Dx nightmare!


I had a patient last week that I have been thinking about. I was just thinking about her medical diagnoses and I think I am completely losing my mind! I guess what I am asking is can a pt just have an unexplained fever with no cause? Or what are some causes that are atypical? Her fever was jumping between 99 and 102 up and down all day.

81 y/o female admitted with mental status change and high fever. Chem 7 and UA normal. CBC showed normal WBC, slightly low RBC, Hgb, and Hct. Blood culture showed no growth.

So no signs of infection, not the cause of the fever.

Her history includes COPD, HTN, CHF, pleural effusion, emphysema, DM, and spinal stenosis.

What am I missing here? I have to be staring it in the face! I have been racking my brain for hours.

I cant just accept my made up explanation of "super fever with no cause".


446 Posts

Specializes in ER, ICU, Medsurg.

I may be reading too deep into it also, so wait for a pro to respond, but....What meds is she on? Won't penicillin and quinidine cause a fever in some cases? There are some other meds too that cause fever but I cant remember them off the top of my head.

Just a thought, I'll be waiting to see what the pros say too! Interesting.

Specializes in M/S, Tele, Sub (stepdown), Hospice. Has 13 years experience.

Or maybe labs haven't revealed anything just yet....may be beginning of something. Elderly usually present with atypical symptoms so it's hard to tell just from mental status change & fever. Also...elderly sometimes have an impaired thermoautoregulation....meaning it's hard for them to cool their bodies down which is why it's bad for them to live in a hot area without air conditioning, etc.

Also not a pro....so hopefully someone else can answer too...

RN BSN 2009

1,289 Posts

How long has the patient been admitted? Sometimes it takes days for blood cultures to grow.

Daytonite, BSN, RN

4 Articles; 14,603 Posts

Specializes in med/surg, telemetry, IV therapy, mgmt. Has 40 years experience.

the hypothalamus of the body regulates body temperature. a fever is an elevation of the hypothalmic set point. this is caused by

    • central nervous system disease
    • malignant hyperthermia
    • strenuous exercise
    • stress
    • chills (produce more heat and, thus, raise the body temperature)
    • thyrotoxicosis
    • heatstroke
    • heart failure
    • congenital absence of sweat glands (sweating helps the body get rid of heat)
      drugs that impair sweating

fever is related to infection. fever is one of the symptoms of infection.

about the symptom of fever in medical diagnosing. . .(page 171, differential diagnosis in primary care, 4th edition, by r. douglas collins)

increased heat in the body is caused by increased production or decreased elimination or dysfunction of the thermoregulatory system in the brain. increased production of heat occurs in conditions with increased metabolic rate such as hyper thyroidism, pheochromocytomas, and malignant neoplasms. poor elimination of heat may occur in congestive heart failure (chf) (poor circulation through the skin) and conditions where sweat glands are absent (congenital) or poorly functioning (heat stroke). most cases of fever are caused by the effect of toxins on the thermoregulatory centers in the brain. these toxins may be exogenous from drugs, bacteria (endotoxins), parasites, fungi, rickettsiae, and virus particles, or they may be endogenous from tissue injury (trauma) and breakdown (carcinomas, leukemia, infarctions and autoimmune disease)."

the point is that there are a lot of causes for a fever. that information comes from a textbook for medical students who are learning to diagnose medical conditions. some on the forums are aware that i am also a medical coder. when the charts of these patients go to the medical records offices, the coders who attach numeric codes to the physician's final diagnoses so the insurance companies can be billed for payment of the hospital bill, sometimes don't have a definitive diagnosis to work with either. the point of a patient being admitted is often to treat their symptoms and attempt to discover what is wrong with them. and, unfortunately, there are situations where an fuo (fever of unknown origin) remains just that. your instructor, if they have any experience in medical nursing should be aware that this happens. all you can do is care plan for all the treatment, testing and anxiety that this patient is going to endure.

the information from page 171 of differential diagnosis in primary care, 4th edition, by r. douglas collins above pertained to the differential diagnosis of the symptom of fever from the standpoint of its physiology. here is the information from the viewpoint of anatomy from that same page. . .

"the infections should be divided into the
systemic diseases
that affect more than one organ, such as typhoid, brucellosis, tuberculosis, syphilis, aids, leptospirosis, and bacterial endocarditis, and the
localized diseases
that usually affect the same specific organ, such as infectious hepatitis, subacute thyroiditis, pneumococcal pneumonia, and cholera. it is wise to divide the localized infectious diseases into the
(e.g., pneumonitis, hepatitis, and prostatitis), and the
(dental abscesses, empyema, perinephric abscess, liver abscess, and subdiaphragmatic abscess).

also, when the physician attempts to recall the special infections, he or she can group them into six categories beginning with the smallest organism and working up to the largest as follows: viruses, rickettsiae, bacteria, spirochetes, fungi, and parasites. endogenous toxins released by infarctions of various organs form another convenient group. finally, the most common neoplasms to cause fever (by tissue breakdown) are illustrated on page 172. [bronchogenic, leukemia, hodgkin's]"

the text continues. . .

approach to the diagnosis

there are certain things to remember when a patient with fever is approached. first, a mild elevation up to 105 degrees f (38 degrees c) rectally may be normal in some people. second, one should rule out malingering by the patient or incorrect recording by hospital personnel. finally, psychogenic disorders must be ruled out.

the duration and severity of the fever are important. if possible, a careful chart of the fever should be made with the patient off all drugs (especially aspirin and steroids). conditions with intermittent or relapsing fever such as brucellosis, malaria, and mediterranean fever will be elucidated in this fashion.

the association with other symptoms is important. fever, right upper quadrant pain, and jaundice suggest cystitis or cholangitis, whereas fever with right-sided flank pain suggest pyelonephritis. after taking a few moments to jot down the differential before launching into the history and physical examination, one can question and examine the patient more appropriately. the differential diagnosis will also lead to more appropriate use of laboratory testing."

and then it list 45 different tests that can be performed and what disease they reveal. your patient had the following tests done:

  • chem 7 - to rule out liver and renal disease
  • ua - to rule out uti
  • cbc - done to look for infectious disease and leukemia
  • blood cultures - to look for septicemia and bacterial endocarditis

hope that information helps you. if you are doing a care plan for this, it is all about how you present the information. and, be aware that the doctor is probably just as stumped as you.


22 Posts

Wow thanks for all that info daytonite! She has been admitted for a week now, and nothing yet so I am curious to see what, if anything, pops up.

She is on Unasyn, lovenox, sinemet, and pregabalin. I am going to look further into this pt even though I get new ones next week, my curiosity has gotten the better of me....

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