A for Azithromycin
Azithromycin as an oral drug is used for both treatment and chemoprophylaxis in patients who can’t be given doxycycline. For example, pregnant women who have been exposed to flooded roads should be given azithromycin 250 mg once a week as a preventive.
B for Biphasic
The classic pattern of fever in mild leptospirosis is biphasic. The first phase is the leptospiremic phase which usually presents with fever, myalgias, and conjunctival suffusion. After 3 to 7 days of this phase there is an afebrile period of 1 to 3 days. The next phase – the immune phase – has milder symptoms that can last a month. 90% of leptospirosis cases are mild and can behave like this. This mild form can be icteric or nonicteric. The severe form, Weil disease, may not have a biphasic nature. More about that later.
C for Cephalosporins
In severe leptospirosis, parenteral penicillin is considered the drug of choice. In practice however, injectable ceftriaxone or cefotaxime are the most commonly used drugs.
D for Doxycycline
Doxycycline is the drug of choice for treating mild leptospirosis and for its prevention. The dose for treatment of is 100 mg twice a day for 7 days. The dose for prevention is 200 mg once a week till the duration of exposure. The contraindications to doxycycline include pregnancy, lactation, and age of 8 or less.
E for Empiric
Once leptospirosis has been suspected on the basis of clinical features and circumstances like flooding, one must start antibiotics empirically without waiting for lab confirmation.
F for Floods
Leptospirosis occurs because of exposure of abraded skin or mucous membrane to water contaminated by urine of rodents or other animals. The urine contains the spirochaete and this bacterium can survive for days in such conditions. In urban India, flooding during monsoons is the commonest situation for a widespread scare. In rural India, where leptospirosis is more common, places like rice (paddy) fields can be a significant risk.
G for Gastrocnemius
Tenderness of muscles of the calf, the anterior abdomen, and the lower back is typical of leptospirosis. In every patient of fever during the monsoons, one must lightly squeeze the gastrocnemius muscle to elicit exquisite tenderness.
H for Hosts
Virtually all mammalian species can harbour leptospires in their kidneys and act as source of infection to humans. However, cattle, buffaloes, horses, sheep, goat, pigs, dogs, and rodents are common reservoirs; especially rodents.
I for Interrogans
Leptospira interrogans is the commonest species causing leptospirosis. The gram negative spirochaete species is so named because it often resembles a question mark!
J for Jarisch-Herxheimer reaction
When penicillin is administered in a spirochaetal disease it can cause release of endotoxins from dying bacteria. This can manifest as aggravation of all symptoms of the disease and hypotension. This is one reason why cephalosporins are routinely preferred over benzylpenicillin.
K for Kayaking in Kundalika river at Kolad!
Water sports, especially during monsoons when rodent urine-containing soil runs off into water bodies, are a risk for leptospirosis. Thus, white water rafting, kayaking etc are risks. 200 mg of prophylactic doxycycline should be considered.
L for Leptospira IgM
IgM ELISA is a rapid serological test and is the most commonly done confirmatory test. It becomes positive after 5 days of onset of fever. It is not as sensitive or specific as culture (which can take weeks to grow leptospira) or MAT (microscopic agglutination test which is done for research) or PCR (which is expensive).
M for Meningitis
If a patient of suspected leptospirosis develops altered sensorium, one must suspect meningitis. The CSF in leptospira meningitis typically shows pleocytosis with lymphocyte predominance and normal proteins and glucose.
N for Nonoliguric Renal Failure
One of the dreaded complications of severe leptospirosis is acute kidney injury. The typical presentation of this is azotemia without oliguria. Another feature is hypokalemia instead of the commoner hyperkalemia seen in AKI. Early dialysis must be considered and is often life-saving.
O for Once-A-Week
This is the frequency of dosing of doxycycline for chemoprophylaxis. The dose is 200 mg as a single dose or 100 mg twice a day for one day every week. The length of treatment depends on the exposure to the bacterium.
P for PCR
The polymerase chain reaction is a test method that detects and amplifies the DNA of the organism to make a diagnosis. It is extremely sensitive and specific though expensive. In leptospirosis, PCR of blood is positive for upto 10 days after onset and PCR of urine stays positive for weeks.
Q for Quinolones
Leptospira are susceptible to many antibiotic groups including quinolones which may come in handy if cephalosporins and macrolides are not tolerated.
R for Reasons for Hospitalization
Any suspected case leptospirosis with icterus, cough, breathlessness, vomiting, dehydration, prostration, altered sensorium or hypotension must be hospitalized. Hypoxia, azotemia, raised bilirubin, and X-ray infiltrates are investigation reports that mandate indoor management. Unfortunately, most cases go undiagnosed as they are managed as ‘viral illness’. Luckily, 90% of cases resolve without correct diagnosis and treatment!
S for Sewer Workers
In cities like Mumbai, those employed to clean sewers and those employed in slaughterhouses (abattoirs) are more prone to leptospirosis. Ideally, they are provided with boots, masks, and gloves.
T for Transaminases and LFT
One peculiar feature of liver affliction in leptospirosis is that the elevation of bilirubin can be marked but transaminases (AST and ALT) are only mildly elevated. Jaundice typically appears around day 5. The bilirubin can rise to 30mg/dL and beyond. Most patients recover from liver injury without complications.
U for Unconventional
What you are reading presently is a highly unconventional method of teaching a topic. This A to Z method is based on the unproven premise that randomly presented facts are more likely to attract attention, appear interesting, and stay in memory. Let us know whether this method is palatable.
V for Veterinarians
Zoonotic diseases are not uncommon amongst vets. Exposure to urine or internal organs can predispose them to leptospirosis.
W for Weil Disease
Weil disease, previously known as Weil’s disease (before ‘s was deleted from all eponymous conditions) is a severe form of leptospirosis. It is a triad of jaundice, acute kidney injury and haemorrhages. The commonest location of haemorrhage is the lungs. Patients of Weil disease require intensive care management and may require hemodialysis and ventilatory support.
X for X-ray Picture
The chest X-ray in a patient with lung involvement shows scattered ill-defined patches (of alveolar haemorrhages) predominantly in the lower lobes.
Y for YouTube Link
The above link details treatment schedules in both mild and severe leptospirosis.
Z for Zoonotic Diseases
Zoonotic diseases or zoonoses are infections by bacteria, parasites or viruses that spread from animals (usually vertebrates) to humans with or without intermediate vectors. Rabies is a zoonosis. Malaria is not.