Colonoscopy prep

Q: It is required to prepare patients treated with 4L of polyethylene glycol for colonoscopy for the optimum view.

A) True

B) False

Answer: B

Evidence shows that patients who consume a low-residue diet or clear liquids for at least 24 hours before colonoscopy, rather than 4 L of polyethylene glycol, have no difference in preparation quality. A low-residue diet is low in fiber*. This means avoiding high-fiber foods, such as fruits, vegetables, and whole grains. Clear liquids include water, clear broth, coffee or black tea (no milk), ice, gelatin, and fruit juices without red pigments, as they can be mistaken for blood or can obscure mucosal viewing.

Some experts recommend a cautious approach with a low-residue diet for three days before colonoscopy, with only clear liquids the day before. Also, per American Society of Anesthesiologists (ASA) guidelines, patients should fast for a minimum of two hours after ingestion of clear liquids and six hours after ingestion of light meals before sedation is administered.

*Advise to refer to credible lists from societies/organizations

#GI

#procedures

References:

1. Scaglione G, Oliviero G, Labianca O, et al. One-Day versus Three-Day Low-Residue Diet and Bowel Preparation Quality before Colonoscopy: A Multicenter, Randomized, Controlled Trial. Dig Dis 2023; 41:708.

2. Park DI, Park SH, Lee SK, et al. Efficacy of prepackaged, low residual test meals with 4L polyethylene glycol versus a clear liquid diet with 4L polyethylene glycol bowel preparation: a randomized trial. J Gastroenterol Hepatol 2009; 24:988.

3. Sipe BW, Fischer M, Baluyut AR, et al. 726 Effect of low residual diet on colonoscopy bowel preparation. Gastrointest Endosc 2012; 75:AB163.

4. Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures: An Updated Report by the American Society of Anesthesiologists Task Force on Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration. Anesthesiology 2017; 126:376.

Classic neurologic triad of early disseminated Lyme disease

Q: What is the classic neurologic triad of early disseminated Lyme disease?

Answer: Although it may not always present as a triad, in classic cases, the triad consists of:

• meningitis
• cranial neuropathy
• motor or sensory radiculoneuropathy

The common neurologic features of early disseminated Lyme disease may include one or all of:

• Lymphocytic meningitis
• Unilateral or bilateral* cranial nerve palsies (mostly facial nerve)
• Radiculopathy
• Peripheral neuropathy
• Mononeuropathy multiplex
• Cerebellar ataxia 
• Encephalomyelitis 

Although the facial nerve is the most commonly affected cranial nerve, other nerves such as the abducens nerve may be involved.

*Lyme disease is one of the few causes of bilateral cranial nerve palsies, along with tuberculosis, sarcoidosis, and trauma. 

#neurology

References:

1. Halperin JJ. Nervous system Lyme disease. Infect Dis Clin North Am 2008; 22:261.

2. Sauer A, Hansmann Y, Jaulhac B, et al. Five cases of paralytic strabismus as a rare feature of lyme disease. Clin Infect Dis 2009; 48:756.

3. Lantos PM, Rumbaugh J, Bockenstedt LK, et al. Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR): 2020 Guidelines for the Prevention, Diagnosis and Treatment of Lyme Disease. Clin Infect Dis 2021; 72:e1.

PSA level and Acetaminophen

Q: Regular use of acetaminophen may cause falsely ____________ level of Prostate Specific Antigen (PSA). - Select one

A) elevated

B) lowered

Answer: B

Although it is known that a regular intake of 5-alpha-reductase inhibitors (like finasteride and dutasteride) decreases PSA by almost 50 percent, it is less known that regular use of NSAIDs and acetaminophen can also give lower PSA levels when compared with men not taking these drugs. This correlation is time-dependent, meaning longer duration of use may cause even lower PSA values, particularly in patients who are habitual users of NSAIDs, possibly due to the anti-inflammatory properties of these drugs.

Similarly, statin or thiazide use for over a year may lower PSA levels.

Either adjust PSA levels in these patients or interpret them with more caution.

#Urology

#pharmacology

References:

1.Etzioni RD, Howlader N, Shaw PA, et al. Long-term effects of finasteride on prostate specific antigen levels: results from the prostate cancer prevention trial. J Urol 2005; 174:877.

2. Singer EA, Palapattu GS, van Wijngaarden E. Prostate-specific antigen levels in relation to consumption of nonsteroidal anti-inflammatory drugs and acetaminophen: results from the 2001-2002 National Health and Nutrition Examination Survey. Cancer 2008; 113:2053.

3. Chang SL, Harshman LC, Presti JC Jr. Impact of common medications on serum total prostate-specific antigen levels: analysis of the National Health and Nutrition Examination Survey. J Clin Oncol 2010; 28:3951

Danger triangle of face

Q: 72-year-old patient who is intubated for a week due to severe ARDS after community-acquired pneumonia, noted to have an abscess of 2 x 3 cm at the nasal fold. The abscess appears slightly deep but is hard to ascertain. On slight palpation, it appears fluid-filled. Your next action?

A) Do needle aspiration

B) Do incision and drainage

C) Consult ENT

D) Observe

Answer: C

This question emphasizes the importance of infections and abscesses in the central triangle of the face (corners of the mouth and the nasal bridge). This area is popularly known as the "Danger Triangle of the Face" as it carries a high risk of septic phlebitis and intracranial extension through the cavernous sinus. 

Radiological workup to assess depth and evaluation by an ENT service are recommended instead of blind bedside incision and drainage. Usually, superficial abscesses can be managed with warm compresses and broad-spectrum antibiotics. However, early investigation is warranted to avoid major complications.

#ID

#ENT

References:

1. Pannu AK, Saroch A, Sharma N. Danger Triangle of Face and Septic Cavernous Sinus Thrombosis. J Emerg Med. 2017 Jul;53(1):137-138. doi: 10.1016/j.jemermed.2017.03.016. Epub 2017 Apr 10. PMID: 28408235.

2. Battistin U, Hallak YO, Hallak F, Hallak O, AlKhani R. Subacute Cavernous Sinus Thrombosis following a Dental Procedure: Case Report and Review of the Literature. Clin Neurol Neurosurg. 2020 Oct;197:106135. doi: 10.1016/j.clineuro.2020.106135. Epub 2020 Aug 16. PMID: 32836064.

3. Thong JK, Ho BJW, Lim EH, Singh S. A Rare Case of an Isolated Nasal Floor Abscess in an Immunocompetent Patient. Cureus. 2025 Nov 24;17(11):e97694. doi: 10.7759/cureus.97694. PMID: 41450431; PMCID: PMC12737980.

Water Hammer effect

Q: What is the "water hammer" effect in blunt aortic injury (BAI) during Motor Vehicle Accidents (MVA)?

Answer: The mechanism revolves around the isthmus

To understand "water hammer" in BAI, it helps to understand the role of the isthmus between the ascending and descending thoracic aorta as a "transition zone." The ascending aorta is more mobile, and as it transits around the isthmus, it becomes relatively fixed as the descending thoracic aorta. Because the isthmus is intrinsically weaker than the rest of the aorta, it stretches with rapid deceleration. For this reason, most BAIs occur at the aortic isthmus just distal to the (left) subclavian artery.

"Water hammer" effect: In MVA, compression of the abdomen secondary to sudden impact occludes the aorta and leads to rupture of the proximal, intrinsically weak isthmus. This phenomenon explains the correlation of geographically distant diaphragmatic rupture and BAI. This effect was first described more than six decades ago.

#trauma

#CVS

References:

Nikolic S, Atanasijevic T, Mihailovic Z, et al. Mechanisms of aortic blunt rupture in fatally injured front-seat passengers in frontal car collisions: an autopsy study. Am J Forensic Med Pathol 2006; 27:292.

LUNDERVALL J. THE MECHANISM OF TRAUMATIC RUPTURE OF THE AORTA. Acta Pathol Microbiol Scand 1964; 62:34.

Rizoli SB, Brenneman FD, Boulanger BR, Maggisano R. Blunt diaphragmatic and thoracic aortic rupture: an emerging injury complex. Ann Thorac Surg 1994; 58:1404.

Richens D, Field M, Neale M, Oakley C. The mechanism of injury in blunt traumatic rupture of the aorta. Eur J Cardiothorac Surg 2002; 21:288.

Night sweats associated with a strong, peculiar, moldy odor

Q: Which Infectious Disease (ID) may present with night sweats associated with a strong, peculiar, moldy odor?

Answer: Brucellosis

Although Brucellosis has many symptoms, it is hard to distinguish from other ID symptoms, such as fever, malaise, night sweats, arthralgias, weight loss, low back pain, headache, dizziness, anorexia, dyspepsia, abdominal pain, cough, and depression, and possibly hepatomegaly, splenomegaly, and/or lymphadenopathy, but the association of night sweats with a strong, peculiar, moldy (or musty) odor is characteristic of Brucellosis.

A couple of good reviews on Brucellosis can be found in the references below.

#ID

References:

1. Qureshi KA, Parvez A, Fahmy NA, Abdel Hady BH, Kumar S, Ganguly A, Atiya A, Elhassan GO, Alfadly SO, Parkkila S, Aspatwar A. Brucellosis: epidemiology, pathogenesis, diagnosis and treatment-a comprehensive review. Ann Med. 2023;55(2):2295398. doi: 10.1080/07853890.2023.2295398. Epub 2024 Jan 2. PMID: 38165919; PMCID: PMC10769134.

2. Khairullah AR, Kurniawan SC, Puspitasari Y, Aryaloka S, Silaen OSM, Yanestria SM, Widodo A, Moses IB, Effendi MH, Afnani DA, Ramandinianto SC, Hasib A, Riwu KHP. Brucellosis: Unveiling the complexities of a pervasive zoonotic disease and its global impacts. Open Vet J. 2024 May;14(5):1081-1097. doi: 10.5455/OVJ.2024.v14.i5.1. Epub 2024 May 31. PMID: 38938422; PMCID: PMC11199761.

3. Alavi SM, Alavi L. Treatment of brucellosis: a systematic review of studies in recent twenty years. Caspian J Intern Med. 2013 Spring;4(2):636-41. PMID: 24009951; PMCID: PMC3755828.

"Paradoxical hypokalemia"

Q: "Paradoxical hypokalemia" is more common in? - Select one

A) Hereditary hypokalemic periodic paralysis

B) Thyrotoxic hypokalemic periodic paralysis

Answer: B

Many patients with thyrotoxic periodic paralysis may develop worsening, "paradoxical" hypokalemia after potassium repletion. This phenomenon may even occur in the nonperiodic phase whenever potassium is repleted. The underlying pathophysiologic mechanism is increased thyroxine concentration, which causes exaggerated potassium uptake.

Interestingly, the treatment is further potassium repletion. Usually, the drop is around 0.4 mEq/L, which can be life-threatening in view of already critical hypokalemia in these patients. Unfortunately, these patients are prone to develop hyperkalemia after repletion.

The differential diagnosis is based on urinary potassium excretion rates. Patients with hereditary hypokalemic periodic paralysis have a low urinary excretion of potassium, while patients with paradoxical hypokalemia have higher urinary potassium excretion rates, higher renin levels, and require higher volumes of saline resuscitation.

#electrolytes

# nephrology

#neurology

References:

1. Shiang JC, Cheng CJ, Tsai MK, et al. Therapeutic analysis in Chinese patients with thyrotoxic periodic paralysis over 6 years. Eur J Endocrinol 2009; 161:911.

2. Sung CC, Cheng CJ, Chiang WF, et al. Etiologic and therapeutic analysis in patients with hypokalemic nonperiodic paralysis. Am J Med 2015; 128:289.

3. Qing G, Zakaria WNA, Rom FZM, Nik WNFHW, Zulkeflee HA, Rahim SNA. Thyrotoxic Hypokalemic Periodic Paralysis: Pathophysiological Mechanisms. Endocrinol Metab (Seoul). 2025 Dec;40(6):821-829. doi: 10.3803/EnM.2025.2554. Epub 2025 Dec 11. PMID: 41376301; PMCID: PMC12765881.

4. Holm-Yildiz S, Krag T, Witting N, Pedersen BS, Dysgaard T, Sloth L, Pedersen J, Kjær R, Kannuberg L, Dahlqvist J, de Stricker Borch J, Solheim T, Fornander F, Eisum AS, Vissing J. Hypokalemic periodic paralysis: a 3-year follow-up study. J Neurol. 2023 Dec;270(12):6057-6063. doi: 10.1007/s00415-023-11964-z. Epub 2023 Sep 1. PMID: 37656291; PMCID: PMC10632268.

Tricks of Bougie

Q: Endotracheal tube (ETT) introducer, popularly known as a 'Bougie ', should not be bent more than? - select one

A) 10 degrees

B) 30 degrees

C) 45 degrees

Answer: B

Three tricks to use Bougie successfully are:

1. Lubricating the lower part of the bougie. This may help the ETT to pass over. Avoid lubricating the part the operator will hold, as it may make it difficult to grasp and control.

2. Enter the bougie and try to keep it in the right corner of the mouth, while keeping the angle of approach to the larynx, and stay as anterior as possible. The objective is to avoid the midline and the incisors. Often, when entering the midline, it may get stuck at the base of the tongue and track posteriorly into the hypopharynx.

3. Bending the introducer at the distal level, depending on the view (from partially visible to the completely obscure view of the vocal cord), to about 10-20 cm. This allows the bougie to curve around the base of the tongue to travel towards the larynx. Some operators "hit-up" the bougie by stripping it firmly between the thumb and finger at about 15 cm from the distal tip. The friction from this maneuver heats up and stretches the material, while inducing a bend. 

The bend should never exceed 30 degrees (choice B); otherwise, the distal coudé tip will angle too anteriorly and may catch on the tracheal rings.

#procedures

#airway

References:

1. Sime J, Bailitz J, Moskoff J. The bougie: an inexpensive lifesaving airway device. J Emerg Med. 2012 Dec;43(6):e393-5. doi: 10.1016/j.jemermed.2010.11.053. Epub 2011 May 7. PMID: 21550750.

2. Shekhar AC, Altman-Ezzard M, Kimbrell J, Stebel J, Ashley E, Mitra A, Friedmann T, Abbott EE, Strother C, Kutzin J. Flexible Tip Bougie for Emergency Tracheal Intubation by Paramedics and Emergency Physicians. Air Med J. 2025 Jan-Feb;44(1):67-69. doi: 10.1016/j.amj.2024.11.013. Epub 2024 Dec 22. PMID: 39993863; PMCID: PMC12266224.

3. Bougie for Difficult Intubation - https://www.youtube.com/watch?v=Q9MlXl3NIzk

pulmonary contusion

Q: 38-year-old male is admitted to the ICU after a motor vehicle accident (MVA) with pulmonary contusion due to rapid inflation of the airbag. The patient is admitted to the ICU. Patient is now on high-flow nasal cannula (HFNC), saturating about 90 percent on pulse oximetry. The patient seems comfortable at rest but requires higher oxygenation while ambulating. There is no hypercarbia while ambulating. CXR shows subjective mild deterioration in 24 hours. The patient should have been intubated earlier and managed with low tidal volumes.

A) True

B) False

Answer: B

In pulmonary contusion, the most important thing is to follow the clinical deterioration. If you can manage hypoxemia with noninvasive oxygenation, you do not need mechanical ventilation. In pulmonary contusion, the patient should be "intubated only when necessary". Intubation and sedation with invasive mechanical ventilation do not either heal lungs fast or stabilize the chest wall. Although hypercapnia is an important marker of worsening gas exchange, clinical judgment supersedes the numbers. Intubation may bring longer lengths of stay and other complications.

If the patient gets intubated, a lung-protective strategy is preferred, and early extubation should always be the priority.

#pulmonary

#trauma

References:

1. Simon B, Ebert J, Bokhari F, et al. Management of pulmonary contusion and flail chest: an Eastern Association for the Surgery of Trauma practice management guideline. J Trauma Acute Care Surg 2012; 73:S351.

2. Shackford SR, Virgilio RW, Peters RM. Early extubation versus prophylactic ventilation in the high risk patient: a comparison of postoperative management in the prevention of respiratory complications. Anesth Analg 1981; 60:76.

3. Cohn SM, Dubose JJ. Pulmonary contusion: an update on recent advances in clinical management. World J Surg. 2010 Aug;34(8):1959-70. doi: 10.1007/s00268-010-0599-9. PMID: 20407767.

Drug interactions with Warfarin

Q: 57-year-old male with a history of atrial fibrillation and stable for the last few years on his medications, including warfarin, is admitted to the ICU with gastrointestinal bleeding (GIB). The patient visited his PCP 2 weeks ago for insomnia and was prescribed an off-label antidepressant for better sleep. Which medicine is probably the culprit? 

 Answer: Trazodone 

 Trazodone is widely used as an anti-insomnia medication off-label, but a few major dangers associated with it are worth considering 

•  Serotonin syndrome 
•  Cardiac arrhythmias due to prolongation of the QT interval 
• Increased risk of bleeding, particularly when used with NSAIDs, warfarin, antiplatelet, and anticoagulant medications 
• Priapism 
• Mania or hypomania 

 #pharmacology 

 References: 

Po AL. Antidepressants and upper gastrointestinal bleeding. BMJ. 1999 Oct 23;319(7217):1081-2. doi: 10.1136/bmj.319.7217.1081. PMID: 10531078; PMCID: PMC1116881.

anti-hypertensive in MH

Q: Which of the following anti-hypertensives should NOT be used in Malignant Hyperthermia (MH)? - select one

A) Beta-Blockers (BBs)

B) Calcium Channel Blockers (CCBs)

Answer: B

CCBs have been shown to worsen hyperkalemia, myocardial depression, and hypotension when co-administered with dantrolene in MH. It is not advisable to initiate CCBs for arrhythmias or hypertension when dantrolene is actively planned.

#pharmacology

References:

1. Rubin AS, Zablocki AD. Hyperkalemia, verapamil, and dantrolene. Anesthesiology 1987; 66:246.

2. Migita T, Mukaida K, Yasuda T, Hamada H, Kawamoto M. Calcium channel blockers are inadequate for malignant hyperthermia crisis. J Anesth. 2012 Aug;26(4):579-84. doi: 10.1007/s00540-012-1347-0. Epub 2012 Feb 16. PMID: 22349750.

CAA

Q: Hemorrhagic stroke in cerebral amyloid angiopathy (CAA) usually occurs at? - Select one

A) lobar locations

B) basal ganglia 

C) brainstem 

Answer: A

CAA is the second most common cerebral small vessel disease. The usual underlying pathophysiology is deposition of beta-amyloid in small arteries and arterioles in the leptomeninges and cerebral cortex. The other type is genetic CAA and causes deposition of other types of amyloid.

Radiologically and clinically, the most prominent changes are a loss of vascular integrity causing both large, symptomatic and small, asymptomatic brain hemorrhages, mostly restricted to typical locations in the cortex or subcortical white matter, known as lobar locations (choice A). The basal ganglia (choice B) and brainstem (Choice C) are usually spared. The reason for this sparing is not known. 

Also, CAA diagnostic criteria are based on the hemorrhage location, known as the 'Boston Criteria'.

#neurology

#vascular-medicine

#amyloidosis

References:

1. Revesz T, Holton JL, Lashley T, et al. Genetics and molecular pathogenesis of sporadic and hereditary cerebral amyloid angiopathies. Acta Neuropathol 2009; 118:115.

2. Vinters HV, Gilbert JJ. Cerebral amyloid angiopathy: incidence and complications in the aging brain. II. The distribution of amyloid vascular changes. Stroke 1983; 14:924.

3. Gilbert JJ, Vinters HV. Cerebral amyloid angiopathy: incidence and complications in the aging brain. I. Cerebral hemorrhage. Stroke 1983; 14:915.

4. Charidimou A, Boulouis G, Frosch MP, et al. The Boston criteria version 2.0 for cerebral amyloid angiopathy: a multicentre, retrospective, MRI-neuropathology diagnostic accuracy study. Lancet Neurol 2022; 21:714.

Steroids and HELLP Syndrome

Q: A 27-year-old female with a first pregnancy at 32 weeks is admitted to the ICU with a subcapsular liver hematoma due to HELLP syndrome. OB service is debating a C-section. Meanwhile, it would be beneficial to administer dexamethasone.

A) True

B) False

Answer: B

Although in the past corticosteroids, particularly dexamethasone, have been tried in HELLP syndrome, evidence has failed to show any benefit. Prompt delivery remained the ideal treatment. 

It did not show any change in maternal death, severe maternal morbidity, perinatal/infant death, the time to recovery of platelet counts and/or aspartate aminotransferase levels, or the frequency of complications.

#OB-GYN

#hepatology

Reference:

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.

Repeat Echo in IE

Q: A 56-year-old male with PMH of end-stage renal disease (ESRD) is recovering in the ICU after a bout of infective endocarditis (IE), while cardiac surgery is considering valve replacement. A repeat echocardiogram is warranted to determine the evolving size of the vegetation.

A) True

B) False

Answer: B

Repeating an 'echo' to determine change in vegetation size or based on the pathogen is not recommended. 'Echo' is highly overused in IE follow-ups.

Echocardiogram, either transthoracic or transesophageal, should be repeated only if a new complication or a clinical change occurs, such as:

• a new murmur
• suspicion of embolic phenomenon
• new or worsening heart failure
• atrioventricular block
• persistent fever 
• persistent bacteremia 
• Switching antibiotics to oral

#cardiology

#ID

References:

1. Tzimas G, Monney P, Antiochos P, Auberson D, Ianculescu N, Guery B, Niclauss L, Kirsch M, Papadimitriou-Olivgeris M. Real-World Diagnostic Performance of Repeat Transthoracic Echocardiography Within a Multimodality Imaging Approach in Patients With Suspected Infective Endocarditis. J Am Heart Assoc. 2026 Aug 18;15(16):e050020. doi: 10.1161/JAHA.126.050020. Epub 2026 Aug 7. PMID: 42568077.

2. Cabell CH, Fowler VG Jr. Repeated echocardiography after the diagnosis of endocarditis: too much of a good thing? Heart. 2004 Sep;90(9):975-6. doi: 10.1136/hrt.2003.031328. PMID: 15310673; PMCID: PMC1768410.

3. Greco CA, Zaccaria S, Casali G, Nicolardi S, Albanese M. Echocardiography in Endocarditis. Echocardiography. 2024 Oct;41(10):e15945. doi: 10.1111/echo.15945. PMID: 39432316.

Toxic megacolon and radiological FU

Q: A 23-year-old male is admitted to the ICU with a flare-up of his ulcerative colitis. CT scan in ED is consistent with Toxic Megacolon. Surgical service wrote for serial KUBs. What's the importance of serial KUBs in Toxic Megacolon?

Answer: May determine the course of toxic megacolon

Although CT is preferred over KUB in toxic megacolon, it's not practical to perform it every few hours. Instead, following clinical signs of toxicity with serial KUBs may help to determine the course of the disease. A progressive increase in small bowel gas on abdominal films may help determine whether toxic megacolon is worsening or improving. As the name implies, signs of clinical toxicity highly correlate with severity of toxic megacolon, such as fever, heart rate, neutrophilic leukocytosis, anemia, dehydration, mental status change, electrolyte abnormalities, and hypotension.

Also, an increase in small-bowel gas on abdominal films, or a changing pattern such as multiple air-fluid levels, may be helpful. If serial KUBs indicate treatment failure along with clinical signs, CT should be considered. Ultrasound has also been used successfully alongside serial KUBs.

#GI

#radiology

#surgical-critical-carew

References:

1. . Hokama A, Ohira T, Kishimoto K, et al. Impending megacolon: small bowel distension as a predictor of toxic megacolon in ulcerative colitis. Intern Emerg Med 2012; 7:487.

2. Arienti V, Campieri M, Boriani L, et al. Management of severe ulcerative colitis with the help of high resolution ultrasonography. Am J Gastroenterol 1996; 91:2163.

3. Moulin V, Dellon P, Laurent O, et al. Toxic megacolon in patients with severe acute colitis: computed tomographic features. Clin Imaging 2011; 35:431.

routes of succinylcholine

Q: 54-year-old male with severe vasculopathy started having seizures in the ICU and lost his IV access. After intramuscular benzodiazepine, the patient started losing his respiratory drive and started desaturating, though he continued to seize. Intubation is called, but due to seizure, may require Succinylcholine. Without IV access, it is OK to administer succinylcholine intramuscularly (IM).

A) True

B) False

Answer: A

Succinylcholine is a depolarizing neuromuscular blockade (NMB) with the fastest onset and shortest duration of all NMBs. Although Succinylcholine is designed and preferred to be given intravenously for Rapid Sequence Induction and Intubation (RSII), if the situation absolutely arises, it can be given IM at a higher dose of 3 to 4 mg/kg, though it may take up to 3-4 minutes for full effect, first reported almost 7 decades ago. 

It can be given intraosseously too and has been found to be comparable to the IV route (reference # 3)

Another less-known use of Succinylcholine is continuous infusion, mostly used in electroconvulsive therapy when a brief period of neuromuscular blockade is required, titrated to twitch depression.

#procedures

#pharmacology

References:

1. GLOWACKI ET, AUSTIN S, GREIFENSTEIN FE. Intramuscular doses of succinylcholine as an adjunct in anesthesia. Anesth Analg. 1958 Jul-Aug;37(4):211-6. PMID: 13583596.

2. VANDERVEEN JL, SNEDDON EA, SCHMIDT SJ. INTRAMUSCULAR SUCCINYLCHOLINE IN ADULTS. A CONTROLLED STUDY. Anesthesiology. 1963 Nov-Dec;24:765-9. doi: 10.1097/00000542-196311000-00003. PMID: 14071406.

2. Moore GP, Pace SA, Busby W. Comparison of intraosseous, intramuscular, and intravenous administration of succinylcholine. Pediatr Emerg Care. 1989 Dec;5(4):209-10. doi: 10.1097/00006565-198912000-00001. PMID: 2602189.

pericardiocentesis in PH patients

Q: Patients with which Pulmonary Hypertension Group (PH) have the highest chance of mortality from pericardial drainage? - select one

A) Group 1

B) Group 2

C) Group 3

D) Group 4

E) Group 5

Answer: A

One remarkable endeavor in pulmonary hypertension (PH) is its classification into five groups based on underlying pathology.

Group 1: Pulmonary Arterial Hypertension (PAH)

Group 2: PH Due to Left Heart Disease

Group 3: PH Due to Lung Diseases and/or Hypoxia

Group 4: Chronic Thromboembolic Pulmonary Hypertension (CTEPH)

Group 5: PH With Unclear or Multifactorial Mechanisms

Although it is known that any patient with PH has a higher chance of hemodynamic collapse during pericardiocentesis, knowing the patient's underlying pathology may help in clinical decision-making if the situation arises. Patients with Group 1 have higher mortality rates compared with other non-PAH groups during such a procedure, with an adjusted odds ratio (aOR) of 2.35 and a 95% confidence interval (CI) of 1.46-3.80.

Some reports suggest that performing this procedure gradually, under the guidance of a Pulmonary Artery Catheter (PAC/Swan-Ganz), may help.

#pulmonary

#procedures

References:

1. Vasquez MA, Iskander M, Mustafa M, et al. Pericardiocentesis Outcomes in Patients With Pulmonary Hypertension: A Nationwide Analysis from the United States. Am J Cardiol 2024; 210:232.

2. Singh A, Mosarla R, Carroll K, Sulica R, Pashun R, Bangalore S, Yuriditsky E. Pericardiocentesis in Severe Pulmonary Arterial Hypertension Guided by a Pulmonary Artery Catheter. JACC Case Rep. 2024 May 1;29(12):102339. doi: 10.1016/j.jaccas.2024.102339. PMID: 38984206; PMCID: PMC11232420.

3. Cabada-Garcia MJ et.al. Safety of pericardiocentesis in pulmonary arterial hypertension: a systematic review. Front Cardiovasc Med. 2025 Aug 18;12:1610419. doi: 10.3389/fcvm.2025.1610419. PMID: 40901363; PMCID: PMC12400511.

iNO weaning

Q: A 54-year-old female is in the ICU due to Pulmonary Arterial Hypertension (PAH) and has been dependent on inhaled Nitric Oxide (iNO) for the last few days. Every time there is an attempt to wean and discontinue iNO, the patient becomes hemodynamically unstable. Which one trick may help to wean and discontinue iNO relatively easily?

Answer: Addition of sildenafil 

It is well known that abrupt discontinuation of inhaled NO, particularly in patients who are dependent on it for many days, can precipitate rapid rebound of pulmonary hypertension and worsening of ventilation/perfusion (V/Q) mismatch, resulting in hypoxemia and/or hemodynamic instability. Risks continue to rise after the first 10-12 hours of dependence, particularly in older patients.

One marker for weaning-related hemodynamic instability is a patient whose blood pressure and hemodynamics respond well at initiation. Responders are at higher risk of instability on discontinuation!

Overlapping weaning with coadministration of sildenafil may transit weaning smoothly, along with slow weaning, may be over the days. Also, keeping FiO2 higher during weaning may help.

#pulmonary

#pharmacology

References:

1. Atz AM, Wessel DL. Sildenafil ameliorates effects of inhaled nitric oxide withdrawal. Anesthesiology 1999; 91:307.

2. Khawaja H, Sanders TA, Schreiber M, Bondi D, Shah P, Brennan G. Sildenafil as Bridge Therapy for Inhaled Nitric Oxide in Preterm Neonates. J Pediatr Pharmacol Ther. 2024 Oct;29(5):525-529. doi: 10.5863/1551-6776-29.5.525. Epub 2024 Oct 14. PMID: 39411417; PMCID: PMC11472410.

K_Kidney-Liver connection

Q: What is the K-Kidney-Liver connection in hepatic encephalopathy?

Answer: Exacerbation of hepatic encephalopathy in hypokalemia 

Although all electrolytes need to be managed in hepatic encephalopathy, potassium plays an integral role. Hypokalemia increases kidney ammonia production, which directly exacerbates hepatic encephalopathy.

Other causes of acute exacerbation of hepatic encephalopathy are:

• Gastrointestinal bleeding
• Infection/sepsis 
• Metabolic alkalosis
• Renal insufficiency
• Hypovolemia
• Hypoxia
• Sedative
• Hypoglycemia
• Constipation
• Hepatocellular carcinoma 
• Hepatic vein or portal vein thrombosis

#hepatology

#neurology

#electrolyte

References:

1. Ullah H, Et.al.. Hypokalemia as a responsible factor related with the severity of hepatic encephalopathy: a wide multination cross-sectional study. Ann Med Surg (Lond). 2023 Jun 23;85(6):2427-2431. doi: 10.1097/MS9.0000000000000470. PMID: 37363515; PMCID: PMC10289733.

2. Javed MW, Ahmad E, Ahmad H, Nayyer ZA. IMPACT OF HYPOKALEMIA ON HEPATIC ENCEPHALOPATHY AND ITS EFFECT ON DURATION OF STAY IN HOSPITAL. J Ayub Med Coll Abbottabad. 2024 Jul-Sep;36(3):506-509. doi: 10.55519/JAMC-03-13014. PMID: 39623823.

3. Mikkelsen ACD, Thomsen KL, Vilstrup H, Aagaard NK. Hypokalaemia - an active contributor to hepatic encephalopathy? Metab Brain Dis. 2023 Jun;38(5):1765-1768. doi: 10.1007/s11011-022-01096-0. Epub 2022 Nov 3. PMID: 36326977.

VPA side effects

Q: Valproic Acid (VPA) overdose may cause? - select one

A) anion gap metabolic acidosis (AGA)

B) non-anion gap metabolic acidosis (NAGA)

Answer: A

VPA has seen renewed enthusiasm in US ICUs because of its efficacy in delirium. That also brings concern for VPA toxicity. Besides the dreaded complications of cerebral edema and subclinical hyperammonemia and Valproate-related hyperammonemic encephalopathy, popularly known as VHE, it can also cause significant electrolyte and metabolic abnormalities. The most common are

• hypernatremia
• hyperosmolality
• hypocalcemia, and 
• elevated anion gap metabolic acidosis

- Hypernatremia occurs because VPA is administered as a sodium salt.

- Hyperosmolality occurs because VPA and its metabolites are low-molecular-weight, osmotically active acids.

- AGA may occur from mitochondrial dysfunction, carnitine deficiency, and/or overproduction of toxic VPA metabolites, which are themselves anions.

- Hypocalcemia occurs as calcium binds to anionic VPA metabolites.

#toxicity

#electrolytes

References:

1. Khoo SH, Leyland MJ. Cerebral edema following acute sodium valproate overdose. J Toxicol Clin Toxicol 1992; 30:209. 

2. Sammar A, Tawfik M, Fatima F, Butler A, Aylor-Lee K. Valproate-Induced Hyperammonemic Encephalopathy Causing New-Onset Seizures. Cureus. 2023 Oct 18;15(10):e47288. doi: 10.7759/cureus.47288. PMID: 38021840; PMCID: PMC10656206.

3. Anderson, GO, Ritland, S. Life threatening intoxication with sodium valproate. Clin Toxicol 1995; 33:279.

CRRT and magnesium

Q: Use of Regional citrate anticoagulation in Continuous Renal Replacement Therapy (CRRT) will cause? - Select one

A) hypermagnesemia

B) hypomagnesemia

Answer: B

Regional citrate anticoagulation should be considered a major intervention in all patients requiring CRRT, as it may cause alkalosis due to citrate. The concentration of buffers, i.e.,  bicarbonate and lactate, should be reduced. Also, citrate can bind magnesium. Dialysate magnesium should be raised to 0.75 mmol/L from 0.5 mmol/L.

#procedures

#nephrology

References:

1. DePriest J, Dodson C, Phelps B. The Impact of Regional Citrate Anticoagulation on Magnesium Replacement During CRRT. Hosp Pharm 2023; 58:255.

2. Billiet N, Merckx L, van der Laenen M, Vanelderen P, Boer W. Magnesium profiles in renal replacement therapy (rrt) on icu: citrate CVVH (CICVVH) vs. intermittent haemodialysis (IHD). Intensive Care Med Exp. 2015 Oct 1;3(Suppl 1):A630. doi: 10.1186/2197-425X-3-S1-A630. PMCID: PMC4796953.

EKG and RVMI

Q: In acute Right Ventricular Myocardial Infarction (RVMI), which electrocardiogram (EKG) lead's ST-elevation has the highest sensitivity and specificity?

Answer: V4R

Patients with inferior-posterior ST-elevation MI mostly have RVMI, causing the classic triad of:

• hypotension
• elevated jugular venous pressure (JVP), and 
• clear lung fields

ST elevation >1 mm in lead V4R has> 90% sensitivity and specificity for scintigraphic evidence of RV infarction and 80% for echocardiographic evidence of RV dysfunction. A clinical pearl to remember is that the right-sided ST elevation is often transient, lasting less than 10 hours in 50% of patients with RV infarction.

#cardiology

References:

1. Watanabe S, Onuma J, Ishida R, Masuda R, Usui M. Clinical Significance of V4R ST-Segment Elevation on a Synthesized 18-Lead Electrocardiogram in Patients With Anterior ST-Segment Elevation Myocardial Infarction. Catheter Cardiovasc Interv. 2026 Jul;108(1):221-227. doi: 10.1002/ccd.70646. Epub 2026 Apr 26. PMID: 42036972.

2. Braat SH, Brugada P, de Zwaan C, et al. Value of electrocardiogram in diagnosing right ventricular involvement in patients with an acute inferior wall myocardial infarction. Br Heart J 1983; 49:368.

3. Candell-Riera J, Figueras J, Valle V, et al. Right ventricular infarction: relationships between ST segment elevation in V4R and hemodynamic, scintigraphic, and echocardiographic findings in patients with acute inferior myocardial infarction. Am Heart J 1981; 101:281.

SAH, SIADH and CSW

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Q: Hyponatremia in Subarachnoid hemorrhage (SAH) due to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and cerebral salt wasting can be distinguished by? 

A) level of hyponatremia 

B) serum osmolality

C) urine sodium

D) urine osmolality 

E) intravascular volume status

Answer: E

Hyponatremia in SAH may occur via two mechanisms, i.e., SIADH or cerebral salt wasting. Both are physiologically distinct entities, but hard to differentiate. Both entities have similar levels of hyponatremia, low serum osmolality (<274 mosmol/kg), high urine sodium (>40 mEq/L), and high urine osmolality (>100 mosmol/kg).

  

The major distinguishing feature is intravascular volume status. Patients with SIADH are euvolemic or maybe even hypervolemic. In contrast, patients with cerebral salt wasting tend to be hypovolemic.

  

#electrolytes

#nephrology

#neurology

  

  

References:

  

1. Muehlschlegel S. Subarachnoid Hemorrhage. Continuum (Minneap Minn) 2018; 24:1623.

  

2. Sterns RH, Silver SM. Cerebral salt wasting versus SIADH: what difference? J Am Soc Nephrol. 2008 Feb;19(2):194-6. doi: 10.1681/ASN.2007101118. Epub 2008 Jan 23. PMID: 18216309.

DAPT score

Q: The DAPT (Dual antiplatelet therapy) score is created to decide whether DAPT should be started, continued, or stopped? - Select one

A) at the time of the insertion of coronary stents

B) in the event of major surgery while the patient is on DAPT

C) at 12 months after insertion of a coronary stent

D) in patients with major bleeding risk

Answer: C

The DAPT score was developed to determine whether extended DAPT (i.e., beyond 12 months) might be appropriate. The DAPT score is based on eleven variables:

• Age 
• Diabetes Mellitus
• Cigarette Smoking Within Last Two Years
• Prior Myocardial Infarction or Percutaneous Coronary Intervention
• History of Congestive Heart Failure or Left Ventricular Ejection Fraction lower than 30%
• Hypertension
• Renal Insufficiency
• Peripheral Arterial Disease
• Myocardial Infarction at Presentation
• Stenting of Vein Graft
• Stent Diameter less than 3mm

Entering the data into the calculator will show the change in Risk if DAPT is continued or discontinued.

*Calculator link in reference #3

#cardiology

References:

1. Tian J, Wang Z, Wang Y, et al. Extended Dual Antiplatelet Therapy for Multivessel Coronary Artery Disease. N Engl J Med 2026; 395:233.

2. Mihatov N, Secemsky EA, Kereiakes DJ, Steg G, Serruys PW, Chichareon P, Shen C, Yeh RW. Utility of the dual antiplatelet therapy score to guide antiplatelet therapy: A systematic review and meta-analysis. Catheter Cardiovasc Interv. 2021 Mar;97(4):569-578. doi: 10.1002/ccd.29352. Epub 2020 Oct 28. PMID: 33111495; PMCID: PMC8620187.

3. https://tools.acc.org/DAPTriskapp/#!/content/calculator/

Vanc in critically ill patients

Q: Critically ill patients may require ___________ vancomycin loading doses? - select one

A) higher

B) lower

Answer: A

Critically ill patients usually have a high volume of distribution, which may increase vancomycin clearance. These patients may require higher vancomycin loading doses up to 25 to 30 mg/kg to achieve optimal vancomycin levels, particularly in the initial phase of illness. 

In these patients, it should be kept in mind that concomitant renal insufficiency or the need for renal replacement therapy/dialysis may significantly alter the need. Close monitoring of peak and, particularly, trough levels should guide therapy.

#pharmacology

#ID

References:

1. Pongchaidecha M, Changpradub D, Bannalung K, et al. Vancomycin Area under the Curve and Pharmacokinetic Parameters during the First 24 Hours of Treatment in Critically Ill Patients using Bayesian Forecasting. Infect Chemother 2020; 52:573.

2. Ishigo T, Ibe Y, Fujii S, et al. Effect of renal clearance on vancomycin area under the concentration-time curve deviations in critically ill patients. J Infect Chemother 2023; 29:769.

3. Alsultan A, Dasuqi SA, Almohaizeie A, et al. External Validation of Obese/Critically Ill Vancomycin Population Pharmacokinetic Models in Critically Ill Patients Who Are Obese. J Clin Pharmacol 2024; 64:353.

Haloperidol vs Droperidol

Q: 52 years old male admitted to ICU for acute psychosis became violent towards medical staff. Pharmacy suggested Droperidol. How Droperidol is different from Haloperidol?

Answer: Droperidol has an advantage over haloperidol in that it has:

• more rapid onset of action 
• shorter duration of effect
• can be used as monotherapy
• IM works as well as IV 

Droperidol is an analog of haloperidol. It has an advantage over haloperidol, with a more rapid onset of action (3-10 minutes) and a shorter duration of action (2-4 hours). In contrast, the onset of action of haloperidol, whether given intravenously (IV) or intramuscularly (IM), occurs within 30 to 60 minutes, and the duration of action can last up to a full day. Droperidol can be given IV or IM; however, compared with haloperidol, IM droperidol is rapidly absorbed and is preferable if the patient is not cooperative enough to allow IV access. Administration of Haloperidol usually requires co-administration of other drugs such as benzodiazepines, whereas droperidol works well as a monotherapy. 

#psychiatry

#pharmacology

References:

1. Battaglia J. Pharmacological management of acute agitation. Drugs 2005; 65:1207.

2. Thomas H Jr, Schwartz E, Petrilli R. Droperidol versus haloperidol for chemical restraint of agitated and combative patients. Ann Emerg Med 1992; 21:407.

3. Knott JC, Taylor DM, Castle DJ. Randomized clinical trial comparing intravenous midazolam and droperidol for sedation of the acutely agitated patient in the emergency department. Ann Emerg Med 2006; 47:61.

4. Page CB, Parker LE, Rashford SJ, et al. A Prospective Before and After Study of Droperidol for Prehospital Acute Behavioral Disturbance. Prehosp Emerg Care 2018; 22:713.

Acute HIV lasting longer than 2 weeks

Q: A 24-year-old male who just returned from vacation presented to the ED with a mononucleosis-like illness. Given a history of unprotected sex while on vacation, an HIV test was sent, which unfortunately came back positive. Patient reports his symptoms have been lasting for the last three weeks. What's the importance of his acute HIV infection lasting longer than usual?

Answer: Correlate with more rapid progression to AIDS 

Symptoms of acute HIV infection are usually most like a mononucleosis-like illness with fever, lymphadenopathy, sore throat, rash, myalgia/arthralgia, diarrhea, and headache. 

It is rarely realized that up to 60 percent of patients who acquire HIV may never experience these symptoms, which is both good and bad! Good - because those patients whose symptoms are severe and last longer than the usual 2-week period are found to correlate with more rapid progression to AIDS. Bad - because they may not get diagnosed for a long time!

During the acute HIV phase, there is rapid viral replication and infection of CD4 cells, and the plasma viral RNA level is usually very high. There may also be a transient drop in CD4 cell count.

#ID

References:

1. Pedersen C, Lindhardt BO, Jensen BL, et al. Clinical course of primary HIV infection: consequences for subsequent course of infection. BMJ 1989; 299:154.

2. Chéret A. Acute HIV-1 Infection: Paradigm and Singularity. Viruses. 2025 Mar 3;17(3):366. doi: 10.3390/v17030366. PMID: 40143294; PMCID: PMC11945883.

3. Cowan E, Vail RM, Shah SS, et al. Diagnosis and Management of Acute HIV Infection [Internet]. Baltimore (MD): Johns Hopkins University; 2024 Dec. Available from: https://www.ncbi.nlm.nih.gov/books/NBK563020/

Colchicine and pericarditis

Q: Colchicine is found to be effective in pericarditis caused by? - select one

A) systemic inflammatory diseases

B) bacterial pericarditis

C) malignancy-related pericarditis

Answer: A

Colchicine is widely used for pericarditis, but it should be reserved for specific situations. Its use may be particularly harmful in bacterial pericarditis, where it may impair the clearance of the infectious organism. Similarly, it has no role in malignancy-related pericarditis and/or pericardial effusion. Also, it is not recommended in patients with recurrent pericarditis.

Said above, colchicine is an effective treatment in acute idiopathic, viral, and pericarditis caused by systemic inflammatory diseases and post-cardiac injury & surgery patients. If used, it is recommended to continue for 12 weeks after an initial episode, though many patients may develop diarrhea, nausea, and vomiting. In such cases, the dose can be decreased. Rare side effects are bone marrow suppression and liver and muscle injuries. The dose should be adjusted for lower renal GFR.

#cardiology

#pharmacology

References:

1. Schulz-Menger J, Collini V, Gröschel J, et al. 2025 ESC Guidelines for the management of myocarditis and pericarditis. Eur Heart J 2025; 46:3952.

2. Alabed S, Cabello JB, Irving GJ, et al. Colchicine for pericarditis. Cochrane Database Syst Rev 2014; :CD010652.

3. Imazio M, Brucato A, Belli R, et al. Colchicine for the prevention of pericarditis: what we know and what we do not know in 2014 - systematic review and meta-analysis. J Cardiovasc Med (Hagerstown) 2014; 15:840.

Transmission of human babesiosis

Q: Babesiosis is mostly transmitted by? - select one

A) blood transfusion

B) solid organ transplantation

C) transplacental

D) tick vectors

Answer: D

The objective of this question is to emphasize that babesiosis has increased considerably in the Northeast of the USA and is an emerging infectious disease of concern. 

The major cause is the rising deer population with concomitant increased tick density, due to lack of predators and insufficient culling of the herd. Another major reason is the expanding real estate in wooded areas.

Rash is the crucial differential diagnosis from Lyme disease, as rash rarely occurs in babesiosis. Both diseases may co-exist, though.

In its severe form, it can cause renal and liver insufficiency, ARDS, CHF, severe anemia, DIC, and shock. Spontaneous splenic rupture may occur from excessive erythrophagocytosis, a marker of high mortality.

#ID

References:

1. Krause PJ, Auwaerter PG, Bannuru RR, et al. Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA): 2020 Guideline on Diagnosis and Management of Babesiosis. Clin Infect Dis 2021; 72:185.

2.  Dumic I, Patel J, Hart M, et al. Splenic Rupture as the First Manifestation of Babesia Microti Infection: Report of a Case and Review of Literature. Am J Case Rep 2018; 19:335.

3. Krause PJ. Human babesiosis. Int J Parasitol. 2019 Feb;49(2):165-174. doi: 10.1016/j.ijpara.2018.11.007. Epub 2019 Jan 26. PMID: 30690090.

Angioedema Following Discontinuation of ACE Inhibitor Therapy

Q: Angioedema may occur even after Angiotensin Converting Enzyme inhibitor (ACE-I) is discontinued?

A) True

B) False

Answer: A

Although it is true that the only reliable treatment of ACE-I-induced angioedema is to discontinue it, it may take many months before it takes effect, and almost half of the patients may have a recurrent episode, particularly in the first month. Risk may get higher if the patient has any other reason to have angioedema.

#pharmacology

References:

1. Beltrami L, Zanichelli A, Zingale L, et al. Long-term follow-up of 111 patients with angiotensin-converting enzyme inhibitor-related angioedema. J Hypertens 2011; 29:2273.

2. Perman B, Narechania S, Malesker M. Geriatric Pharmacotherapy Case Series: Recurrent Angioedema Following Discontinuation of ACE Inhibitor Therapy. Sr Care Pharm. 2023 Jan 1;38(1):16-20. doi: 10.4140/TCP.n.2023.16. PMID: 36751921.

DDAVP and Hemophilia

Q: Desmopressin (DDAVP) can be given in bleeding patients with? - select one

A) hemophilia A

B) hemophilia B 

Answer: A

Hemophilia is simply divided into two types of factor deficiency

• Hemophilia A - deficiency of Factor VIII
• Hemophilia B - deficiency of Factor IX

DDAVP is a synthetic analog of vasopressin that also releases factor VIII and its carrier protein, von Willebrand factor (VWF), from storage pools in platelet granules and endothelial cells.

Factor IX is not present in storage pools; therefore, DDAVP has no role in Hemophilia B.

#hematology

References:

1. Reardon B, Pasalic L, Favaloro EJ. A Review of Desmopressin Use in Bleeding Disorders: An Unsung Hero? Biomolecules. 2025 Jul 5;15(7):967. doi: 10.3390/biom15070967. PMID: 40723839; PMCID: PMC12292229.

2. Kavakli K, Aydinok Y, Karapinar D, Balkan C. DDAVP treatment in children with haemophilia B. Br J Haematol. 2001 Sep;114(3):733-4. doi: 10.1046/j.1365-2141.2001.02924-2.x. PMID: 11553008.

3. Leissinger C, Carcao M, Gill JC, Journeycake J, Singleton T, Valentino L. Desmopressin (DDAVP) in the management of patients with congenital bleeding disorders. Haemophilia. 2014 Mar;20(2):158-67. doi: 10.1111/hae.12254. Epub 2013 Aug 12. PMID: 23937614.

RBC Ghosts

Q: Red Blood Cell (RBC) ghosts can be seen mostly with which bacterial infection?

Answer: Clostridium perfringens

RBC ghosts are RBC membranes devoid of hemoglobin. This occurs when intravascular lysis causes hemoglobin to leak into the plasma. RBC ghosts are usually seen in fulminant bacteremia, and most commonly with Clostridium perfringens. Other major infections that may create RBC ghosts are:

• Malaria
• Babesia
• Leishmania
• Bartonella
• Protozoa

C. perfringens can cause massive, life-threatening hemolysis via its alpha toxin, a pore-forming toxin that binds glycosylphosphatidylinositol (GPI) anchored proteins and inserts into cell membranes. Interestingly, this massive hemolysis may give rise to laboratory errors, such as faulty sample collection.

#hematology

#ID

#laboratory-science

References:

1. Hübl W, Mostbeck B, Hartleb H, et al. Investigation of the pathogenesis of massive hemolysis in a case of Clostridium perfringens septicemia. Ann Hematol 1993; 67:145.

2. Kennedy CL, Lyras D, Cordner LM, et al. Pore-forming activity of alpha-toxin is essential for clostridium septicum-mediated myonecrosis. Infect Immun 2009; 77:943.

3. Rodriguez FJ, Ritter MJ, Tauscher CD, Moore SB. Transfusion medicine illustrated. Massive hemolysis secondary to alpha-toxin release. Transfusion 2005; 45:127.