Medico-Legal Ramifications when Diagnosing or Missing Infection
Diagnosing infection is generally straight forward, as one will present with a fever along with relevant physical symptoms. Chest, gut and urinary tract infections are probably the most common.
In the community, fevers and a cough and sore throat are managed conservatively without antibiotics as they are mostly viral and self-limiting. If the symptoms persist and the patient becomes increasingly unwell, they may speak to a GP who may simply prescribe antibiotics. The presence of diarrhoea and/or vomiting usually indicates gastroenteritis.
At certain times of the year community outbreaks of viruses such as Norovirus can occur, and spread rapidly. Urinary tract infections are a common occurrence in the elderly. In younger patients kidney infections -especially in women- are a common cause of hospital admission.
The severity of the infection depends on other parameters such as a low blood pressure, which can cause dizziness and collapse, a fast heart rate, and body shaking (called rigors), which may indicate spread into the blood stream (septicaemia). Undiagnosed, septicaemia can proceed to septic shock and death.
Not all patients may show obvious signs of infection. In the elderly, there may be no fever present. The classic symptom associated with a urinary tract or chest infection in the elderly, is mental confusion or collapse. The causes of confusion are numerous and include the presence of stroke, chemical disturbances from dehydration and medication. Collapse may also be due to strokes, heart attacks, medication, low blood pressure, dehydration, anaemia, or heart rhythm disturbances.
With the wide range of causes of confusion or collapse, there is a high reliance on investigations to make the diagnosis of infection, and the absence of fever can be deceptive. In medical practice, there is an increased reliance on blood tests to make a diagnosis, often at the expense of physical features. Certainly the presence of a low blood pressure and fast heart rate should indicate a high likelihood of infection.
Blood tests themselves may prove misleading, as the white blood cell count may be normal and delay the diagnosis. The contrary is also true, in that a raised white cell count may also be due to non-infective causes of inflammation. Other tests of inflammation include CRP (C-reactive protein is one of the plasma proteins whose plasma concentrations increase or decrease by 25% or more during infections). There is a high reliance on this test for making the diagnosis or excluding infection, despite modern guidelines suggesting it that it is not a particularly accurate test. Thus, infections may be missed by the false premise of “normal inflammatory markers”.
Fundamentally the diagnosis of infection is clinical, and the role of blood tests is an additional measure. Ideally where severe infection is suspected, blood cultures or sampling from the relevant body organs before treatment is important. Samples may be taken from urine, sputum, or spinal fluid to localise the infection. This may help target the subsequent treatment depending on the bacterial sensitivity to different antibiotics.
It takes several days to obtain bacterial growth and sensitivities, so general antibiotics are given according to guidelines or microbiologist advice, and modified when the results become available. If antibiotics are given before cultures are taken, the subsequent results may be nullified.
The exception to this is when meningitis is suspected. This is a serious infection of the membranes of the brain and normally presents with fever, headache, hypersensitivity to light (photophobia), and neck stiffness. If suspected, it is the one time that high dose treatment with antibiotics may be given before blood and spinal fluid samples are taken.
The patient’s overall clinical state needs to be taken into account. Infections are more likely in patients with reduced immunity, such as in diabetes, HIV infection, or cancer. In addition the effects of infection are likely to be more serious. Moreover, dehydration can take over during infection, which may compromise kidney function, increasing the chances of patient morbidity.
Infections may also spread to other locations with adverse effects. Infections in the lower limbs can spread through the veins upwards causing liver and lung abscesses. Typically, abscesses show a spiking pattern of fevers that come and go. They are more likely to be detected if accurate temperature charts are kept. Another common infection is Osteomyelitis (bone infection). Thus in any patient complaining of painful bones, Osteomyelitis should have been considered, as bone destruction can result in deformity and neurological damage (e.g. paralysis).
Endocarditis (heart infection) deserves a special mention. Classically they occur from a blood borne infection that may have originated anywhere, including the mouth after dental work. Bacteria or fungi may lodge on heart valves especially if they are leaky or narrowed, or if there are “abnormal holes in the heart”, e.g. atrial septal defects, or pacemaker wires in the heart. Infection tends to slowly develop sometime taking several months to be diagnosed. Thus, in any patient with known heart abnormalities, Endocarditis should be considered in unexplained fevers. Failure to do so can result in severe heart de-compensation.
The response to antibiotics and length of treatment should be monitored. Guidelines exist to suggest the length of treatment. Insufficient courses of treatment may result in partially treated infections, which may recur. If an infection does not appear to be responding to oral antibiotics, better tissue penetration with intravenous antibiotics may be advisable. In those already on intravenous antibiotics, it would suggest specific resistance to medication, or the presence of another type of infection, such as a fungus or tuberculosis. Any lack of response to treatment needs to be investigated further, and a microbiologist consulted.
Summary of Medico-Legal checklist / issues:
- There is an increasing reliance on blood tests (inflammatory markers to make a diagnosis of infection. This may be misleading, as they may be normal even in severe infections.
- In anyone presenting with confusion or collapse, infection should have been considered even in the absence of fever.
- If serious infections are suspected, ideally blood samples and appropriate cultures should be undertaken before antibiotics are initiated.
- If meningitis is suspected, antibiotics need to be administered as early as possible, sometimes before cultures can be taken.
- The severity of infection needs to be highlighted by the presence of dehydration, fast heart rate and whether the blood pressure is low (septicaemia). Failure to ascertain this may result in death.
- Infections should be considered early in patients with reduced immunity.
- Kidney function and hydration status should be monitored carefully in significant infections.
- Abscesses are more likely to be detected by accurate temperature charts showing spike patterns.
- In any infection, the presence of bone pain should suggest osteomyelitis. Failure to diagnose this can result in permanent deformity and neurological damage.
- Patients with certain heart conditions should raise the possibility of endocarditis
- Failure to respond to antibiotics should raise the possibility of resistance or other organisms such as fungi or tuberculosis.
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NB This article does not constitute legal advice and should not be relied on as such. No responsibility for the accuracy and/or correctness of the information and commentary set out in the article, or for any consequences of relying on it, is assumed or accepted by any member of Dutton Gregory LLP.