Sea Turtle Physical Examination: Part 2

Introduction

Physical examination is often an underutilized tool in the wildlife rehabilitation process. A complete physical examination should be performed upon patient presentation and then regularly during the rehabilitation process (Fig 1). All sea turtles are protected by the Endangered Species Act and a permit is required to handle, transport, and provide physical examination of and medical care to sea turtles. Use an examination form to record biological data and note external abnormalities such as shell fractures, missing flippers, and lacerations. Take photographs to document specific lesions or injuries. A Sea Turtle Stranding and Salvage Network (STSSN) form must be completed for each turtle.

Green sea turtle with Horner's-like syndrome.

Figure 1. Perform regular physical examinations on all sea turtles presented for care. Shown here, a green sea turtle (Chelonia mydas) with Horner’s-like syndrome. Photo credit: Dr. Terry Norton. Click image to enlarge.

While Sea Turtle Physical Examination Part 1 explores evaluation of the eyes, ears, nose, and throat, the remainder of the physical exam will be described here in Part 2 and in Body Condition Scoring the Sea Turtle.

Cardiopulmonary system

Peripheral pulses are not palpable in sea turtles and cardiac auscultation is not possible due to the presence of the external shell. Assess heart rate and rhythm with a Doppler or ultrasound probe placed on the skin between the neck and the proximal front flipper. Normal heart rate in the conscious turtle at 24ºC (75ºF) ranges from 30 to 60 beats per minute. Bradycardia is common in partially or fully submerged sea turtles, those with hypothermia, after administration of injectable anesthetics, and in a variety of disease states including neurologic loggerhead syndrome.

The left and right cervicobrachial acoustic windows can also be used to visualize the heart and great vessels ultrasonographically. All turtles have four chambered hearts: a large sinus venosus, two large atria, and a ventricle. The ventricle is thick-walled and internally subdivided into three compartments: the cavum venosum, cavum arteriosum, and cavum pulmonae. These three ventricular compartments are separated only partially from one another and this configuration results in some mixing of oxygenated and non-oxygenated blood.

Respiratory rate will vary with temperature and activity level. Specialized physiology for diving provides sea turtles with an extremely efficient oxygen transport system and the ability to breath hold for long periods of time. Breath holding (apnea) is normal and occurs both in water and out of water. Respirations consist of a forced exhalation followed by a rapid inhalation. Inhalation requires downward movement of the plastron and upward movement of the carapace; it is coordinated by the pectoral and shoulder muscles. As in other reptiles, coughing or gagging does not occur in sea turtles due to the absence of a diaphragm, however tracheal obstruction or respiratory disease can manifest as gurgling, wheezing, or repeatedly opening the mouth.

Temperature

Deep cloacal temperature is representative of the sea turtle’s recent environmental temperature, and is an important parameter to obtain and monitor in both hypothermic and hyperthermic patients (Fig 2). Use of a noncontact, infrared laser thermometer (e.g. Raynger St, Raytek Corporation, 1201 Shaffer Road, PO Box 1820, Santa Cruz, California) directed at the inguinal area shows promise for monitoring core body temperature and is less stressful to the turtle than using a deep cloacal temperature probe.

Deep cloacal temperature is representative of the turtle’s recent environmental temperature exposure.

Figure 2. Deep cloacal temperature is representative of the turtle’s recent environmental temperature exposure. Photo credit: Dr. Charles Innis.

Skin

Carefully examine the skin every time the turtle is taken out for treatment because fibropapillomas often begin as subtle plaque-like lesions (Fig 3). Fibropapillomas (FP) are wart-like lesions associated with herpesviral infection. Although FP can occur in all sea turtle species, it is most frequently observed and is most severe in green turtles (Chelonia mydas). External papillomas can be found on the skin, shell, eyelids, conjunctiva, and cornea of infected sea turtles (Fig 4). Suspicious lesions should be biopsied and submitted for histopathology and PCR for confirmation. Proper protocols should be followed to quarantine suspect FP patients to minimize disease transmission.

Fibropapillomatosis in the sea turtle often begins as subtle, plaque-like lesions.

Figure 3. Fibropapillomatosis in the sea turtle often begins as subtle, plaque-like lesions seen here as many circular, tan lesions on the inguinal skin of this green turtle (Chelonia mydas). (This turtle is missing its right hind flipper). Photo credit: Dr. Terry Norton. Click image to enlarge.

External papillomas in the sea turtle are often found on the cornea and adnexa.

Figure 4. External papillomas can become quite large as seen in this juvenile green sea turtle (Chelonia mydas). Papillomas are often found on the skin, carapace, cornea, and adnexa. Photo credit: Dr. Terry Norton. Click image to enlarge.

Internal FP tumors can occur in almost any organ but are most common in the lungs, kidneys, and liver (Fig 5). Although advanced lesions may be visible on survey radiographs, turtles can be screened for the presence of internal fibropapillomatosis with ultrasound, laparoscopy, magnetic resonance imaging, and/or computed tomography.

Internal fibropapillomas in the kidneys and left adrenal gland of a green sea turtle

Figure 5. Dorsal view of viscera showing internal fibropapillomas in the kidneys and left adrenal gland (arrows) of a green sea turtle (Chelonia mydas). Photo credit: Dr. Terry Norton. Click image to enlarge.

 

Euthanasia is indicated if internal tumors are documented, however external lesions can sometimes be managed by surgical removal.

Visit the following links for additional information on fibropapillomatosis in sea turtles:

Evaluate the skin for excessive sloughing or shedding, abscesses, scars, and wounds. Lesions commonly observed include embedded fishhooks, monofilament line wrapped around the flippers or neck, and shark bite injuries (Fig 6, Fig 7). Male turtles can be quite aggressive during courtship, and bite wounds can also be observed in females typically around the neck. Smaller sea turtles that survive being sucked through a dredge may have a sand blasted appearance to their skin.

Rope wrapped around both upper flippers causing vascular compromise to the distal flipper in a loggerhead sea turtle

Figure 6. Rope wrapped around both upper flippers causing vascular compromise to the distal flipper in a loggerhead sea turtle. Photo credit: Georgia Sea Turtle Center. Click image to enlarge.

Shark bite injury in a loggerhead sea turtle.

Figure 7. Shark bite injury of the left forelimb in a loggerhead sea turtle (Caretta caretta). The head is to the left. Photo credit: Dr. Terry Norton. Click image to enlarge.

Cold stunned patients may develop swelling of the distal limbs with subsequent open or scabbed over wounds secondary to focal osteomyelitis (Fig 8).

Cold stunning can induce external swelling of the digits and open or scabbed over wounds secondary to focal osteomyelitis.

Figure 8. Cold stunning can cause external swelling of the digits and open or scabbed over wounds secondary to focal osteomyelitis lesions as seen in this Kemp’s ridley sea turtle (Lepidochelys kempii). Photo credit: Dr. Terry Norton. Click image to enlarge.

Although epibiota on the shell can be a normal finding in loggerhead sea turtles, debilitated turtles often have excessive epibiota, such as many small barnacles and leeches on the skin. Some epibionts may induce secondary shell and skin lesions. (See epibiota below for additional information).

While evaluating the flippers, be sure to closely inspect the claws for evidence of trauma and infection. Most cheloniids have two claws on the flipper (Fig 9); green turtles usually have a single claw. Claw I is more proximal and is usually larger in species with two claws and it becomes strongly curved in adult males. There are the same number of claws on the front and hind limbs.

Close up of a juvenile green sea turtle claw

Figure 9. Close-up view of a juvenile green sea turtle (Chelonia mydas) claw. Photo credit: Dr. Terry Norton. Click image to enlarge.

Shell

Evaluate both the carapace and plastron. The carapace is composed of bone covered by keratinous scutes in cheloniids (Fig 10). The scutes do not align with the underlying bony sutures. Younger or smaller turtles have fibrous tissue filling fontanelles between the distal rib ends and the peripheral bones. In the leatherback turtle (Dermochelys coriacea), blubber overlies ribs and vertebrae and is covered dorsally with waxy skin and embedded dermal ossicles.

The scutes are keratinous epidermal structures that grow above the carapace bones.

Figure 10. The scutes are keratinous epidermal structures that grow above the carapace bones. Photo credit: Jeanette Wyneken. Click image to enlarge.

In sea turtles, the plastron is composed of one unpaired bone, the entoplastron, and four pairs of bones. From anterior to posterior, these paired bones are the epiplastron, hyoplastron, hypoplastron and xiphiplastron (Fig 11).

The plastron is composed of one unpaired bone and four paired bones.

Figure 11. The plastron is composed of one unpaired bone and four paired bones. Photo credit: Jeanette Wyneken. Click image to enlarge.

Evaluate the shell for evidence of abnormal keratinization, changes in firmness and pliability, propeller injury, ulceration, vesicles, osteomyelitis, shark bites, deformities, fibropapillomas, and fractures (Fig 12-Fig 15). Caudal carapacial fractures involving the distal spinal cord are a common cause of flotation of the hind end or “pelvic float syndrome” and are particularly common in green turtles.

Carapacial fracture in a loggerhead sea turtle

Figure 12. Longitudinal carapacial fracture in a loggerhead sea turtle (Caretta caretta). Photo credit: Dr. Terry Norton. Click image to enlarge.

Ulcerative shell disease in a green sea turtle

Figure 13. Ulcerative shell disease in a green sea turtle (Chelonia mydas). Photo credit: Dr. Terry Norton. Click image to enlarge.

Marginal scute osteomyelitis in a Kemp’s Ridley sea turtle

Figure 14. Marginal scute osteomyelitis in a Kemp’s ridley sea turtle (Lepidochelys kempi). Photo credit: Dr. Terry Norton. Click image to enlarge.

Shark bite injury involving the shell in a loggerhead sea turtle

Figure 15. Shark bite injury involving the plastron and peripherals in a loggerhead sea turtle (Caretta caretta). Note the multiple curved lacerations of the axilla cranial to the large defect spanning the inframarginal scutes and some peripheral bones. Photo credit: Dr. Terry Norton. Click image to enlarge.

Epibiota

One of the unique characteristics of the loggerhead turtle (Caretta caretta) is the community of organisms, or epibiota, carried on the shell. Over 80 epibiont species have been reported on the shell of loggerheads nesting on barrier islands in Georgia. These epibionts include algae and various invertebrates such as barnacles, tunicates, sponges, corals, anemones, snails, sea slugs, bivalves, segmented worms, and crustaceans including crabs and skeleton shrimp.

The presence of excessive epibiota, particularly small barnacles and leeches on the skin, can indicate debilitation (Fig 16-Fig 18). Epibiota may overgrow when the turtle becomes inactive.

A large epibiotic load

Figure 16. A large epibiotic load, as shown in this loggerhead (Caretta caretta), is indicative of debilitation. Photo credit: Dr. Terry Norton. Click image to enlarge..

The presence of algae on the shell indicates excess exposure to sunlight and is often observed in sea turtles with flotation abnormalities

Figure 17. The presence of algae on the shell indicates excess exposure to sunlight and is often observed in sea turtles with flotation abnormalities. Photo credit: Dr. Terry Norton. Click image to enlarge.

Leeches can contribute to overall debilitation and should be removed from the sea turtle

Figure 18. Leeches, seen here at the commissure of the mouth and along the neck, and barnacles can contribute to overall debilitation and should be removed from the sea turtle patient. Photo credit: Georgia Sea Turtle Center. Click image to enlarge.

Carefully remove epibiota after the sea turtle arrives and before performing radiographs. Placing the turtle in fresh water for 12-24 hours will kill or loosen up most epibionts for easier removal. Use caution as epibiont removal can result in scute loss and bone exposure in extremely debilitated patients.

Long bones and joints

Palpate front and hind flippers to evaluate range of motion, muscle tone, and strength. Note any swelling, crepitus, or skeletal deformities.

Injuries that commonly involve the long bones include shark bites and fishing line wrapped around a limb. It is not uncommon for there to be severe swelling present distal to the fishing line. Amputation may be necessary if blood supply and nerve function are significantly compromised. Fortunately most free-ranging sea turtles do well with one flipper missing, although the long-term data is lacking.

Small green turtles are prone to proximal humeral fractures when improper restraint is used and only trained personnel should handle struggling patients. These lesions usually heal with rest and minimal handling.

Lytic lesions are a common sequelae to osteomyelitis in green turtles and Kemp’s ridley turtles (Lepidochelys kempi) (Fig 19). Cold stunning is a predisposing factor for the development of osteomyelitis.

Lytic lesions secondary to osteomyelitis in a green sea turtle

Figure 19. Lytic lesions secondary to osteomyelitis (arrow) in a green sea turtle (Chelonia mydas). Photo credit: Dr. Terry Norton. Click image to enlarge.

Coelomic evaluation

Inguinal palpation is a routine part of the turtle exam. Abnormalities that may be evident include excess coelomic fluid, gastrointestinal tract distention, and renomegaly. Distention caused by follicles or eggs in gravid females can be palpated.

The inguinal region can also be used as an acoustic window for ultrasonography and it serves as a common site for rigid laparoscope insertion. The inguinal fossa, cranial to the femur typically has a thick fat pad overlying three to five muscle layers that form the lateral wall and floor of the fossa.

Cloaca and tail

The cloaca is the common receiving chamber of the gastrointestinal, urinary, and reproductive tracts (Fig 20). Digital examination of the cloaca for foreign material, mass lesions, or swellings is part of a complete physical examination. Use of endoscopy and saline distention can assist in further evaluation.

Ventral view of a juvenile green sea turtle cloaca

Figure 20. The cloaca is located between the vent and the distal plastron within the tail. Shown here, the ventral view of a juvenile green sea turtle (Chelonia mydas) cloaca. Photo credit: Dr. Terry Norton. Click image to enlarge.

Masses, such as fibropapillomas or neoplasms, can occur in or around the cloaca. Cloacal prolapse may occur in individuals that have been out of the water or are suffering from intestinal impaction or obstruction. Lubricate mildly prolapsed tissue to prevent ulceration. Once the patient is returned to the water, most prolapses resolve without treatment. Intestinal prolapse, penile prolapse, or oviductal prolapse can also occur in sea turtles; the underlying cause for these conditions is the same as in other species. It is important to return prolapsed tissue to a normal position as soon as possible.

No external differences in gender are seen until the turtle enters puberty. Laparoscopy and plasma testosterone levels can be used to determine sex in immature sea turtles. Among members of family Cheloniidae, mature males have a longer, thicker tail that extends beyond the carapace, whereas the female tail is smaller and usually does not extend beyond the carapace (Fig 21). The vent remains somewhat proximal in females, the vent of the pubescent male or adult male is located toward the distal tail tip. In leatherbacks, the tail extends beyond the carapace in both sexes however the vent is located more distally in males.

The tail of the male sea turtle tends to be longer and thicker.

Figure 21. The tail of the male sea turtle tends to be longer and thicker and the vent is distally located when compared to females. Photo credit: Dr. Terry Norton. Click image to enlarge.

Neurological examination

Perform a brief, standardized neurological examination on every patient and a more detailed neurologic evaluation of patients exhibiting neurological deficits. Chrisman et al (1997) adapted a dog and cat neurologic exam to evaluate sea turtles. The exam has three parts: in-water (see below), dry docked in ventral recumbency, and dry docked in dorsal recumbency. Observation of swimming substitutes for gait evaluation.

Sea turtle possess 12 cranial nerves. Use physiological nystagmus, evaluation of jaw musculature and throat expansion via buccal pumping or hyoid depression, pupillary light response, eye position, palpebral reflex, and menace response to assess cranial nerve function. Menace can diminish rapidly after the first attempt or it can be overridden behaviorally. The corneal reflex can only be tested in the obtunded animal.

It is not possible to evaluate conscious proprioception, wheel-barrowing, or hopping, however withdrawal reflexes, nociception, and deep pain can be evaluated. If neurologic disease is suspected, evaluate righting reflexes in and out of the water. (Note: Medium and large sea turtles typically cannot right themselves when placed in dorsal recumbency on land).

In-water examination

At some point during the rehabilitation process, an in-water assessment should take place prior to the routine “out-of-the-water” physical exam components. Once a turtle has been placed in a circular tank for the first time or after a prolonged procedure, the animal may enter a panic-like state with rapid respiration and hyperactivity or agitation. This phase should last no more than a few minutes. If the panic phase is prolonged, then the turtle should be removed from the water and allowed to rest while “dry-docked”.

Evaluate sea turtles in the water for activity level, swimming ability, vision, and flotation abnormalities (Fig 22). Activity level and attitude usually improve dramatically when the sea turtle is placed in the water.

ctivity level and behavior usually improve dramatically when the turtle is placed in the water

Figure 22. This loggerhead sea turtle (Caretta caretta) showed both a head tilt and circling. Photo credit: Mote Marine Laboratory.

During the in-water exam, the observer should note:

  • Head position for evidence of a head tilt or generalized weakness
  • Respiratory rate, effort, and sound

If the turtle is debilitated, observation for 5-10 minutes is needed to ensure that the patient can lift its head out of the water to breathe. Also ensure that breaths are regular and normal. Gurgling or weak respirations warrant further dry dock, lowering the water level, or some type of in-water support. Observations should include:

  • Position of the body in water
  • Swimming activity:  The front flippers are normally used for propulsion and the hind flippers for steering. Failure to use a limb in the water constitutes lameness or paresis.
  • Maneuverability around the tank
  • Feeding behavior
  • Ability to submerge

Sea turtles are often presented with buoyancy disorders in which they float abnormally at the surface. Any condition leading to gas or air accumulation in a body organ or within the coelomic cavity can cause abnormal buoyancy. Common causes of this condition include pneumonia, free air in the coelomic cavity caused by a lung tear or intestinal leakage and microbial fermentation, and accumulation of gas within the gastrointestinal tract. Gastrointestinal (GI) motility disorders, obstructive processes such as a foreign body, and spinal cord injury can all lead to gas accumulation within the GI tract.

Record buoyancy abnormalities using anatomic location such as right cranial or central caudal. It is also helpful to estimate the percentage of carapace exposed or use a marking system to indicate the water line. If the flotation abnormality shifts from one side to another it is more likely intestinal gas and less likely due to a torn lung, which is valuable clue when developing a diagnostic and therapeutic plan.

Summary

Important clues, that can be used to guide a diagnostic and treatment plan, can be gleaned from a careful and complete physical examination of the sea turtle. As in any debilitated patient, a complete exam may not be possible all at the same time. Instead, it may be necessary to evaluate the animal in stages as clinical status allows.

There are a number of normal physical examination findings that reflect the sea turtle’s adaptations to a marine lifestyle. Specialized physiology for diving provides the sea turtle with an extremely efficient oxygen transport system and the ability to breath hold for long periods of time. Therefore like many chelonian patients, breath holding is a common exam finding. Normal heart rate in the conscious turtle ranges from 30 to 60 beats per minute, however bradycardia is common in partially or fully submerged turtles, as well as hypothermic or clinically ill individuals.

Every sea turtle physical examination should screen the patient for the presence of wart-like lesions or fibropapillomas. Although fibropapillomatosis can occur in all hard-shelled sea turtle species, this condition is most frequently observed and is most severe in green turtles.

The loggerhead sea turtle carries epibiota, or a community of organisms including algae and various invertebrates on its shell. The presence of excessive epibiota, particularly small barnacles and leeches on the skin, can indicate debilitation however the absence of a large epibiotic load does not mean the turtle is healthy.

Looking for more information on sea turtles?

Visit:

**Login to view references**

References