

C) liver

D) kidney

E) intestine

Answer: A

Although nocardia begins as a localized disease at the port of entry, it can disseminate directly or hematogeneously. The two most common entry sites are lungs and skin, with lungs in almost two-thirds of the cases. The most common site of hematogenous dissemination is the brain.

Symptoms begin as fever and cough and progress to night sweats, fatigue, anorexia, weight loss, hemoptysis, dyspnea, and pleuritic chest pain. Almost 50 percent of lung infections disseminate hematogenously, mostly to the brain, irrespective of immunocompetent status. 

Spread to adjacent structures may cause empyema, mediastinitis, pericarditis, and superior vena cava syndrome.

#ID

#pulmonary

#neurology

References:

1. Martínez-Barricarte R. Isolated Nocardiosis, an Unrecognized Primary Immunodeficiency? Front Immunol 2020; 11:590239.

2. Coussement J, Lebeaux D, van Delden C, et al. Nocardia Infection in Solid Organ Transplant Recipients: A Multicenter European Case-control Study. Clin Infect Dis 2016; 63:338.

3. Corsini Campioli C, Castillo Almeida NE, O'Horo JC, Challener D, Go JR, DeSimone DC, Sohail MR. Clinical Presentation, Management, and Outcomes of Patients With Brain Abscess due to Nocardia Species. Open Forum Infect Dis. 2021 Apr 7;8(4):ofab067. doi: 10.1093/ofid/ofab067. PMID: 33855101; PMCID: PMC8026153.

VCP

Q: In vocal cord paralysis (VCP), the wheezing is usually? (select one)

A) expiratory

B) inspiratory

Answer: B

Intubation is one of the most common procedures in the ICU. Vocal cord paralysis is a common side effect of intubation. During intubation, either due to trauma or a bigger size tube, the vocal cords may stay adducted to a median position. This airflow obstruction is pronounced in inspiration. During expiration, the paralyzed cords open due to the force of alveolar air.

Other causes of VCP are neck surgery (mostly anterior approach) and various neurologic disorders.

#pulmonary

#procedures

#ENT

References:

1. Seyed Toutounchi SJ, Eydi M, Golzari SE, Ghaffari MR, Parvizian N. Vocal cord paralysis and its etiologies: a prospective study. J Cardiovasc Thorac Res. 2014;6(1):47-50. doi: 10.5681/jcvtr.2014.009. Epub 2014 Mar 4. PMID: 24753832; PMCID: PMC3992732.

2. Salik I, Winters R. Bilateral Vocal Cord Paralysis. 2023 Jul 10. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. PMID: 32809687.

Zone 4 for retroperitoneal region

Q: The retroperitoneum is usually divided into three zones from a surgical perspective. What does zone 4 mean when it is mentioned?

Answer: The retroperitoneum is usually divided into 3 zones from the trauma or surgical perspective. When the surgeon speaks of Zone 4, it means more than one zone is involved. It may carry a higher mortality. It may affect the injury severity score. It may be interesting to learn that mortality is usually higher for blunt trauma than for stab wounds. The usual domino effect and cause of death are multiorgan failure (MSOF), hypovolemic shock, and sepsis. Other factors that may lead to death are a delay of surgery beyond 6 hours and the extent of the injury.

Besides zone 4, zone 1-only injury is also considered high risk.

#trauma

References:

1. Manzini N, Madiba TE. The management of retroperitoneal haematoma discovered at laparotomy for trauma. Injury 2014; 45:1378.

2. Manzini N, Madiba TE. The management of retroperitoneal haematoma discovered at laparotomy for trauma. Injury. 2014 Sep;45(9):1378-83. doi: 10.1016/j.injury.2014.01.026. Epub 2014 Feb 3. PMID: 24606980.

Exchange transfusion and life-threatening malaria.

Q: Exchange transfusion is an effective treatment for life-threatening malaria.

A) Yes

B) No

Answer: B

Although theoretically, it makes sense that removing infected red blood cells and lowering the parasite load by replacing the unparasitized cells should help in severe malaria, the evidence fails to support this hypothesis. There are no differences in outcome. Although previously Centers for Disease Control and Prevention (CDC) supported this hypothesis but does not recommend exchange transfusion for treatment of severe malaria anymore.

Similarly, WHO guidelines does not make any such recommendations.

#ID

#hematology

References:

1. World Health Organization. Guidelines for malaria, 25 November 2022. https://www.who.int/publications/i/item/guidelines-for-malaria (Accessed on March 3, 2024).

2. Riddle MS, Jackson JL, Sanders JW, Blazes DL. Exchange transfusion as an adjunct therapy in severe Plasmodium falciparum malaria: a meta-analysis. Clin Infect Dis 2002; 34:1192.

3. Tan KR, Wiegand RE, Arguin PM. Exchange transfusion for severe malaria: evidence base and literature review. Clin Infect Dis 2013; 57:923.

Static and Dynamic hemodynamic monitoring

Q: Central Venous Pressure (CVP) is considered as a _________ hemodynamic  monitoring? (Fill in the blank - select one)

A) Static 

B) Dynamic 

Answer: A

In acute care settings, there are two types of hemodynamic monitoring

- Static 

- Dynamic

In comparison, dynamic monitoring is more reliable. Static monitoring is assessible more readily on electronic medical record and trend provides a good sense of hemodynamics.

Static monitoring includes – blood pressure & Mean Arterial Pressure (MAP). Also, the following static measurements via central line can be used to determine adequate management:

• CVP
• ScvO2 (Central venous oxygen saturation)

Dynamic monitoring includes

• Respiratory variation in the vena caval diameter (via ultrasound)
• radial artery pulse pressure variation
• aortic blood flow peak velocity
• left ventricular outflow tract velocity-time integral
• carotid or brachial artery blood flow velocity 
• passive leg-raising maneuver

Said that, dynamic monitoring is highly dependent on cardiac rhythm and respiratory pattern. Tachypnea and arrhythmia can artifact reading and clinical judgement.

#hemodynamic

#cardiology

References:

1. Evans L, Rhodes A, Alhazzani W, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021. Crit Care Med 2021; 49:e1063.

2. Rivers E, Nguyen B, Havstad S, et al. Early goal-directed therapy in the treatment of severe sepsis and septic shock. N Engl J Med 2001; 345:1368.

3. ProCESS Investigators, Yealy DM, Kellum JA, et al. A randomized trial of protocol-based care for early septic shock. N Engl J Med 2014; 370:1683.

4. ARISE Investigators, ANZICS Clinical Trials Group, Peake SL, et al. Goal-directed resuscitation for patients with early septic shock. N Engl J Med 2014; 371:1496.

Properties of Librium

Q: Chlordiazepoxide (Librium) is a commonly used drug in ICU. Describe its four essential properties?

Answer: Chlordiazepoxide is unique in a sense and a good choice in alcohol withdrawal not only because its active metabolite has a very long half-life but also because it is

• amnestic,
• anxiolytic,
• hypnotic and
• skeletal muscle relaxant

#pharmacology

#toxicity

References:

1. Ahwazi HH, Patel P, Abdijadid S. Chlordiazepoxide. 2024 Jan 29. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. PMID: 31613439.

2. Kumar CN, Andrade C, Murthy P. A randomized, double-blind comparison of lorazepam and chlordiazepoxide in patients with uncomplicated alcohol withdrawal. J Stud Alcohol Drugs. 2009 May;70(3):467-74. doi: 10.15288/jsad.2009.70.467. PMID: 19371497.

Oxygenation Index

Q: What is the Oxygenation Index?

Answer: 

The Oxygenation Index (OI) is defined as the reciprocal of PF times MAP (Mean Airway Pressure)

OI = (FiO2 × mean airway pressure)/PaO2

It is proposed that OI is a better representative of oxygenation dysfunction as it takes in account mean airway pressure from the ventilator. A lower oxygenation index is better. As the oxygenation of a person improves, they will be able to achieve a higher PaO2 at a lower FiO2

#ventilators

#pulmonary

References:

1. Vadi S. Correlation of Oxygen Index, Oxygen Saturation Index, and PaO2/FiO2 Ratio in Invasive Mechanically Ventilated Adults. Indian J Crit Care Med. 2021 Jan;25(1):54-55. doi: 10.5005/jp-journals-10071-23506. PMID: 33603302; PMCID: PMC7874290.

2. Dechert RE, Park PK, Bartlett RH. Evaluation of the oxygenation index in adult respiratory failure. J Trauma Acute Care Surg. 2014 Feb;76(2):469-73. doi: 10.1097/TA.0b013e3182ab0d27. PMID: 24458052.

3. Myers LC, Mark D, Ley B, Guarnieri M, Hofmeister M, Paulson S, Marelich G, Liu VX. Validation of Respiratory Rate-Oxygenation Index in Patients With COVID-19-Related Respiratory Failure. Crit Care Med. 2022 Jul 1;50(7):e638-e642. doi: 10.1097/CCM.0000000000005474. Epub 2022 Feb 7. PMID: 35120044; PMCID: PMC9196918.

A cardiology case in a young patient

Case: 24 years old male with no past medical history presented to ER with SVT (Supraventricular Tachycardia). His heart rate is 210. Patient was given Adenosine and went into ventricular fibrillation. CPR started and converted to NSR (normal sinus rhythm) with cardioversion. What is your first thought?

Answer: Wolff-Parkinson-White syndrome (WPW)

People with WPW syndrome have an extra electrical pathway between the atria and the ventricles. This "accessory pathway," is also known as the bundle of Kent. This accessory pathway may conduct electrical activity at a significantly higher rate than the AV node, particularly when it is blocked and may degenerate into ventricular fibrillation.

Adenosine and other AV node blockers should be avoided, including calcium channel and beta blockers. Patients with atrial fibrillation and rapid ventricular response are better treated with procainamide or cardioversion in hemodynamic instability.

#cardiology

References:

1. Gupta AK, Shah CP, Maheshwari A, Thakur RK, Hayes OW, Lokhandwala YY. Adenosine induced ventricular fibrillation in Wolff-Parkinson-White syndrome. Pacing Clin Electrophysiol. 2002 Apr;25(4 Pt 1):477-80. doi: 10.1046/j.1460-9592.2002.00477.x. PMID: 11991373.

2. Walker KW, McAnulty JH, Kron J, Silka MJ, Halperin BD. Unmasking accessory pathway conduction with adenosine-induced atrioventricular nodal block after radiofrequency catheter ablation. Chest. 1993 Nov;104(5):1614-6. doi: 10.1378/chest.104.5.1614. PMID: 8222839.

3. Bartlett TG, Friedman PL. Current management of the Wolff-Parkinson-White syndrome. J Card Surg. 1993 Jul;8(4):503-15. doi: 10.1111/j.1540-8191.1993.tb00401.x. PMID: 8353339.

4. Redfearn DP, Krahn AD, Skanes AC, Yee R, Klein GJ. Use of medications in Wolff-Parkinson-White syndrome. Expert Opin Pharmacother. 2005 Jun;6(6):955-63. doi: 10.1517/14656566.6.6.955. PMID: 15952923.

Haldol in burn

Q: Why should Haloperidol be used with caution in burn patients?

Answer: Neuropsychiatric complications are commonly seen in major burn patients. Haloperidol is frequently used to treat severe psychopathic behavior. In burn patients, there could be an increased tendency for severe muscle rigidity, an extrapyramidal side effect of the agent. Haloperidol causes a relative imbalance of dopaminergic and cholinergic neuronal activity in the basal ganglia, with a relative increase in cholinergic activity responsible for EPS. The burn patient may be more prone to extrapyramidal symptoms because of the increased sensitivity of skeletal muscle neuromuscular junctions to acetylcholine after thermal injury.

#pharmacology

#burn

References:

1. Datta PK, Roy Chowdhury S, Aravindan A, Saha S, Rapaka S. Medical and Surgical Care of Critical Burn Patients: A Comprehensive Review of Current Evidence and Practice. Cureus. 2022 Nov 15;14(11):e31550. doi: 10.7759/cureus.31550. PMID: 36540501; PMCID: PMC9754771.

2. Huang V, Figge H, Demling R. Haloperidol complications in burn patients. J Burn Care Rehabil. 1987 Jul-Aug;8(4):269-73. doi: 10.1097/00004630-198707000-00006. PMID: 3654715.

3. Chang CM, Wu KY, Chiu YW, Wu HT, Tsai YT, Chau YL, Tsai HJ. Psychotropic drugs and risk of burn injury in individuals with mental illness: a 10-year population-based case-control study. Pharmacoepidemiol Drug Saf. 2016 Aug;25(8):918-27. doi: 10.1002/pds.3995. Epub 2016 Mar 28. PMID: 27476980.