Adenosine Stress Test

Q: What is the mechanism behind using Adenosine for chemical stress test?

Answer: Adenosine causes vasodilation in the small and medium-sized arterioles (less than 100 µm in diameter). When adenosine is administered, it causes a coronary steal phenomenon, where the vessels in healthy tissue dilate as much as the ischemic tissue, and more blood is shunted away from the ischemic tissue that needs it most. This is the principle behind adenosine stress testing.

Adenosine is quickly broken down by adenosine deaminase, which is present in red cells and the vessel wall.

#cardiolgy

References:

1. Müller-Suur R, Eriksson SV, Strandberg LE, Mesko L. Comparison of adenosine and exercise stress test for quantitative perfusion imaging in patients on beta-blocker therapy. Cardiology. 2001;95(2):112-8. doi: 10.1159/000047356. PMID: 11423717.

2. Alzahrani T, Khiyani N, Zeltser R. Adenosine SPECT Thallium Imaging. 2022 Sep 12. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. PMID: 30725755.

Adult testicular torsion

Q: 19 years old college student presented to the Emergency Room with acute scrotal pain. The surgical ICU team has been called. Testicular torsion is suspected. In testicular torsion cremasteric reflex would be? (select one)

A) positive

B) negative

Answer: B

The cremasteric reflex is incited by stroking the ipsilateral thigh of the troubled site of the testis. If the testis does not pull up, the test is considered negative, and a presumptive diagnosis of testicular torsion should be made. Another important aspect of a physical exam in testicular torsion is to look for bell clapper deformity with a high-riding testis. Profound testicular swelling is very common. Diagnosis should be confirmed with scrotal ultrasound as soon as possible since testicular torsion is a urologic emergency. 

A delay of a few hours may cause testicular nonviability up to the extent that if a surgical route is not available, manual detorsion should be performed.

#urology

#surgical-critical-care

References:

1. Rabinowitz R. The importance of the cremasteric reflex in acute scrotal swelling in children. J Urol 1984; 132:89.

2. Kutikov A, Casale P, White MA, et al. Testicular compartment syndrome: a new approach to conceptualizing and managing testicular torsion. Urology 2008; 72:786.

3. Cummings JM, Boullier JA, Sekhon D, Bose K. Adult testicular torsion. J Urol 2002; 167:2109.

Dry purpura and wet purpura.

Q: Dry purpura is more pathognomonic than wet purpura.

A) True

B) False

Answer: B

Purpura is defined as coalesced petechiae, which are small, flat, red, and discrete areas of bleeding.

Dry purpura usually means purpura in the skin, and wet purpura means hemorrhagic blisters in mucous membranes. The most common cause is thrombocytopenia. Wet purpura is the most predictive of severe bleeding.

Purpura due to vasculitis is usually palpable and may be pruritic, and the distribution does not follow dependent areas.

#physical-exam

#dermatology

#hematology

References:

1. Mishra K, Jandial A, Malhotra P, Varma N. Wet purpura: a sinister sign in thrombocytopenia. BMJ Case Rep. 2017 Sep 1;2017:bcr2017222008. doi: 10.1136/bcr-2017-222008. PMID: 28864561; PMCID: PMC5589040.

2. Crosby WH. Editorial: Wet purpura, dry purpura. JAMA. 1975 May 19;232(7):744-5. doi: 10.1001/jama.232.7.744. PMID: 1173178.

QTc risk factors

Q: 43 years old patient is started in ICU on Quetiapine for possible delirium. The patient is noted to have progressive prolongation of QTc on EKG. Which gender is more prone to have Torsade de pointes (TdP)? (select one)

A) Male

B) Female

Answer: B

There are multiple risk factors for drug-induced TdP. The more risk factors, the more the chances of prolonged QTc degenerating into TdP. Out of all the risk factors, being a female gender carries the highest risk. Risk factors in line of descent include:

• Female sex 
• History of heart disease 
• Concurrent use of two QT-prolonging drug
• Hypokalemia
• High drug dose 
• Prior history of Long QTc 

#cardiology

References:

1. Drew BJ, Ackerman MJ, Funk M, et al. Prevention of torsade de pointes in hospital settings: a scientific statement from the American Heart Association and the American College of Cardiology Foundation. Circulation 2010; 121:1047.

2. Drici MD, Knollmann BC, Wang WX, Woosley RL. Cardiac actions of erythromycin: influence of female sex. JAMA 1998; 280:1774.

Nitrates MOA

Q: Anti-anginal effects of nitrates are primarily due to? (select one)

A) coronary vasodilatation

B) systemic vasodilation 

Answer: B

Nitrates are probably one of the oldest but still the first line of drugs for the relief of angina pectoris since last more than 150 years.

Although nitrates indeed vasodilate coronaries the primary anti-anginal effect is systemic vasodilation which reduces the left ventricular systolic wall stress. Nitrates are primarily venodilators, and have a modest arteriolar vasodilator effect. They have a synergetic effect when used with beta-blockers or calcium channel blockers.

Clinicians should stay aware that if a patient is hypovolemic, (s)he may have a precipitate drop in blood pressure due to arteriolar vasodilatation.

Nitrates may have some coronary effect by reversing coronary vasospasm, and indirectly improve subendocardial blood flow in synergism with decreased left ventricular end-diastolic pressure due to its systemic venous dilatation. Nitrates may also lower the resistance to collateral vessel blood flow.

It is less known that nitrates also have antiplatelet and antithrombotic characteristics.

#cardiology

#pharmacology

References:

1. Murrell W. Nitro-glycerine as a remedy for angina pectoris. Lancet 1879; 1:80.

2. Gibbons RJ, Abrams J, Chatterjee K, et al. ACC/AHA 2002 guideline update for the management of patients with chronic stable angina www.acc.org/qualityandscience/clinical/statements.htm (Accessed on August 24, 2006).

3. Abrams J. Hemodynamic effects of nitroglycerin and long-acting nitrates. Am Heart J 1985; 110:216.

4. Knight CJ, Panesar M, Wilson DJ, et al. Different effects of calcium antagonists, nitrates, and beta-blockers on platelet function. Possible importance for the treatment of unstable angina. Circulation 1997; 95:125.

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

ETT diameter

Q; Size of an Endotracheal Tube (ETT) represents? (choose one)

A) Internal diameter of ETT

B) External diameter of ETT

Answer: B

The “size” of an ET tube refers to its internal diameter. 

A “size 7 ” ET tube, means one with an internal diameter of 7 mm. ET tubes are usually labeled as ID (internal diameter) and OD (outside diameter).

#procedures

References:

1. Haas CF, Eakin RM, Konkle MA, Blank R. Endotracheal tubes: old and new. Respir Care. 2014 Jun;59(6):933-52; discussion 952-5. doi: 10.4187/respcare.02868. PMID: 24891200.

2. Esianor BI, Campbell BR, Casey JD, Du L, Wright A, Steitz B, Semler MW, Gelbard A. Endotracheal Tube Size in Critically Ill Patients. JAMA Otolaryngol Head Neck Surg. 2022 Sep 1;148(9):849-853. doi: 10.1001/jamaoto.2022.1939. PMID: 35900743; PMCID: PMC9335245.

3. Ahmed RA, Boyer TJ. Endotracheal Tube. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539747/

calcitonin in severe hypercalcemia

Q: 48 years old male with known metastatic lung cancer is admitted to ICU with severe hypercalcemia of 16.3 mg/dL. The patient appears to be very vasculopath and the patient arrived from the ER with one peripheral IV, which also appears to be infiltrated now. Which route would be more efficacious to administer Calcitonin at this point? (select one)

A) subcutaneous

B) intra-nasal 

Answer: A

Intra-nasal Calcitonin is usually not effective. Even if a good IV line is available, the best route to administer calcitonin is either intramuscularly (IM) or subcutaneously (SC). The patient can be either calcitonin responsive or not. The initial dose is 4 units/kg. If the patient is responsive, the calcium level should decrease in the next 6 hours by 1 to 2 mg/dL. If the patient is responsive, the total further course is every 12 hours for the next 24 to 48 hours till the calcium level drops to a desirable level. 

If the patient appears unresponsive or partially responsive, the dose can be increased to 8 units/kg every 6 to 12 hours, for the next 24 to 48 hours. Simultaneous standard management of hypercalcemia with IV hydration should be pursued.

After 48 hours body develops tachyphylaxis due to receptor downregulation. The mechanism of action is dual i.e., via renal excretion of calcium and by decreasing bone resorption.

#electrolytes

References:

1. Chevallier B, Peyron R, Basuyau JP, et al. [Human calcitonin in neoplastic hypercalcemia. Results of a prospective randomized trial]. Presse Med 1988; 17:2375.

2. Kiriakopoulos A, Giannakis P, Menenakos E. Calcitonin: current concepts and differential diagnosis. Ther Adv Endocrinol Metab. 2022 May 21;13:20420188221099344. doi: 10.1177/20420188221099344. PMID: 35614985; PMCID: PMC9125613.

3. Walker MD, Shane E. Hypercalcemia: A Review. JAMA. 2022 Oct 25;328(16):1624-1636. doi: 10.1001/jama.2022.18331. PMID: 36282253.

Asymptomatic candiduria in a renal transplant patients

Q: 46 years old patient with a history of successful kidney transplant about 6 years ago is admitted to ICU with chest pain and EKG changes. The night float intern sent urinalysis due to previous history though the patient did not have any urological complaints. The patient is found to have asymptomatic candiduria. Asymptomatic candiduria in a renal transplant is an absolute indication for the treatment.

A) True

B) False

Answer: B

Asymptomatic candiduria after renal transplantation is not an absolute indication for treatment, unless there is a high risk for graft involvement or the patient still carries a ureteral stent (like in the early phase of post-transplant).

A clinician may consider continuing management with an ultrasound of the KUB (Kidney, Ureter, Bladder) system to rule out any underlying possibility of fungus balls in high-risk patients like diabetics.

This conservative approach is to prevent resistant Candida infections in the future. A clinician should look for and reduce the risk factors that may be contributing to candiduria. If candiduria persists in the case of chronic bladder catheters or stents, replacement should be considered.

Patients who are required to undergo major surgery or have neutropenia may be considered for treatment at a provider's discretion.

#ID

#urology

References:

1. Pappas PG, Kauffman CA, Andes DR, et al. Clinical Practice Guideline for the Management of Candidiasis: 2016 Update by the Infectious Diseases Society of America. Clin Infect Dis 2016; 62:e1.

2. Sobel JD, Kauffman CA, McKinsey D, et al. Candiduria: a randomized, double-blind study of treatment with fluconazole and placebo. The National Institute of Allergy and Infectious Diseases (NIAID) Mycoses Study Group. Clin Infect Dis 2000; 30:19.

3. Jacobs DM, Dilworth TJ, Beyda ND, et al. Overtreatment of Asymptomatic Candiduria among Hospitalized Patients: a Multi-institutional Study. Antimicrob Agents Chemother 2018; 62.

Diphenhydramine in Palliative Care Patients

Q: 74 years old male is converted to hospice care after transfer to ICU due to distant metastases from pancreatic cancer. The patient requested a gentle medicine for proper sleep. Diphenhydramine (Benadryl) is an appropriate choice.

A) True

B) false

Answer: B

The above question intends to cover two objectives.

First, noise pollution in ICUs and inpatient wards is still an underestimated issue. Frequent alarms, ventilator noise, and blood draws at odd hours disrupt patients' sleep patterns and increase the rate of delirium in hospitals.

Non-pharmacological interventions always supersede pharmacological interventions.

The second objective is to underline the abuse of Diphenhydramine for insomnia in hospitals. It is conventionally believed that Diphenhydramine is a benign entity as it is easily available over the counter and is a good sedative to use as a sleep aid. Wrong. Although its antihistamine property makes it a sedative its anticholinergic effect decreases cognitive function and may cause delirium.

There is no reliable data on its use or safety particularly in hospice and palliative care patients.

#end-of-life-care

#pharmacology

Reference:

1. Nolen A, Dai T. Diphenhydramine Use Disorder and Complicated Withdrawal in a Palliative Care Patient. J Palliat Med. 2020 Sep;23(9):1279-1282. doi: 10.1089/jpm.2019.0308. Epub 2019 Dec 5. PMID: 31808723.

singers' emboli

Q: What is Singers' emboli?

Answer: Helium gas emboli in singers

An interesting cause of "Helium emboli" (popularly known as Singers' Emboli can occur from inhalation of pressurized helium. Some singers intentionally inhale high-pressure helium to enhance tone or to produce a change in their voice. Inhaled high-pressure gas can produce high trans-pulmonary pressure sufficient to rupture alveoli and surrounding blood vessels, introducing gas into the pulmonary veins and allowing systemic embolization through the left heart; particularly in an upright person!

But the more common cause of "helium emboli" is from IABP. Intra-aortic balloon Pump (IABP) Counter-pulsation utilizes helium gas to inflate its balloon. As Helium is a low density as well as an inert gas, in case of balloon rupture it is easily absorbed into the bloodstream. However, fairly well-numbered incidents of "Helium emboli" after balloon rupture have been described in the literature.

A major clinical sign of helium embolus is a neurological deficit associated with other findings of balloon rupture as blood in the tubing. Treatment is hyperbaric oxygen.

#pulmonary

References:

1. Cerebral and coronary gas embolism from the inhalation of pressurized helium Critical Care Medicine: May 2002 - Volume 30 - Issue 5 - pp 1156-1157

2. Cerebral Gas Embolism Resulting From Inhalation of Pressurized Helium - Annals of Emergency Medicine Volume 28, Issue 3, Pages 363-366, September 1996

Screening test for claustrophobic feeling in MRI

Q: 34 years old female is scheduled to go for a brain MRI in ICU. She never had an MRI before but has heard of claustrophobic feelings in MRIs. A screening test is requested from radiology. Which of the following is NOT a part of the screening test? (select one)

A) Tied up with hands behind back for 15 minutes

B) Standing for 15 minutes in a straight jacket

C) Working under a sink for 15 minutes

D) Lying on a bottom bunk bed

E) Driving long distance in an electric car 

Answer: E

A six-question test can fairly easily screen patients for MRI-induced claustrophobia. A score of nine or above is found to be highly predictive of panic during the scan. 

The core is divided into two parts with each section having three questions. Each question is graded from 0 to 4 (Not at all anxious to Extremely anxious)

Restriction items

1. Tied up with hands behind back for 15 minutes

2. Standing for 15 minutes in a straightjacket

3. Having your legs tied to an immovable chair

Suffocation items

1. Working under a sink for 15 minutes

2. Standing in an elevator on the ground floor with the doors closed

3. Lying on a bottom bunk bed

#radiology

#psychiatry

Reference:

McIsaac HK, Thordarson DS, Shafran R, Rachman S, Poole G. Claustrophobia and the magnetic resonance imaging procedure. J Behav Med. 1998 Jun;21(3):255-68. doi: 10.1023/a:1018717016680. PMID: 9642571.

Magnesium in ETOH withdrawal

Q: Severe alcohol withdrawal is usually associated with? (select one)

A) Hypomagnesemia 

B) Hypermagnesemia 

Answer: A

The three most common electrolyte imbalances in severe alcohol withdrawal are

• Hypokalemia 
• Hypomagnesemia and
• Hypophosphatemia 

Hypomagnesemia carries significant clinical predisposition with dysrhythmias, seizures, inhibition of response to thiamine.

#electrolytes

References:

1. Stasiukinene VP, Pilvinis VK, Reĭngardene DI. Gipomagniemiia u bol'nykh khronicheskim alkogolizmom vo vremia abstinentnogo sindroma [Hypomagnesemia in patients with chronic alcoholism in the course of alcohol withdrawal syndrome]. Ter Arkh. 2004;76(11):97-9. Russian. PMID: 15658551.

2. Elisaf M, Merkouropoulos M, Tsianos EV, Siamopoulos KC. Pathogenetic mechanisms of hypomagnesemia in alcoholic patients. J Trace Elem Med Biol. 1995 Dec;9(4):210-4. doi: 10.1016/S0946-672X(11)80026-X. PMID: 8808192.

Acute cholangitis: Diagnosis

Q: Laboratory evidence of cholestasis ____________ imaging with biliary dilation or evidence of the underlying etiology is required to make a diagnosis of acute cholangitis? (select one)

A) and

B) or

Answer: A

A diagnosis of acute cholangitis requires one of the following:

• Fever and/or shaking chills.
• Laboratory evidence of an inflammatory response via abnormal WBC, high CRP, or any lab suggestive of inflammation

and both of the following:

• Evidence of cholestasis: Bilirubin ≥2 mg/dL or abnormal liver chemistries (elevated alkaline phosphatase, gamma-glutamyl transpeptidase, alanine aminotransferase, or aspartate aminotransferase, to >1.5 times the upper limit of normal).
• Imaging with biliary dilation or evidence of the underlying etiology (eg, a stricture, stone, or stent).

#hepatology

References:

1. Nezam H Afdhal - https://www.uptodate.com/contents/acute-cholangitis-clinical-manifestations-diagnosis-and-management Link: https://www.uptodate.com/contents/acute-cholangitis-clinical-manifestations-diagnosis-and-management @ UptoDate (last accessed February 10, 2024)

2. Sokal A, Sauvanet A, Fantin B, de Lastours V. Acute cholangitis: Diagnosis and management. J Visc Surg. 2019 Dec;156(6):515-525. doi: 10.1016/j.jviscsurg.2019.05.007. Epub 2019 Jun 24. PMID: 31248783.

Fatal familial insomnia

Q: 58 years old Italian male is admitted to ICU from the ER due to symptoms of visual hallucinations, aggression, ataxia, myoclonus, and dysautonomia. While talking, his voice appears husky. The family reports progressive insomnia,  cognitive and memory deficits, as well as weight loss over the last 12 months. Subsequent workup from neurology service led to the diagnosis of autosomal FATAL FAMILIAL INSOMNIA. The family wants to know what other members should do besides genetic testing to avoid these symptoms?

Answer: Consider Doxycycline 

Fatal familial insomnia is an autosomal disease first reported in Italian families. It manifests in the fifth decade with symptoms of progressive insomnia and dream-like confusion state during waking hours; it is fatal and progresses rapidly, accompanied by neuropsychiatric symptoms. Motor disturbances such as myoclonus, ataxia, parkinsonism, and spasticity can also occur. Dysautonomia may lead to hyperhidrosis, hyperthermia, tachycardia, obstipation, and hypertension. Endocrine disturbances are also common. Diagnosis is via genetic testing. 

As the name suggests it is fatal and progresses rapidly with a mean duration of 13 months. Treatment is only supportive though agomelatine has been used.

Interestingly, doxycycline may provide some prophylaxis to humans with FFI mutation carriers.

#neurology

#genetics

References:

1. Krasnianski A, Bartl M, Sanchez Juan PJ, et al. Fatal familial insomnia: Clinical features and early identification. Ann Neurol 2008; 63:658.

2. Pedroso JL, Pinto WB, Souza PV, et al. Complex movement disorders in fatal familial insomnia: a clinical and genetic discussion. Neurology 2013; 81:1098.

3. Froböse T, Slawik H, Schreiner R, et al. Agomelatine improves sleep in a patient with fatal familial insomnia. Pharmacopsychiatry 2012; 45:34.

4. Forloni G, Tettamanti M, Lucca U, et al. Preventive study in subjects at risk of fatal familial insomnia: Innovative approach to rare diseases. Prion 2015; 9:75.

Steroids in HELLP

Q: 36-week pregnant patient presented with Right Upper Quadrant (RUQ) pain, elevated liver enzymes, severe hypertension (HTN), and thrombocytopenia. Patient is diagnosed with HELLP syndrome. The Obstetrics team is notified. Steroids have a beneficial effect in HELLP syndrome and should be used as an adjuvant treatment while awaiting delivery.

A) True

B) False

Answer: B

HELLP syndrome in pregnancy refers to the cluster of clinical myriad consists essentially of

• Hemolysis with a microangiopathic blood smear
• Elevated liver enzymes, 
• Low platelet count

HTN is common, and that's why many experts (though controversial) consider it a form of preeclampsia. Birth is the cornerstone of the treatment.

Though once considered an adjuvant treatment, steroids have no role in HELLP syndrome.

#OB-Gyn

#hepatology

#hematology

References:

1. Fonseca JE, Méndez F, Cataño C, Arias F. Dexamethasone treatment does not improve the outcome of women with HELLP syndrome: a double-blind, placebo-controlled, randomized clinical trial. Am J Obstet Gynecol 2005; 193:1591.

2. Katz L, de Amorim MM, Figueiroa JN, Pinto e Silva JL. Postpartum dexamethasone for women with hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome: a double-blind, placebo-controlled, randomized clinical trial. Am J Obstet Gynecol 2008; 198:283.e1.

Target of Urine PH in Salicylate toxicity

Q: In Salicylate toxicity what is the target of Urine PH?

Answer: 8

Renal elimination of salicylate can be achieved by alkaline diuresis to increase urine pH, ideally to more than/= 8. Alkaline diuresis is indicated for patients with any symptoms of poisoning and should not be delayed until salicylate levels are determined. This intervention is safe and exponentially increases salicylate excretion. Because hypokalemia may interfere with alkaline diuresis, patients are given a solution consisting of 1 L of 5% D/W, with 3 (50-mEq) ampules of NaHCO3, and 40 mEq of KCl. Serum K should be monitored closely.

Intensivists should also remember that there is always a risk of rebound salicylate toxicity following cessation of urine alkalinization. 

#toxicology

#nephrology

References:

1. American College of Medical Toxicology. Guidance document: management priorities in salicylate toxicity. J Med Toxicol. 2015 Mar;11(1):149-52. doi: 10.1007/s13181-013-0362-3. PMID: 25715929; PMCID: PMC4371029.

2. O'Keefe M, Stanton M, Feldman R, Theobald J. Incidence of rebound salicylate toxicity following cessation of urine alkalinization. Clin Toxicol (Phila). 2023 Jul;61(7):536-542. doi: 10.1080/15563650.2023.2227998. Epub 2023 Jul 10. PMID: 37427892.

Premedication for Fe infusion

Q: A 32-year-old female is prescribed intravenous (IV) iron by the hematology service in the ICU. The patient has a mild history of childhood asthma in the remote past. It would be important to premedicate with diphenhydramine (benadryl).

A) Yes

B) No

Answer: B

Premedication with diphenhydramine for iron deficiency anemia is associated with an increased likelihood of an infusion reaction and is not recommended to either treat or prevent the reaction from iron infusion. Diphenhydramine may cause hypotension, somnolence, flushing, dizziness, irritability, nasal congestion, wheezing, and supraventricular tachycardia (SVT).

In usual cases, including a mild history of asthma, no premedication is required. The best approach is to give infusion slowly. For patients who are at high risk of reaction, asthma,  inflammatory arthritis, and multiple drug allergies, premedication with steroids and an H2 blocker should be sufficient.

#allergy

#hematology

References:

1. Rampton D, Folkersen J, Fishbane S, et al. Hypersensitivity reactions to intravenous iron: guidance for risk minimization and management. Haematologica 2014; 99:1671.

2. Arastu AH, Elstrott BK, Martens KL, et al. Analysis of Adverse Events and Intravenous Iron Infusion Formulations in Adults With and Without Prior Infusion Reactions. JAMA Netw Open 2022; 5:e224488.

right-sided colonic diverticulitis

Q: Right-sided (cecal) diverticulitis is more common in younger patients?

A) True

B) False

Answer: A

Right-sided diverticulitis is relatively unknown in the Western world but is common in Asian countries. It tends to occur in younger patients and fortunately tends to have fewer complications as well as recurrences. Medical management is usually sufficient, and very rarely requires surgery. Many of these patients get misdiagnosed as having appendicitis

Treatment with antibiotic is usually sufficient. In a systematic review and meta-analysis of 11 studies, the pooled recurrence rate after nonoperative management was 12 percent (95% CI 10 to 15 percent) with a median follow-up of 34 months [113]. Only 10 percent of those who recurred required urgent surgery at the first recurrence, and there was no mortality. A right hemicolectomy may be required if there is a suspicion of underlying carcinoma.

#GI

#surgical-critical-care

References:

1. Oh HK, Han EC, Ha HK, et al. Surgical management of colonic diverticular disease: discrepancy between right- and left-sided diseases. World J Gastroenterol 2014; 20:10115.

2. Lee YF, Tang DD, Patel SH, et al. Recurrence of Acute Right Colon Diverticulitis Following Nonoperative Management: A Systematic Review and Meta-analysis. Dis Colon Rectum 2020; 63:1466.

3. Hildebrand P, Kropp M, Stellmacher F, et al. Surgery for right-sided colonic diverticulitis: results of a 10-year-observation period. Langenbecks Arch Surg 2007; 392:143.

IVF and postop ileus

Q: Liberal use of intravenous fluid during surgery is directly proportional to the postoperative ileus time.

A) True

B) False

Answer: A

Liberal or excessive perioperative fluid administration may lead to an extended time to the first flatus. This may also increase the Length of Stay (LOS), subjecting the patient to hospital-acquired infections (HAIs) and Deep Vein Thrombosis (DVTs).

Excessive perioperative fluid administration leads to edema of gastrointestinal walls and the ileus.

The ideal approach is to adopt perioperative "goal-directed" fluid administration.

#surgical-critical-care

References:

1. Nisanevich V, Felsenstein I, Almogy G, et al. Effect of intraoperative fluid management on outcome after intraabdominal surgery. Anesthesiology 2005; 103:25.

2. Corcoran T, Rhodes JE, Clarke S, et al. Perioperative fluid management strategies in major surgery: a stratified meta-analysis. Anesth Analg 2012; 114:640.

Triad of meningitis

Q: Which patient population usually presents with the classic triad of acute bacterial meningitis? (select one)

A) Older 

B) Younger

Answer: A

The classic triad of acute bacterial meningitis consists of the following:

• fever
• nuchal rigidity and 
• change in mental status

Patients in the sixth and above decades are more prone to present with a triad. In contrast, only one-third of younger patients present with a full triad, making it difficult to recognize the disease. 

Usually, patients present with sudden onset. Headaches are universal in all patients besides the above triad. Other associated symptoms are nausea, altered mental status, possibly seizures, aphasia, hemiparesis, cranial nerve palsy, rash, arthritis, papilledema, and coma.

Meningitis may occur secondary to sinusitis, otitis,, pneumonia, endocarditis or any other systemic disease.

#neurology

References:

1. van de Beek D, de Gans J, Spanjaard L, et al. Clinical features and prognostic factors in adults with bacterial meningitis. N Engl J Med 2004; 351:1849.

2. Weisfelt M, van de Beek D, Spanjaard L, et al. Community-acquired bacterial meningitis in older people. J Am Geriatr Soc 2006; 54:1500.

3. Attia J, Hatala R, Cook DJ, Wong JG. The rational clinical examination. Does this adult patient have acute meningitis? JAMA 1999; 282:175.

ethanol or a simple saline solution for bleeding peptic ulcers?

Q: If an 'epi' injection is not available during endoscopy, ethanol or a simple saline solution can be used for bleeding peptic ulcers.

A) True 

B) False

Answer: A

For bleeding peptic ulcers, different modalities can be applied to stop bleeding, including thermal coagulation, endoscopic clip placement, and/or injection with diluted epinephrine.

Epi injection provides local tamponade and vasospasm and is a good way of achieving temporary hemostasis. It is applied in four quadrants within 3 mm of the bleeding site. Another less-known advantage of epi is its potential to provide a cleaner field to evaluate the bleeding site. 

Though commonly used in the past, injection of absolute ethanol can be used instead of diluted epi with relatively same efficacy.

Interestingly, saline injection has also been used but has a higher chance of recurrent bleeding.

#GI

References:

1. Koyama T, Fujimoto K, Iwakiri R, et al. Prevention of recurrent bleeding from gastric ulcer with a nonbleeding visible vessel by endoscopic injection of absolute ethanol: a prospective, controlled trial. Gastrointest Endosc 1995; 42:128.

2. Lazo MD, Andrade R, Medina MC, et al. Effect of injection sclerosis with alcohol on the rebleeding rate of gastroduodenal peptic ulcers with nonbleeding visible vessels: a prospective, controlled trial. Am J Gastroenterol 1992; 87:843.

3. Laine L, Estrada R. Randomized trial of normal saline solution injection versus bipolar electrocoagulation for treatment of patients with high-risk bleeding ulcers: is local tamponade enough? Gastrointest Endosc 2002; 55:6.

Picture Diagnosis

 

Answer: Emphysematous Cholecystitis

Emphysematous cholecystitis is an acute infection of the gallbladder wall caused by gas-forming organisms. A supine view of the abdomen shows air in the wall (blue arrows) of the gallbladder (GB). There is also a lucency within the lumen of the gallbladder suggesting air inside the lumen. Just superior to the gallbladder is another collection of air (red arrow) that represents a pericholecystic abscess. The yellow arrow points to the PEG tube in the stomach.

#hepatology

Further reads:

1. Wu JM, Lee CY, Wu YM. Emphysematous cholecystitis. Am J Surg. 2010 Oct;200(4):e53-4. doi: 10.1016/j.amjsurg.2010.01.027. PMID: 20887835.

2. Kowalski A, Kashyap S, Mathew G, et al. Clostridial Cholecystitis. [Updated 2023 Feb 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448099/

Correct calcium by albumin level

Q: Correct calcium level is usually calculated by albumin level. What percentage of calcium is usually bound to albumin? (select one)

A) 15-25%

B) 40-45%

C) 60-75%

Answer: B

The objective of this question is to highlight the fact that conventional formulae used at the bedside to correct calcium given albumin level is not a reliable science as only 40-45% of Ca is bound to proteins, primarily albumin.

The formula usually used is 

Corrected [Ca]  =  Measured total [Ca] + (0.8  x  (4.0 - [Alb]))

Studies have shown that this widely used formula is very unreliable, particularly for ICU patients, and patients with renal insufficiency.

The gold standard method is to measure the ionized calcium.

On the same token, hyperalbuminemia may cause pseudo-hypercalcemia.

#electrolytes

References:

1. Gauci C, Moranne O, Fouqueray B, et al. Pitfalls of measuring total blood calcium in patients with CKD. J Am Soc Nephrol 2008; 19:1592.

2. Lian IA, Åsberg A. Should total calcium be adjusted for albumin? A retrospective observational study of laboratory data from central Norway. BMJ Open 2018; 8:e017703.

3. Ridefelt P, Helmersson-Karlqvist J. Albumin adjustment of total calcium does not improve the estimation of calcium status. Scand J Clin Lab Invest 2017; 77:442.

4. Smith JD, Wilson S, Schneider HG. Misclassification of Calcium Status Based on Albumin-Adjusted Calcium: Studies in a Tertiary Hospital Setting. Clin Chem 2018; 64:1713.

5. Slomp J, van der Voort PH, Gerritsen RT, et al. Albumin-adjusted calcium is not suitable for diagnosis of hyper- and hypocalcemia in the critically ill. Crit Care Med 2003; 31:1389.

Normal stool water osmolality

Q: Normal stool water osmolality is approximately equal to serum osmolality.

A) Yes

B) No

Answer: A

It is of clinical importance to understand the normal composition of stool. A normal human excretes only 100 mL of water each day. Due to this small amount, despite stool's high electrolyte concentrations, very little sodium i.e., 4 mEq, and potassium i.e., 9 mEq are lost in normal stool each day. Similarly, the total daily loss of bicarbonate plus organic acid anion salts is not significant.

Stool water osmolality is similar to the osmolality of serum i.e., 300 mOsm/kg.

Paying attention to stool water osmolality and electrolyte abnormalities may guide toward the underlying cause of diarrhea (see references.)

#GI

References:

1. Gennari FJ, Weise WJ. Acid-base disturbances in gastrointestinal disease. Clin J Am Soc Nephrol 2008; 3:1861.

2. Steffer KJ, Santa Ana CA, Cole JA, Fordtran JS. The practical value of comprehensive stool analysis in detecting the cause of idiopathic chronic diarrhea. Gastroenterol Clin North Am 2012; 41:539.

erythropoietin in optic neuritis

Q: Erythropoietin may have a ______________ effect on acute optic neuritis. (select one)

A) beneficial

B) deleterious

Answer: A

Although corticosteroids remain the mainstay of treatment for optic neuritis, other treatments have been either tried or in clinical trials. One such treatment with a beneficial effect is Erythropoietin. A probable mechanism of action is improved oxygen supply to the tissues by alleviating anemia.

At least in one clinical trial, when compared with a placebo, active treatment with Erythropoietin appears safe and is associated with reduced retinal nerve fiber layer thinning on optical coherence tomography and shortened latencies on visual evoked potential at 16 weeks.

Other treatments tried with various efficacy but no proven benefit yet are Dalfampridine, phenytoin, amiloride, and anti-LINGO monoclonal antibody.

#neurology

References:

1. Sühs KW, Hein K, Sättler MB, et al. A randomized, double-blind, phase 2 study of erythropoietin in optic neuritis. Ann Neurol 2012; 72:199.

2. Toosy AT, Mason DF, Miller DH. Optic neuritis. Lancet Neurol 2014; 13:83.

3. Horton L, Conger A, Conger D, et al. Effect of 4-aminopyridine on vision in multiple sclerosis patients with optic neuropathy. Neurology 2013; 80:1862.

Supratherapeutic INR

Q: 52 years old patient with active colon cancer and atrial fibrillation is admitted from ER to ICU with INR of 9 but no visible clinical bleed. The patient was sent to the ER after his scheduled INR blood draw at an outpatient clinic. Patient's active underlying cancer will ____________ the recovery of INR to therapeutic level? (Select one)

A) expedites

B) slows

Answer: B

Patients with supra-therapeutic levels between INR 4.5 to 10 without visible clinical bleeding usually do not require vitamin K administration. Holding of warfarin is usually sufficient. Said that at least one retrospective review shows that few conditions may slow this recovery, and there should be a low threshold for administration of Vitamin K in these patients' population.

• Older age - described as odds ratio [OR] 1.2 per decade of life
• Higher index INR - described as OR 1.25 per unit of elevation
• Lower warfarin maintenance dose described as OR 0.87 per 10 mg increase in total weekly dose
• Decompensated heart failure (OR 2.79)
• Active cancer (OR 2.48)
• Lack of rapid access to medical care

#hematology

Reference:

Hylek EM, Regan S, Go AS, et al. Clinical predictors of prolonged delay in return of the international normalized ratio to within the therapeutic range after excessive anticoagulation with warfarin. Ann Intern Med 2001; 135:393.