Analysis of a Fatal Left Ventricular Assist Device Infection: A Case Report and Discussion

Neal Stuart Gerstein, MD FASE¹

Henry G. Chou, MD²

Andrew Lewis Dixon, MD¹

¹Department of Anesthesiology & Critical Care Medicine

University of New Mexico

Albuquerque, NM

²Department of Anesthesiology

Cedars-Sinai Medical Center

Los Angeles, CA

Introduction

Left ventricular assist device (VAD) therapy is an increasingly utilized treatment as a bridge to heart transplantation or as long-term destination therapy. Recent reports show there is a 22% - 32% incidence of VAD-associated infections with staphylococci and nosocomial gram-negative bacilli being the most common causative organisms (1,2). These organisms are often found in intensive care units, where they have the highest proportion of resistance, thus exposing already critically ill patients to the possibility of resistant organism VAD-associated infections (3). Mortality rates exceed 60% when sepsis develops in a patient with a continuous flow left VAD and infection is the number one cause of death in those awaiting cardiac transplantation (4,5). With continued left VAD use clinicians will likely see multidrug-resistant (MDR) or even pandrug-resistant organism VAD-associated infections. Clinicians need to be prepared to manage such an intimidating entity.

Case Report

We report a case of a 25 year-old male with a pandrug-resistant Pseudomonas aeruginosa VAD-associated infection. The patient’s medical history is significant for a diagnosis of idiopathic dilated cardiomyopathy refractory to maximal medical therapy requiring implantation of a HeartMate II (Thoratec Co., Pleasanton, CA, USA) continuous flow left VAD (Figure 1).

Figure 1. HeartMate II^® left VAD schematic (reprinted with the permission of Thoratec Co., Pleasanton, CA, USA).

His course was complicated with multiple hospital admissions for recurrent VAD-associated infections and numerous episodes of P. aeruginosa bacteremia that had been treated with a multitude of antipseudomonal antibiotics. He presented to our hospital for management of severe volume overload in the setting of VAD-associated infections. Transesophageal echocardiography demonstrated a left ventricular ejection fraction of 24% with severe left and right ventricular dilatation. Chest x-ray revealed cardiomegaly and multiple devices including the left VAD (Figure 2).

Figure 2. Chest X-ray demonstrating an enlarged cardiac silhouette, the HeartMate II axial pump (*) with inflow (down arrow, ↓) and outflow (up arrow, ↑) cannulas, biventricular pacer with leads in right atrium (A), coronary sinus (B), and right ventricle (C) (dashed arrows).

Blood cultures revealed MDR P. aeruginosa; except for showing intermediate sensitivity to tobramycin there was resistance to all antimicrobials tested. In vitro synergy testing revealed modest bacterial inhibition when only colistin, fosfomycin, imipenem, and tobramycin were combined. After maximizing medical therapy, multiple left VAD pocket washings and implantation of tobramycin beads followed. Intraoperative findings included an encapsulated infection around the driveline and obvious infection of the left VAD pocket. Repeat blood cultures showed P. aeruginosa had developed resistance to all antimicrobials including tobramycin. Subsequently the left VAD was explanted and the patient was transitioned to an extracorporeal membrane oxygenator (ECMO) in attempt to clear the infection. He was then transitioned to a TandemHeart (CardiacAssist Inc., Pittsburgh, PA, USA), a percutaneous LVAD, as he was not dependent on ECMO for oxygenation. He was able to clear the bacteremia after removal of the infected HeartMate II while on colistin, fosfomycin, tobramycin, azithromycin and rifampin, but was not able to clear the remaining left VAD pocket infection, which again spread systemically. Despite maximal medical and surgical interventions, he died from profound septic shock and multisystem organ failure. To date this is the first known case of a pandrug-resistant P. aeruginosa VAD-associated infection reported in the literature.

Discussion

P. aeruginosa organisms have intrinsic resistance to numerous broad spectrum antibiotics, and can easily develop acquired resistance to most if not all available antimicrobial agents (3). Risk factors for the development of pandrug-resistant P. aeruginosa include previous treatment with antipseudomonal antibiotics and prolonged treatment times. Given our patient had multiple P. aeruginosa infections, treated with multiple rounds of antipseudomonal antibiotics, it is not surprising that pandrug-resistance developed. Few therapeutic options are available for treatment and no new agents are available to evade the known resistance mechanisms. Treatment can be optimized using synergistic combination therapy, which may be the only medical management option in patients with pandrug-resistant P. aeruginosa infections. Some have suggested that rifampin in combination with colistin may be a promising approach (3). Some experts recommend in vitro synergy testing when an organism is resistant to currently recommended antibiotic regimens (6,7). However, a recent review of antibiotic therapy for gram-negative infections describes the utility of in vitro synergy testing equivocal in the context of Pseudomonas infection (8). We managed our patient with combination therapy; however, not until pandrug-resistant P. aeruginosa was isolated did we introduce rifampin in combination with colistin.

A recent review of VAD-associated infections showed the majority were managed without surgical intervention; only 13% required surgical debridement and only in cases of severe infection and/or failed conservative treatment was left VAD explantation required. Since this case there has been a proposed algorithm for management of VAD-associated infections (2); our management, though prior to published guidelines, was in step with the algorithm. Of note, there was no discussion of explanting an left VAD to ECMO to aid in clearing a resistant infection. We felt this was a rational option given our inability to clear the infection. It is unclear as to exactly why our patient was never able to fully clear his infection. Given the patient’s other pre-existing extensive cardiac hardware (i.e. implanted pacer), it is possible that he remained colonized even after maximal surgical and medical therapy. Though speculative, it is possible that removing all foreign material may have allowed for complete infection clearance.

Aside from aggressive medical and surgical management, systolic heart failure with VAD-associated infections may be effectively managed with heart transplantation (9). Our consensus was that this option was neither in the best interest of the patient nor the best use of available resources given the severity of his condition.

Conclusion

Clinicians will continue to see VAD-associated infections with resistant organisms. To minimize adverse outcomes, including VAD-associated infection, prudent patient selection and timing of VAD placement is paramount, as VAD’s placed in critically ill patients have been consistently associated with adverse outcomes (10).

References

1. Gordon RJ, Weinberg AD, Pagani FD, Slaughter MS, Pappas PS, Naka Y, Goldstein DJ, Dembitsky WP, Giacalone JC, Ferrante J, Ascheim DD, Moskowitz AJ, Rose EA, Gelijns AC, Lowy FD. Prospective, multicenter study of ventricular assist device infections. Circulation. 2013;127:691-702. [CrossRef] [PubMed]
2. Nienaber JJ, Kusne S, Riaz T, Walker RC, Baddour LM, Wright AJ, Park SJ, Vikram HR, Keating MR, Arabia FA, Lahr BD, Sohail MR. Clinical manifestations and management of left ventricular assist device-associated infections. Clin Infect Dis. 2013;57:1438-48. [CrossRef] [PubMed]
3. Zavascki AP, Carvalhaes CG, Picao RC, Gales AC. Multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii: resistance mechanisms and implications for therapy. Expert Rev Anti Infect Ther. 2010;8:71-93. [CrossRef] [PubMed]
4. Topkara VK, Kondareddy S, Malik F, Wang IW, Mann DL, Ewald GA, Moazami N. Infectious complications in patients with left ventricular assist device: etiology and outcomes in the continuous-flow era. Ann Thorac Surg. 2010;90:1270-7. [CrossRef] [PubMed]
5. Bartoli CR, Demarest CT, Khalpey Z, Takayama H, Naka Y. Current management of left ventricular assist device erosion. J Card Surg. 2013;28:776-82. [CrossRef] [PubMed]
6. Balaji V, Jeremiah SS, Baliga PR. Polymyxins: Antimicrobial susceptibility concerns and therapeutic options. Indian J Med Microbiol. 2011;29:230-42. [CrossRef] [PubMed]
7. Martis N, Leroy S, Blanc V. Colistin in multi-drug resistant Pseudomonas aeruginosa blood-stream infections: a narrative review for the clinician. J Infect. 2014;69:1-12. [CrossRef] [PubMed]
8. Tamma PD, Cosgrove SE, Maragakis LL. Combination therapy for treatment of infections with gram-negative bacteria. Clin Microbiol Rev. 2012;25:450-70. [CrossRef] [PubMed]
9. Prendergast TW, Todd BA, Beyer AJ, 3rd, Furukawa S, Eisen HJ, Addonizio VP, Browne BJ, Jeevanandam V. Management of left ventricular assist device infection with heart transplantation. Ann Thorac Surg. 1997;64:142-7. [CrossRef] [PubMed]
10. Lietz K, Long JW, Kfoury AG, Slaughter MS, Silver MA, Milano CA, Rogers JG, Naka Y, Mancini D, Miller LW. Outcomes of left ventricular assist device implantation as destination therapy in the post-REMATCH era: implications for patient selection. Circulation. 2007;116:497-505. [CrossRef] [PubMed] 

Reference as: Gerstein NS, Chou HG, Dixon AL. Analysis of a fatal left ventricular assist device infection: a case report and discussion. Southwest J Pulm Crit Care. 2015;10:16-20. doi: http://dx.doi.org/10.13175/swjpcc139-14 PDF 

January 2015 Critical Care Case of the Month: Who's Your Momma?

Carlos Hartmann, MD

Layth Al-Jashaami, MD

Timothy T. Kuberski, MD

Department of Medicine

Maricopa Integrated Health Services

Phoenix, AZ USA

History of Present Illness

A 39-year-old Hispanic woman was admitted complaining of shortness of breath and bilateral lower extremity edema. She was felt to be in acute hypoxic respiratory failure.

Past Medical History

• Systemic lupus erythematosus
• Congestive heart failure with an ejection fraction of 40%
• End-stage renal disease on dialysis secondary to lupus nephritis

Medications

• Rituximab 550 mg once a week
• Prednisone 40 mg daily
• Plaquenil 200 mg twice a day

Physical Examination

The patient was tachypneic in obvious respiratory distress. She was afebrile. Crackles at the bases. Heart was tachycardic. There was 3+ bilateral pitting pretibial edema.

Laboratory

CBC: Hemoglobin 7.8 g/dL, WBC 11 X 10⁹ cells per liter, differential: neutrophils 98%, eosinophils 0%, lymphocytes 1%.

Electrolytes: Potassium 5.8 mEq/L, sodium 143 mEq/L, creatinine 3.3 g/dL, BUN 98 mg/dL.

Brain naturetic peptide: 4055 pg/ml.

Imaging

Admission chest x-ray showed cardiomegaly and bilateral interstitial prominence suggestive of congestive heart failure.

Which of the following are appropriate initial management? (Click on the correct answer to proceed to the 2nd of 4 panels)

1. Bronchoscopy with bronchoalveolar lavage
2. Hemodialysis
3. Increased methylprednisolone for a potential lupus "flare"
4. 1 and 3
5. All of the above 

Reference as: Hartmann C, Al-Jashaami L, Kuberski TT. January 2015 critical care case of the month: who's your momma? Southwest J Pulm Crit Care. 2015:10(1):11-15. doi: http://dx.doi.org/10.13175/swjpcc145-14 PDF

Brief Review: Delirium

Evan D. Schmitz, MD

Jack B. Vu, MD

University of Washington

Seattle, WA

A significant number of patients develop a decline in cognitive function while hospitalized. Delirium in the intensive care increases mortality and healthcare costs and should be recognized and treated promptly (1,2). 

This is a brief review of delirium and important treatment options such as early percutaneous tracheostomy, neuroleptics, propofol, daily awakenings and reorientation by all team members. We recommend neither neuroimaging nor neurology consultation unless physical exam suggests an acute cerebral vascular accident or status epilepticus as the majority of these patients require no neurologic intervention and may be harmed by transportation to obtain additional testing.

The DSM-5 defines delirium as a disturbance in attention (reduced ability to direct, focus, sustain, and shift attention) and awareness (reduced orientation to the environment). The disturbance develops over a short period of time (usually hours to a few days), represents a change from baseline attention and awareness, and tends to fluctuate in severity during the course of a day. Delirium may also be a disturbance in cognition (memory deficit, disorientation, language, visual spatial ability, or perception).

The leading cause of delirium in the intensive care unit is metabolic encephalopathy caused by the patient’s primary disease and exacerbated by treatment with life saving measures such as intubation with mechanical ventilation. The required anesthesia and analgesia during intubation contribute to worsening delirium. The quicker the patient is extubated, the better is the overall prognosis. Delirium makes it more difficult to extubate the patient, independent of the disease process as the clinician is uncertain if the patient will be able to protect their airway and breathe on their own. This is further compounded by the increasing need for nursing during this critical period. There are numerous studies showing the benefits of sedation vacation and reorientation by nursing. If you were to speak with nurses they will tell you how difficult it is dealing with a delirious patient as the patient can become combative and difficult to console. As hospitals continue to cut back on nurses, nursing aids, respiratory therapists and sitters, it becomes increasingly more difficult to care for these patients.

Nursing is one of the most dangerous careers according to the U.S. Bureau of Labor (3). Delirium is directly responsible for traumatic injuries nurses suffer from combative patients while caring for the critically ill. It is therefore understandable why a majority of nurses are concerned when they are told to extubate these delirious patients.

We make it a point to educate nurses that they should extubate the patient as soon as possible. Once a plan is established, including neuroleptics to control agitation, it is important that the physician conducts bed rounds on the patient multiple times during the day. The physician should also explain to the nocturnal staff the importance of avoiding re-intubation, as these delirious patients do respond to neuroleptics and redirection. We only recommend extubation if the whole team is on board.

We have been performing percutaneous tracheostomies since 2006 and have noticed a significant decrease in ventilator days and duration of delirium in those patients receiving this surgery. Once a percutaneous tracheostomy is placed, a patient can be ventilated with minimal or no sedatives which allows improvement in their cognitive function.

Immediately after paralytics have worn off after performing a bedside percutaneous tracheostomy, we stop all sedatives and narcotics to allow the patient to regain consciousness. We use neuroleptics to treat delirium while awaiting for the return of cognitive function. With a tracheostomy in place, the respiratory therapists and nurses appear much more comfortable allowing patients to recover without giving any narcotics or sedatives resulting in a much faster recovery. Patients with neurological impairment, including delirium, demonstrate tachypnea out of proportion to their respiratory needs. Recognition of this type of breathing pattern is important. Educating the staff about this type of breathing pattern also helps nurses and respiratory therapists to cope with the resultant high minute ventilation. If there are periods of apnea with irregular periods of hyperventilation, the breathing pattern is called Biot’s breathing (4).

Once placed, percutaneous tracheostomy as opposed to endotracheal intubation, requires neither anesthetic nor analgesic. Since the tracheostomy is usually placed between the first and second tracheal cartilaginous rings, the vocal cords are free from damage including swelling that occurs with endotracheal tubes. Endotracheal tubes are very uncomfortable and analgesia and anesthesia are required to keep patients comfortable. This can cause delirium. The incidence of tracheal stenosis does not appear to be greater with percutaneous tracheostomy as opposed to endotracheal intubation.

Percutaneous tracheostomy can be performed safely at the bedside in the intensive care unit. As long as one physician is controlling the airway while performing direct visualization via bronchoscopy and the other is performing the percutaneous tracheostomy, any adverse complications can be managed promptly. Remember to place a sign in the patient’s room warning staff not to replace the tracheostomy if it were to fall out within the first seven days and to call a code for prompt intubation. This will avoid misplacement which can lead to death.

Although we are not recommending tracheostomy just for the treatment of delirium, we do recommend early tracheostomy within a few days as opposed to waiting to perform a tracheostomy when anticipated ventilation is longer than ten days. Most of our colleagues who perform percutaneous tracheostomy agree (Schmitz ED, unpublished observations.

Haloperidol (Haldol®) has been around for decades. Haloperidol is a butyrophenone antipsychotic which acts primarily by blocking postsynaptic mesolimbic dopaminergic D2 receptors in the brain. This results in depression of the reticular activating system (5).

As opposed to sedatives and analgesics, haloperidol does not suppress intellectual function or cause respiratory failure. It appears underutilized because of concern about prolonging the QT interval and increasing the risk for a cardiac arrhythmia (6). Although it is true that neuroleptics can prolong the QT interval, the fear associated with this rare phenomenon inhibits the use of the most effective treatment for delirium we have at our disposal. 

Newer antipsychotics such and olanzapine, risperidone and ziprasidone may be used as well, but they also have been associated with inducing cardiac arrhythmias. These drugs appear to have less extrapyramidal side effects caused by the excitatory actions of unopposed cholinergic neurons. These newer antipsychotics block the serotonin receptor 5HT and to a lesser extent D2, and therefore, they decrease the likelihood of acute dystonic reactions, pseudo-parkinsonism, akathisia and tardive dyskinesia (7).

We have had great success with intravenous haloperidol. We recommend starting with a 5-10 mg intravenously and repeating this dose every 15 minutes until the patient’s agitation is controlled. We then schedule haloperidol intravenously as needed. Depending on which newer neuroleptics are available, we schedule these drugs until the patient recovers from their delirium. We have also had success with sublingual or intramuscular olanzapine 10 mg every 8 to 12 hours. Much higher doses, greater than 200 mg a day, have been reported in hospice patients without adverse cardiac effects (8).

Prior to instituting neuroleptics, ensure that the patient’s electrolytes are normal which will decrease the likelihood of an arrhythmia. Try to avoid haloperidol in patients with Parkinson’s disease because it diminishes the availability of dopamine.

An additional measure to decrease the risk and length of delirium is by using propofol and fentanyl for sedation rather than a benzodiazepine. Recent studies have shown that using propofol instead of a benzodiazepine decreases mortality, ventilator days and delirium (9). The elderly and those with liver impairment appear to benefit the most from propofol because of the faster metabolism of this class of drug. Side effects such as hypotension can be easily managed with fluids and a low dose of norepinephrine.

Renal failure is common in critically ill patients. It is important to monitor patients closely for signs of uremic encephalopathy which occurs when patients are unable to adequately excrete nitrogenous waste and other factors (10).

Nitrogen is excreted by the kidneys as urea and ammonium. Amino acids are catabolized by transamination which is the process of transferring their alpha-amino group to alpha-ketoglutarate which produces glutamate. The two most important are alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Alpha-ketoglutarate is an essential intermediate substrate in the citric acid cycle (11).

Glutamate can be oxidized to form free ammonia or it can combine with ammonium in the presence of ATP to form glutamine in the muscle, liver and nervous system providing a nontoxic storage and transport form of ammonia. 

In renal failure hyperammonemia occurs leading to tremors, slurring of speech and blurring of vision. In the presence of elevated ammonia, alpha-ketoglutarate combines with ammonia to form glutamate. Glutamate accumulates which causes cytotoxicity to nerve cells and death via NMDA-type synapses which mediate calcium influx (5). As the concentration of alpha-ketoglutarate declines, the brain cannot produce the energy it needs through the citric acid cycle which can lead to coma and death.

Although drugs used to treat hyperammonemia in patients with liver failure such as neomycin, lactulose and rifaximin will help decrease the amount of urea and ammonia reabsorbed in the intestines, in patients with renal failure, dialysis is imperative to recovery. After only one treatment with dialysis, the cognitive improvement is profound. As the acute kidney injury resolves, dialysis is no longer necessary.

It is unclear whether antiepileptics can also help with delirium. Valproic acid may inhibit glutamates action on the NMDA receptor. Glutamate mediated neuronal excitotoxicity has been postulated as a cause of nerve cell death. Antiepileptics may be beneficial at attenuating the deleterious effects of glutamate in the brain.

Delirium can also be caused by too much serotonin. Medications such as serotonin re-uptake inhibitors (SSRIs), linezolid, metoclopramide, fentanyl and baclofen can cause the serotonin syndrome. Patients typically exhibit some type of clonus (12). We recommend stopping all antidepressants in critically ill patients exhibiting signs of delirium. After the delirium subsides, resuming the SSRI appears appropriate. Depression is common as patients recover from their critical illness and the addition of an SSRI may be beneficial prior to transfer out of the intensive care unit.

By adhering to the above recommendations, you will be able to recognize delirium and institute effective lifesaving treatments. Patients and their family members will be grateful as they will be able to communicate with their loved ones once again. Nurses will also be happier as they will suffer less emotional and physical trauma. This will lead to a faster patient recovery and a shorter length of hospitalization.

References

1. Yamaguchi T, Tsukioka E, Kishi Y. Outcomes after delirium in a Japanese intensive care unit. Gen Hosp Psychiatry. 2014;36(6):634-6. [CrossRef] [PubMed]
2. Hsieh SJ, Soto GJ, Hope AA, Ponea A, Gong MN. The Association Between ARDS, Delirium, and In-hospital Mortality in ICU Patients. Am J Respir Crit Care Med. 2014 Nov 13. [Epub ahead of print] [CrossRef] [PubMed]
3. U.S. Department of Labor, Bureau of Labor Statistics. Lost-worktime injuries and illnesses: characteristics and resulting time away from work 2010. Available at: http://www.bls.gov/news.release/osh2.nr0.htm (accessed 12/22/14).
4. Wijdicks EF. Biot's breathing. J Neurol Neurosurg Psychiatry. 2007;78(5):512-3. [CrossRef] [PubMed]
5. Waxman SG. Clinical Neuroanatomy. 25th edition. New York, NY: McGraw Hill Medical; 2003.
6. Hatta K, Kishi Y, Wada K, Odawara T, Takeuchi T, Shiganami T, Tsuchida K, Oshima Y, Uchimura N, Akaho R, Watanabe A, Taira T, Nishimura K, Hashimoto N, Usui C, Nakamura H. Antipsychotics for delirium in the general hospital setting in consecutive 2453 inpatients: a prospective observational study. Int J Geriatr Psychiatry. 2014;29(3):253-62. [CrossRef] [PubMed]
7. Howland RD. Phamacology. 3rd edition. Philadelphia. Lippincott, Williams & Wilkins. 2003. Howland RG. Pharmacology. 3rd edition. Philadelphia, PA: Lippincott, Williams and Wilkins; 2006.
8. Bascom PB, Bordley JL, Lawton AJ. High-dose neuroleptics and neuroleptic rotation for agitated delirium near the end of life. Am J Hosp Palliat Care. 2014;31(8):808-11. [CrossRef] [PubMed]
9. Lonardo NW, Mone MC, Nirula R, Kimball EJ, Ludwig K, Zhou X, Sauer BC, Nechodom K, Teng C, Barton RG. Propofol is associated with favorable outcomes compared with benzodiazepines in ventilated intensive care unit patients. Am J Respir Crit Care Med. 2014;189(11):1383-94. [CrossRef] [PubMed]
10. Scaini G, Ferreira GK, Streck EL. Mechanisms underlying uremic encephalopathy. (10) Rev Bras Ter Intensiva. 2010;22(2):206-211. [CrossRef] [PubMed]
11. Champe PC, Harvey RA. Biochemistry. 2nd edition. Philadelphia:JB Lippincott-Raven;1994.
12. Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med. 2005;352(11):1112-20. [CrossRef] [PubMed] 

Reference as: Schmitz ED, Vu JB. Brief review: delirium. Southwest J Pulm Crit Care. 2014;9(6):343-7. doi: http://dx.doi.org/10.13175/swjpcc166-14 PDF

Ultrasound for Critical Care Physicians: Lung Sliding and the Seashore Sign

Spencer M. Lee, MD

Gregory T. Chu, MD

Banner Good Samaritan Medical Center

Phoenix, AZ

A 70-year-old Native American woman was having increasing difficulty with ventilation. She had an extensive past medical history including quadriplegia after a motor vehicle accident in 2009, chronic mechanical ventilation since the accident, end-stage renal disease, and diabetes mellitus. A feeding tube had recently been inserted. A portable chest radiograph was performed (Figure 1).

Figure 1. Portable chest radiograph.

A lung ultrasound was performed (Figure 2).

Figure 2. Lung ultrasound of the left lung (upper panel) and of the right lung (lower panel).

M-mode images of the ultrasound are shown in Figure 3.

Figure 3. M-mode image of the left lung (panel A on left) and the right lung (Panel B on right).

Which of the following are true regarding the images presented? (Click on the correct answer to procced to the next and final panel)

1. The chest x-ray shows the feeding tube in the right lung
2. The M-mode image shows the seashore sign on the left suggestive of a pneumothorax
3. The ultrasound shows an absence of lung sliding on the right suggestive of a pneumothorax
4. 1 and 3
5. All of the above

Reference as: Lee SM, Chu GT. Ultrasound for critical care physicians: lung sliding and the seashore sign. Southwest J Pulm Crit Care. 2014;9(6):337-40. doi: http://dx.doi.org/10.13175/swjpcc163-14 PDF

December 2014 Critical Care Case of the Month: Weak for Weeks

Bhupinder Natt MD¹

Shadi Koleilat MD²

Janet Campion MD¹

¹Division of Pulmonary, Allergy, Critical care and Sleep Medicine

²Department of Neurology

University of Arizona Medical Center

Tucson, AZ

History of Present Illness

A 65 year old woman presents with weakness involving both upper and lower extremities that is intermittent over the last 3 months, but in the last 2 weeks she has also noticed increasing neck weakness, droopy eyelids and increased drooling. Prior to this she was able to walk without difficulty and ride a recumbent bike for 20 minutes, but now is having difficulty walking on her own. She denies fevers, weight loss, shortness of breath, chest pain, palpitations, LE edema, joint pain, rash, any recent or current GI/GU symptoms and no new medications.

Past Medical History, Social History, and Family History

The patient has a past history of hypertension, hyperlipidemia, diabetes mellitus Type II, GERD, obstructive sleep apnea (compliant with BiPAP), atrial fibrillation and hypothyroidism. She has a 40 pack-year history of tobacco use. Family history is noncontributory.

Medications

• Dabigatran 75mg BID
• Esomeprazole 20 mg BID
• Furosemide 30 mg BID
• Insulin glargine 50 Units BID and Lispro per sliding scale
• Levothyroxine 88 mcg per day
• Losartan 50 mg QD,
• Pregabalin 75 mg BID
• Rosuvastatin 40 mg per day

Physical Examination

Vital signs: Afebrile. Pulse 86, respiratory rate 20, PaO2 92% on room air

General: Awake, fully oriented, dysarthric speech.

HEENT: Non-icteric, ears, nares, oropharynx unremarkable; there is no neck LAD, elevated JVP or thyromegaly.

Respiratory: Normal breath sounds, no wheeze or rhonchi.

CVS: Irregularly irregular rhythm, no murmurs. Peripheral vascular exam normal.

Abdomen: Obese, soft, non-tender with normal bowel sounds. No organomegaly appreciable.

Extremities: Trace pedal edema, normal muscle bulk and tone.

CN: Ptosis bilaterally, no nystagmus, reactive pupils, extra-ocular muscles intact, sensation intact, weak cheek puff, symmetric palate excursion, normal tongue protrusion.

Motor: Neck flexion and extension 4-/5, bilateral pronator drift, no focal lower extremity weakness, no muscle atrophy, no tremors or fasciculations.

Sensation: Intact to light touch hands and feet.

Reflexes: 2+ and symmetric throughout.

Gait: Wide-based and slow, can only walk short distances before experiencing bilateral leg weakness.

Laboratory: Normal electrolytes, complete blood count, and liver function tests. Creatinine mildly elevated at 2.1 mg/dL.

EKG

Atrial Fibrillation.

What is the most likely diagnosis? (Click on the correct answer to proceed to the next panel)

1. Guillain-Barré syndrome (GBS)
2. Hypothyroidism
3. Lambert-Eaton myasthenic  syndrome (LEMS)
4. Motor neuron disease (ALS)
5. Myasthenia gravis crisis

Reference as: Natt B, Koleilat S, Campion J. December 2014 critical care case of the month: weak for weeks. Southwest J Pulm Crit Care. 2014;9(6):302-8. doi: http://dx.doi.org/10.13175/swjpcc141-14 PDF