A kind reader directed my attention late yesterday to an article on the Boston Globe’s web site about three schools closing in Boston because of absenteeism from flu-like illnesses. I was struck by a comment made by a freshman at Boston Latin that seemed to get it exactly right:
The closing surprised freshman Wilhelmina Moen, who noted it was nice that authorities were concerned about the student’s health.
“I’m not that worried,” said Moen, who lives in Brighton. “It’s the same thing as the other kind of flu. That flu kills too.” (Stephen Smith, Andrew Ryan, Elizabeth Cooneym Boston.com)
So far illness caused by this virus seems similar to the illness caused by seasonal flu. The word “mild” is sometimes applied to flu that doesn’t kill you or send you to the hospital. If you’ve had flu — this one or the more usual seasonal kind — that won’t be much comfort to the wracking muscle and joint pains, fever and miserable respiratory symptoms. But at least you didn’t wind up in the hospital, although you could have. Influenza can be very nasty, and as the young highschool student, it can kill you.
What if you do wind up in the hospital from swine flu? We now know something about hospitalized cases in California, thanks to a report in CDC Morbidity and Mortality Weekly Reports (MMWR). As of May 17, California had 553 probable or confirmed cases of novel H1N1 (swine flu), of whom 30 wound up in the hospital for 24 hours or longer. Mainly longer. The median length of stay of the 23 for whom it is known because they have been discharged is 4 days; but for the 7 still hospitalized it is already 15 days.
Age range was older than other reported (non-hospitalized) cases, with a median age of 27.5. Two thirds had underlying medical conditions. A good example of how flu might contribute to death or serious illness is given by one of the detailed case histories in the MMWR:
Patient 29. A woman aged 87 years with multiple medical problems, including recently diagnosed breast cancer with possible abdominal metastasis, hypertension, diabetes mellitus, coronary artery disease, cerebrovascular disease, chronic renal insufficiency, and obesity, was brought for care at an emergency department on April 21 after being found unconscious by her daughter. The patient had reported onset of fever, cough, and weakness 2 days before admission and also new onset of orthopnea and bilateral leg swelling. She was wheelchair bound and had no recent history of travel or known contact with ill persons. In the emergency room the patient was afebrile, with a blood pressure of 57/39 mmHg, pulse 57, respiratory rate of 14 breaths per minute, and oxygen saturation of 87% on room air. Electrocardiogram was suggestive of non Q-wave myocardial infarction. Chest radiograph showed bilateral pneumonia and congestive heart failure with marked cardiomegaly. . . . The patient went into respiratory arrest and was subsequently intubated and started on low dose dopamine, and admitted to the ICU with a diagnosis of myocardial infarction, congestive heart failure, pneumonia and presumed sepsis. A chest computed tomography (CT) scan showed complete atelectasis of the right middle lobe, bilateral ground glass opacities of the upper lobes, and bilateral pleural effusions. A subsequent bronchoscopy identified a large cauliflower-shaped mass in the right lower lobe airway. Multiple blood, urine, and sputum cultures were unrevealing; rapid antigen test was positive for influenza A, with subsequent confirmation of novel influenza A (H1N1) at the CDPH VRDL. The patient remains hospitalized in critical condition under intensive care.
Without the intensive surveillance I doubt this woman’s concurrent infection with influenza would ever have been diagnosed. It is certainly the case that the contribution of flu to other causes of death is underestimated when using the death certificate coding for influenza.
For the hospitalized patients the most common admitting diagnosis was pneumonia and dehydration, accompanied by fever, cough, vomiting (but not diarrhea) and shortness of breath. 60% had chest x-ray signs of pneumonia. Six (20%) wound up in intensive care and 4 on ventilators. Here’s another case history from MMWR:
Patient 18. A man aged 32 years with a history of obstructive sleep apnea sought care at an emergency department on May 5 with a 3-day history of fever, chills, and productive cough. The patient reported he had been taking amoxicillin for a diagnosis of sinusitis, following complaints of vertigo and dizziness, for the past 2 weeks. His vital signs showed a temperature of 99.1°F (37.3°C), blood pressure of 89/58 mmHg, and heart rate of 84 beats per minute. Physical exam of the chest showed good air movement bilaterally, although chest radiograph revealed bilateral infiltrates. His complete blood count and chemistries were normal except for an elevated white blood cell count of 13.8 cells/mm3 with a differential of 94% segmented neutrophils and 4% lymphocytes. An arterial blood gas showed respiratory acidosis and hypoxemia with pO2 of 80 mm Hg on room air. The patient was admitted to the ICU on empiric broad spectrum antibiotics and required intubation on the second hospital day for worsening hypoxemia. Initial microbiologic workup and influenza rapid antigen tests were negative; the patient was started on oseltamivir on hospital day 2. A repeat rapid antigen test and bronchoalveolar lavage viral culture were positive for influenza A, with subsequent confirmation of novel influenza A (H1N1). The patient improved, was extubated on hospital day 5, and was discharged on hospital day 10.
This was a relatively healthy young adult who went rapidly downhill with respiratory distress and also wound up on a ventilator. His body temperature was below the threshold used to define influenza-like illness (100 degrees F.) and originally a rapid flu test was negative for influenza. False negatives occurred in 5 out of 30 of the hospitalized cases reported on here. This patient did have swine flu and became critically ill and had a stay in the intensive care unit. His influenza was certainly not “mild” in any sense of the word.
As far as we know at the moment, these patients are not unusual in the sense that their experience is unlike “the usual” seasonal influenza. On the contrary, one reason for concern about a flu virus that can spread faster and to more people (and younger people) is not that its illness is unlike seasonal influenza but that the illness it causes is (so far) very much like seasonal influenza.
Any influenza is not a walk in the park. Unless it’s the kind of park a prudent person wouldn’t walk through late at night. Then, maybe, it is a walk in the park.