My patient with brain tumor suffered a myocardial infarction (MI) just before having a diagnostic brain surgery. Could the tumor have placed him at higher risk of a coronary event?

Yes! Arterial thromboembolism—just as venous thromboembolism— is more common in patients with cancer.

In a large 2017 epidemiologic study involving patients 66 years of age or older, the 6-month cumulative incidence of MI was nearly 3-fold higher in newly-diagnosed cancer patients compared to controls, with the excess risk resolving by 1 year. 1 These findings were similar to a previous report involving patients with newly-diagnosed cancer, although in that study the overall coronary heart disease risk remained slightly elevated even after 10 years. 2

In addition, the incidence of coronary events and unstable ischemic heart disease during the 2 year period prior to the diagnosis of cancer is 2-fold higher among cancer patients suggesting that ischemic heart disease may be precipitated by occult cancer. 3

The association of cancer and thromboembolic coronary events may be explained through several mechanisms, including development of a prothrombotic or hypercoagulable state through acute phase reactants, abnormal fibrinolytic activity and increased activation of platelets which are also significantly involved in the pathophysiology of acute coronary syndrome (ACS). 4 Coronary artery embolism from cancer-related marantic endocarditis may also occur.5

More specific to our case, primary brain tumors may be associated with a hypercoagulable state through expression of potent procoagulants such as tissue factor and tissue factor containing microparticles, with a subset producing carbon monoxide, another procoagulant. 6

So our patient’s MI prior to his surgery for brain tumor diagnosis might have been more than a pure coincidence!

Bonus Pearl: Did you know that cancer-related prothrombotic state, also known as  “Trousseau’s syndrome” was first described in 1865 by Armand Trousseau, a French physician who diagnosed the same in himself and died of gastric cancer with thrombotic complications just 2 years later? 7,8

References

  1. Navi BB, Reinder AS, Kamel H, et al. Risk of arterial thromboembolism in patients with cancer. JACC 2017;70:926-38. https://www.ncbi.nlm.nih.gov/pubmed/28818202
  2. Zoller B, Ji Jianguang, Sundquist J, et al. Risk of coronary heart disease in patients with cancer: A nationwide follow-up study from Sweden. Eur J Cancer 2012;48:121-128. https://www.ncbi.nlm.nih.gov/pubmed/22023886
  3. Naschitz JE, Yeshurun D, Abrahamson J, et al. Ischemic heart disease precipitated by occult cancer. Cancer 1992;69:2712-20. https://www.ncbi.nlm.nih.gov/pubmed/1571902
  4. Lee EC, Cameron SJ. Cancer and thrombotic risk: the platelet paradigm. Frontiers in Cardiovascular Medicine 2017;4:1-6. https://www.ncbi.nlm.nih.gov/pubmed/29164134
  5. Lee V, Gilbert JD, Byard RW. Marantic endocarditis-A not so benign entity. Journal of Forensic and Legal Medicine 2012;19:312-15. https://www.ncbi.nlm.nih.gov/pubmed/22847046
  6. Nielsen VG, Lemole GM, Matika RW, et al. Brain tumors enhance plasmatic coagulation: the role of hemeoxygenase-1. Anesth Analg 2014;118919-24. https://www.ncbi.nlm.nih.gov/pubmed/24413553
  7. Thalin C, Blomgren B, Mobarrez F, et al. Trousseau’s syndrome, a previously unrecognized condition in acute ischemic stroke associated with myocardial injury. Journal of Investigative Medicine High Impact Case Reports.2014. DOI:10.1177/2324709614539283. https://www.ncbi.nlm.nih.gov/pubmed/26425612
  8. Samuels MA, King MA, Balis U. CPC, Case 31-2002. N Engl J Med 2002;347:1187-94. https://www.nejm.org/doi/pdf/10.1056/NEJMcpc020117?articleTools=true

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My patient with brain tumor suffered a myocardial infarction (MI) just before having a diagnostic brain surgery. Could the tumor have placed him at higher risk of a coronary event?

My middle-aged patient with a history of mediastinal irradiation for Hodgkin’s lymphoma in his 20s now has moderate aortic regurgitation. Could his valvular disease be related to the radiation he received over 20 years ago?

Absolutely! Mediastinal irradiation is associated with several cardiac complications, including coronary artery disease, pericarditis, systolic or diastolic dysfunction and valvular disease. Valvular disease may occur in 2-37% of patients after mediastinal irradiation, is dose-dependent, and generally does not manifest until 10-20 years after the radiation exposure.1 Since mediastinal irradiation is common in young adults diagnosed with Hodgkin’s lymphoma, these complications may be seen in early middle-age or later.

Valvular retraction is usually the first radiation-induced valvular change, and most commonly leads to mitral and aortic valve regurgitation.2 This retraction tends to occur within 10 years of the radiation therapy, followed by fibrosis and calcification of the valves after 20 years.

Although the pathophysiology of radiation-induced valvular disease is not entirely understood, activation of fibrogenic growth factors (eg, tissue growth factor β1 and myofibroblasts) which promote the synthesis of collagen has been postulated.1 Additionally, irradiation of aortic interstitial cells has been shown to cause transformation to an osteogenic phenotype that produces bone morphogenic protein 2, osteopontin and alkaline phosphatase, all important factors in bone formation and possibly valvular calcification.3

Since radiation-induced heart disease is the most common cause of non-malignant morbidity and mortality in patients who have undergone mediastinal irradiation, some have recommended screening of asymptomatic patients for valvular disease every 5 years by echocardiography beginning 10 years after radiation therapy. 2  If an abnormality is found, the screening frequency should increase to every 2-3  years,  if the valvular abnormality is mild, or annually if the abnormality is moderate. For severe valvular abnormalities, the patients should be considered for valve replacement.

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References

    1. Gujral DM, Lloyd G, Bhattacharyya S. Radiation-induced valvular heart disease. Heart 2016;102:269–276. https://heart.bmj.com/content/heartjnl/102/4/269.full.pdf
    2. Cuomo JR, Sharma GK, Conger PD, Weintraub NL. Novel concepts in radiation-induced cardiovascular disease. World J Cardiol. 2016; 8 (9):504-519. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5039353/
    3. Nadlonek NA, Weyant MJ, Yu JA, et al. Radiation induces osteogenesis in human aortic valve interstitial cells. J Thorac Cardiovasc Surg 2012;144:1466–70. doi:10.1016/j.jtcvs.2012.08.041 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3665422/

Contributed by Rachel Wallwork, MD, Mass General Hospital, Boston, MA

 

My middle-aged patient with a history of mediastinal irradiation for Hodgkin’s lymphoma in his 20s now has moderate aortic regurgitation. Could his valvular disease be related to the radiation he received over 20 years ago?

Does erythrocyte sedimentation rate (ESR) have diagnostic utility in my patient with chronic renal failure?

Short answer: often not! This is because most studies have shown frequently high ESR’s in stable “uninflamed” patients with chronic renal failure (CRF) (including those on dialysis) at levels often associated with infection, connective tissue disease, or malignancy. 1-4  

In fact, in a study involving patients with CRF, 57% of patients had markedly elevated ESR (greater than 60 mm/h), with 20% having ESR greater than 100 mm/h; type or duration of dialysis had no significant effect on ESR levels.1 Another study reported a specificity for abnormal ESR of only 35% for commonly considered inflammatory conditions (eg, infections or malignancy) among patients with CRF. 2

But is it the chronic inflammation in diseased kidneys or the uremic environment that elevates ESR? A cool study compared ESR in CRF in patients who had undergone bilateral nephrectomies with those with retained kidneys and found no significant difference in the ESR between the 2 groups. 4  So it looks like it’s the uremic environment, not diseased kidneys themselves that result in elevated ESR in these patients.

The mechanism behind these observations seem to reside entirely within the patients’ plasma, not the erythrocytes. Within the plasma, fibrinogen (not gammaglobulins) seem to be the most likely factor explaining elevated ESR among patients with CRF. 1,2

Bonus pearl:  Did you know that ESR is nearly 100 years old, first described in 1921? 5

References

  1. Barthon J, Graves J, Jens P, et al. The erythrocyte sedimentation rate in end-stage renal failure. Am J Kidney Dis 1987;10: 34-40. https://www.ncbi.nlm.nih.gov/pubmed/3605082
  2. Shusterman N, Morrison G, Singer I. The erythrocyte sedimentation rate and chronic renal failure. Ann Intern Med 1986;105:801. http://annals.org/aim/fullarticle/700910
  3. Arik N, Bedir A, Gunaydin M, et al. Do erythrocyte sedimentation rate and C-reactive protein levels have diagnostic usefulness in patients with renal failure? Nephron 2000;86:224. https://www.ncbi.nlm.nih.gov/pubmed/11015011
  4. Warner DM, George CRP. Erythrocyte sedimentation rate and related factors in end-stage renal failure. Nephron 1991;57:248. https://www.karger.com/Article/PDF/186266
  5. Fahraeus R. The suspension stability of the blood. Acta Med Scan 1921;55:70-92. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0954-6820.1921.tb15200.x

 

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Does erythrocyte sedimentation rate (ESR) have diagnostic utility in my patient with chronic renal failure?

Can non-steroidal anti-inflammatory drugs (NSAIDs) suppress cancer metastasis?

A 2017 meta-analysis reported that NSAIDs are associated with lower risk of distant metastasis in patients with breast, prostate, lung, and colorectal cancer.1

The mechanism accounting for this observation is not fully understood. However, since inflammation has been implicated as a driving force for tumor metastasis 2, blunting the inflammatory microenvironment that surrounds tumors may explain NSAIDs’ reported beneficial effect.

NSAIDs may also have a direct effect on cancer cells. In-vitro studies demonstrate that NSAIDs induce the expression of a protein (p75 neurotrophic receptor, p75NTR) associated with suppression of tumor growth and metastasis in prostate cancer; this protein also suppresses growth of bladder cancer cells.3,4

Ibuprofen and indomethacin are among the commonly available NSAIDS shown to exhibit such anti-tumor effect. Interestingly, non-COX-inhibiting NSAIDS (eg, [R] flurbiprofen, an enantiomer of ibuprofen) may also be effective suggesting that inhibition of cell survival may not be COX-mediated.

Although these findings and observations are promising, randomized-controlled trials are clearly needed to better define the role of NSAIDs in the clinical management of cancer.

 

References: 

  1. Zhao X, Xu Z, Li H. NSAIDs use and reduced metastasis in cancer patients: Results from a meta-analysis. Sci Rep 2017; 7:1875. https://www.ncbi.nlm.nih.gov/pubmed/28500305
  2. Qian BZ. Inflammation fires up cancer metastasis. Semin Cancer Biol 2017; 47:170-176. https://www.ncbi.nlm.nih.gov/pubmed/28838845
  3. Khwaja F, Allen J, Lynch J, Andrews P, Djakiew D. Ibuprofen inhibits survival of bladder cancer cells by induced expression of the p75NTR tumor suppressor protein. Cancer Res 2004; 64:6207-6213. https://www.ncbi.nlm.nih.gov/pubmed/15342406
  4. Krygier S, Djakiew D. Neurotrophin receptor p75NTR suppresses growth and nerve growth factor-mediated metastasis of human prostate cancer cells. Int J Cancer 2002; 98:1-7. https://www.ncbi.nlm.nih.gov/pubmed/11857376

Contributed by Camilo Campo, Medical Student, Harvard Medical School, Boston, MA.

Can non-steroidal anti-inflammatory drugs (NSAIDs) suppress cancer metastasis?

My patient with COPD has new clubbing of his finger tips. What is the mechanism of clubbing?

The mechanism behind digital clubbing has yet to be fully elucidated, with hypotheses ranging from a circulating vasodilator, tissue hypoxia, a neurocirculatory reflex, and genetic factors. 1 Although hypoxemia is often cited as a cause of clubbing, it is often absent in the presence of clubbing and many patients with hypoxemia do not have clubbing.

A potentially unifying pathophysiologic mechanism of clubbing revolves around platelet clustering and associated growth factor release. 2.3 Platelet clumps/megakaryocytes—either because of circumvention of the lung capillary network (eg, in intracardiac shunts or lung cancer) or increased production (eg, in left-sided endocarditis or chronic inflammatory conditions)—may wedge in the fine vasculature of distal fingertips or toes and cause release of platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF).

Together, PDGF and VEGF promote neovascularization, increase vessel dilation and permeability, and modify connective tissue to create the distinct club-like appearance. Local hypoxic condition from reduced capillary perfusion is thought to further stimulate the release of these growth factors.

Potential causes of clubbing in our patient include lung cancer, interstitial lung disease, bronchiectasis, core pulmonale and secondary polycythemia, among many others. 1

Fun Fact: Did you know that clubbing, also known as “Hippocratic finger”, was first described by Hippocrates in a patient with chronic empyema (don’t ask how chronic empyema was diagnosed in 400 BC!)?1

 

References

  1. McPhee SJ. Clubbing. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths;1990. Chapter 44. Available from https://www.ncbi.nlm.nih.gov/books/NBK366/
  2. Dickinson CJ, Martin JF. Megakaryocytes and platelet clumps as the cause of finger clubbing. Lancet 1987;2:1434-4. https://www.ncbi.nlm.nih.gov/pubmed/2891996/ 
  3. Atkinson S, Fox SB. Vascular endothelial growth factor (VEGF)-A and platelet-derived growth factor (PDGF) play a central role in the pathogenesis of digital clubbing. J Pathol 2004;203:721-8. https://www.ncbi.nlm.nih.gov/pubmed/15141388

 

Contributed by George Bugarinovic, Medical Student, Harvard Medical School

My patient with COPD has new clubbing of his finger tips. What is the mechanism of clubbing?

My patient is asking about the benefits of smoking cessation. How soon should she realize the health benefits of quitting her habit?

She should realize the health benefits of smoking cessation (SC) almost immediately! As the effect of nicotine wears off, just 15-20 minutes after her last cigarette, her heart rate and blood pressure should begin to fall.1,2Other health benefits, some within a year others longer, soon follow. 3,4 Between 2-12 weeks after SC, your patient may notice an improvement in her breathing and pulmonary function tests.

Between 1-9 months, the cilia in the lungs should begin to regenerate and regain normal function, allowing her to adequately clear mucus and bacteria with a decrease in cough and shortness of breath.

At 1 year, the risk of cardiovascular disease (eg, myocardial infarction, stroke) falls by one-half.

At 5 years, the risk of mouth, throat, esophagus, and bladder cancer also drops by one-half.

It takes 10 years for the risk of lung cancer to drop by one-half, and 15 years for it to approach that of non-smokers asymptotically. 4

 

Fun fact: Did you know that in hypertensive patients who smoke, the blood pressure lowering effect of beta-blockers may be partly abolished by tobacco smoking,  whereas alpha-blockers may maintain their antihypertensive effects? 5

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References

  1. Omvik P. How smoking affects blood pressure. Blood Press. 1996;5:71–77. https://www.ncbi.nlm.nih.gov/pubmed/9162447
  2. Mahmud A, Feely J. Effect of smoking on arterial stiffness and pulse pressure amplification. Hypertension. 2003;41(1):183-187. https://www.ncbi.nlm.nih.gov/pubmed/12511550
  3. US Surgeon General’s Report, 1990, pp. 193, 194, 196, 285, 323
  4. US Surgeon General’s Report, 2010 and World Health Organization. Tobacco Control: Reversal of Risk After Quitting Smoking. IARC Handbooks of Cancer Prevention, Vol. 11. 2007, p. 341.
  5. Trap-Jensen. Effects of smoking on the heart and peripheral circulation. Am Heart J 1988;115:263-7.   https://www.ncbi.nlm.nih.gov/pubmed/3276115

Contributed by Felicia Hsu, Medical Student, Harvard Medical School

My patient is asking about the benefits of smoking cessation. How soon should she realize the health benefits of quitting her habit?

My middle age patient complains of night sweats for several months, but she has had no weight loss and does not appear ill. What could I be missing?

Night sweats (NS) is a common patient complaint, affecting about a third of hospitalized patients on medical wards1.  Despite its long list of potential causes, direct relationship between the often- cited conditions and NS is usually unclear2, its cause may remain elusive In about a third to half of cases in the primary care setting, and its prognosis, at least in those >65 y of age, does not appear to be unfavorable 2,3.

Selected commonly and less frequently cited conditions associated with NS are listed (Table)2-9.  Although tuberculosis is one of the first conditions we think of when faced with a patient with NS, it should be emphasized that NS is not common in this disease (unless advanced) and is rare among hospitalized patients as a cause of their NS1,9.

In one of the larger study of adult patients seen in primary care setting, 23% reported pure NS and an additional 18% reported night and day sweats5; the prevalence of NS in both men and women was highest in 41-55 y age group. In multivariate analyses, factors associated with pure NS in women were hot flashes and panic attacks; in men, sleep disorders. 

Table. Selected causes of night sweats

Commonly cited Less frequently cited
Neoplastic/hematologic (eg, lymphoma, leukemia, myelofibrosis)

Infections (eg, HIV, tuberculosis, endocarditis)

Endocrine (eg, ovarian failure, hyperthyroidism, orchiectomy, carcinoid tumor, diabetes mellitus [nocturnal hypoglycemia], pheochromocytoma)

Rheumatologic (eg, giant cell arteritis)

Gastroesophageal reflux disease

B-12 deficiency

Pulmonary embolism

Drugs (eg, anti-depressants, SSRIs, donepezil [Aricept], tacatuzumab)

Sleep disturbances (eg, obstructive sleep apnea)

Panic attacks/anxiety disorder

Obesity

Hemachromatosis

Diabetes insipidus

References

  1. Lea MJ, Aber RC, Descriptive epidemiology of night sweats upon admission to a university hospital. South Med J 1985;78:1065-67.
  2. Mold JW, Holtzclaw BJ, McCarthy L. Night sweats: A systematic review of the literature. J Am Board Fam Med 2012; 25-878-893.
  3. Mold JW, Lawler F. The prognostic implications of night sweats in two cohorts of older patients. J Am Board Fam Med 2010;23:97-103.
  4. Mold JW, Holtzclaw BJ. Selective serotonin reuptake inhibitors and night sweats in a primary care population. Drugs-Real World Outcomes 2015;2:29-33.
  5. Mold JW, Mathew MK, Belgore S, et al. Prevalence of night sweats in primary care patients: An OKPRN and TAFP-Net collaborative study. J Fam Pract 2002; 31:452-56.
  6. Feher A, Muhsin SA, Maw AM. Night sweats as a prominent symptom of a patient presenting with pulmonary embolism. Case reports in Pulmonology 2015. http://dx.doi.org/10.1155/2015/841272
  7. Rehman HU. Vitamin B12 deficiency causing night sweats. Scottish Med J 2014;59:e8-11.
  8. Murday HK, Rusli FD, Blandy C, et al. Night sweats: it may be hemochromatosis. Climacteric 2016;19:406-8.
  9. Fred HL. Night sweats. Hosp Pract 1993 (Aug 15):88.
My middle age patient complains of night sweats for several months, but she has had no weight loss and does not appear ill. What could I be missing?

Can my patient with cirrhosis and hepatocellular carcinoma still qualify for a liver transplant?

 

Hepatocellular carcinoma (HCC) is the 3rd most common cause of cancer-related deaths1. Liver transplant removes the HCC tumor and addresses the underlying cirrhosis. Unfortunately, the demand for liver transplants exceeds the supply of available livers, making it necessary to select patients with the best recurrent-free survival following transplantation. .

Mazzaferro2 found that patients who had one lesion <5 cm, no more than 3 lesions each <3 cm, and no extrahepatic involvement or vascular invasion had significantly higher rates of recurrent-free survival following liver transplant than patients with tumors exceeding this criteria (92% vs 59% at 4 years, respectively, P = .002). This criteria, also known as the Milan criteria, has been substantiated by numerous studies3 and widely adopted. Other more inclusive criteria has also been proposed, including the UCSF criteria4 (one tumor <6.5 cm, no more than 3 tumors, all <4.5 cm and cumulative size <8cm) which have good survival rates, but have not been adopted due to limited supply of available livers.

Interestingly, patients with HCC not initially meeting the Milan criteria but who receive treatment to meet the criteria have similar post-transplantation recurrence-free survival rates as those who meet the criteria without downstaging4,5.

 

References

  1. El–Serag HB, Rudolph KL. Hepatocellular carcinoma: epidemiology and molecular carcinogenesis. Gastroenterology. 2007 Jun 30;132(7):2557-76.
  2. Mazzaferro V, Regalia E, Doci R, et al. L. Liver transplantation for the treatment of small hepatocellular carcinomas in patients with cirrhosis. N Engl J Med 1996; 334: 693-699.
  3. Mazzaferro V, Bhoori S, Sposito C, et al. Milan criteria in liver transplantation for hepatocellular carcinoma: an evidence‐based analysis of 15 years of experience. Liver Transplantation 2011;17(S2): S44-S57.
  4. Yao FY, Ferrell L, Bass NM, et al. Liver transplantation for hepatocellular carcinoma: comparison of the proposed UCSF criteria with the Milan criteria and the Pittsburgh modified TNM criteria. Liver transplantation. 2002 Sep 1;8(9):765-74.
  5. Ravaioli M, Grazi GL, Piscaglia F, et al. Liver transplantation for hepatocellular carcinoma: results of down-staging in patients initially outside the Milan selection criteria. Am J Transplant. 2008;8:2547–2557.
  6. Yao FY, Kerlan RK, Hirose R, et al. Excellent outcome following down-staging of hepatocellular carcinoma prior to liver transplantation: an intention-to-treat analysis. Hepatology. 2008;48:819–827.

Contributed by Marissa Shoji, Medical Student, Harvard Medical School

Can my patient with cirrhosis and hepatocellular carcinoma still qualify for a liver transplant?

What complications should I look for in my hospitalized patient suspected of having check-point inhibitor toxicity?

Targeting the host immune system via monoclonal antibodies known as checkpoint inhibitors (CPIs) is an exciting new strategy aimed at interfering with the ability of cancer cells to evade the patient’s existing antitumor immune response. CPIs have been shown to be effective in a wide variety of cancers and are likely to be the next major breakthrough for solid tumors1-3. Unfortunately, serious—at times fatal— immune-related Adverse Events (irAEs) have also been associated with their use4,5.

IrAEs occur in the majority of patients treated with nivolumab (a programmed death 1 [PD-1] CPI] or ipilimumab (a cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4] CPI)1. The severity of irAEs may range from mild (grade 1) to very severe (grade 4). Grading system categories discussed in more detail at link below:

https://www.eortc.be/services/doc/ctc/CTCAE_4.03_2010-06-14_QuickReference_5x7.pdf.

Although fatigue, diarrhea, pruritis, rash and nausea are not uncommon, more severe grade (3 or 4) irAEs may also occur (Figure). The most frequent grade 3 or 4 irAEs are diarrhea and colitis; elevated ALT or AST are also reported, particularly when CPIs are used in combination. Hypophysitis, thyroiditis, adrenal insufficiency, pneumonitis, enteritis sparing the colon with small bowel obstruction, and hematologic and neurologic toxicities may also occur.

Generally, skin and GI toxicities appear first, within a few weeks of therapy, followed by hepatitis and endocrinopathies which usually present between weeks 12 and 245. High suspicion and early diagnosis is key to successful management of irAEs.

Figure. Selected irAEs associated with nivolumab and ipilimumab (adapted from reference 1).

chceky2

References

  1. Larkin J, Chiarion-Sileni V, Gonzalez R, et al. Combined nivolumab and ipilimumab or monotherapy in untreated melanoma. N Engl J Med. 2015;373:23-34.
  2. Borghaei H, Paz-Ares L, Horn L, et al. Nivolumab versus docetaxel in advanced nonsquamous non-small-cell lung cancer. N Engl J Med. 2015;373:1627-1639.
  3. Brahmer J, Reckamp KL, Baas P, et al. Nivolumab versus docetaxel in advanced squamous-cell non-small-cell lung cancer. N Engl J Med 2015; 373:123-135.
  4. Weber JS, Yang JC, Atkins MB, Disis ML. Toxicities of immunotherapy for the practitioner. J Clin Oncol 2015;33:2092-2099.
  5. Weber JS. Practical management of immune-related adverse events from immune checkpoint protein antibodies for the oncologist. Am Soc Clin Oncol Educ Book. 2012:174-177.

Contributed by Kerry Reynolds, MD, Mass General Hospital, Boston.

 

 

 

 

What complications should I look for in my hospitalized patient suspected of having check-point inhibitor toxicity?

How should I interpret high serum vitamin B12 levels in my patient with anemia?

High serum B12 levels, aka hypercobalaminemia (HC),  is not rare among hospitalized patients with 1 study reporting “high” (813-1355 pg/ml) and “very high” (>1355 pg/ml) serum B12 levels in 13 and 7% of patients, respectively1.

Common causes include excess B12 intake, solid neoplasms (particularly, hepatocellular carcinoma and metastatic neoplastic liver disease), blood disorders (eg, myelodysplastic syndrome, CML, and acute leukemias, particularly AML3), and other liver diseases, including alcohol-related diseases as well as acute and chronic hepatitis.  Other inflammatory states and renal failure have also been reported2.  

Paradoxically, even in the presence of HC, a functional B12 deficiency may still exist. This may be related to poor B12 delivery to cells due to its high binding by transport proteins transcobalamin I and III in HC which may in turn cause a decrease in the binding of B12 to transcobalamin II, a key player in B12 transport to tissues2.  In this setting, elevated serum methylmalonic acid and homocysteine levels may be helpful.

References:

  1. Arendt JFB, Nexo E. Cobalamin related parameters and disease patterns in patients with increased serum cobalamin levels. PLoS ONE 2012;9:e45979. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0045979
  2. Andres E, Serraj K, Zhu J. et al. The pathophysiology of elevated vitamin B12 in clinical practice. Q J Med 2013;106:505-515.https://www.ncbi.nlm.nih.gov/pubmed/23447660
How should I interpret high serum vitamin B12 levels in my patient with anemia?