Case Scenario: A 28-year-old man with a history of intravenous drug abuse presents with a 6- week history of recurrent sweats and weight loss. He comes to the Emergency Department because he is feeling increasingly unwell.
On examination he is tachycardic and has a swollen, hot and tender left knee joint and a faint pansystolic murmur at the left sternal edge.
You are called to assess him.
1. How will you approach to this case.?
2. Give the important points to ask in history?
3. What examination would be important?
4. Give the Differential diagnosis?
5. The investigations that would help in the diagnosis?
Discussion:
In the presence of a murmur, whether new or not, the diagnosis of Infective endocarditis (IE) must be the favored differential diagnosis. Also the use of intravenous drugs in the patient presented in the scenario favors towards a diagnosis of Infective endocariditis.
A careful history and examination are essential to help rule out other non infective and non-cardiac causes for his symptoms, although these would clearly be very unlikely in this case.
History of the Presenting problem: The history (and examination) will be dominated by consideration of the most likely diagnosis (IE), but clues may emerge that take you in another direction. Keep in mind the other differential diagnosis( given below) as you take the history and examine the patient.
- Determine the severity of the patient’s condition. In acute IE, the fever is high with rigors and prostration.
- Ask :‘Have you had attacks of really bad shivering and shaking?
- Have you sweated so much that you had to change your clothes or the sheets on the bed?’
The current history is more suggestive of a subacute presentation, which is associated with a low-grade fever, malaise and weight loss.
- Explore whether the patient has been injecting drugs at any point over the past 2–3 months, emphasising the point that even a single episode may be enough to result in a very dangerous infection.
- Also enquire about dental procedures or medical investigations (particularly if invasive), which are other wellrecognised risk factors for endocarditis.
- Ask the patient about symptoms of heart failure: has he been breathless when walking, at rest or lying flat in bed at night? Have his ankles become swollen? These signs may be insidious. If present they raise the possibility of haemodynamic compromise from aortic or mitral regurgitation.
- Sudden episodes of pulmonary oedema may be suggestive of significant valve degeneration.
- Ask about chest pain and haemoptysis
- Pleuritic chest pain and/or haemoptysis would suggest pulmonary abscess or infarction, commonly from tricuspid valve endocarditis.
Other relevant history: Endocarditis has a very wide range of extracardiac manifestations), and hence many other aspects of the history could be relevant. For instance, the swollen knee joint could be secondary to infective seeding from bacteraemia or the result of a mycotic embolus from the heart (in the latter, the infection would have to affect a left-sided cardiac valve).
Ask about systemic manifestations of the other conditions( differential diagnosis) especially autoimmune disorders, TB and (in this case because of the knee problem) joint/bone infections.
The following can be seen with both IE as well as autoimmune disorders:
• skin rashes;
• changes in the nails;
• blood in the urine;
• back or abdominal pain;
• changes in vision;
• sudden periods of arm or leg weakness;
• episodes of difficulty speaking.
Although uncommon, vasculitic rashes can occur with IE, but they are not specific and may occur with several of the differential diagnoses.
Also rare, but much more suggestive, are transient changes in the hands and feet: painful lesions in the finger or toe pulps (Osler’s nodes) or painless ones in the palms or soles (Janeway’s spots or lesions).
The glomerulonephritis that may accompany IE or autoimmune conditions often results in
microscopic haematuria, which goes unnoticed by the patient, although macroscopic haematuria (a
symptom that can also be caused by renal infarction or hypernephroma) is also possible.
Back pain may simply result from myalgia, but severe loin pain suggests renal infarction, abscess or tumour, although the latter is not normally painful.
Similarly, pain in the left hypochondrium radiating to the left shoulder may result from splenic infarction or abscess.
Regarding other infective causes, ask the patient the following questions.
• Have you had a cough? Does this produce any phlegm or blood?
• Have you traveled abroad recently?
• Have you ever had TB? Have you been in contact with anyone who has TB?
• Have you had any injuries to your knee?
• Did your cough or knee injury start before or after your sweats and temperature?
• Have you had any swollen glands?
Have you had any problems with the blood or the lymph glands in the past?
• Have you had arthritis?
• Have you had any odd illnesses in the past?
Past Medical History: Concerning past history, ask the following.
• Has anyone ever told you that you have a ‘mumur’ or ‘hole’ in your heart?
• Have you had rheumatic fever?
• Have you had any antibiotics recently? Are you absolutely sure about that? (A common reason
for negative blood cultures in endocarditis is partial treatment with antibiotics, which render the blood cultures sterile but do not cure the condition.)
Differential Diagnosis Of Fever And Weight Loss Of 6 Weeks Duration:
1. Infective Causes:
- Infective endocarditis
- Tuberculosis
- Liver abscess
- Primary joint
- infection/osteomyelitis
- Soft-tissue infection
- Rheumatic fever
2. Autoimmune disorders and/or vasculitis:
- SLE
- Rheumatoid arthritis
- Polymyalgia rheumatica
- Potentially any other vasculitic condition
(SLE and also some other rheumatic disorders can affect the heart valves leading to murmurs and can cause substantial diagnostic difficulty)
3. Malignancy:
- Lymphoma
- Hypernephroma
Examination
1. General features: Just as the history may be relatively non-specific, the examination findings may also be so. As always, get an overall impression. Patients with IE are likely to look unwell, although elderly patients presenting atypically may simply be confused.
General points must include the following.
• Temperature: a fever of <39°C is typical of endocarditis, although higher is occasionally seen.
• Pallor and anemia: these can suggest chronic disease.
• Look at the hands, feet, skin, conjunctiva and mucous membranes for splinters/vasculitic manifestations of endocarditis.
2. Cardiovascular:Take particular note of the following.
• Peripheral perfusion.
• Pulse: check rate (often tachycardic as in this case), rhythm and character (‘collapsing’ pulse in significant aortic regurgitation).
• JVP: this may be elevated if there is tricuspid valve regurgitation (often seen in right heart infective
endocarditis) and/or heart failure.
• Apex: will be hyperdynamic in sepsis and if displaced is suggestive of long-standing heart disease.
• Heart sounds: are there any murmurs or added sounds? The pansystolic murmur could be tricuspid or mitral regurgitation, but take care to listen carefully for aortic and/or pulmonary incompetence. Be aware that a difficult murmur/funny sound could (extremely rarely) be a ‘tumour plop’.
3. Other systems:Check specifically for the following.
• Lymphadenopathy: this is not a feature of endocarditis and would point towards another infective
cause or a lymphoproliferative condition.
• Chest: are there any signs at all? Consider TB but remember, as stated previously, that right heart
IE may give rise to pulmonary mycotic emboli.
• Abdomen: can you feel the spleen? The splenic tip or a mildly enlarged spleen can be felt in endocarditis, but a moderately or grossly enlarged spleen would favor lymphoma as the diagnosis. Is the liver palpable or tender (consider liver abscess), and can you feel a renal mass (hypernephroma)?
• Neurological: are there any focal signs? These are likely to have been caused by emboli from an
infected valve in this clinical situation.
• Fundi: is there any evidence of endocarditic lesions
Critical investigations in the patient with chronic fever, malaise and weight loss include the following.
• Blood cultures: at least three taken 1 hour apart from separate well-cleaned sites.
• FBC, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP): is there evidence of systemic inflammation?
• Urine: look for haematuria and proteinuria, which suggest glomerulonephritis (autoimmune, vasculitic or endocarditic).
• Chest radiograph: look for TB, lung abscess or lymphadenopathy.
• Echocardiography: check for evidence of endocarditis.
Management: depends on the specific diagnosis.
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