Daily Clinical Briefing · Educational reading for healthcare professionals
Recognise Lyme from expanding rashes or disseminated symptoms, even without a remembered tick bite.
Erythema migrans is usually painless, expands beyond 5 cm and does not require central clearing or a recalled tick bite.
An expanding red patch on the leg may be the first recognisable sign of Lyme disease. But what if the rash has no pale centre, the patient cannot remember a tick bite, and they have not visited a recognised Lyme hotspot?
Those details can easily lead us away from the diagnosis.
Erythema migrans typically appears 3–30 days after an infected tick bite. It expands beyond 5 cm, is usually painless and often has uniform redness rather than the familiar bull's-eye appearance. It may also be difficult to identify on darker skin or in less visible locations.
The exposure history is less reliable than we might assume. Around half of patients do not recall a tick bite, and approximately 30% do not develop erythema migrans. Restricting suspicion to known hotspots, summer or patients who remember removing a tick will therefore miss some infections.
The clinical picture changes as Borrelia spreads beyond the skin.
Early Lyme neuroborreliosis can produce severe radicular pain, often worse at night, facial nerve palsy and lymphocytic meningitis. These features may occur together or separately.
A patient with facial weakness and severe radiating leg pain may have little neck stiffness despite cerebrospinal fluid inflammation. Finding lymphocytes in the cerebrospinal fluid does not establish a viral cause. The combination of symptoms and possible exposure deserves closer attention.
Different Borrelia species also influence the presentation. Neurological manifestations are more prominent in the UK and Europe, while joint disease is more common in the United States.
Lyme carditis provides another distinctive pattern. Atrioventricular block can fluctuate between first, second and third degree rather than progressing predictably. Some patients develop palpitations, while others with first-degree block have few symptoms. Higher-degree block may require monitoring or pacing.
Lyme arthritis is generally a later manifestation. Adults can develop dramatic swelling of a large joint, particularly the knee, with surprisingly little pain and preserved weight-bearing. The swelling may improve and recur.
Relevant travel may have occurred one or two years earlier, making a recent exposure history insufficient. Children can present differently, with considerably more pain and inability to bear weight, potentially resembling septic arthritis.
Even the interpretation of investigations needs care. After Lyme arthritis treatment, persistent inflammation or positive polymerase chain reaction (PCR) findings may reflect an immune response and residual bacterial material rather than ongoing bacterial replication.
The next patient with unexplained nocturnal radicular pain, fluctuating heart block or recurrent knee swelling may have no memory of the exposure that started it. Recognising the clinical pattern matters more than obtaining a convincing story about the tick.
Adding fentanyl to ketamine and rocuronium during emergency intubation reduces hypertension but increases hypotension. The FAKT trial found similar rates for its combined blood-pressure endpoint, demonstrating how a composite outcome can conceal clinically important differences.
Lyme disease may present with an expanding rash, painful radiculitis, facial palsy, fluctuating heart block or large-joint swelling. Neither a remembered tick bite nor a bull's-eye rash is required, and late manifestations can follow exposure many months earlier.
Chronic liver disease can produce portal hypertension and ascites without jaundice or encephalopathy. Examination establishes the clinical syndrome rather than its cause, while the serum–ascites albumin gradient and further investigations help identify complications and guide management.
Ask about outdoor exposure and relevant travel even when patients cannot recall a tick bite. Assess an expanding rash by its timing, size and symptoms rather than expecting a bull's-eye appearance. Consider Lyme neuroborreliosis in unexplained severe nocturnal radicular pain or facial palsy, and recognise that fluctuating atrioventricular block may require cardiac monitoring or pacing.
An adult presents with severe pain radiating down one leg, particularly at night, alongside unilateral facial nerve palsy and headache. Cerebrospinal fluid examination demonstrates lymphocytic inflammation, but neck stiffness is minimal. The patient remembers no tick bite or preceding rash. Which diagnosis should be considered?
Early Lyme neuroborreliosis. Severe radiculitis, facial nerve palsy and lymphocytic meningitis may occur together or separately. Neither an absent rash nor a forgotten tick bite excludes the diagnosis.
A patient undergoing emergency rapid sequence intubation receives fentanyl alongside ketamine and rocuronium. A randomised trial reports similar rates of blood pressure outside its specified range compared with placebo. What important difference between the treatments can this combined outcome conceal?
Fentanyl reduces post-induction hypertension but increases hypotension. Similar composite outcome rates can conceal different haemodynamic effects, so the high and low blood-pressure outcomes need separate interpretation.
A patient with chronic liver disease has abdominal distension, palmar erythema, spider naevi and splenomegaly. There is no jaundice or encephalopathy, but examination confirms ascites. Which finding establishes that the liver disease has decompensated?
Ascites is evidence of decompensation, even when jaundice and encephalopathy are absent. The examination supports chronic liver disease with portal hypertension but does not establish its underlying cause.
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